P134

Cerebral vasospasm – more frequent following endovascular aneurysm coiling?

R.Stendel, A.Schilling, T. Picht, A. Derdilopoulos, C. DaSilva, J. Heidenreich, T. Pietilä, M. Brock

Dept. of Neurosurgery, UKBF, Free University of Berlin, Germany

Background: Cerebral vasospasm is the most common cause of morbidity and mortality in patients with subarachnoid hemorrhage. The early removal of subarachnoid blood and irrigation of the basal cisterns during surgery has been reported to reduce the incidence of vasospasm. In contrasst to aneurysm clipping, endovascular treatment does not allow removal of subarachnoid blood. The present study compares the incidence and severity of symptomatic cerebral vasospasm following endovascular treatment and aneurysm surgery in patients with subarachnoid hemorrhage due to aneurysm rupture.

Methods: A total of 52 patients with subaracnoid hemorhage classified as Hunt and Hess grdaes I to III were included. From these, 25 patients underwent aneurysm clipping and 27 endovascular aneurysm coiling. The amount of blood on computerized tomography was classified by means of Fisher´s scale. Hypertensive, hypervolemic, hemodilution therapy was used to treat vasospasm.

Results: Vasospasm occurred in 8 (35%) patients following clipping, and in 11 (41%) following endovascular treatment. The eman duration of vasospasm was 17.5 days in the coiling group as compared to 10.7 days in the clipping group (p<0.05). The mean blood flow velocity in the middle cerebral artery during the first 21 days following subarachnoid hemorrhage was 117.4 cm per second in the coiling group and 94.9 cm per second in the clipping group.

Conclusions: The incidence of cerebral vasospasm after aneurysmatic subarachnoid hemorrhage seems to be higher in patients following endovascular aneurysm coiling as compared to patients following clipping.

P135

A NON-LINEAR MODEL FOR THE ESTIMATION OF ICP from MCA flow velocity and arterial blood pressure

B. Schmidt ¹, S. Bocklisch ², M. Päßler ², M. Czosnyka ³, J. Schwarze ¹, J. Klingelhöfer ¹

¹ Dept. of Neurology, Chemnitz Medical Centre, Chemnitz, Germany

² Dept. of Systems Theory, Technical University, Chemnitz, Germany

³ Academic Neurosurgical Unit, Addenbrooke's Hospital, Cambridge, UK

Background and Purpose. A model previously introduced by the authors allowed a non-invasive estimation of intracranial pressure (nICP) by the installation of a linear relationship between certain hemodynamic parameters and the quotient of mean ICP and arterial blood pressure (ICP / ABP). Former results suggested that this relationship might vary with the patient’s disease and other parameters, e.g., the state of cerebral autoregulation. In this approach the former global linear relationship between hemodynamic parameters and the ICP / ABP ratio was split into pieces of local linear functions in order to adapt the model to a potentially non-linear relationship. Methods and Results. Simultaneous recordings of cerebral flow velocity (FV), ABP and ICP in 66 traumatic brain injured patients (mean age: 39, range:6-73 years) with impaired autoregulation were studied. Hemodynamic parameters, calculated at several time points from FV and ABP recordings, as well as the time corresponding ratios ICP / ABP were sampled and analysed. A method called Fuzzy Pattern Classification was used to identify substructures (classes) in the set of all parameter samples. On each of the classes a specific linear function which related hemodynamic parameters to the ICP/ABP ratio was defined. In the current basic model we defined constant functions (mean ICP/ABP ratio) in each class. Using this model ICP was estimated as follows: From FV and ABP the hemodynamic parameters were calculated and related to the matching class(es). ABP multiplied by the class specific estimator(s) of ICP/ABP yielded the estimated value of ICP. Median error between ICP and nICP was 6.9 mmHg. A-waves of ICP and nICP significantly agreed, and long-term trends of ICP could be assessed properly. Conclusion. The results encourage the application of this model for nICP assess-ment. The class structure of the method allows modular extensions of applicability in heterogeneous patient groups without affecting the previous validity. This might enable the inclusion of patients with irregularities like vasospasm or hyperemia.

P136

Clinical and ultrasound findings after percutaneous transluminal stent angioplasty of the internal carotid artery: a mid-term follow up

Becker U, Gahn G, Hallmeyer-Elgner S, Mueller A, Mucha D, Reichmann H, von Kummer R

Departement of Neurology and Neuroradiology, University Hospital Dresden, Germany

Objective: To assess complications after percutaneous transluminal stent angioplasty (PTSA) in the proximal internal carotid artery (ICA).

Material and Methods: Since 1998, we consecutively and prospectively investigated the clinical and sonographical course of 46 PTSA in the ICA of 43 patients (mean age 67.5+9.1, 9 women, 34 men). Indications for intervention were symptomatic stenosis > 70% (38), asymptomatic progressive stenosis > 90% (6) and symptomatic stenosis < 70% (2) (NASCET). The mean grade of stenosis was 80.1+11.8%. We used self-expanding stents in conjunction with angioplasty. All patients received a combination of aspirin and clopidogrel for 4 weeks, thereafter aspirin (30), clopidogrel (2), aspirin and clopidogrel (6) or warfarin (2). Neurological examination and color-coded duplex sonography (CCDS) were performed before and after the procedure. Fourty patients (93.0%) were follwed by CCDS and clinical interview after 1, 4, 10, 22 and 34 months (mean follow up 9.3+7.4 m).

Results: During PTSA 3 patients (6.5%) had an ischemic stroke. CCDS detected 7 residual stenoses (15.2%) directly after PTSA. Six of them were due to narrowing of the stent, were not progressive and remained asymptomatic. One of them was due to an acute symptomatic stent-thrombosis. This stenosis was treated with rt-PA and recanalized completly within 1 week.

During follow up 1 patient (2.2%) had a recurrent stroke after 4 weeks, 3 patients (6.5%) died due to another reason than stroke. CCDS detected 6 asymptomatic restenoses (13.0%). Diagnostic angiography showed intimal hyperplasia. In one patient incomplete stent expansion at the common carotid artery caused a double lumen. All restenoses remained clinically asymptomatic. The ipsilateral external carotid artery was in all cases patent.

Conclusion: PTSA has an acceptable clinical risk in the treatment of symptomatic or critical ICA stenoses. The risk of recurrent strokes is low. CCDS appears to be a useful technique to detect restenoses.

P137

MICROVASCULAR DOPPLER ULTRASONOGRAPHY MONITORING IN NEUROSURGICAL PROCEDURES.

Ghadirpour R, Farneti M, * Zoppellari R,* Guberti A and Padovani R.

Department of Neurosurgery, *Service of Anesthesiology, St. Anna Hospital - University of Ferrara, Italy

Background: Vascular injuries occurring during neurosurgical operations can be responsible for high morbidity. Therefore, we consider of help detecting in real time the location and the integrity of critical vessels, the damage of which may cause a worse outcome.

Methods: With the use of a 20 MHz microprobe, 2 mm in size, all arteries located within 15 mm from the tip of the probe could be rapidly and noninvasively revealed, without interfering with the operative field. We present some illustrative cases of our experience on microvascular doppler ultrasonography monitoring (MDUM) during transsphenoidal, aneurysms, spinal dural arteriovenous fistulae (AVF), carotid endarterectomy (CEA) and skull-base tumours surgery.

Results: During transphenoidal surgery, the device is used to identify the intracavernous portion of ICA embedded in the tumour mass or in the presence of aberrant anatomic course. In aneurysms surgery the MDUM let us control an inadvertent occlusion of an adjacent vessel by the aneurysm clip or an incomplete aneurysm closure. In spinal AVF, detecting the variation of the arterial spectrum on the perimedullary draining veins before and after the interruption of the arteriovenous shunt, the monitoring is able to confirm complete obliteration of the fistula. In CEA it is possible to evaluate the anatomical extension of the stenosis, to verify the absence of flow after clamping and to control the plaque removal. The skull-base tumours, like meningiomas, can encase and displace the middle cerebral artery or other branches of the circle of Willis; the 20 MHz microprobe can localize these vessels inside the tumour, avoiding their direct mechanical injury during the procedures of dissection and removal of the lesion.

Conclusion: Microvascular doppler ultrasonography enhanced operative safety with technical simplicity and should be used routinely in neurosurgical procedures.

P138

CEREBRAL AUTOREGULATION MONITORING BY TRANSCRANIAL DOPPLER DURING LIVER TRANSPLANTATION

A. Arrigo, G. Ardizzone*, G. Brusa, M. Messina*, C. Siani*, G.A. Ottonello

Neurofisiopatologia-Ospedale S. Martino, *V SAR-Università, Genoa, Italy

Background: Patients undergoing orthotopic liver transplantations (OLTx) for end stage liver failure frequently have hepatic encephalopathy, condition which is associated with impairment of Cerebral Autoregulation (CA). During OLTx hemodynamic instability is frequently encountered and the most dramatic hemodynamic imbalance is mainly seen after reperfusion of the liver graft.

Cerebral blood flow velocity (CBF-V) and CA changes were studied, on line, during 24 OLTx by transcranial doppler.

Method: CBF-V was continuously recorded by a fixed (helmet) 2 Mz probe through the transtemporal window on the MCA. CA was studied by linear regression analysis between parallel CBF-V and MABP percentual changes from baseline during slow phenilephrine infusion. We calculated the slope "S" of the regression line in each patient. The line slope "S" corresponds to cerebrovascular resistance (CVR) since it is the ratio of the corresponding variations of CBF-V on MABP. When the slope "S" tends to "0" CVR are fully preserved and CA is maintained. On the contrary when the slope "S" is ≥ 1, CVR are markedly reduced and CA is lost.

Results: Wilcoxon’s test showed a significant slope "S" increase between ANHEPATIC vs POST-REPERFUSION PHASE (first hour after graft reperfusion) and a recovery in the NEOHEPATIC phase (end of surgery).

Conclusions: Our data show that in the first hour after graft reperfusion there is a failure of CA coupled to a reduction of CVR. This phoenomenon causes an increase of CBF-V and could expose the brain to hyperperfusion when MABP rises and could not avoid the onset hypoperfusion during systemic hypotension.

In addition, transcranial doppler has been an usefulness tool for the cerebral hemodynamics changes monitoring in operatory room, having allowed to identify on line cerebral hemodynamics imbalances.

P139

CEREBRAL AUTOREGULATION DURING ANAESTHESIA IN CIRRHOTICS PATIENTS: A TRANSCRANIAL DOPPLER STUDY

A. Arrigo, G. Ardizzone*, G. Brusa, E. Riccò*, C. Siani*, G.A. Ottonello

Neurofisiopatologia-Ospedale S. Martino, *V SAR-Università, Genoa, Italy

Background: Patients undergoing liver transplantation for end stage liver failure frequently have hepatic encephalopathy, condition which is associated with impairment of Cerebral Autoregulation (CA). The aim of this study is to verify the influence of anesthetics (isoflurane and propofol without N₂O) on CA studied with TCD, in cirrhotics patients during liver transplantation.

Methods: 24 patients (17 males, 52 ± 5.4 y.rs) were studied. Anesthesia was carried on in the first hour with isoflurane at an end tidal concentration of 0,6% without N₂O. During the second hour, after discontinued isoflurane, propofol was infused at the rate of 0.6 ± 0.2 mg/kg/h. Mean CBF velocity (CBF-V) was measured by transcranial doppler on the MCA. CA was studied by linear regression analysis between parallel CBF-V and MABP percentual changes from baseline during slow phenilephrine infusion. We calculated the slope "S" of the regression line in each patient. The line slope "S" corresponds to cerebrovascular resistance (CVR) since it is the ratio of the corresponding variations of CBF-V on MABP. When the slope "S" tends to "0" CVR are fully preserved and CA is maintained. On the contrary when the slope "S" is ≥ 1, CVR are markedly reduced and CA is lost. Differences were studied by nonparametric Wilcoxon's signed rank test.

Results: Slope "S" resulted statistically higher during isoflurane (0.9 ± 0.5) than propofol (0.55 ± 0.2) anesthesia (P< 0.01). No differences were found in MABP and CO₂ between the two stages.

Conclusions: In our patients 0.5 MAC of isoflurane is sufficient to impair CA and to produce a CVR reduction. Propofol is able to perform better condition for CA. TCD monitoring has allowed to study the cerebral hemodinamic on line in operatory room and it has offered the possibility to find the anesthetic of choice in the patients with end stage liver failure.

P140

EARLY DETECTION OF HYPERPERFUSION SYNDROME (HS) BY DAILY TRANSCRANIAL DOPPLER INVESTIGATION (TCD) DURING DAY 0-4 AFTER CAROTID ENDARTERECTOMY (CEA)

A.Schaafsma, L.vd.Veen and J.P.M.Vos, Martini Ziekenhuis Groningen,

the Netherlands.

Methods: at our hospital all CEA patients with sufficient temporal windows receive daily TCD-investigation of ipsi- and contralateral middle cerebral artery (MCA) on postoperative days 0-4. This has enabled pre-symptomatic detection of 2 cases of definite HS in nearly 150 consecutive patients.

Results: 1 patient showed abnormally high MCA flow velocities (FV) straight after surgery. Based upon TCD measurements we advised prolonged intensive care monitoring. On postoperative day 2 the patient developed surges of hypertensive blood pressures up to 210 / 105. Prompt administration of anti-hypertensive drugs probably prevented secondary complications. A second patient developed abnormally high MCA FV on postoperative day 3. We advised against discharge from hospital. On postoperative day 4 the patient developed a focal status epilepticus contralateral to the side of CEA together with surges of hypertensive blood pressures up to 210 / 120. Despite the prompt administration of anti-hypertensives and anti-epileptics the patient suffered a worsening of pre-existent hemiplegia.

Conclusion: daily TCD-monitoring after CEA may enable presymptomatic detection of HS. Abnormal increases in MCA flow velocity seem to develop prior to other symptoms of HS, such as malignant hypertension, focal status epilepticus, focal neurological deficit and, ultimately, brain hemorrhage and death.

Ref.: Eur.J.Vasc.Endovasc.Surg. Vol 23(1) pp. 17-22.

P141

MONITORING OF CEREBRAL BLOOD FLOW WITH POWER MODE DOPPLER TCD DURING RETROGRADE CEREBRAL PERFUSION

Z. Garami¹, A. Estrera², R. Sheinbaum³, S. Calleja¹, O. Chernyshev¹, K. Uchino¹, M. Malkoff¹,A. V. Alexandrov¹, H. Safi²

¹ Department of Neurology, ² Dept of Cardiothoracic and Vascular Surgery,³ Dept. Of Anesthesiology,

University of Texas-Houston, USA

Background: Retrograde cerebral perfusion (RCP) is used for cerebral protection during repairs of the ascending and transverse aortic arch with profound hypothermic circulatory arrest (PHCA). A single channel transcranial Doppler (TCD) monitoring has been used previously with varying success. The purpose of the study was to determine the effectiveness of a new technology, Power Motion-mode Doppler (PMD or M-mode), in detection of retrograde flow dynamics in the major intracranial arteries during RCP.

Method: A prospective, observational study of patients undergoing ascending and transverse aortic arch repairs was performed using PMD and single gate spectral TCD combined in a TCD 100M unit, Spencer Technologies. PMD simultaneously displays flow intensity and direction over 6 cm of intracranial space and makes it easier to select depth for spectral waveform analysis. Data on pump-flow characteristics and patient recovery were collected.

Results: A total of 26 patients were studied (one patient did not have temporal window). In 5 patients with suboptimal windows we monitored ICA, vertebral arteries (2-2) and basilar artery (1). Mean RCP time was 34.8 minutes, and mean RCP pump flow and RCP peak pressure for identification of cerebral blood flow were 0.62 L/minute and 31.3 mmHg, respectively. Retrograde cerebral blood flow during RCP was detected in 100% of cases with a mean TCD flow velocity of 16.8 cm/sec. In the study group, 30-day mortality was 15.4% (4/26). The incidence of stroke and temporary neurological deficits were 7.7% (2/26) and 26.9% (7/26), respectively.

