XVII. European Stroke Conference
Nice, France

Poster Session: Vascular imaging: new developments
 

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Value of Susceptibility-Weighted Imaging in Acute Ischemic Stroke with Perfusion Defect
E.J.Chung    S.I.Sohn    C.H.Sohn     H.W.Chang     S.H.Choi                                    
 
Keimyung University, Dongkang Hospital, Daegu, South Korea

SOUTH KOREA

Background and purpose: Susceptibility-weighted MR imaging (SWI) is a useful technique in the detection of hemorrhagic signals, susceptibility effect of doexyhemoglobin in thrombi, or venous vasculature. We evaluated the usefulness of SWI in patients with the acute ischemic stroke associated with perfusion defect by the large cerebral or carotid artery occlusion. Methods: Consecutive patients were scanned within 24 hours after symptom onset using 3.0-T whole body system with identical acute MRI protocol. We identified occlusion site on MR angiography, susceptibility vessel signs and hypointense vein signs in SWI and T2-gradient echo imaging (GRE), perfusion defect on perfusion-weighted imaging (PWI) and DWI-PWI mismatch. We inspected the relationship between susceptibility vessel sign (SVS) on SWI and stroke subtype and between hypointense vein signs (HVS) in SWI and perfusion defect. We also compared findings of SWI with GRE. Results: Fifty patients (mean age 66 years, 56% women) had highly severe stenosis or occlusion in the internal carotid (5 of 50 patients, 10%) or middle cerebral artery (90%) and subsequently perfusion defects on perfusion-weighted imaging in the territory of the anterior cerebral circulation. The mean time from symptom onset to taken MRI was 6.0 +/- 7.6 hours. Mean initial NIHSS score was 13 +/- 6.6. SVS on SWI and GRE was more commonly associated with cardioembolic stroke patients (88%, 82%) than with other stroke subtypes respectively (52%, 52%; P =0.023, P=0.032). Asymmtrical HVS on SWI were identified in 48 (96%) of the 50 patients with perfusion defect. The detection of HVS on GRE was identified in 75%. HVS on SWI was not associated with PWI-DWI mismatch. Conclusion: SWI is superior to GRE in the detection of SVS or HVS. In patients with acute ischemic stroke, SWI appear to be a viable alternative for use in identifying clot composition and acute perfusion defect.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
A Clinical and Radiological study of Vulnerable Plaque by using Multi-detector-row CT
L. Saba    C. Branca    R. Montisci     R. Sanfilippo     G. Mallarini                                    
 
Azienda Ospedaliero Universitaria di Cagliari

ITALY

OBJECTIVES: The so called “Vulnerable plaque” identifies a plaque at high risk of rupture. Our purpose was to evaluate MDTCA plaque characteristics of vulnerability in a cohort of 167 patients studied by using MDCTA who underwent carotid endarterectomy. METHODS: 39 patients were studied with MDCTA to assess carotid arteries and underwent afterwards carotid endarterectomy (CEA). The following features were studied: the type of the plaque (fatty, mixed and calcified), plaque morphology (regular versus irregular) and presence of ulcerations; we evaluated also stenosis degree (according to the NASCET criteria). We correlated MDCTA data with surgical results and with the presence\absence of ischemic events. Statistic analysis was provided to determine if an interaction existed between presence of ischemic episodes and specific plaque characteristics as confirmed by surgery. RESULTS: We found a positive correlation between presence of ulcerations and symptomaticity (p < 0.05), irregular morphology and symptomaticity (p < 0.05) and presence of fatty plaque and symptomaticity. Concordance between MDCTA ad surgical results was very high. CONCLUSION: Fatty plaques, ulcerations, and irregular plaque morphology are statistically significant risk factor for ischemic episodes. These plaque characteristics individuate a high risk, “ vulnerable” plaque.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
18FDG-PET/CT and Ultrasonography of the Carotid Plaque: a pilot study on symptomatic and asymptomatic patients with 50-99% stenosis
C. Bonvin    J.P.Willi    R. Osman     R. Sztajzel                                            
 