Conclusions: PMD-TCD monitoring can be used to effectively determine reversal of flow in the M2, M1 MCA, and vertebro-basilar segments in all patients undergoing RCP. Potential for PMD-TCD to identify patients at risk of perioperative events can be determined in an interventional study with stratified adjustment of pump-flow settings using intracranial reversed flow measurements.

P142

Microembolusdetection in patients with Fabry's disease - Further support for the primarily microangiopathic origin of early cerebrovascular symptoms

M. A. Ritter, R. Dittrich, D. W. Droste

Department of Neurology, Universitätsklinikum Münster, Germany

Introduction: Fabry’s disease is a sex-linked recessive storage disorder leading to cerebrovascular symptoms in many cases. Fabry’s disease predominantly results in small vessel disease, but also may affect large arteries. This is why the primary origin of cerebrovascular symptoms is under debate.

Microembolic signals indicative of an active embolic source can be recorded by transcranial Doppler sonography (TCD). We report on three patients with Fabry’s disease from one kindred in whom we carried out microembolus detection recordings.

Methods: Three patients of our department from one family were examined clinically and by ultrasound. Fabry’s disease was diagnosed by pathologically decreased a-galactosidase activity in lysomsomes of lymphocytes. The right MCA was continuously insonated by TCD through the temporal window for one hour in all patients. The Doppler signal was recorded onto digital audio tape (DAT) and an experienced observer analysed the tape off-line blinded to the patients’ diagnosis.

Results: No microembolic signals were found in one-hour-recordings in all patients.

Conclusion: Our results support the thesis that early cerebrovascular symptoms in patients with Fabry’s disease arise from small vessel occlusion and not from embolic sources. MES-detection might proof useful to justify therapeutic means such as antiaggregation or anticoagulation in patients with Fabry’s disease who have had cerebrovascular symptoms.

P143

B-MODE AND COLOR-CODED DUPLEX SONOGRAPHY OF THE OPTIC NERVE AND OF THE CENTRAL RETINAL VESSELS IN OPTIC NEURITIS

U. Walter¹, U. Kirchhoff², V. Hingst³, U.K. Zettl¹, R. Guthoff², R. Benecke¹

University of Rostock, Germany, ¹Department of Neurology, ²Department of Ophthalmology, ³Institute of Diagnostic and Interventional Radiology

Background: To investigate the frequency and degree of abnormalities detected by B-mode sonography (BS) and color-coded duplex sonography (DS) in patients with acute unilateral optic neuritis.

Method: 25 patients aged 38 ± 10 years with unilateral optic neuritis were prospectively studied. BS was performed through the abducted ocular bulbus imaging the transsectional area of the optic nerve (ON). Diameters of the affected and the contralateral ON were measured. The quotient of both diameters was calculated for each patient. If the quotient exceeded 1,1 the affected ON was considered as swollen. MRI was performed to objectively localize and measure the ON lesions. In 10 patients DS of the ophthalmic arteries and the central retinal vessels was performed. Peak systolic flow velocity, mean flow velocity, and resistance indices were calculated for each vessel.

Results: In 17 of the 25 patients the affected ON was swollen. The mean diameter of the affected ON of all patients was 3,6 ± 1,0mm, and of the contralateral ON 2,7 ± 0,4mm. The difference was statistically significant (t test, p < 0,001). A significant difference was also found in the resistance index in the central retinal artery between the affected and unaffected eyes.

Conclusion: In patients with acute unilateral optic neuritis abnormalities of ON morphology and of central retinal artery perfusion may be frequently detected by sonography. BS and DS appear to be sensitive tools which are of potential use for disease monitoring.

P144

THE STUDY OF INTRACEREBRAL ANEURYSMS BY USING TRANS-CRANIAL-COLOR-DOPPLER

S. Sanguigni, C. Paci, T. Carboni, R. Gobbato, G. Malferrari¹, F. Accorsi², G. Galletti³, G. Landini⁴, L. Curatola

Department of Neurology, San Benedetto del Tronto, Italy

Dept of Neurology, Reggio Emilia¹, Dept of Medicine, Bologna², Dept of Neurology, Forlì³, Dept of Medicine, Firenze⁴ – Italy

Background: The probable presence of intracranial aneurysms and their possibility rupture with conseguent subarachnoidal hemorrage can cause very important problems in precocious diagnosis and screening. Furthermore the incidence of aneurysms by autopsy is about 2%. At present, angiography and angio-RMN represent the gold-standard methods for the diagnosis of cerebral aneursyms.

Nevertheless Trans-Cranial-Color-Doppler (TCCD), occasionally associated with contrast agent (Levovist , SonoVue), can be useful to dectect intracranial aneurysms.

Methods: In the last year we observed 12 cases of patients with intracranial aneurysm. In our laboratories we used ACUSON 128XP10 with sectorial probe at 128 channels.

Results: We report some borderline cases which include aneurysm of:

a) middle cerebral artery- cm 1 x 0.5-; b) sovraclinoideus syphon, partially thrombosed ; c) top of the basilar d) M2 segment .

Conclusions: The possibility of dectecting both partially thrombosed aneurysms and small ones, emphasizes the importance of TCCD in the precocious diagnosis of cerebral aneurysms.

P145

Microvascular Doppler Monitoring in Surgery of Superficial Arteriovenous Malformations

V.B. Semenyutin, P.I. Nikitin, B.B. Govorov

Russian Polenov Neurosurgical Institute, St. Petersburg, Russia

Background: The study goal was to estimate potentialities of microvascular dopplerography (MVD) in identifying afferent (feeding), efferent (draining) and transit vessels and controlling totality of resection of superficial arterivenous malformations (AVM), localized in eloquent areas of the brain.

Methods: We examined 14 patients with superficial cerebral AVM, localized in eloquent areas. Blood flow velocity (BFV) in afferent, efferent and transit vessels was recorded before and after AVM removal. It was done with the help of microvascular Doppler using a 20 MHz probe (MDX system, DWL, Germany).

Results: Before AVM removal afferent vessels of 11 out of 14 cases were characterized by mean BFV of 33-95 cm/s (56.6+17.3) and pulsatility index (PI) of 0.26-0.66 (0.40+0.12). Spectra of BFV in draining vessels of all 14 patients had a marked arterial pattern. Transit vessels were identified in 10 out of 14 cases. Values of BFV (13.2+3.9 cm/s) and PI (1.10+0.19) were normal. After AVM removal spectra of BFV in afferent vessels of 9 patients were characterized by low-amplitude spike signals, confirming absence of blood flow. Mean BFV and PI in efferent vessels of all patients reduced up to 5.0+1.0 cm/s and 0.25+0.07 respectively. BFV reduction was accompanied by disappearance of an arterial component in its spectrum. The observed pattern was typical of normal veins. Disappearance of the arterial component in BFV spectrum of efferent vessels was indicative of AVM total removal. Control angiographic examination, carried out on discharge was indicative of AVM total exclusion from blood circulation.

Conclusions: MDV ensures dynamic estimation of BFV in afferent, efferent and transit arteries of superficial AVM, localized in eloquent brain areas and permits to control totality of AVM resection. Preservation of blood flow in transit arteries of superficial AVM, localized in these areas, helps to avoid additional disability of patients after radical operations.

P146

A pilot study of preoperative transcranial Doppler examinations to predict cerebral hyperperfusion following carotidendarterectomies

R.W.M. Keunen, H.W. Nijmeijer, D.L.J. Tavy, R.C. Edelenbos, E.B. Muskens, C.M.S Bruijnincks, J.C. Sier, C.J. Stam

Dept of Neurovascular Medicine Leyenburg Hospital The Hague

Background: The objective was to determine if pre-operative transcranial

Doppler (TCD) examinations have the potential to predict post-operative cerebral

hyperperfusion following carotidendarterectomies (CEA).

Methods: 55 patients (mean age 64.4 yrs/ ratio male/female 31/14) with symptomatic

internal carotid artery stenosis were included. TCD examinations included pre-

operative measurements of bloodflowvelocities (BFV) and pulsatility indices (PI)

of the ipsilateral middle cerebral artery (MCA). Patients were monitoried by TCD

during the CEA procedure and upto 1 hour post CEA.

Normal pre-operative hemodynamics were defined when the product of BFV*PI

was > 36 cm/s; abnormal pre-operative cerebral hemodynamics were present as the

BFV*PI < 36 cm/s. Cerebral hyperperfusion was defined when the BFV pre and post-

operative showed and increase of > 100 % in the MCA.

Results: The range of changes between pre- and postoperative BFV varied between

-44.4 % and + 182.6 % (mean change 27.7 %). Cerebral hyperperfusion occurred in 9.9 %.

Cerebral hyperperfusion was seen in 31 % of the patients with abnormal pre-operative

hemodynamics. None of the patients with normal pre-operative hemodynamics

experienced a post-operative cerebral hyperperfusion. The post-operative stroke risk

was in patients with abnormal pre-operative hemodynamics ten-fold higher compared

to patients with normal cerebral hemodynamics.

Conclusion: pre-operative TCD examinations can reliable identify patients who will

not have a risk for cerebral hyperperfusion following CEA. Poor pre-operative hemo-

dynamics were associated with an increase chance for cerebral hyperperfusion following

CEA and an increased post CEA stroke risk. Larger prospective studies

are warranted to base firm evidence for the observationss of this pilot study.

P147

Vestibular caloric stimulation causes prevailing Activation of the right hemisphere

M. Rosenkranz, U. Sonnemann*, D. Burkhardt, W. D. Niesen, W. Zangemeister, C. Weiller, U. Sliwka.

Depts. of Neurology and ENT*, University Hospital Eppendorf, Hamburg, Germany

Objective: To assess activation of the vestibular cortex during vestibular caloric stimulation by means of functional TCD.

Methods: Simultaneous TCD from both MCA was performed during caloric irrigation (CI) of the external ear canal in 6 healthy right-handed subjects. 5 cycles of CI were performed for either ear. Computing the ratio of the right and left CBFV traces (MCAR/MCAL) separated specific laterality of flow responses from global changes in CBF.

Results: CI caused rotatory vertigo and horizontal nystagmus in all subjects and induced complex bilateral alterations of CBFV, probably attributed to multisensory, vestibular, and ocular motor functions. However, 2.15± 1.19 sec after start of CI the averaged MCAR/MCAL ratio increased rapidly (2.34±2.06%/sec), reached a peak (7.1±2.62%) 7.5±3.43 sec after start of CI, and declined back to baseline after CI ceased. No significant differences between the MCAR/MCAL ratio of left and right CI was observed.

Conclusions: The CBF changes indicated by changes in CBFV reflect functional activation of the vestibular cortex. Unilateral stimulation of either horizontal semicircular canal being associated with prevailing right-hemispheric activation reflects right-hemispheric dominance of the vestibular cortex.

P148

Cerebral Hemodynamics and Bioelectrical Brain Activity in Patients after Uterine Extirpation with Adnexa.

M. R. Bekouzarova, MD, PhD., T. A. Adyrkhaev, V. V. Brodgenko

Russian State Medical University, Department of Neurology and Neurosurgery, Moscow

Background: To analyze functional conditions of nervous system, insufficiency of cerebral hemodynamics, bioelectrical brain activity and hormonal status of women in age 35-50 years, after uterine extirpation with adnexa, in connection with uterine mioma, before and after substitution hormone therapy. To work out methods of complex therapy for this patients.

Methods: Investigation of psychological status (Mini Menta State, Folstein M.T., 1975), transcranial Doppler sonography, electroencephalography, laboratory analysis of female hormones. Investigations conducted at the Department of Neurology and Neurosurgery of the Russian State Medical University, based at the 1-st City Clinic Hospital (Moscow).

Results: We analyzed 15 women in age of 35-50 years, after uterine extirpation with adnexa, in connection with uterine mioma. Medium age of this patients 40,5 years, they are women of reproduction age. In a year after uterine extirpation with adnexa, at the background of insufficiency of female hormones, developed an alarm-depression disturbances, vegetative-vascular syndrome (headache, dizziness, hypertension, climacteric cardiopathy, climacteric neurosis, disturbance of sleep, sweating, hot flushes of the upper half of the body, fatigability, enhanced emotional lability). To analyze cerebral hemodynamics, using transcranial Doppler sonography, in this patients determined the Vertebral-Basilar insufficiency (more causes) and in some causes our patients had insufficiency in carotid and medium cerebral artery system. All of this patients had a dysfunction of mese-diencephalon structures of brain (according to electroencephalography investigations). After the uterine extirpation with adnexa arise a disturbances of complicated neuro-endocrinology interactions in hypotalamus-hypophysis-adnexa-adrenalcortex-thyroid system.

P149

FUNCTIONAL SIGNIFICANCE OF AFFERENT VESSELS OF CEREBRAL ARTERIOVENOUS MALFORMATIONS: INTRAOPERATIVE ASSESSMENT

V.B. Semenyutin, P.I. Nikitin, I.M. Bukhaev, V.V. Alexeev, S.K. Sergienko

Russian Polenov Neurosurgical Institute, St. Petersburg, Russia

Background: Modelling of cerebral hemodynamics in patients with cerebral arteriovenous malformations (AVM) by Gao et al. (1997) showed dependence of blood pressure (BP) in afferent vessels on a degree of shunting (volumetric blood flow through AVM). Nornes et al. (1980) established dependence of an afferent vessel diameter on volumetric blood flow through it. Use of modern technologies of microsurgical engineering, in particular microcatheters for embolization, allows to measure BP in afferent vessels; it appears that its value may be used for estimation of functional significance of AVM afferent vessels under the above conditions.

Methods: 8 patients with cerebral AVM of grades 3-5 according to Spetzler, Martin (1986) were examined. They were subject to 9 superselective embolizations with the help of Magic STD 1.8F microcatheters (Balt, France) and sedation-analgesia. The M-34 mingograph (Siemens-Elema, Sweden) was used for direct measurement of systemic blood pressure (SBP) in a femoral artery and BP in AVM afferent vessels. Wada test was performed before every embolization with administration of 30-50 mg of thiopental sodium via a microcatheter.

Results: Wada test was negative in 9 cases. BP in afferent vessels, whose diameter did not exceed 3 mm, varied from 15 up to 43 mmHg; it made 21.4-48.6% from SBP. A value of BP was indicative of low functional significance of afferent vessels in all 9 cases; it was in compliance with computation data obtained on the aforesaid model. BP in afferent vessels, whose diameter did not exceed 3 mm, was within the range of 56-72 mmHg in 3 cases with positive Wada test; it made 50.7-64.2% from SBP. According to computation data and results of Wada test, these afferent vessels provided partial blood supply of eloquent brain structures. AVM embolization through these efferent vessels was not carried out.

Conclusions: A value of BP in an AVM afferent vessel can serve the basis for assessment of its functional significance. The method is demonstrative and informative for AVM of various localization; it allows to achieve considerable reduction of a number of complications, increasing a risk of invalidism in performing superselective embolization through afferent vessels.

P150

CO-RELATION BETWEEN TRANSCRANIAL DOPPLER SONOGRAPHY, CALORY TEST OF VESTIBULARIS AND ELECTRONISTAMOGRAPHY IN CASE OF VERTEBRO BALISAR INSUFFICIENCY

J.Đelilović, V. Demarin, H. Lončarević, S. Žarković

Neurology Clinic, U.K.C. Sarajevo, Sestre Milosrdnice Clinic, Zagreb, Croatia

Introduction

Transcranial Doppler Sonography is non-invasive, ultrasound diagnostic method, which provides insight into the status of hemo dynamic of the frontal carotid and rear VB system, as well as such method of selection in diagnosis of VB insufficiency. This method is in use since 1982. For the purpose of confirmation of VB insufficiency diagnosis are used test of calorie testing of vestibularis and electronystagmogryphy, as additional method in some cases.