University Hospital and Medical School Geneva

SWITZERLAND

BACKGROUND: Atherosclerosis plays a key role in the pathophysiology of stroke. However, identification of vulnerable plaques remains a challenge. Inflammation responsible for their progression and destabilization can be imaged by 18FDG-PET which is used in the present study in association with carotid US to assess symptomatic and asymptomatic patients. METHODS: 8 patients (5 males, 76±10y) with 50-99% carotid stenosis were enrolled in this pilot study. Symptomatic patients were considered having a carotid ischemic stroke or TIA after complete workup. PET/CT was performed on a Biograph 64 scanner (Siemens). Metabolic activity of carotid lesions was measured by maximal standardized uptake value (SUV) with an arbitrary cut-off value of 1.5 for significant activity (suggested by published data). Patients also underwent Duplex US, MRI-MRA and transcranial microembolic signal detection (MES) according to standardized protocols. Degree of stenosis was determined by combination of US, MRA and CTA data and then categorized into moderate (50-69%) and severe (70-99%). RESULTS: 5 patients were symptomatic (4 strokes, 1 amaurosis fugax) and 3 of them (60%) had severe carotid stenosis. 2 out of 3 (67%) asymptomatic ones had severe stenosis. Among the stroke cases, 3 (75%) were PET+ with embolic lesions on MRI. One subject was PET- and had a typical watershed stroke. Asymptomatic patients were all PET-. 2 symptomatic patients had positive MES detection but none of the asymptomatic ones. Considering severe stenosis (n=5) only one subject was PET+ whereas 2 out of 3 (66%) had a PET+ in the moderate stenosis group. CONCLUSION: This pilot study suggests that hypermetabolic activity of carotid plaques might correlate with the presence of symptoms and is not related to the degree of stenosis.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Atherosclerotic stenosis of basilar artery is proved by high resolution MRI and transcranial Doppler, although time-of-flight MR angiography of basilar artery may appear normal
J. Lee    H.W.Jang    S.J.Lee                                                    
 
Yeungnam University School of Medicine

SOUTH KOREA

Background: Basilar artery stenosis on transcranial Doppler (TCD) does not correlated with MR angiography in some cases. We attempt to evaluate usefulness of MR angiography, high resolution MRI(HR MRI), and TCD in patients with basilar artery stenosis. Methods: We studied consecutive patients with pontine infarcts who were admitted to our stroke unit within one week after symptom onset. The vascular findings on the MR angiography and HR MRI and Time-of-flight MR angiography (TOF MRA) were obtained for the analysis of the basilar artery atherosclerotic plaques. Results: Our study consisted of 15 women and 21 men, from 44 to 85 years of age. Twenty-eight had paramedian pontine infarcts and 8 had lacunar pontine infarct. In cases of paramedian infarcts, 6 patients (21.4%) had normal TOF MRA and HR MRI, 15 (53.6%) had normal TOF MRA and atherosclerotic plaques on HR MRI, and 7 (25%) had stenosis on TOF MRA and atherosclerotic plaques on HR MRI (p>0.05). In cases of lacunar infarcts, 3 patients (37.5%) had normal TOF MRA and HR MRI, 2 (25%) had normal TOF MRA and atherosclerotic plaques on HR MRI, and 3 (37.5%) had stenosis on TOF MRA and atherosclerotic plaques on HR MRI (p>0.05). TCD studies were conducted on 33 patients and showed abnormally increased flow velocities of basilar artery in 12 patients with paramedian pontine infarcts and 3 patients with lacunar pontine infarcts (p>0.05). TCD provided better sensitivity for identifying basilar stenosis compared with TOF MRA (54.7% versus 34.6%). For 24 patients who appeared normal flows on TOF MRA, 11 (45.8%) showed abnormal TCD findings with basilar artery atherosclerotic plaques on HR MRI. All 11 patients with abnormally increased flow velocities of the basilar artery showed basilar atherosclerotic plaques on HR MRI, whereas TOF MRA of basilar artery appeared normal. Discussion: HR MRI is useful for identification of basilar atherosclerotic plaques in patients with pontine infarcts. HR MRI and TCD reveal a basilar atherosclerotic stenosis, although TOF MRA of basilar artery may appear normal.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Lack of association of knock-type Doppler signals (KTDS) with the presence of cerebral ischemia in the territory of the affected intracranial vessels.
G. Tsivgoulis    V.K.Sharma    B.L.Man     A.Y.Lao     HT Nguyen    K. Vadikolias     C. Piperidou     C. Bairaktaris    A.W.Alexandrov   A.V.Alexandrov
 
Comprehensive Stroke Center, University of Alabama at Birmingham Hospital, Birmingham, Alabama