Materials Subjects and Methods

During the work were made analyses of group of 50 individuals with symptoms of VB Insufficiency, age of 40 – 60 years, and control group of 50 healthy individuals of the same age. From all individuals were taken history, neurology examination, laboratory results (blood count, sugar in blood, lypidogram and blood pressure), ophthalmologic examination, EKG and cardiology examination, RTG of neck spine, transcranial Doppler (TCD), calorie test of vestibularis, test of electronystagmography, EEG and CT of brain.

Work results

After examination by transcranial Doppler using sonography, pathological (reduced) value of SBSK were found in investigative group with 30% of individuals AV right, in control group only 12%, but AV left was found with 54% in investigative group and only 10% in control group, in AB with 52% individuals in investigative group and with 8% in control group. Calorie test of vestibularis was pathological in investigative group with 78% of individuals, but in control group only with 14% of individuals: the majority findings were asymmetric and areflectic.

88% of individuals in investigative group had pathological test of electronystamography, but in control group only 16%.

Statistic is significant among groups in all three mentioned groups.

Conclusions:

1. Transcranial Doppler sonography is method of selection in establishment of diagnosis of VB insufficiency.
2. This is diagnostic method which gives the information on neurovascular disorder in case of VB insufficiency.
3. Additional diagnostic methods, application of calorie test of vestibularis and test of electronystagmography before all, provide objective diagnosis of VB insufficiency with 90% of individuals.

P151

Ultrasound Imaging of atlas loop of vertebral artery

M.V. Sidor, K.V. Smirnov, J.V. Smirnova

Altai Diagnostic Center, Barnaul, Russia

Background: Existing ways of ultrasound visualizations of V3 portion of vertebral artery (atlas loop or V3) do not allow to get imaging of all its length. Consequently diagnostic of circulation desorders in V3 are little efficient by using this ways. That is why were developed new way to ultrasound visualizations of V3 by using different ultrasound mode: B-mode, Color Doppler and Power Doppler (invention №2001114954 from 31.05.2001).

Methods: The methods of ultrasound vizualisation B-mode, Color Doppler and Power Doppler Imaging were performed in 20 voluntaries. Investigation has been performed with ultrasound scanner (Spectra Masters "Diasonics", USA) on claimed technique.

Results: Distal and proximal part of V3 portion of vertebral artery was successful vizualisated in all cases (100%) by using Color and Power Doppler imaging. By using only B-mode it was possible to get image of distal part of V3 portion in 80% (n=16) and proximal one in 55% (n=11).

Conclusion: It suggests that new way of atlas loop of vertebral artery vizualisation allows to examine over the whole length of the vessel. Vizualisation V3 segment of vertebral artery in Color and Power Doppler mode is more effective than in B-mode.

P152

UltrasonographIC Measurement of Global Cerebral Blood Volume in Healthy Adults

F. Doepp, S. Schreiber, J.M. Valdueza

Department of Neurology, University Hospital Charité, Berlin, Germany

Background: Up to now values of cerebral blood volume could only be assessed by MRI, SPECT or PET techniques. We present a new ultrasonographic approach to determine the global cerebral blood volume (CBV).

Methods: 41 healthy subjects, age ranging from 20 to 79 years (mean± SD: 45± 19, median: 48) were studied. CBV was determined as the product of global cerebral blood flow (CBF) and the global cerebral circulation time (CCT). CBF was calculated as the sum of the flow volume in both internal carotid arteries (ICA) and vertebral arteries using duplex sonography. CCT was measured as the time delay of echocontrast bolus arrival between the ICA and the contralateral internal jugular vein at the submandibular level using 2-MHz-Doppler probes. In 5 subjects reproducibility studies and measurements under controlled hyperventilation were performed.

Results: Measurement was successful in all subjects. CBV ranged from 45 to 108 ml (mean± SD: 77± 14 ml) and did not correlate with age, end tidal CO₂, heart rate or blood pressure. Mean difference after repeated testing in 5 subjects was 16± 16 ml. Under hyperventilation, CCT increased from 5.7± 0.7 sec to 7.8± 0.8sec (p<0.05), CBF decreased from 765± 72 ml/min to 518± 52 ml/min (p<0.05). However, CBV values did not show a significant difference (71± 8 ml vs.68± 11 ml, p=0.4).

Conclusions: Ultrasonographic measurement of global CBV is a reliable and easy method demonstrating values in good agreement with previously published data. Hyperventilation results in the expected CBF and CCT changes, supporting the robustness of our test. Interestingly, CBV did not seem to be significantly altered.

P153

CAN BE USEFUL TRANS-CRANIAL-COLOR-DOPPLER TO CONFIRM A RARE CASE OF RIGHT SIDED TEMPORAL LOBE VARIANT OF FRONTO-TEMPORAL DEMENTIA (FTD)?

S. Sanguigni, C. Paci, T. Carboni, R. Gobbato, G. Malferrari*, F. Accorsi ^, L. Curatola

Department of Neurology, San Benedetto del Tronto, Italy

Dept. of Neurology, Reggio Emilia*, Dept of Medicine, Bologna – Italy

Background: Fronto-temporal dementia involves progressive dysfunction of the anterior temporal frontal lobes. Despite the presence of relatively uniform pathology, some patients display diffuse, bilateral frontal and temporal degeneration, whereas others may suffer degeneration primarily in the frontal or temporal lobe. The degeneration can be either symmetric or highly asymmetric, affecting primarily on frontal or temporal region.

Methods: We describe a 70 years old woman affected by a right sided temporal lobe variant of FTD. Nine months ago the patient presented impairment in her executive and attentional abilities while the memory was minimally involved. She had difficulty to relate to others such as her friends or family. She showed dishinibition, distractibility, sterotypes and alterated speech output. All cognitive disorders were confirmed by a general neuropsichological battery that evaluated attention, executive functions and problem solving abilities, language, verbal and spatial memory, praxias and visuo-spatial abilities. Brain MRI scan, SPECT and Transcranial-Color-Coded-Duplex Sonography (TCCD) were obtained in our patient.

Results: MRI showed a right temporal lobe atrophy while SPECT revealed severe hypoperfusion in right fronto-temporal lobe.

The TCCD study was performed with the use of Acuson 128 XP10 and showed an important reduction of cerebral blood flow detected at the right middle cerebral artery compared with the controlateral one.

Conclusions: TCCD study represents an important diagnostic technique to confirm a rare case of right temporal lobe variant of FTD.

P154

IMPAIRED VISUALLY EVOKED RESPONSE IN POSTERIOR CEREBRAL ARTERY IN PATIENTS WITH ADVANCED CAROTID STENOSIS OR OCCLUSION

Roje Bedeković M, Lovrencic-Huzjan A, Bosnar Puretic M, Demarin V

Neurology Depr University Hospital "Sestre milosrdnice", Zagreb, Croatia

Background: Up to now vasoreactivity testing was almost always performed investigating middle cerebral artery or rearly anterior cerebral artery, showing similar reactivity in both. Testing of posterior circulation using visual stimuli was described only in few studies, mostly on healthy individuals, although visual stimulation is noninvasive, and the most powerful stimuli of metabolism in visual cortex. The aim of the study was to investigate visual evoked response in posterior cerebral artery (PCA) in patients with carotid disease.

Methods: Mean blood flow velocities (MBFV) of the PCA were investigated in patients with advanced carotid stenosis or occlusion by means of transcranial Doppler (TCD), 2 MHz probe MultiDop X4 DWL. Velocities were measured successively in the dark and during white light visual stimulation three times. Mean reaction changes in MBFV compared to dark in all stimulations were calculated. Mean reaction time (time to peak velocities) was measured. The data were compared with 8 healthy controls.

Results: We investigated 16 male patients: 8 with subtotal internal carotid artery (ICA) stenosis (5 right, 3 left), 5 ICA occlusion (2 right, 3 left), and 3 patients with bilateral stenosis or occlusion. During light stimulation mean MBFV increase was 46,56 +2,56% on the right and 44,13+3,01% on the left. In healthy controls right PCA MBFV increase was 44,71+6,5%, and 42,67+6,65% on the left. Mean reaction time in patients with carotid disease was 26,79+6,72 s in the right PCA, and 27,06+7,6s in the left PCA. In healthy controls mean reaction time was 15+3,3 s in the right and 15+3,3 s in the left PCA (p<0.05).

Conclusions: TCD testing using visual stimuli showed prolonged visual evoked response in patients with carotid disease, although MBFV changes didn’t differ compared to healthy controls. TCD testing using visual stimuli is an usefull method in the evaluation of vascular reserve capacity in patients with carotid disease.

P155

THREE DIMENSIONAL ULTRASOUND OF THE PLAQUE ULCERATION

Kesic MJ, Lovrencic-Huzjan A, Zavoreo Husta I, Demarin V

Neurology Depr University Hospital "Sestre milosrdnice", Zagreb, Croatia

Background: Carotid plaque ulceration is associated with an increased risk of cerebral embolism. Still controversy of the diagnostic ability of conventional two-dimensional ultrasound and angiography to detect plaque ulcers exists. Three-dimensional ultrasound (3D US) facilitates visualisation of the luminal plaque surface.

Methods: We tried to display 6 stenosed internal carotid arteries (ICA) with plaque ulcers by mean of B mode, color Doppler flow imaging (CDFI), power Doppler flow imaging (PDFI), 3D US and 3D PD. We performed 3D US examination of 6 ICA plaques with an ulcerated surface. B mode slices were obtained with 10 MHz linear array transducer. CDFI and PDFI were done in a standardised manner. 3D data sets were obtained with the same probe, free handed, in a defined period of time (10 seconds). The recorded images were reconstructed (TomTec imaging system) and volumetry was done.

Results: Plaque ulcers were good visualised by B mode in 2/6 ICA, by CDFI mode in 4/6, by PDFI mode in 5/6 ICA and by 3D US and 3D PDFI in 6/6 ICA. The diameter of the plaque ulcers couldn’t be measured by means of B mode. Mean diameter of plaque ulcers was in CDFI 2,7±0,44mm, in PDFI 3,1±0,8mm, in 3D US 2,55±0,21mm and in 3D PDI 2,74±0,29mm. Surface area of the ulcer wasn’t measurable in B mode. Mean plaque ulcer surface was in CDFI 4,83±0,75mm², in PDFI 5,6±0,3mm², in 3D US 7,56±0,4mm², and in 3D PDI 7,89±0,12mm². Plaque volume couldn’t be measured by mean of B mode. Mean plaque ulcer volume was in CDFI mode 12,9±1,3 mm^3, in PDFI mode 17,5±4,4 mm³, in 3D US 19,1±2,6mm³ and in 3D PDFI 21±2,4mm³.

Conclusions: 3D US accompanied by PD enabled good visualisation and measurement of the plaque ulcers diameter, surface and volume.

P156

Is ultrasound safe when applied parallel with thrombolysis?

G.Panczel, V.Kemeny*, P.Bönöczk, Z.Nagy

National Stroke Center Budapest, Hungary

Ferenc Flór Hospital Kerepestarcsa, Hungary

Background: Fibrinolysis is associated with substantial risk of hemorrhagic complication. Insonation with ultrasound (US) parallel with systemic thrombolysis may increase efficacy, however, safety of US insonation with special respect to heating effect should first be evaluated.

Methods: A low-frequency, high-energy US transducer (100 kHz, 3 W energy intake) and a standard 2 MHz TCD transducer were applied at maximal power output, for a 60- minute insonation of 10-10 cadaver brains through temporal window and the temperature was monitored simultaneously at 1-2-and 3 cm depths from temporal bone in the brain parenchyma along the axis of US propagation.

Results: The baseline temperature of brain parenchyma was an average of 22.2 ± 2.6, 21.9 ± 2.7, 21.5 ± 2.6° C, and 22.3 ± 3.0, 21.9 ± 3.1, 21.8 ± 3.0 ° C for 100KHz and 2 MHz insonations respectively at 1-2-and 3 cm depths, they did not differ significantly between the two insonation groups. The temperature increased by 1.14± 0.35, 0,99 ± 0.31, 0.82 ± 0.24 ° C, and 0.16 ± 0.15, 0.18± 0.15, 0.17± 0.1 ° C during insonation with 100 KHz and 2 MHz transducers respectively at the 3 different depths. Differences between the 2 groups at a given depth were significant (p<0.05 for all depths).

Conclusions: The 100 KHz insonation exerted a mild heating with significant decrement with increasing depth while the 2 MHz insonation was practically not associated with temperature elevation. Temperature increase is presumably higher in cadavers than in living persons given the cooling effect of circulating blood. US insonation may be considered safe as heating side-effect is mild and can be overweighed by the benefit of its recanalyzing effect.

P157

ULTRASOUND AND tPA ENHANCED THROMBOLYSIS: INFLUENCE OF ULTRASOUND FREQUENCY AND PULSE LENGTH

A. Voie, D. Amory, J. Amory, M. Moehring, M. Spencer

Spencer Technologies, Seattle WA, USA; Institute of Applied Physiology & Medicine, Seattle WA, USA; University of Washington, Seattle WA, USA

Background. Studies indicate that ultrasound (US) may enhance the thrombolytic properties of tPA. The aim of this study was to contrast the enhancement of low-frequency (200 kHz) US with diagnostic (2 MHz) pulsed US, using low intensity (50 mW/cm²) as might be experienced in transcranial diagnostic evaluation. Additionally, the influence of cycles per pulse (cpp) at each of the US frequencies was examined.

Methods. 48 rabbits were used, divided into 6 groups of n = 8. In addition to the 4 US groups (3 & 8 cpp at 200 kHz, 8 & 30 cpp at 2MHz) a control group received no therapy, and 1 group received tPA only. In each experiment, a fresh autologous clot (66 μl) was injected into an isolated segment of the abdominal aorta via a cannula in the left renal artery. After flow meter confirmation that the embolic clot had caused a total occlusion at a 40 % stenosis site on the aorta, therapy was initiated.

Results. Mean clot weight (MCW) was 29.8 mg for the control group. That of the tPA-only group was 4.6 mg, a significant reduction (p = 0.02). The MCW in groups receiving tPA and 2 MHz US (8 & 30 cpp) were 6.4 mg and 4.0 mg, respectively, which did not differ significantly from the tPA-only group (p = 0.439 & 0.419). The MCW for the group receiving tPA and 200 kHz US (3 cpp) was 7.2 mg, which also did not differ significantly from the group receiving tPA only (p=0.221). However, the MCW for the group receiving tPA and 200 kHz US (8 cpp) was 0.8 mg, which was significantly less than the group receiving only tPA (p = 0.006).

Conclusions. In this model, tPA caused significant clot lysis, but enhancement was not observed using 2 MHz US at 8 or 30 cpp, nor with 200 kHz US at 3 cpp. However, 200 kHz US at 8 cpp did significantly enhance the thrombolytic effect of tPA.

P158

CEREBRAL HEMODYNAMICS IN LEUCOARAIOSIS, REDUNDANT INTERNAL CAROTID ARTERY AND NORMAL AGED

A.Berchio, G.Ottone, C.Valenzano

D.E.A. Osservazione Medicina – A.S.O. San Giovanni Battista – Torino (Italy)

Cronic ischaemia should be the most likely mechanism of leucoaraiosis. The role of redundant (kinks, coils and loops) internal carotid artery (ICA) as stroke risk factor is still controversial. The aim of the paper was to relate the middle cerebral artery (MCA) flow parameters in subjects affected by leucoaraiosis with the ones recorded in ICA redundancy bringers.

Methods: we studied 19 pz. with leuco-araiosis based on head-CT and 25 pz. with ICA redudancy. The following MCA parameters were examined: · peack systolic velocity · end-diastolic velocity · some derived parameters: 1) mean flow velocity 2) PI (Gosling pulsatility index) 3) RI (Pourcelot resistence index). Measurements were also made in a normal aged control group. ECST method > 30° ICA and > 50% MCA stenosis were excluded.

Results: average ages were: leucoaraiosis group 77,2± 6,8 ; redundancy bringers 67,9 ± 14,9; normal aged 74,3 ± 3,1. Statistically increased relevant values were observed between: ¨ leucoaraiosis group vs. normal aged PI and RI: both p<0,000 and peack systolic velocity: p< 0,002 ¨ redundancy bringers vs. normal aged PI and RI: both p<0,000 and ¨ redundancy bringers vs. leucoaraiosis group end-diastolic flow velocity and middle flow velocity: respectively p<0,004 and p<0,01.

Discussion: the increased peack systolic flow, PI and RI in the leucoaraiosis group might be expression of poor collateral supply for white matter, atherosclerosis and narrowing of small vessel lumen. The P.I. and R.I. reduction in the redundancy bringers might be expression of the reduction of arterial vascular resistence due to the activation of a compensatory mechanism to flow reduction due to ICA tortuosity. Since there were no significative differences in flow parameters values between leucoraiosis and redundancy bringers, both groups might be considered at risk because of a vascular disesase on a haemodynamic basis.

P159

USEFULNESS OF COLOR-CODED DUPLEX SONOGRAPHY FOR AN ASSESSMENT OF INFANTILE HYDROCEPHALUS

A. Cerniauskaite¹, J. Valaikiene², V. Basys¹

Clinics of Neonatology¹ and Neurology², University of Vilnius, Lithuania

Background: In most cases only the anatomical data are evaluated in an assessment of infantile hydrocephalus, however evaluating of cerebral haemodynamics is extremely important. Our purpose of the study was to determine cerebrovascular resistance index (RI) by transcranial color-coded duplex sonography (TCCS) in infantile hydrocephalus and to assess the relationship between RI and ventricular index (VI).

Method: 60 infants (age range 36-80 weeks) were examined by TCCS: for 12 infants with severe hydrocephalus confirmed by CT were performed 32 examinations, comparing with 48 healthy infants group. The aetiology of hydrocephalus was posthaemorrhagic in 9, was postmeningitic in 2 and of congenital origin in 1. Such haemodynamical parameters as systolic, diastolic, mean velocities and RI of the anterior cerebral artery (ACA) were obtained performing TCCS through the anterior fontanelle. On a frontal section, through the head of the caudate nucleus were assessed VI by US according formula: laterolateral diameter between the points of the frontal horns/distance between the left and right internal table on that section.

Results: RI and VI in infants with hydrocephalus was statistically significant (p<.0001) higher comparing with healthy infants group (0,93 +/- 0,06 v.s. 0,67+/-0,06 and 0,58+/- 0,07 v.s. 0,24+/- 0,045).

Correlation analysis of the data (Spearman’s test) showed a statisticaly significant positive correlation between RI and VI (P<.0001)

Conclusion: Our study indicates that TCCS is a reliable method for a noninvasive assessment of infantile hydrocephalus, evaluating such indices as RI and VI.

P160

THE Changes in catecholamine metabolism in the brain and heart tissues under the condition of hypokinesia

V. P. Hakopyan, V. H. Karapetyan, O. P. Sotsky

Yerevan State Medical University, Yerevan, Republic of Armenia

Background: Our previous studies have shown expressed the morphological changes in the cerebral microcirculation in animals under the condition of hypokinesia (HK). Taking into account the important role of catecholamine in the cerebral blood flow regulation we have studied the dynamic changes in the content of adrenaline (A) and noradrenaline (NA) in the brain cortex and in myocardium of white rats under HK.

Methods: The experiments were done on white male rats, weighing 150-180 g. HK was achieved by placing the rats in the individual small cages. The animals were decapitated on the 15^th, 30^th and 45^th days of HK. As a control were used the rats kept in similar conditions in vivarium. Catecholamine were determined by fluorometric methods by Euler&Lishajko.

Results: The obtained results have shown that NA quantity in brain cortex is decreased by 41,3% on the 15^th day of HK, and the quantity of A - by 56%. On the 30^th day of HK the content of NA in brain cortex is normalized, whereas the quantity of A is sharply decreased. On the 45^th day of HK the level of NA is sharply decreased (by 66,5% as compared with control) and the quantity of A approaches to normal one. Taking into account the different origin of NA in the brain tissue and viscera we also studied the changes of catecholamine quantity in the heart tissue at the same terms of HK. At the same time the morphological studies of the heart and brain tissues were carried out. The comparison of the tendency of the catecholamine shifts in both tissues has shown that only on the 15^th day the direction of the changes in A and NA content coincides, whereas on the 30^th day the A and NA content in the heart is more than the control one, but less in the brain tissue. On the 45^th day the amount of NA in both tissue and A in brain tissue is less than in the control ones, and the A content in the heart tissue is the same as in animals on the 15^th day of HK.

Conclusion: The analysis of the dynamics of biogenic amine content in the different terms of HK proves that on the 15^th day of HK unidirection of A and NA changes in both tissues is due to the same reason i.e. hypoxic-metabolic stress. And in the late terms, when the process of adaptation occurs, other mechanisms defining the specifity of this stress are involved

P161

Second Harmonic Imaging and Perfusion Magnetic Resonance Imaging to Assess Perfusion of High-grade Gliomas

¹Judith U. Harrer, MD, ²Walter Möller-Hartmann, MD, ¹Christof Klötzsch, MD.

¹Dept. of Neurology, ²Dept. of Neuroradiology, University Hospital Aachen, Germany

Background and Purpose: To evaluate the potential of second harmonic imaging (SHI) for the assessment of perfusion of high grade gliomas and to compare this ultrasound technique with perfusion magnetic resonance imaging (MRI).

Methods: Eight patients with high-grade gliomas underwent a transtemporal second harmonic imaging investigation and a perfusion-sensitive MRI procedure (spin-echo EPI technique). After application of 2.5 g (400 mg/ml) of LevovistÒ , 62 time-triggered images (1 frame/s) were recorded. Time-intensity curves of 2 different regions of interest (tumor tissue (ROItt); brain tissue (ROIbt)) were calculated off-line and the following parameters were compared between the two methodologies; time-to-peak-intensity (TP [ s] ), the ratios of the peak intensities (PI-ratio) and the ratios of the time-to-peak-intensities (TP-ratio) of tumor to healthy tissue. P < .05 was considered statistically significant.

Results: Sonographically focal abnormal echogenicity could be detected in native B-mode in all patients. Administration of the contrast agent lead to remarkable echo contrast enhancement in the tumor tissue, corresponding to the calculated time-intensity curves. The analysis of SHI and MRI data showed no significant differences of all examined parameters; TP 15,5 s vs. 22,2 s (p = 0.1); PI-ratios 2.63 vs.1.67 (p = 0.2); TP ratios 0.40 vs. 0.91(p = 0.1); Wilcoxon-signed-rank-test.

Conclusions: SHI provides a new technique to assess brain tumor perfusion. Overall comparison of this methodology with perfusion MRI was encouraging. Having shown its feasibility to evaluate brain tumor perfusion, further SHI studies are needed to evaluate the clinical potential of SHI in brain tumors especially in view of tumor response to non-invasive treatment and tumor recurrence.

P162

TRANSCRANIAL SONOGRAPHY OF THE SUBSTANTIA NIGRA IN PATIENTS WITH PARKINSON`S DISEASE

L. Niehaus, N. Savyer, R. Hertel, C.H. Nolte

Department of Neurology, Charité, CVK, Humboldt-University Berlin

Background: Recently it has been shown that patients with idiopathic Parkinson´s disease (IPD) exhibit an increased echogenicity of the substantia nigra (SN) on transcranial sonography (TCS). TCS using conventional B-mode imaging (CI) is limited by low contrast resolution. Tissue harmonic imaging (THI), as a new diagnostic tool, promises a more detailed visualization of parenchymal brain structures on TCS. The purpose of the study was to investigate whether THI is also useful to delineate the SN within the mesencephalic brainstem and to demonstrate abnormal echo pattern in IPD.

Methods: Mesencephalic brainstem was investigated by TCS (Sonoline Elegra, Siemens) in 40 healthy volunteers and 45 patients with IPD. TCS examination was performed with a 2.5 MHz phased-array probe using conventional B-mode and tissue harmonic imaging. The SN was visually identified by two investigators separately and the area-size of elevated echogenicity was measured. Results: THI more frequently failed to show SN than CI (22% vs. 12%) due to insufficient bone window.The mean area-size of SN in healthy volunteers did not differ when measured by CI (13.6 ± 3.2 mm²) and by THI (12.2 ± 4.2 mm² ). In IPD patients the SN area was significantly larger when both CI (19.4 ± 5.0 mm², p<0.01) and THI (19.2 ± 7.1 mm², p<0.01) were applied.

Conclusion: Transcranial ultrasonography may be applied to differentiate IPD patients from healthy subjects by assessing the area size of the SN. Using both CI and THI the present study demonstrates that the SN area is greater in IPD patients than in healthy subjects. The main advantage of THI is the improvement of visualization of the mesencephalon and SN. However, its usefulness is slightly more restricted by a higher frequency of insufficient bone windows in comparison to conventional TCS.

P163

CONTRAST BURST DEPLETION IMAGING (CODIM): A NEW METHOD FOR SEMI-QUANTITATIVE ULTRASONIC PERFUSION IMAGING

J. Eyding, W. Wilkening, M. Reckhardt, G. Schmid, S. Meves, H. Ermert, H. Przuntek, T. Postert

Background

Established methods of ultrasonic perfusion imaging using a bolus application of echo contrast agent provide only qualitative data due to various physical phenomena. This study was intended to investigate if a new ultrasound perfusion imaging method called "Contrast Burst Depletion Imaging (CODIM)" may provide semi-quantitative measures of parenchymal perfusion independent of examination depth and acoustic energy distribution.

Methods and Results

In a system of constant concentration of contrast agent, analyzing the decrease in image intensity that occurs with mircobubble-destructive imaging modes yields parameters that are considered to be correlative to tissue perfusion. This method was evaluated in 17 human volunteers using two different contrast agents with the main resulting parameter "perfusion coefficient" (PC). Results were correlated with perfusion weighted MRI examinations. PC did not show significant differences in gray matter areas (ranging from 1.466·10^-2s^-1 to 1.641·10^-2s^-1) of the brain despite of different insonation depths (e.g. ipsilateral and contralateral thalamus). In contrast, white matter exhibited significantly lower perfusion values in both imaging modes (PC: 0.604·10^-2s^-1-0.745·10^-2s^-1, p<0.05).

Conclusions

CODIM is a promising new tool of imaging parenchymal (brain) perfusion in healthy individuals. The method provides semi-quantitative and depth-independent perfusion parameters and in this way overcomes the limitations of the perfusion methods using bolus kinetics. Further investigations have to be done to evaluate the potential of the method in patients with perfusion deficits.

P164

Internal Jugular Valves Incompetence: A Study Using Air-Contrast Ultrasonography on General Population

N. Maalikjy Akkawi, C. Agosti, B. Borroni, L. Rozzini, M. Magoni, M.L. Colleoni, L.A. Vignolo, A. Padovani

Background: Internal jugular (IJ) valves are the only venous valves between the heart and the brain. Conditions, such as cough and other precipitating activities may result in retrograde cerebral venous flow due to absence or presence of incompetence of IJ valves, allowing a brief transmission of high venous pressure and resulting in brain disturbance.

Methods: In this study, we apply air-contrast ultrasound venography (ACUV) to a large sample of normal subjects (n=125) in order to evaluate ultrasonographic aspects of IJ valves and their competence.

Results: The valves were observed in 96.8% subjects, and were present bilaterally in 85.6% and unilaterally in 11.2%. In four subjects we did not detect the valves. Retrograde venous flow (RVF) was present in 38.4% of subjects. The frequency of IJ valve incompetence was significantly higher on the right side (30.2%) than on the left (6.4%) (p<0.0001). RVF due to incompetence of jugular valves was significantly more frequent in the more advanced age (20% age<50 and 38.75% age ≥ 50; p<0.03).

Conclusion: This study showed that ACUV is a non-invasive method to evaluate IJ valves and to identify RVF. These information may be useful in clinical and interventionalist care.

P165

Estimation of non-invasive Cerebral Perfusion Pressure using Transcranial Doppler Ultrasonography during infusion test

Schmidt EA, Czosnyka M, Czosnyka Z, Momjian S, Pickard JD

Academic Neurosurgery, Addenbrooke’s hospital, Cambridge, UK

Background: The estimation of Cerebral Perfusion Pressure (CPP) using Transcranial Doppler (TCD) has been recently evaluated [1,2]. We investigated whether changes in flow velocity (FV) and in estimation of the CPP during infusion study were correlated with changes in cerebrovascular parameters.

Methods: 35 patients presenting symptoms of hydrocephalus with enlarged ventricles underwent a computerised infusion test. The intracranial pressure (ICP) was measured intraventricularly, and steady baseline level was recorded. Then the saline solution was infused with until an ICP plateau has been reached. Simultaneously we recorded flow velocity by using transcranial Doppler, and arterial blood pressure (ABP) with a Finapress finger cuff. Pulsatility index (PI), CPP and a non-invasive CPP (eCPP) was also calculated as:

eCPP = ( ABP_mean * FV_diatolic / FV_mean ) + 14 [2]

Results: Between baseline and plateau, the changes in FV_{systolic, diastolic or mean} were not correlated with the changes in ICP, CPP nor ABP. However, changes in PI and ratio FV_diatolic / FV_mean were correlated with changes in ICP (r² =0.36, p=0.0001 and r² =0.25, p=0.002), but not with changes in ABP nor CPP. The changes in CPP were correlated with changes in both eCPP (r² =0.69, p=0.0001) and ABP (r² =0.64, p=0.0001), but not with ICP.

Conclusion: During infusion study change in CPP is flawed by a rise in ABP, which compensates for increase in ICP. Change in ICP produces modification of cerebrovascular haemodynamics which can be depicted by the change in PI and in ratio FV_diatolic / FV_{mean .}The estimation of CPP, using the ratio FV_diatolic / FV_mean, is able to express non-invasively changes in CPP related to change in ICP.

[1] Schmidt EA J Neurol Neurosurg Psychiatry 2001;70:198-204 [2] Czosnyka M J Neurosurg 1998;71:673-80

P166

WEB-BASED INTERACTIVE DATABASE SYSTEM FOR THE TRANSCRANIAL DOPPLER ULTRASOUND LABORATORY

M. Gorman, B. Jacobs, S. Levine, K. Agee, R Carhuapoma, J. Kraus, R. Madhavan, M. Castellanos, Wayne State University, Detroit and NYC, USA

Background: TCD is limited by a number of variables that are inherent to the test modality such as the problem of angle correction, that it is a blind insonation and the difficulty in penetrating the skull in many patients. TCD is also limited by the lack of standardized protocols for performance of the various types of examinations, criteria for localization and confirmation of vessel identification, and interpretation of the tests varies substantially between laboratories. Handling of the data in laboratories is often inefficient.

Methodology and Conclusions: A web-based interactive database system for the cerebrovascular u/s lab provides convenient solutions to several of these non-inherent problems. Publication of a laboratory’s protocols for test performance, vessel identification and interpretive paradigms via public-accessible web pages allows interested parties to understand the way the data is obtained and processed in that lab, improving communication between physicians and labs. In this particular system, a database of test and test-related information is created and the interpreting physician reviews the data while the study report is being generated (improving validity of the data). The completed patient reports are directly e-mailed to the referring physicians and are available in a secure manner over the web, allowing for rapid and flexible interpretation as well as access to patient care information for the treating physician. Normative data is dynamically compiled by the individual lab and is presented for comparison during report interpretation. Sharing this system provides the potential for linkage of u/s labs worldwide, encouraging acceptance of standardized test protocols and interpretive paradigms. This would encourage validity and applicability of cerebrovascular u/s research by standardizing procedures, by facilitating collection of research data and could serve to establish regional and national normative databases. A demonstration of the system and of other potential benefits will be presented.