USA

Background: Knock-type Doppler signals (KTDS) are detectable by TCD and it has been hypothesized that they are related to an occlusion of a small perforating artery and microvascular ischemia. However, the nature of KTDS has not been prospectively defined. We aimed at describing the spectral and power motion Doppler characteristics of KTDS and evaluating their potential association with cerebral infarction or microvascular ischemia in the territory of the affected intracranial vessels. Methods: Consecutive patients referred with symptoms of stroke or transient ischemic attacks to our cerebrovascular ultrasound laboratory were screened for the presence of KTDS. The presence of microvascular ischemia (hyperintense signal shown in the first and second echo images with sharp margins, <2.5 cm in diameter, located in the deeper structures and irrigated by penetrating branches) was assessed using brain MRI. Statistical analyses were performed by univariate and multivariate logistic regression models. Results: Among 327 patients with cerebrovascular symptoms, 46 (14%) had KTDS. KTDS was detected more frequently in posterior circulation vessels [VA, BA, PCA; 2.6% (42/1635)] than in the anterior circulation arteries [ACA, MCA, TICA; 0.5% (9/1962); p<0.001]. The frequency of KTDS was similar in patients with stroke (13%) and TIA (19%, p=0.312). The frequency of KTDS did not differ between patients with or without brain ischemia in the distribution of VA (p=0.607), BA (p=0.429), PCA (p=0.457) and MCA (p=1.000). There was no association between ultrasound identification of KTDS and the presence of brain ischemia in the distribution of any vessel (OR:0.37, 95%CI: 0.09-1.53, p=0.171) on univariate logistic regression analyses. KTDS was not related to the presence of microvascular ischemia on brain MRI (OR:1.12, 95%CI: 0.55-2.29, p=0.761). Discussion: Although KTDS can be distinguished from other spectral flow signals, they can be found in normal vessels, do not seem to be associated with the vessel affected by ischemia and should not be over-interpreted.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Safety of CT Angiography and Perfusion Imaging in the Emergency Evaluation of Acute Stroke
J.J.Hopyan    D.J.Gladstone    G. Mallia     J. Schiff     A.J.Fox    S.P.Symons     S.E.Black     R.I.Aviv             
 
Sunnybrook Health Sciences Centre, University of Toronto

CANADA

Background: Multimodal computed tomography (CT) imaging with contrast-enhanced CT angiography (CTA) and CT perfusion (CTP) is increasingly being used to guide the emergency management of acute stroke. However, little has been reported about the safety of intravenous contrast administration associated with these studies in the acute stroke population, especially when baseline creatinine values are unknown. We investigated the incidence of contrast-induced nephropathy (CIN), defined as a ≥25% increase in baseline creatinine level within 72 hours, in patients receiving CTA +/- CTP at our regional stroke centre. Methods: We identified consecutive patients who underwent contrast CT studies for evaluation of acute ischemic or hemorrhagic stroke at our centre (2003-2007). As part of our emergency stroke imaging protocol, patients without a known history of renal impairment underwent CTA +/- CTP within minutes of arrival to hospital, often before knowledge of the creatinine level. Through retrospective chart abstraction, we analyzed serial creatinine levels (baseline to day 3), and later values (>/=day 4) where available. The main outcome was the proportion of patients with CIN. Results: Of 175 patients with serial creatinine measurements between baseline and day 3, only 5 (2.9%) developed CIN, and none required dialysis or had permanent renal sequelae. The incidence of CIN was 1.8% in patients who were scanned before a baseline creatinine level was available. Conclusion: The incidence of CIN is low in acute stroke patients undergoing emergent multimodal CT scanning. Prompt CTA/CTP imaging of acute stroke need not be delayed in those with no history of renal impairment.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Carotid artery stenosis: diagnosis of diabetes predicts increased vulnerability of plaques irrespective of the degree of stenosis
L. Esposito    P. Heider    O. Wolf     R. Feurer     K. Holzer    S. Sadikovic     D. Sepp     B. Hemmer    H. Poppert      
 
Technical University of Munich,Klinikum rechts der Isar

GERMANY

Background Diabetes mellitus (DM) represents a well established risk factor for atherosclerosis, but its specific influence on plaque vulnerability in carotid artery stenosis is not clear. High resolution magnetic resonance imaging (MRI) allows risk classification of carotid plaques in distinct lesion types (I-VIII) according to American Heart Association (AHA) criteria. Lesion types IV-V and VI are regarded as high risk plaques. This study investigates weather DM is related to MRI-detected high risk plaques in patients presenting with high-grade carotid artery stenosis (CAS). Methods 107 patients (41 female) with CAS > 70 % were imaged with a 1.5 T scanner with bilateral phased array carotid coils. T1-, T2, time-of-flight (TOF) and proton-density (PD)-weighted studies were obtained. Carotid plaques were classified as lesion type I-VIII according to the modified AHA-criteria. For 19 patients histology was obtained. DM type II was correlated with symptomatic CAS and with MRI-detected unstable plaques. Results 42 patients presented with a symptomatic CAS. In symptomatic patients unstable lesion types were predominant as compared to asymptomatic ones (64.3 % vs. 21.5 %; P<0.0001; two-tailed Pearson-Test). Correlation between histology and MRI-classification was 82.61%. 31 patients presented with DM II. In these patients symptomatic CAS (54.8 % vs. 32.9%; P = 0.035) and MRI-based high-risk plaques were (61.3 % vs. 30.3 %; P = 0.04) predominant as compared to patients presenting with CAS but without DM II. Discussion DM II represents a predictor for the development of vulnerable carotid plaques. Diabetics seem to be at higher risk for the development of vulnerable MRI-detected plaques than other patients with high-grade CAS. .

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Necessary Temporal Sampling Rate in Perfusion Computed Tomography in Patients with Acute Ischemic Stroke
A. Ringelstein    B. Turowski    H.J.Wittsack     R. Lanzman     F. Schellhammer    V. Klar     K. Andersen     M. Cohnen             
 
Institute for Diagnostic Radiology, HH University Duesseldorf

GERMANY

Purpose: Assessment of the necessary temporal sampling rate (TSR) in dynamic perfusion CT (dPCT) to safely diagnose acute cerebral ischemia. Methods: Fourteen patients with clinically acute neurological deficit underwent a dPCT study at a 64-Detector-Row CT. Scanning was performed with a collimation of 20 x 1.2 mm at 80 kV and 270 mAs with acquisitions every second for a time period of 40 seconds. 40 cc of non-ionic contrast material were injected at 5 ml/sec in an antecubital vein. Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and the time point of the maximum of the residue function (Tmax), respectively, were calculated by deconvolution analysis using singular value decomposition with varying TSR of one image acquired every second, every two, and every three seconds, respectively (TSR 1,2, and 3). Results: Using TSR 1, the ischemic area could be clearly diagnosed in all cases. At TSR 2 the difference in CBF, CBV and Tmax compared to uneffected brain parenchyma was diminished leading to a less distinct definition of infarct size. However, MTT showed visually constant results at TSR 2. At TSR 3, none of the parameter maps revealed correct information. Conclusions: A reduction of the temporal sampling rate in perfusion CT to less than one image per second leads to a significant reduction of the mapped infarct size. This method in order to reduce patient´s radiation exposure cannot be recommended.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Correlation between the ultrasonographic and perioperative macroscopic finding in the differentiation of acute internal carotid artery occlusion
R. Herzig    D. Skoloudik    M. Kral     D. Sanak     P. Bachleda    P. Utikal     P. Havranek     S. Burval    J. Chmelova   I. Vlachova
 
Dpt. of Neurology,Surgery II,Radiology, Palacky Univ./Univ. Hosp.,Olomouc and Ostrava,Czech Republic

CZECH REPUBLIC

Background:Acute ischemic stroke (AIS) may occur both in the acute and chronic internal carotid artery occlusion (ICAo).Thus, it is important to assess the character of ICAo when considering the recanalization method.The aim was to assess the correlation between the ultrasonographic (US) and perioperative macroscopic finding in patients with AIS with acute ICAo, undergoing an emergent carotid endarterectomy.Methods:In a retrospective,hospital-based,two-center study,the set consisted of 36 patients (27 males; age 49-79, mean 63.9±9.1 years).ICAo character was classified as an acute thromboembolus either isolated or in combination with atherosclerotic plaque using the US (B-mode) and the macroscopic perioperative evaluation.Cohen’s Kappa was applied when assessing statistical significance.Results:An acute ICAo character diagnosed by US was confirmed by the perioperative macroscopic evaluation in all cases.US and perioperative macroscopic findings were consistent in 31 (atherosclerotic plaque+acute thromboembolus in 27; acute thromboembolus in 4) and discrepant in 5 (US finding of atherosclerotic plaque+acute thromboembolus classified as acute thromboembolus in perioperative macroscopic evaluation in 2; US finding of acute thromboembolus classified as atherosclerotic plaque+acute thromboembolus in perioperative macroscopic evaluation in 3) cases.The correlation between both methods in the classification of acute ICAo was 86.1% (95% CI: 74.8-97.4%),Kappa=0.531 (p=0.001).Discussion:US is a reliable method in the diagnostics of the acute character of ICAo and it has a moderate correlation with perioperative macroscopic finding regarding a differentiation of atherosclerotic plaque and fresh thromboembolus.Thus, US can be used when considering the various recanalization methods.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
The “Donut” sign on Carotid CT angiography: New imaging sign to detect intra-luminal Carotid thrombus.
A.M. Al-Khathaami    M. Alzawahmah    P. Sharma     C. O’Reilly     S. Tymchuk    T. Watson     M. Goyal     A. Demchuk             
 