P167

FUNCTIONAL TRANSCRANIAL DOPPLER (fTCD): DEMONSTRATION OF ITS CLINICAL USE BY INTRODUCING A CONTROL SYSTEM APPROACH FOR EVALUATION

B.Rosengarten, A.Dost, M.Kaps

Justus-Liebig University of Giessen, Germany

Background: With some exceptions functional Doppler tests did not reveal a wide clinical relevance due to the high inter- and intraindividual variability of the overshoot parameter, flawing statistical comparisons. Assuming features of an underlying regulative principle behind the activity-flow coupling we tested a control system approach for data evaluation with respect to its clinical use.

Method: A 40 s silent reading task which was validated against a checkerboard stimulation paradigm was used to evoke a flow response in the posterial cerebral artery. The averaged relative flow changes from 10 test cycles were used to specify parameters of a second order linear system model which were time delay, gain, attenuation, natural frequency and rate time.

Results: Within- and intersession reproducibility of data was high compared with that of the resting phase. Interindividual variability was higher but less than that of the overshoot. Systolic- and enddiastolic indices differed in their time course with a higher sensitivity of the latter. The response due to stimulation as well as cessation of stimulation can be described with the same model. States of endothelial dysfunction such as migraine and diabetes mellitus can be quantified. Gene polymorphisms such as angiotensin-converting-enzyme, aldosteron-synthase: C344T, G-protein-ß3-subunit: C825T, angiotensin II receptor 1: A1166C, angiotensinogen: M235T, endothelial NO-synthase (eNOS): G894T and intron4-deletion/insertion potentially involved in pressure regulation showed for the eNOSG894T an association with the attenuation parameter.

Conclusions: The clinical use of the fTCD method might be increased if a more detailed analysis of dynamic features of the activity-flow coupling is undertaken.

P168

ADBF technology for non-invasive real-time ICA volume blood flow measurements

D. Manor, O. Hornick, J. F. Soustiel

Cardiosonix Hydrodynamic Laboratory, Hod Hasharon, Israel, and Rambam Medical Center, Haifa, Israel

Background: The ideal system for determining cerebral blood flow was characterized by Doberstein and Martin (1996) as "portable, have high spatial resolution, have the capacity for continuous or frequent measurements, and be noninvasive and easy to perform". The Angle-independent Doppler Blood Flow (ADBF) technology was designed to address the above requirements, with a focus on global, rather then regional blood flow.

Method: The technique is based on the simultaneous application of two PW beams with a known geometrical configuration, digital Doppler, simultaneous spectral analysis of hundreds of sample volumes and a special algorithm for real-time determination of vessel boundaries, angle of insonation, blood flow velocity profile, and ultimately volume blood flow. The technology was tested under various in vitro conditions and with healthy volunteers vs. Duplex measurements and with EtCO2 modulation.

Results: High correlation was found between ADBF and electromagnetic and time-collected flow measurements in the in vitro setup. Mean normative CCA and ICA flow volumes were 456 ± 39 and 277 ± 25 ml/min, respectively. Average ICA flow was significantly lower during hyperventilation relative to hypoventilation.

Conclusions: The method provides an opportunity to allow simple identification of global cerebral hyperemic and ischemic events. Further clinical evaluation of this technique should be carried out.

P169

ON THE VARIABILITY OF MICRO-EMBOLIC SIGNAL FEATURES FOR REPEATED SAME-EMBOLUS MEASUREMENTS, AND ON BACKGROUND SPECKLES VARIANCE.

C.Lucchesi², G.Darbellay³, V.Kemény¹, J.M.Vesin³, G.Devuyst¹ and G.Dietler².

¹ CHUV, Lausanne, Switzerland; ² Lausanne University, Lausanne, Switzerland; ³ EPFL, Lausanne, Switzerland.

Background and aims: As academic research groups and R&D services focus on finding ways of differentiating solid and gaseous emboli, and of determining e.g. emboli sizes, it is of interest to analyze the variability that may plague repeated measurements of one embolic particle, as well as the variance of the background blood flow speckles.

Methods: An invitro setup has been specifically developed for allowing repeated signal acquisition on the same, re-circulating embolus mimic. Such measurements have been performed for various artificial emboli, as well as for biological particles dissected from ulcerated areas of human atheromatous plaques. Background speckles above 4dB have also been measured in vivo, and compared to invitro results.

Results: We show (for the various materials listed above) that for one repeatedly measured embolus mimic most signal features – such as frequencies, envelope slope, etc – show a variability (defined as the standard deviation over the mean) of 20-50%. Furthermore, the signal power does not correlate with emboli sizes, therefore making size predictions based on MES power questionable. The background speckles countings also show a high variability, both invivo and invitro.

Conclusions: The variability of MES features, e.g. of the signal power, can possibly be explained by effects such as the non-homogeneity of the sample volume insonation. In any case, such a variability should be taken into account when exploring ways of predicting emboli characteristics from MES signal processing.

P170

AMBULATORY TRANSCRANIAL DOPPLER MONITORING

A. D. Mackinnon R. Aaslid H. S. Markus

St. George's Hospital Medical School, University of London, England

Background and Purpose: Transcranial Doppler (TCD) detection of circulating asymptomatic emboli is currently limited to short recordings by equipment size. Embolisation shows marked temporal variability and prolonged recordings reduce this and improve sensitivity. We have evaluated a portable TCD machine for continuous ambulatory recording of the middle cerebral artery (MCA) Doppler signal and subsequent embolic signal detection.

Methods: The system consists of a 18x11.5x3.2 cm battery powered Doppler unit, connected to a 13mm diameter servo-controlled 2MHz transducer probe mounted on spectacles (or headband). The MCA spectrum is shown and the transducer position optimised by display on a laptop, which is disconnected when the MCA was located. An autosearch algorithm restores the vessel insonation during recording if signal quality falls. The quadrature raw audio signal is stored on flash disk and simultaneously on digital audiotape (DAT) for later analysis. Recordings (2-4 hours) were made on normal volunteers (N=3) and ambulatory acute stroke patients (N=7) to optimise transducer fixation. Consecutive ambulatory acute stroke patients (N=15) then had recordings for >5 hours per patient.

Results: Of the 15 ambulatory acute stroke patients 11 were male, median age 74 (Range 42-88). Median set-up time was 15-30 minutes. The maximum available capacity of the current size flash disk was 5 hours 25mins. The median ambulatory time was 5.5 hours (R: 303-385min). Of the data recorded onto flash disk the median time a MCA signal was achieved was 5 hours exactly (R: 134-326 min).

Discussion: Ambulatory TCD is possible and patients tolerated recordings of 5 hours well. We are now applying this technique for emboli detection in patients to determine the additional yield from performing prolonged recordings.

P171

particulate Microembolic signal signature evaluated with a customized Radiofrequency based analysis

W.H.Mess(1), J.M.Willigers(2), R.G.A.Ackerstaff(3), A.P.G.Hoeks(2); University Hospital Maastricht (1). University Maastricht(2), St.Antonius Hospital, Nieuwegein(3)

Background: Particulate and gaseous microembolic signals (MES) differ in their appearance when evaluated with conventional Doppler systems. The detected trajectory of MES has even been used as a criterion for differentiating between both groups since gaseous MES, compared to particulate MES, can be observed over a longer depth range because of their high reflectivity. The aim of the present study was to evaluate whether a difference in MES signature could be observed when an RF based analysis system with a high spatial resolution was employed.

Methods: Four patients were monitored after carotid endarterectomy with transcranial Dopplersonography (TCD) with a 2 MHz probe fixed over the right temporal bone window. It was assumed that the MES acquired were particulate. The MES were stored on a customized RF based system, connected to the TCD device. The amplitude of the RF signals containing an MES was median filtered and then color coded and plotted as a function of time and depth. The spatial resolution achieved was on the order of 2 mm, depending mainly on the length of the ultrasound burst emitted.

Results: 52 particulate MES were available for analysis. The particulate MES had a relatively low S/N ratio, which made the determination of flow direction in 15 signals impossible. In the remainder, the particulate MES appeared as straight lines as has been described for gaseous MES. There was a limited depth range of occurrence and a rather consistent length (5.1 mm +/- 2.1 mm [SD]), which was comparable to the data of the gaseous MES (4.5 mm +/- 1.6 mm [SD]; n=122; observed in a separate study with the same system applied; MES acquired during heart valve surgery). The particulate MES did not exhibit a change of flow direction.

Conclusions: In general, particulate and gaseous MES exhibit a comparable signature. There is a consistent depth range of appearance, while no significant velocity changes in the course of particulate MES could be observed. The detected length was comparable to that of gaseous MES, showing that the RF based system used is insensitive for absolute signal intensity in detecting the depth range of an MES. These results can be explained by the fact that the color coded amplitude display scales all amplitude values with respect to the maximal value. Still, the rather low S/N ratio of particulate MES did not allow for velocity analysis of about ¼ of MES.

P172

ASSESSMENT OF TEMPORAL BONE BEAM DISTORTION WHEN USING MULTIFREQUENCY DOPPLER TO DIFFERENTIATE CEREBRAL MICROEMBOLI

R. Brucher, D. Russell, R. Ulm University of Applied Sciences, Germany, and the National Hospital, University of Oslo, Norway

Background: The aim of this study was to assess the influence of temporal bone beam distortion when multifrequency Doppler is used to differentiate between solid and gaseous cerebral microemboli.

Methods: The beam characteristics of dual frequency transcranial Doppler (TCD) probes were scanned in a water bath without and after passing through human temporal bone ( depth = 5 mm). Scanning was carried out using a calibrated hydrophone (0.2mm) at a depth range from 38mm to 65mm, for 2MH_Z and 2.5MH_Z frequencies, with a spatial stepping resolution of 50µm. The trace in time of an Embolus-Blood-Ratio signal was calculated by assessing a sample volume with an axial length of 10mm along the beam axis. The blood background signal was calculated as the mean value of the spatial beam intensity distributed in the assumed sample volume when insonating the red blood cells of a theoretical artery. Several spatial paths for microemboli corresponding to an intensity distribution along a line through the sample volume were calculated as dB-time traces for the two frequencies.

Results: The focal area of the transducer was moved approximately 4mm closer to it when insonating through the temporal bone due to the additional focusing effect of the bone layers on both the 2MH_Z and 2.5MH_Z frequencies. The lateral extension of the focal area for 2.5MH_Z was 0.5mm smaller than that for 2.0MH_Z. This results in higher EBR maximum values when an embolus is travelling through the beam axis for 2.5 compared to 2.0MHz. Within 6dB (25%) beam limits characteristics for both frequencies showed a difference of less than 1.5 dB. This can therefore lead to similar underestimations of EBR differences when differentiating between solid and gaseous microemboli.

Conclusion: In this study of EBR curves using temporal bone we found that for solid microemboli the difference between EBR values for 2.5 and 2.0MH_Z (dEBR) were from -0.8 dB to 2.05 dB which is similar to in vitro findings.

P173

RISK FACTORS OF PLAGUE WIDTH IN CAROTID BIFURCATION.

M.Bar,D.Skoloudik,O Skoda,D.Vaclavik, P.Hradilek,K.Simickova.

Dept.Neurology, Faculty Hospital,Czech Republic

Dept.Neurology,BMA Hospital Ostrava , Czech Republic

Dept.Neurology ,City Hospital Pelhrimov Czech Republic

Backgrounds: The aim of study was to find correlation between risk factors and width of atherosclerotic plague in carotid bifurcation at patients with hypercholesterolaemia.

Materials and method: During 24 months , in three neurosonology laboratories we have screened patients with not know and not treated hypercholesterolaemia who had atherosclerotic plagues in carotid bifurcation over 2 mm of width.

All patients with total cholesterol level > 5mmol/l were included to the study.

We found out : age, gender, BMI, history of hypertension (HT),diabetes mellitus(DM),smoking(Sm),stroke and TIA(S/T)CHD and laboratory data :level of total cholesterol (Ch),LDL-cholesterol (L-Ch),HDL-cholesterol(H-Ch),

and triglycerides(TG). Correlation between plague width and risk factors or laboratory data we tested by Student´s t-test(p),Pearson´s coefficient(P) and linear correlation.

Results: 377 patients we enrolled to study during 24 months, 237 male and 140 female. Mean age was 63,3 years (35-84), mean plague width 3,05mm.

233 patients had HT(62%), 88DM(23%), 87Sm(23%), 184S/T(49%), 99CHD(26%).

Plague width was dependent on male gender(p=0,000009), hypertension (p=0,0007),stroke or TIA(p=0,04 for<50years versus >70 years).

Mean cholesterol level was 6,5mmol/l. No correlation was found between plague width and Ch(P=0.07), L-Ch(P=-0.1), H-Ch(P-0.14), TG(P=0,1)

Conclusion: At patients with hypercholesterolaemia , a width of atherosclerotic plague in carotid bifurcation is dependent on age , male gender ,hypertension ,

a history of stroke or TIA and CHD. We are not found any correlation between plague width and level of cholesterol , LDL-cholesterol, HDL-cholesterol or triglycerides. Also plague width was not dependent on diabetes mellitus , BMI and smoking.

P174

New Way of Visualizing of the Blood Flow: B-flow Sonography of the Cervical Main Arteries (comparative study)

L.Németh MD.’ K..Hiramatsu MD."C. Mihara PhD." J.Nikl MD’,T.Shima PhD."

County Hospital, Zalaegerszeg, Hungary Dept.of Neurology’; Chugoku Rosai Hospital, Kure-City, Japan, Dept.of Neurosurgery

Background and Purpose: The Color (CDI)-and Power (PDI)-mode Ultrasonography (US) have a number of limitations that degrade their utility for assessing hemodynamics in the supraaortic main vessels. B-Flow is a new digital imaging technique that provides real-time visualization of vascular hemodynamics by directly visualizing blood reflectors and presenting this information in a grey scale display. We compared the efficacy of the conventional US methods in examining the cervical arteries.

Patients and Methods: We observed the carotid and vertebral arteries of 76 consecutive patients (54 male) by GE Logiq 700 system and measured the hemodinamic parameters, analysed the plaques (stenosis degree, surface, echodensity, length, blood and ulceration), and examined the detectability of vertebral artery connected with the depth from the surface by B-flow, CDI and PDI. Ten criteria were used to evaluate the diagnostic advantages. To semiquantify the subjective impression 0-3 points were given. The statistical analysis was made by T-test and by linear regression analysis (LRA).

Results: The results with the B-flow were significantly better evaluating the flow detectability (mean difference, MD=0,11 p=0,01), in the symultanean depicture of the flow with high and low velocity (MD=1,03; p=0,009), in the depicting of the small vessels (MD=0,51 p< 0,001), in differentiation of the total and subtotal stenosis (MD=0,44 p=0,002), and in the quantity of color artefacts (MD=0,89 p< 0,001), and of course extraluminal flow signal was not detected. There was no difference in the capacity of differentiation between arteries and veins, in the observation of the surface of the plaque and in the induce of wall artefacts. The CDI was found to be better in the wall observation (MD=0,14 p=0,07 ns). The PDI fall behind CDI in most point of the assessment. The depth of the vertebral artery is in inverse ratio to the detectability by B-flow. LRA saw closely significant colleration in estimating the stenosis degree with all methods.

Conclusions: B-Flow has been found to be one of the most clinically significant vascular imaging tools to visualise the flow, the haemodinamical changes and stenotic lesions of cervical arteries. Its usage combined with conventional US techniques can be suggested.

P175

Is Transcranial doppler a suitable technique for Leukoaraiosis evaluation?

RM Sánchez-Perez, JM Moltó-Jordà, J Carneado, L Castaño, C Díaz-Marín, R Hernández-Lorido. Neurosonology Laboratory. Neurology Department. Hospital General Universitari d’Alacant

Background: Leukoaraiosis is a frequent finding in aging people. Cerebral hemodynamic changes have been implicated in its pathogenesis. However there are not many data about hemodynamic parameters in vivo in humans. TCD can be a useful technique for this purpose. Method: 116 patients between 60 and 90 years old were evaluated prospectively in our laboratory. Patients were recruited form the neurology outpatient clinic including those with unspecific symptomatology. Exclusion criteria were very low educational level, recent stroke (< 6 months), previous diagnosis of dementia and unwillingness to collaborate. They all went through a clinical interview and they were administered the MMSE test and the clock test. Afterwards a complete neurosonological evaluation was done with both carotid artery duplex evaluation and transcranial doppler. Leukoaraiosis was evaluated by means of Fazekas scale. Results: Mean age was 74,4 ± 6,3 years. There was a slight preponderance of women 62,1%. Leukoaraiosis was present in 68,7% of the patients, with no differences regarding sex, but with a higher percentage in the eldest group of patients. Leucoaraiosis correlated in a positive way with higher age, presence of lacunar strokes, past history of stroke, cognitive impairment and lower systolic and diastolic velocities in middle cerebral artery and higher pulsatility indexes. M In multivariant analysis only lower diastolic velocity maintained its statisitical significance. Conclusions: TCD can be an effective tool for evaluating cerebral hemodynamics in patients with leukoaraiosis as we have found specific abnormalities in them. Future works should address the question wether these findings are either the cause or the consequence of pathological findings in this entity.

P176

Risk factors associated to either intracraneal or extracranial stenosis: are they so different?

S. Bustos, JM Moltó-Jordà, J. Carneado, T Frutos, V Medrano, L Castaño, R Sánchez, R Hernández-Lorido, R Mañes. Neurosonology Lab. Neurology Department, Hospital General Universitari d’Alacant. Alacant. Spain

Background: There are controversial data about the different incidence of some risk factors in cases of intracraneal stenosis or carotid stenosis and they are mainly derived from eastern countries population. Our aim was to evaluate this in a Caucasian population of latin origin.

Method: After a thorough review of the Neurosonology register we identified 53 patients with intracraneal stenosis (IS) and 85 patients with extracranial stenosis (ES) evaluated between January 1999 and June 2001. Patients with stenosis in both territories were excluded. We paid attention to the main risk factors. No analysis was performed of emerging risk factors as the sample would have been to small.

Results: Sex and age distributions were similar in both groups. Stroke mechanism was also not different in both groups, mainly atherothrombotic (47,1 (ES) vs 54% (IS)) and lacunar in (24.7 (ES) vs 20% (IS)). Undetermined stroke cases were more prevalent in extracranial disease cases (22.4% (ES) vs. 12 % (IS)) but without reaching statistical significance. Hypertension was slightly more prevalent in extracranial disease but it did not reach statistical significance. Hyperlipemia and Diabetes were evenly distributed in both groups.

Conclusions: In our series we have not found any relevant differences in the main risk factors for stroke associated to cases of either extracranial or intracraneal artery disease. There must be some other determinants for the selective damage to either intracraneal or extracranial arteries besides the classical risk factors for stroke, specially in Caucasian populations.

P177

ULTRASONOGRAPHIC ASSESSMENT OF GLOBAL CEREBRAL CIRCULATION TIME (CCT), TOTAL CEREBRAL BLOOD FLOW (CBF) AND CEREBRAL BLOOD VOLUME (CBV) IN A PATIENT WITH DIFFUSE CEREBRAL ANGIOMATOSIS

S.J. Schreiber, F. Doepp, A. Bender, J.M. Valdueza

Dept. of Neurology, University hospital Charité, Berlin, Germany

Background: Multifocal diffuse cerebral arteriovenous shunts are very rare forms of vascular malformations. We present the case of a 30 year old patient with a bihemispherial diffuse cerebral angiomatosis with retinal involvement. Ultrasound assessments of CCT, CBF and CBV are presented and compared with a healthy control group.

Methods: Dopplersonographic global CCT was determined as the time delay of an echo-contrast bolus arrival, detected in the extracranial internal carotid artery (ICA) and internal jugular vein (IJV). Global CBF was assessed as the sum of duplexsonographic flow volume in both ICA and vertebral arteries (VA). CBV was calculated as the product of CCT and CBF. Data of our patient were compared with values of 10 healthy controls (age: 30± 4 years).

Results: CCT in our patient was 2.9 sec (CCT_controls: 6.3± 1.5 sec), the arterial CBF was 2620 ml/min (CBF_controls: 754± 93 ml/min) and the CBV was 126ml (CBV_controls: 79± 19 ml). The patients venous CBF (flow volume in both IJV and vertebral veins) was 2577 ml/min.

Conclusions: In contrast to conventional sonography, the ultrasound based assessment of CCT, CBF and CBV reveals valuable additional information about the cerebral hemodynamic status. Applied to a patient with diffuse cerebral angiomatosis we found a markedly increased global CBF, a reduced CCT and an increased CBV, correlating well with the status, seen on digital subtraction angiography.

P178

Pseudotumor cerebri (PTc) after unilateral radical neck dissection (rND) - A case report

F. Doepp, S. Schreiber, G. Benndorf, A. Radtke, J. Gallinat, J.M. Valdueza

Dept. of Neurology, University Hospital Charité, Berlin, Germany

Background: rND involves the resection of the internal (IJV) and external jugular vein and their tributaries on one or both sides of the neck. Intracranial hypertension is one of the rare neurological complications, due to an impaired venous drainage.

Case: A 61 year old patient with tonsil carcinoma underwent right sided rND. The initial postoperative recovery was unremarkable. 10 days after surgery he developed impaired vision and diplopia. Clinical examination revealed binocular papilloedema, reduced visual acuity, a right sided ptosis and abducens nerve palsy. Cranial CT and MRI scan were normal. PTC was suspected and the subsequent lumbar puncture revealed a markedly elevated intracranial pressure (ICP = 44 cm H₂O). Therapy was started with high dose acetazolamide (up to 3000 mg/d p.o.) and repeated lumbar spinal fluid drainage. In the course of the following two months ICP remained within the range of 18–28 cm H₂O while clinical symptoms disappeared. Duplex ultrasound showed a high flow volume in the left IJV (600 ml/min). Total flow in both vertebral veins (VV) was 20 ml/min. Under manual IJV compression for evaluation of further alternative drainage pathways VV flow did not increase. Cerebral angiography after right rND demonstrated a dominant right lateral sinus and no ipsilateral IJV drainage. Main venous drainage went via the hypoplastic left lateral sinus into the left IJV and via the deep neck veins but not via the VV. Left IJV compression led to a remarkable flow increase in deep neck veins but not in the VV.

Conclusion: An insufficient venous collateral network might lead to a critical increase of ICP with clinical symptoms of PTC, even after unilateral rND. Duplex ultrasound assessment of venous blood flow might add valuable information on the presence of venous collaterals in these cases.

P179

TRANSCRANIALCOLORDOPPLER (TCCD) for detection of MIDDLE CEREBRAL ARTERY (MCA) and vertebrobasilar (V-B) stenosis

G. Malferrari§, F. Accorsi*

§ Arcispedale S.M. Nuova, Reggio Emilia, *Ospedale Maggiore. Bologna. Italia

Backgrounds: The aim of this study is to compare TCCD with neuroradiological (NR) tests (angiography, angioCT and angioMRI) in detecting MCA and V-B stenosis.

Methods: From 1/9/1998 to 31/12/2001 we studied 1000 patients, symptomatic and asymptomatic, with TCCD. In these patients the TCCD was preceded by an extracranial ultrasound (US) approach. We did not use contrast agents.

The TCCD criteria for diagnosis of MCA and V-B stenosis were published by Baumgartner and coll.(1).

When TCCD demonstrated MCA or V-B stenosis, these arteries were studied by NR tests. Two NR tests were performed on 4 out of these 55 arteries (59 tests in all).

Results: We diagnosed 55 intracranial stenosis (35 MCA, 14 vertebral and 6 basilar) in 49 patients (17 woman,32 men, mean age = 65, min.= 40, max.=84).The test performed were: angiography (7), angioCT (14) or angioMRI (38)

The NR tests were concordant with TCCD diagnosis in 50 out of 59 arteries. The 9 discordant diagnoses concerned: a) 3 intracranial vertebral artery occlusion not confirmed by angioMRI ( whose diagnosis was haemodynamic stenosis); b) 2 MCA stenosis not confirmed by angioMRI; c) 4 MCA stenosis not confirmed by angioCT (but angioMRI and angiography, performed afterwards, confirmed the TCCD diagnosis).

Conclusion : In our experience TCCD: a) has strong correlation with angioMRI and angiography and lower correlation with angioCT; b) is the first approach to select patients to be evaluated with NR tests for possible thrombolytic and/or interventional therapy.

1)Baumgartner R.W: Assesment of>50% and <50% Intracranial Stenosis by transcranial color-coded duplex sonography. Stroke 99;30:87-92.

P180

PULSATILE TINNITUS: DETECTION OF DURAL ARTERIOVENOUS FISTULA OF THE TRANSVERSE-SIGMOID SINUS WITH DUPLEX ULTRASOUND

R Lagos M.D., L Fernández M.D., S Blanco PhD, U Nobo M.D., S Ameriso M.D

Instituto de Investigaciones Neurológicas Raul Carrea (FLENI), Buenos Aires, Argentina

BACKGROUND:

Pulsatile tinnitus (PT) is a common complaint among patients seen in Neurology/ENT clinics. The etiology of this condition is diverse and may include dural arteriovenous fistula (DAVF) of the transverse-sigmoid sinus, carotid atherosclerotic disease, carotid dissection, and glomus tumors. Diagnosis usually requires digital substraction angiography (DSA). Thus, it is important to find non-invasive screening procedures that can select a subset of patients likely to benefit with the use of invasive ones. Duplex ultrasound (DU) can detect changes in the flow characteristic of patients with cranial vascular abnormalities.

METHODS:

We described four patients in whom the findings on carotid DU suggested the presence of DAVF of the transverse-sigmoid sinus, that was later confirmed by cerebral DSA

RESULTS:

There were two females and two males, aged 52, 60, 61 and 70 years old. All presented with PT and normal otological and neurological examination.

DU of the neck depicted similar findings in every subject: 1) Increased diastolic velocity of the external carotid artery (ECA) territory specially in the occipital artery (OA) (pattern of low distal resistance flow), 2) Arterialization of the internal jugular vein flow, 3)The rest of the supra-aortic vessels were normal as well as transcranial Doppler examination. DSA confirmed the presence of DAVF of the transverse-sigmoid sinus in every subject.

CONCLUSION:

The existence of increased diastolic velocities along the ECA and the OA with pattern of low distal resistance flow together with the arterialization of the internal jugular vein flow is highly suggestive of DAVF of the transverse-sigmoid sinus.

Carotid DU is a safe, non-invasive tool that when used appropriately can guide the diagnostic strategy of patients with PT.

P181

RAPID PROGRESSION OF RADIATION-INDUCED CAROTID ARTERY DISEASE ASSESSED BY CAROTID DUPLEX ULTRASOUND

R Lagos M.D., L Fernández M.D., S Blanco PhD, U Nobo M.D., S Ameriso M.D.

Instituto de Investigaciones Neurológicas Raul Carrea (FLENI), Buenos Aires, Argentina

BACKGROUND:

Radiation-induced carotid stenosis is a known complication of radiation treatment of head and neck malignancies. Early arterial occlusion can develop within the early months following radiotherapy. Later development of accelerated atherosclerosis seems to be the most frequent complication. The natural history of this condition remains unclear.

METHODS:

We report a patient with rapid progression of carotid disease from stenosis to occlusion diagnosed by Duplex Ultrasound (DU).

RESULTS:

This was a 61 years old man, with history of mild hypercholesterolemia, tabaquism, and laryngeal squamous cell carcinoma diagnosed in June 1998. He had partial laringectomy followed by adjunctive external radiotherapy (70 Gy total dose). On routine follow up examination, an asymptomatic left carotid bruit was heard. A neck DU showed segmentary narrowing of both carotid bulbs with marked thickening of the carotid walls. A superimposed atherosclerotic plaque was observed in the right internal carotid artery (R ICA). Axial cuts demonstrated decreased section area compatible with 80% stenosis on the R ICA and 60-70% in the left internal carotid artery (L ICA). Common carotid arteries were normal. He was treated with angioplasty/stenting of the R ICA.

A follow up DU of the neck 107 days later showed patent R ICA and stable 60-70% L ICA stenosis.

Four-and-a-half months after the last DU (8 months from the time of angioplasty), on a routine follow up visit, the left carotid bruit was absent. A repeat DU of the neck showed complete occlusion of the LICA, which was also confirmed by neck Magnetic Resonance Angiography. The patient remained asymptomatic.

CONCLUSION:

We report rapid progression of radiation induced carotid disease from moderate stenosis to occlusion. Carotid DU is a sensitive and specific tool for the assessment of these high-risk individuals. Several questions remains unanswered, particularly whether DU should be done routinely in the follow up of these patients, at what frequency, and when to intervene as the natural history of this condition is still unknown.

P182

STROKE: NEUROSONOLOGIC FINDINGS IN AN UNDER 45 YEARS POPULATION

I. Mendes, I. Henriques, C. Barata, L. Rebocho, A. Talhinhas, T. Tribolet-Abreu

Hospital do Espirito Santo, Évora, Portugal

Background: Stroke in the young may be devastating

And frequently no cause can be found. Recurrence of stroke

is frequent and a major cause of disability. The authors started

this study to determine the major neurosonologic findings in

our stroke patients less than 45 years, and to correlate them

with the clinical aspects, to characterize our young

stroke population.

Method: The findings of routine cervical

and transcranial triplex scan in ischemic stroke patients will

be reviewed. As our Laboratory started in January 2002 we

will include patients from January to April 2002. At this time we

have 8 patients. Besides the routine cervical and transcranial

triplex scan, all patients have an exhaustive investigation

of the stroke etiological factors, namely CT or MRI, ECG,

chest x-ray, transthoracic and transesophageal

echocardiography, VDRL, cholesterol, antithrombin III,

proteins C and S, Factor V-Leiden mutation,

homocysteinemia, antiphospholipid and anticardiolipin

antibodies, screens for a multisystem vasculitis, APTT, PT,

platelet count, fibrinogen and in particular cases the

CSF examination. These results will be reviewed and

correlated with the cervical and transcranial triplex scan

findings.

Results and Conclusion: The results will be presented

at the meeting. We will characterize our young stroke population

to find some specific characteristics of our population to use

in clinical practice.

P183

STROKE AND NEUROSONOLOGIC FINDINGS: COMPARISON OF A YOUNGER WITH AN OLDER POPULATION

I. Mendes, I. Henriques, C. Barata, L. Rebocho, A. Talhinhas, T. Tribolet-Abreu

Hospital do Espirito Santo, Évora, Portugal

Background: Studies on the etiology of stroke in patients under 45 years have found differences when compared with older patients. To strengthen the difference, we decided to study our stroke patients under 45 and over 45 years, to determine the major neurosonologic differences between them and to correlate them with the clinical aspects. Method: The findings of routine cervical and transcranial triplex scan in ischemic stroke patients will be reviewed. Only those with both cervical and transcranial triplex scan will be included. As our Laboratory started in January 2002 we will include patients from January to April 2002. At this time we have 40 patients. The neurosonologic differences will be correlated with age and other risk factors (smoking, hypertension, dislipidemia and diabetes). Results and Conclusion: Will be presented at the meeting.