University of Calgary, Calgary stroke programme

CANADA

Purpose: - To describe the radiological appearance of Intra-Luminal Carotid Thrombus (ILCT) detected by CT angiography and review our experience with this entity. Methods: - Retrospective review of 1100 carotid CT angiographies done for evaluation of cerebral ischemia acutely. ILCT was defined as filling defect completely surrounded by contrast in at least two contiguous axial source images. Stenosis was measured by NASCET criteria. The four reviewers were blinded to clinical information. Results: Twenty seven patients with ILCT were identified. The radiological appearance of ILCT resembles the shape of a ring donut, hence called “donut sign”. “Donut sign” was in the left carotid in 62%, right carotid in 38 %, no bilateral “donut signs” were found and all were ipsilateral to symptomatic side. After average of 10 days of anticoagulation and/or antiplatelets therapy, two patients only had recurrent strokes, two had intracerebral hemorrhage and 85 % had modified Rankin scale 0-2 at three months. Repeated CTA in 12 patients showed complete resolution of “donut sign” in all cases and improved baseline stenosis by at least 30% in 5 patients. ILCT was due to atherosclerotic plaque in 21 patients, post endarterectomy in two, dissection in three and cardiac embolization in one patient. Conclusion: CTA has a value in diagnosis of intraluminal carotid thrombus by the detection of a “donut sign” represented as a filling defect surrounded completely by contrast. Aggressive medical therapy results in complete resolution of the “donut sign” but is not free of adverse effects. Prospective studies are needed to evaluate different treatment options for this condition.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Magnetic resonance-guided [18-F] fluorodeoxyglucose positron emission tomography in human carotid and vertebral arteries. Comparison of methods, reproducibility and partial volume correction
D. IZQUIERDO-GARCIA    J.R.DAVIES    M.J.GRAVES     J.H.F.RUDD     J.H.GILLARD    P.L.WEISSBERG     T.D.FRYER     E.A.WARBURTON             
 
WOLFSON BRAIN IMAGING CENTRE UNIVERSITY OF CAMBRIDGE

UNITED KINGDOM

Background Inflammation is a major risk factor for atherosclerotic plaque rupture and clinical events. Previous studies have shown that 18F-fluorodeoxyglucose (FDG) using positron emission tomography (PET) is able to identify inflamed plaques in stroke patients with carotid and vertebral disease. In this study we examined the reproducibility of three methods of quantifying plaque FDG uptake in the carotid and vertebral arteries using PET: vessel wall to blood ratio (VBR), standardized uptake value (SUV) and influx rate (Ki). The correlation between the two simplified uptake parameters (SUV and VBR) and the gold standard technique (Ki) was determined. We used magnetic resonance imaging (MR) to correct carotid plaque FDG uptake for partial volume error. Methods 7 patients with a recent carotid territory transient ischaemic attack were imaged twice within 8 days using MR and FDG-PET. Regions of interest were delineated on MR and PET was coregistered to MR to determine plaque FDG uptake and facilitate partial volume correction (PVC). Results SUV and VBR were the most reproducible measures for carotids (mean absolute inter-scan difference 5.7% and 6.4% respectively) and vertebrals (7.9%, 9.5% respectively). VBR correlated better to Ki than SUV for both the carotids (r=0.58 VBR, r=0.35 SUV) and vertebrals (r=0.96 VBR, r=0.68 SUV). PVC improved the correlation for carotid plaque to r=0.81 for VBRPVC and r=0.67 for SUVPVC. However, PVC also degraded reproducibility: SUVPVC was the most reliable measure after PVC (mean absolute % difference: 10.5%; SD: 11.6%, ICC: 0.84). Discussion MR-guided FDG PET is a highly reproducible technique for quantifying plaque inflammation in both the carotid and vertebral artery territories. SUV and VBR have similar reproducibility but VBR correlates better with influx rate. The excellent anatomical detail provided by MR facilitates PVC, which improved the correlation between the simplified methods and influx rate. A key area where this technique can be applied is proof of principle studies of plaque stabilising agents.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Pattern of deep isolated infarction on perforating middle cerebral artery (MCA) territory and its association with stenosis of MCA
S.G.Shan Gao    W.W.Wei Wang                                                           
 