P184

The Influence of severe extra- and intracranial artery disease on BOLD signal in Functional MRI

Farsin Hamzei, René Knab, Cornelius Weiller and Joachim Röther

Department of Neurology, University of Hamburg, Germany

Background - Functional magnetic resonance imaging (fMRI) is based on the vascular response due to neuronal activation. The underlying mechanism of fMRI is the blood oxygenation level dependent (BOLD) effect – a complex interplay between changes in the cerebral metabolisation rate of oxygen (CMRO2), neurovascular coupling and the resulting hemodynamic response. An intact neurovascular coupling is essential for the detection of the BOLD signal and a severely disturbed cerebrovascular reserve capacity (CVRC) alters the BOLD response.

Methods - We tested the hypothesis that extra- or intracranial artery disease influences the BOLD signal during a motor paradigm in asymptomatic patients with symptomatic artery stenosis or occlusion.

Results - Six out of 15 patients showed a significantly reduced (n = 4), a negative (n=1) or no BOLD signal (n = 1) in the affected as compared to the unaffected primary sensorimotor cortex. In a subgroup of patients (n=6) we tested the CVRC by means of TCD or SPET.

Discussion - Extra- or intracranial artery disease may influence the BOLD signal in the sensorimotor cortex after a motor paradigm. This observation is important for the clinical application of fMRI paradigms especially in presurgical mapping.

P185

CAROTID ENDARTERECTOMY AND COGNITION: DOES CEREBRAL PERFUSION PRESSURE HAVE A ROLE?

L Soinne ¹, I Tikkala, J Helenius, E Saimanen, O Salonen, M Hietanen, PJ Lindsberg,, E Lehtonen-Smeds, K Nuotio, M Kaste

¹Department of Neurology, Helsinki University Central Hospital, Helsinki, Finland

Background: Subtle changes have been reported in cognitive testing after carotid endarterectomy. We studied the neuropsychological performance and cerebral perfusion in patients undergoing endarterectomy for a high-grade carotid stenosis.

Methods: Of the 44 patients (aged 64.3 ± 8.8 years) with carotid stenosis (mean ± SD 78.1 ± 8.6 %), 23 were asymptomatic and 21 symptomatic. A comprehensive neuropsychological battery and perfusion-weighted bolus tracking MR imaging were performed thrice: preoperatively, and 4 and 100 days after endarterectomy. Singular value decomposition algorithm was used for deconvolution, and cerebral perfusion pressure (CPP) was determined as the inverse of mean transit time. Healthy volunteers (n=20) matched for sex, age, and education underwent the same neuropsychological evaluation.

Results: The cerebral perfusion pressure tended to increase after endarterectomy (p=.06), and the change was significant in the white matter and watershed areas ipsilateral to stenosis (from baseline to late control, 0.l8 – 0.22 – 0.21 1/sec, p< .001). The compound cognitive score (CCS) declined marginally at the early postoperative follow-up (-0.05 SD vs. +0.27 SD in controls, p<.01), and was significantly increased by the late control time point (+0.27 SD, overall p < .0001). There were no significant differences between asymptomatic and symptomatic subgroups or sides of stenosis. The positive correlation between the change in CCS and ipsilateral CPP at the late follow-up was abolished by correction for learning effect.

Conclusions: Carotid endarterectomy seems to have a minor adverse effect on cognitive functioning, followed by subsequent improvement, which is essentially accountable with re-test setting. The subtle cognitive changes that occur are primarily unrelated to the significant improvement in cerebral perfusion.

P186

intima-media complex of carotid arteries as a risk factor of Alzheimer’s disease.

S. Ochudło, G. Opala, Z. Kalina, B. Jasińska-Myga, A. Gorzkowska

Silesian Medical Academy, Dept. Late Age Neurology, (Katowice, PL)

Background: the thickness of intima-media complex (I-MC) of cammon carotid artery

(CCA) is associated with the prevalence of cardiovascular disease. We examined the association beetwen the thickness of ICA and CCA and the incidence of Alzheimer’s disease (AD).

Methods: noninvasive measurements of the I-MC of the CCA and internal carotid artery (ICA) were made with high resolution ultrasonography in 36 (75-80 years old subjects) of AD and in 25 sex- and age-matched subjects of control group without any symptoms of cognition impairment. The value of Hachinski scale in AD group was 4.6± 1.3 and 3± 1.2 in controls. MMSE=19.7 in AD group .

Results: We found a possitive association betweene AD and I-MC thickness of CCA and not ICA. I-MC of CCA in AD: o.862 ± o.17, in controls: o.766± o.2 (p<o.o1). I-MC thickness of ICA in AD: o.65± o.12, controls: o.54± 0.2.

Conclusions: increases in thickness of the I-MC of CCA, as measured noninvasively by ultrasonography, are associated with high risk of AD.

P187

Assessment of intracerebral hemodynamic and brain electrical activity in patients with transitory ischemic attack.

V. Yavorskaya, O. Mashkin

Kharkiv Medical Academy of Postgraduate Education, Kharkiv, Ukraine

Background: Study of both cerebral blood flow with transcranial dopplerosonography (TCD), and functional state of the brain with electroencephalography (EEG) are considered important investigations in patients with transitory ischemic attack (TIA). These two methods may provide valuable data, which influence the appropriate strategy of treatment aimed at prevention of cerebrovascular accident (CVA). We decided to study the significance of intracerebral hemodynamic and brain electrical activity relations in prediction of CVA occurrence and course.

Method: In 25 patients with anterior circulation TIA and in 26 patients with posterior circulation TIA TCD and EEG investigations were performed.

Results: In both groups of patients decreased mean linear blood flow velocity in intracranial arteries was found. The values were in internal carotid arteries 51.5 +/- 4.5 cm per second (cm/s), in medium cerebral arteries 45.5+/-5.5 cm/s, in anterior cerebral arteries 44.5+/-3.5 cm/s, in posterior cerebral arteries 32.5+/-4.2 cm/s. TCD revealed significant stenoses and occlusions of carotid arteries in combination with vertebral arteries stenoses in 30 patients (58.8%).

EEG mapping in 14 patients (56%) with carotid artery TIA revealed foci of pathological slow activity (delta- and theta-rhythm) in homolateral hemisphere. Interhemishere asymmetry in alpha band with predominance of unaffected hemisphere activity was found. In 20 (77%) patients with posterior circulation TIA mixed low-voltage EEG was registered.

The correlations between TCD and EEG findings were statistically significant.

Conclusions: Absence of significant EEG abnormalities in patients with TIA was a characteristic feature of "benign" course of the disease and probably was related to good cerebral blood flow compensation abilities.

P188

Common Carotid Artery Volume Flow Rates in Carotid Endarterectomy Patients: Color Velocity Imaging-Quantification Technique

Lee, Jun Hong

Dept. of Neurology, National Health Insurance Corporation Ilsan Hospital, Rep. Of Korea

Background and Purpose: Compared with other methods, ultrasound based measurements of cerebral blood volume flow rates have a unique advantage, especially the color flow M-mode ultrasound technique (color velocity imaging-quantification) which has demonstrated its ability for blood flow evaluation in vitro and in vivo. However, comparison with the "gold standard" is lacking. The purpose of this study is to compare the common carotid artery volume flow rates using the color velocity imaging-quantification technique, with cerebral angiographical and pathological measurement, in various degrees of ICA stenosis.

Methods: We retrospectively reviewed 1017 endarterectomy cases. Bilateral CCA volume flow rates, cerebral angiography, and intact endarterectomies of 124 of those cases were available. Angiographies were measured by the NASCET method, and linear measurements at the tightest area of the lumen of the endarterectomy specimens were completed. Using regression testing, these results were compared with ipsilateral CCA volume flow rates. To observe the influence of the contralateral ICA stenosis on the common carotid artery volume flow rates, the 124 cases were divided into four groups by angiographic measurements. The following comparison was made: Group A (ipsilateral ICA <70% and contralateral ICA <70%), group B (ipsilateral<70%, contralateral>70%), group C (ipsilateral>70%, contralateral<70%), and group D (ipsilateral>70%, contralateral>70%).

Results: Ipsilateral CCA volume flow rates were well correlated with each stenotic degree of the ipsilateral ICA measured by angiography and pathology. When considering the contralateral side, each group showed reasonable results. In group A, ipsilateral CCA volume flow rates were 300+91ml/min, in group B ipsilateral CCA volume flow rates were increased and contralateral decreased. Conversely, the ipsilateral CCA volume flow rates were decreased and contralaterals were increased in group C, suggesting compensatory overflow in both groups B and C. In group D, CCA volume flow rates did not show significant differences with the hemodynamically significant stenosis of the unilateral ICA, suggesting the importance of the carotid system as a collateral channel.

Conclusion: The well correlated relationship between ipsilateral CCA volume flow rates and each stenotic degree of the ipsilateral ICA measured by angiography or pathology, were consistent with known physiologic phenomena. Color velocity imaging-quantification measurement of CCA volume flow rates can be a useful tool for clinical and physiologic understanding of carotid stenotic disease.

P189

THE RESISTANCE INDEX IN SMALL AND LARGE VESSEL DISEASE

D.Vaclavik,D.Skoloudik

Blessed Mary Anthony hospital,Ostrava Vitkovice,Czech republic

Backround: This study was designed to assess a difference in the Pourcelot rezistance index between large and small vessel disease using transcranial color coded sonography ( TCCS ).

Method: We measured the peak systolic velocity ( PSV),the end diastolic velocity ( EDV) and the Pourcelot resistance index ( RI ) of the middle cerebral artery ( MCA ) in 40 patients with acute ischemic stroke and clinical or radiological ( CT,MRI ) signs of small vessel disease (SVD).The clinical findings of SVD included lacunar strokes,vascular subcortical dementia,,extrapyramidal signs and pseudobulbar signs when other etiology was not found.All disease with posibillity of raised intracranial pressure were excluded ( intracerebral hemorhages,brain tumors,hydrocephalus).The CT and MRI signs of SVD included bilateral lacuar and subcortical infarcts ,bilateral white matter lesion (periventricular leukoariosis) and lacunar brain stem infarcts.This cohort was age - and hypertension – matched with 40 patients with acute large vessel stroke according to clinical and CT findings of cortical teritorial stroke.69 MCA were examined in the group of small vessel disease stroke patients and compared to 64 MCA in the large vessel disease group.The MCA with hemodynamically significant stenoses or obstruction in ipsilateral ICA were excluded.

Results: The mean PSV/EDV were 80/28 ( cm/s ) in the small vessel disease group and 84/34 ( cm/s ) in the large vessel disease group.The mean RI in the first group was 0,64 compared to 0,6 in the second group.Statistical analysis using the nonpaired Student´s t- test compared PSV,EDV and RI between both groups.There were a significant decrease in EDV ( p = 0,003),significantly higher RI ( p < 0,0001) in patients with small vessel disease than in large vessel disease.No signficant changes was found in PSV(p= 0,15).

Conclusion: The study shows significant difference in the Resistance index between small and large vessel disease.We consider RI a useful criteria for distinguishing between small and large vessel disease by TCCS.

P190

TranscranialColorDoppler (TCCD) for detection of basilar steal (BS).

F. Accorsi*, G. Malferrari§, V.Arienti*

*Ospedale Maggiore,Bologna. § Arcispedale S.M. Nuova, Reggio Emilia,Italia

Backgrounds: TCCD is considered an accurate method for detection of BS. The aim of this study is to report: a) our experience in detecting BS with TCCD; b) the follow up of our patients with BS.

Methods: From 1/9/1998 to 31/12/2001 we studied 1000 patients, symptomatic and asymptomatic, with TCCD. In these patients the TCCD was preceded by an extracranial ultrasound (US) approach. The TCCD marker for diagnosis of BS is: spontaneous alternating flow in the basilar artery (BA), downward in the systolic phase and upward in the diastolic one. When TCCD demonstrated BS, neuroradiological tests( angiography and CT or RMN) were performed.

Results: We diagnosed 7 BA steal ( 2 f. and 5 m., mean age=69). In 6 patients there was an association between the haemodynamic stenosis (HS), or occlusion, of the right vertebral artery (segment V0 or V1) and the HS, or occlusion, of the left subclavian artery (SA). In 1 of these 5 patients was associated the HS of the internal carotid artery (ICA) right. In one patient the bilateral occlusion of SA and the occlusion of the right ICA were associated. The angiographic study, unable to show the spontaneous alternating flow in the BA, always showed the coexisting extracranial pathology previously diagnosed by US. The neuroradiological studies ( CT or MRI) performed in our 7 patients showed ischemic areas in 4 of them: in 1 an occipital ischemic area, in 1 a bulb ischemic area and in 2 lacunar infarcts. Of our patients 3 were asymptomatic (but 1 of them had transitory hemiamopsia and hemiparesthesia, 4 years before) and 4 were symptomatic: 1 was ataxic and 3 had drop attacks. Follow up. Drop attacks disappeared in three patients: in 1 patient after the stenting of the stenotic SA, in 2 after improving antipertensive treatment. One patient had sudden death, 1 disattended the follow up and two patients are asymptomatic.

Conclusions: In our experience TCCD is: a) effective screening test for BS; b) very useful to improve medical treatment; c) first approach to select patients to evaluate by angiography for a possible interventional treatment.

P191

CORRELATION OF TRANSCRANIAL TEMPORAL WINDOWS WITH TEMPORAL BONE THICKNESS AND DENSITY MEASURE ON CT SCAN

CF Chan, WEH Lim*, HY Gan, MP Lee, C Chen, MC Wong, HM Chang

Dept of Neurology and Dept of Diagnostic Radiology*, Singapore General Hospital, Singapore

Background: Transcranial color-coded Duplex Sonography (TCCD) is limited by the absence of the temporal bone windows (TBW). Studies have shown that 8-25% of patients have inadequate TBW, especially in the Asian population. Aim: To determine if computed tomography (CT) radiographic parameters for bone thickness (temporal bone thickness –TBT) and bone density (Hounsfield Units -HU) predicts for the absence of TBW. Methods: All patients admitted with TIA or stroke who had TCCD and CT performed over a 4 month period were eligible. TCCD was performed with GE Vingmed System 5 and CT scan with Toshiba Xvision, using 5 mm cuts. TBT and HU were measured on the CT scan 5mm below the clinoids, blind to TCD findings. The average of 3 readings was taken. TBW were defined as inadequate (short segments of vessel or no vessel insonated) or adequate (all vessels studied adequately). Results: 356 out of 423 admitted patients were eligible. 712 temporal windows were studied. 56.5 % were male and the mean age was 65.9 years (range 32-94). Adequate TBW was present in 58% patients on the right and 56% on the left. TBW was adequate in 80% males and 20% females. Mean TBT and HU for patients with adequate TBW were 0.31cm (0.12 - 0.65 cm) and 1113.9 (511.5 – 1727.0) as compared to 0.43 cm (0.2-0.86) and 912.8 (456.6 – 1628.2) respectively in patients with inadequate TBW. Univariate analysis showed the following were significantly different (p<0.05) between patients with adequate and inadequate TBW : age, ethnicity, gender, history of ischaemic heart disease, hypertension, smoking, atrial fibrillation, stroke sub-type, TBT and HU. Multiple logistic regression showed that the following factors independently predicted for TBW: TBT (p<0.0005), HU (p<0.0005), gender (p<0.0005), age (p<0.0005) and stroke sub-type (p<0.027). Conclusions: In an Asian population, temporal bone thickness, temporal bone density, gender, age and stroke sub-type predicted the presence of temporal bone window.

P192

TEMPORAL BONE WINDOWS IN A MIXED ASIAN STROKE POPULATION – A TRANSCRANIAL DOPPLER STUDY

Venketasubramanian N, Au WL, Chuah L

National Neuroscience Institute, Singapore

Background: Transcranial Doppler Doppler (TCD) allows non-invasive evaluation of intracranial blood flow, using naturally occuring bony windows. This study determines the availability of an acoustic temporal bone window in a mixed Asian population.

Methods: Consecutive stroke patients referred to our Cerebrovascular Ultrasound Laboratory between January and December 2001 were studied. Intracranial circulation was assessed via the trans-temporal approach using a DWL TCD Multi Dop X4 (Elektronische Systeme GmbH, Germany) with a 2MHz hand-held probe. Absent temporal bone window was defined as a failure to detect any flow signal on either side after a careful search of at least 10 minutes. Data was analyzed using SPSS.

Results: A total of 269 patients (153 men,116 women), comprising 65.4% Chinese, 17.1% Malays, 13.8% Indians, and 3.7% other races were studied. The mean age was 61.8 years(SD13.8). Temporal bone window was absent in 30.5%: 38.1% of Chinese, 19.6% of Malays, 16.2% of Indians, 0% of Other races. Using logistic regression, we found a significant association between the availability of a bone window and age, gender and race(p<0.0001). Women were 11 times likely to have no bone window compared to men, especially among older patients. Chinese were 3 times more likely to have absent bone window compared to Malays(p=0.019), and 3.7 times compared to Indians(p=0.015).

Conclusions: Acoustic temporal bone window is absent in 30.5% of Asian stroke patients. It is more likely to be absent among Chinese, women, and older patients.

P193

VERTEBROBASILAR DISEASE: A DUPLEX SONOGRAPHY STUDY IN SINGAPORE STROKE PATIENTS

Gan HY, Lee MP, Chang HM, Wong MC.

Department of Neurology, Singapore General Hospital.

Background: The incidence of extracranial vertebral artery (ECVA), intracranial vertebral artery (ICVA) and basilar artery (BA) disease varies from about 2 – 5% (USA), to 20% (Hong Kong). We assessed the prevalence of vertebrobasilar disease in 394 consecutive ischemic stroke/TIA patients admitted to the Department of Neurology from June to September 2001 using Duplex, Doppler and Transcranial colour coded Duplex (TCCD) studies. Methods: ECVA Duplex sonography and ICVA/BA TCCD sonography were performed with GE Vingmed System 5. Patients with Subclavian Steal Syndrome (n=3) were analysed separately. Diagnostic criteria were: ECVA/ICVA/BA occlusion - no flow; ECVA stenosis - mean flow velocity (MFV) ³ 50cm/s or Pulsatility Index >2.5 with normal ICVA; normal ECVA – MFV <50cm/s; ICVA/BA stenosis - peak systolic velocity (PSV) ³ 120cm/s; normal ICVA/BA – PSV <120cm/s. Results: Of 391 patients, 221 (57%) were men, mean age 66 years. 86% were ethnic Chinese, 8% Malay, 4% Indian and 2% Others. 1 ECVA and 10 BA were not assessed for technical reasons. Of 781 ECVA studied, 746 (96%) were normal, 26 (3%) stenosed and 9 (1%) occluded. Of 782 ICVA studied, 702 (90%) were normal, 53 (7%) stenosed and 27 (3%) occluded. Of 381 BA studied, 330 (87%) were normal, 49 (13%) stenosed and 2 (0.5%) occluded.

Table: Distribution of Vertebrobasilar disease amongst 391 stroke patients

Normal (%)

Only ECVA disease (%)

Only ICVA/BA disease (%)

Both ECVA and ICVA/BA disease (%)

289 (74)

16 (4)

69 (18)

17 (4)

By multiple logistic regression, the following parameters were predictive for vertebrobasilar disease: diabetes (p=0.002), stroke subtype (p=0.008), and hypertension (p=0.029). Conclusions: 26% of our Asian stroke patients have significant Vertebrobasilar disease. This is higher than published reports in the literature and identifies a group of patients who may have increased risk of future posterior circulation stroke.

P194

TRANSCRANIAL COLOR-CODED DUPLEX SONOGRAPHY IN THE DETECTION OF UNRUPTURED INTRACRANIAL ANEURYSM

J. Petrova, E. Vassileva, P. Shotekov

University Hospital "Alexandrovska", Sofia, Bulgaria

Background: To assess transcranial color-coded duplex sonography for detecting intracranial unruptured aneurysm.

Methods: 76 patients with suspected intacranial aneurysm were examined by continuous wave Doppler sonography, transcranial Doppler sonography and transcranial color-coded duplex sonography. The patients with intracranial aneurysm underwent digital subtraction angiography.

Results: 59 patients (39 women and 20 men, mean age 45 years) had adequate bone window. Intracranial aneurysms were found in 50 patients. Aneurysms were proven by digital subtraction angiography in 44 patients (88%). The diameter range from 5,5 mm to 20 mm. Multiples aneurysms undiagnosed by ultrasound examination were found in 7 patients (< 5,5 mm in diameter).

Conclusions: Transcranial color duplex sonography is a noninvasive test for intracranial aneurysm > 5,5 mm in diameter.

P195

Multiple Regression Models of Combined Duplex Criteria for Detecting Threshold Carotid Stenosis and Predicting the Exact Degree of Carotid Stenosis

Chi-Shin Hwang, MD; Kuo-Meng Liao, MD, PhD*; and Charles H. Tegeler, MD.**

Department of Neurology, Chung-Hsiao Municipal Hospital, Taipei, Taiwan

Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taiwan*

Department of Neurology, Wake Forest University Baptist Medical Center, Winston-Salem, N.C., USA**

Background: Duplex scanning is the most commonly used method for non-invasive evaluation of carotid stenosis. Different kinds of combined duplex criteria were used in different vascular laboratories for grading carotid stenoses. However, most of these combinations are basically just empirical selection. There was not enough statistic data to support that which combination was better. This study was completed by using multiple regression models with the angiographic data as a gold standard to evaluate the accuracy of different combined duplex criteria for detecting threshold carotid stenosis, and predicting the exact degree of carotid stenosis.

Methods: We referred back to 147 endarterectomy patients with complete data of pre-operative carotid duplex and angiograms. Patients with non-detectable Doppler flow or damping flow signal on either side of carotid arteries were further excluded. Each one of internal carotid arteries was treated as an individual case. Finally, we collected 266 sets of single-side carotid duplex examinations and angiogragaphic data. The 266 sets of data were randomly divided into a trained group and a validated group. The trained group was first evaluated by multiple logistic regression for detecting 70% threshold carotid stenosis. Age, Sex, Systolic blood pressure, Diastolic blood pressure, Doppler systolic velocity (DSV), Doppler diastolic velocity (DDV), Systolic Carotid Ratio (SCR), and the Ophthalmic artery flow direction were tested as validating variables. Furthermore, a multiple linear regression model was developed for predicting the exact degree of carotid stenosis. Finally, we used the validated group to evaluate the efficacy of the developed multiple regression models.

Results: In the multiple logistic regression model, Age, Sex, DSV and SCR were found to be the valid determining variables. While DDV, Systolic blood pressure, Diastolic blood pressure, and the Ophthalmic artery flow direction did not show significant validity. The best regression model for detecting 70% threshold carotid stenosis was as the following:

The probability of > 70% stenosis on angiogram =

Exp ^{(1.9088 – 0.0552 Age –0.9259 Sex + 0.0092 DSV + 0.2035 SCR)} ／ [ 1 + Exp ^{(1.9088 – 0.0552 Age – 0.9259 Sex + 0.0092 DSV + 0.2035 SCR )} ].

Meanwhile, we developed a multiple linear regression model for predicting the exact degree of carotid stenosis. The best predicting model was as the following:

The degree of carotid stenosis on angiogram = 8.5 + 0.2 DSV – 0.07 DDV + 0.4 SCR.

Finally, we used the validated group to evaluate the validity of the two models. The results showed that the logistic regression model was valid (chi-squared test, p<0.001), and the linear regression model was also valid enough (correlation test, p<0.05, correlation coefficiencent = 0.77).

Conclusions: Our study showed that Doppler examination is a valid tool for detecting threshold carotid stneosis and predicting the exact degree of carotid stenosis on angiogram. The regression models, those we provided here, is helpful for clinical use. Though the developed formula is a bit complicated, it will be very convenient and useful if we built the formula into a computer or the program of a new duplex machine and let the machine to auto-calculate the examination data for predicting the degree of carotid stenosis.

P196

BLOOD FLOW VOLUME MEASUREMENT IN COMMON CAROTID ARTERY CAN PREDICT INTERNAL CAROTID ARTERY STENOSIS

L. Lien, C. Hwang, P. Reynolds, C. Tegeler. Department of Neurology, Shin Kong WHS Memorial Hospital, Taiwan

Background: Extracranial flow volume (FV) of common carotid artery (CCA) can be measured with color duplex M-mood system. Volumetric changes of CCA can be expected in the high-grade stenosis of ipsilateral neck internal carotid artery (ICA). The aim of present study was to set the criteria based on FV in CCA to predict high-grade stenosis in ICA.

Methods: Angiograms and duplex Doppler scans of 220 patients within 3 months of each other were reviewed. Color velocity imaging (CVI) of quantification allowed the calculation of the FV rate in the CCAs. Angiographic stenosis of the ICAs were determined by the NASCET method. FV in the CCAs to predict ICA stenosis were performed in 3 models: 1. one side of FV in CCA to predict the ipsilateral ICA stenosis; 2. ratio (larger FV/smaller one) to predict ICA stenosis in the smaller FV side; 3. difference (larger FV minus smaller one) to predict ICA stenosis in the smaller FV side. We used a receiver-operating characteristic curve with final results chosen based on maximal diagnostic accuracy.

Results: For ICA stenosis >70%, one side FV of CCA is best indicated by FV< 220 ml/min (sensitivity 59%; specificity 82%), a ratio by 1.4 (sensitivity 78%; specificity 70%) and a difference by 80 ml/min (sensitivity 77%; specificity 66%). For ICA stenosis > 90%, one side FV of CCA is best indicated by FV< 200 ml/min (sensitivity 68%; specificity 86%), a ratio by 1.8 (sensitivity 72%; specificity 82%) and a difference by 190 ml/min (sensitivity 57%; specificity 86%).

Conclusions: FV in CCAs by CVI can predict ICA stenosis in a moderate accuracy. It would be very helpful when Doppler in ICA cannot be obtained.

P197

Ultrasonic Evaluation of Vertebral Venous Valves

A-Ching Chao, *Chi-Hsiang Chou, *Han-Hwa Hu,

Kaohsiung Medical University, Chung-Ho Memorial Hospital, Kaohsiung, Taiwan

*Veteran General Hospital-Taipei, Taiwan

Background : Vertebral venous valves just have been described in anatomy textbooks, but no clinical or ultrasonic studies about them before. The authors demonstrated that these valves were able to be studied noninvasively using ultrasound techniques and relate this to possible clinical implications. The clinical relevance to intracranial hypertension is also stressed.

Methods: Four volunteers received these examinations by real-time, pulsed Doppler and M-mode ultrasound technique. Two were healthy adults, and the other two had headache history but was symptom free during the examination.

Result: Two cups of the vertebral venous valves opening and closing at the junction of vertebral vein and brachiocephalic vein could be clearly demonstrated by the real-time ultrasound. The movement of the vertebral venous valves was synchronized with the internal jugular venous valves, which was demonstrated by M-mode study.

Conclusion: It is the first time to study the vertebral venous valves using clinical sonography. This might provide a new point of view to evaluate the clinical significance of the vertebral venous valves.

P198

Dual Origin of Vertebral Arteries Diagnosed by Sonography

A-ching Chao, *Han-Hwa Hu,

Department of Neurology, Kaohsiung Medical University, Chung-Ho Memorial Hospital, Kaohsiung, Taiwan, * Department of Neurology, Veteran General Hospital, Taipei, Taiwan

Background: In general, the vertebral arteries (VA) enter into the spinal canal at C6 level. However, we found several cases while performing sonography having double origins of vertebral artery and they almost all joined with each other at level above C6.

Methods: During performing sonography, we picked up 7 cases with suspected double origins of vertebral arteries, right or left side. MR angiography (MRA) or digital subtraction angiography (DSA) were arranged to survey their cerebral vasculature.

Results: The double origins of VA come from subclavian arteries both, or one subclavian artery and one brachiocephalic trunk in the right side, or one subclavian artery and one aorta in the left side, and conjoint mostly above C6 level. In most cases, only trickle flow was noted through the ordinary vertebral pathway, but stronger flow was noted in the other branch. MRA and/or DSA of vertebral arteries revealed dual origin of vertebral arteries in only one of these cases, and suggested normal vertebral arteries in the remaining cases.

Conclusion: The artery which was often considered as collateral artery by sonography but consider as normal vertebral artery by MRA or DSA, is likely to be a case of double origin of vertebral artery. Besides, double origin of VA is not so uncommon as we thought before.

P199

"ATYPICAL" TCD PATTERNS IN VERTEBOBASILAR SYSTEM CORRELATED WITH VASCULAR IMAGING FINDINGS. REPORT OF TWO CASES.

B. Bruk, M. Bakun, D. Tanne, M. Hadani

Sheba Medical Center, Tel Hashomer, Israel

Background: Vascular abnormalities in the vertebrobasilar system may produce an "atypical" TCD picture that suggests the necessity for vascular imaging examination. Presented here are 2 cases of abnormal TCD findings in posterior circulation that correlated with the MRA and cerebral angiography findings.

Case 1. A 66 years old male patient with acute signs of cerebellar disorders. CT scan on admission showed no pathologic findings. TCD insonation of the left VA and BA at the depths between 65 – 81 mm revealed a short systolic peak signal, directed towards the probe, along with normal signal from the left VA. MRI and MRA, performed a week later, showed left cerebellar infarct, normal right PICA and absence of the left PICA.

Case 2. A 51 years old male with history of intense headaches and normal CT scan a month prior to admission was admitted with acute headache. CT scan on admission showed hemorrhage in the IV ventricle. TCD demonstrated presence of high velocity low pulsatility, almost "venous" signal, in the left VA at the depth of 60-63 mm. At the depth of 70 mm pattern in the left VA was practically normal. Angiography revealed dural AV fistula, supplied from the left VA.

Conclusions: Changes in Doppler waveforms or appearance of "atypical" signals in vertebrobasilar system are a significant diagnostic finding that provide sufficient reason for further patient examination using vascular imaging techniques.

P200: CEREBRAL EMBOLIZATION IS REDUCED BY PERFORMING CORONARY ARTERY BYPASS SURGERY ON "THE BEATING HEART"

C. Lund, R. Lundblad, K. Sundet, B. Tennøe, R.Brucher, E. Fosse, D.Russell.

The National Hospital, University of Oslo, Norway

Background: Coronary artery bypass surgery (CABG) using cardiopulmonary bypass (on-pump surgery) carries a substantial risk for cerebral injury due to cerebral embolization. This is due to the whole-body inflammatory response which is induced by the heart-lung-machine, and the fact that cannulation and cross-clamping of the ascending aorta produces atheromatous embolization. CABG performed without cardiopulmonary bypass (off-pump surgery) may therefore lead to a reduced risk of cerebral embolization and subsequent cerebral injury. In this prospective, randomised study we have assessed the rate of cerebral embolization during off-pump compared to on-pump surgery.

Material and methods: Transcranial Doppler (TCD) was used to determine the number of cerebral microemboli in the left middle cerebral artery during coronary artery bypass surgery in 52 patients, of which 29 were carried out off-pump. Clinical, neuroradiological and neuropsychological assessments were also performed one day prior to surgery and again three months later.

Results: There was significantly fewer cerebral microemboli in the off-pump group compared to the on-pump group (16 (range 0-131) versus 66 (range 15-274), p<0.005). One ischemic stroke occurred in the on-pump group. Neuropsychological impairment (>20% reduction in at least 2 tests) was found in 8 (35%) of the on-pump and 8 (29%) of the off-pump patients.

Conclusion: This study has shown that the number of perioperative cerebral microemboli is significantly reduced by carrying out CABG using the off-pump technique. There was no significant difference, however, in the neuropsychological findings in the two groups which suggests that embolus composition may be as important as the total number of emboli with regard to cognitive outcome.