Peking Union Medical College Hospital

CHINA

Backgrounds: The pattern of isolated infarction on the area of perforating middle cerebral artery (MCA) with or without MCA stenosis has not been clearly demonstrated, although latest studies have proven that it can be produced by MCA stenosis. We analyzed the association between the pattern on diffusion-weighted imaging (DWI) and presence of MCA stenosis on magnetic resonance angiography (MRA). Methods: We identified 55 patients who were admitted within three days after stroke onset and had deep acute isolated infarction on perforating MCA territory revealed by DWI, and who was performed MRA. Patients with stenosis >50% of proximal internal carotid artery and potential cardiac sources of embolism were excluded. The maximum diameter, area and volume of infarction were calculated for every lesion on DWI. The infarction was classified into traditional lacunar infarction (TLI) with a diameter ≤ 2cm group and straptcapsular infarction (SCI) with a diameter > 2cm group. Results: Among these 55 patients, 26% had ipsilateral MCA stenosis. The diameter, area or volume of infarction in MCA stenosis was not larger than in normal MCA (P>0.05). 71% of patients had TLI in MCA stenosis, and 66% in normal MCA (P=0.701). There was no difference in the location of infarction on basal ganglia, peri-ventricle or both sites between MCA stenosis and normal MCA (P=0.52). The involvement of the basal ganglia, the peri-ventricle and both sites was as follows: 32%, 17%, 51% on normal MCA and 36%, 28%, 36% on MCA stenosis respectively. The percentage of patients with the concomitance of silent subcortical multiple small infarcts and leucoariosis was higher in normal MCA than in MCA stenosis (P=0.032). Conclusion: It is impossible to distinguish the pathologic mechanisms of deep isolated small infarctions in areas of MCA according to the size, volume or distribution of the lesion. The concomitance of silent subcortical multiple small infarcts and leucoariosis may suggest an extensive small artery disease.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Stroke, carotid artery wall thickness and type of plaque: an analysis by using Multi-detector-row CT
L. Saba    C. Giancarlo    C. Urigo     R. Sanfilippo     M. Conri    R. Montisci     A. Porcu     G. Mallarini             
 
Azienda Ospedaliero Universitaria di Cagliari

ITALY

Purpose: Increased carotid artery wall thickness was reported to occur in an earlier phase of the atherosclerotic process. The purpose of this work is to determine if carotid artery wall thickness (CAWT) evaluated by using multi-detector-row CT angiography (MDCTA) is associated with a specific type of plaque (fatty, mixed, calcified) development. Methods: In this retrospective study we analyzed 121 patients by using a multi-detector row CT scanner. In each patient we measured CAWT and measurements were made with an internal digital caliper. We divided patients into 3 groups: in the first group (group A) were include patients with fatty plaque (n = 43), in the second group (group B) were included patients with mixed plaque (n = 37) and in the third group (group C) patients with calcified plaque (n = 41) and we made a statistical analysis to asses the CAWT difference in the 3 examined groups. Results: Measurements of the distal common CAWT varied from 0.6 to 2.2 mm. In the group A average CAWT was 1.105 mm (0.226 SD) in group B was 1.044 mm (0.256 SD) and in group C was 0.839 (0.184 SD). CAWT in group A patients showed statistical difference (p < 0.01) compared to group C. Discussions: Results of our study suggest that an increased CAWT is associated with the fatty plaque development. This data should be considered by physician because it is well demonstrated that fatty plaques frequently (21 times the calcified plaques) determine TIA or strokes.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
A New Intraparenchymatous Probe for Combined Monitoring of Intracranial Pressure (ICP) and Cerebral Blood Flow (CBF)
E. Keller    C. Muroi    S. Mink     J. Froehlich                                            
 
University Hsopital Zürich

SWITZERLAND

Background: The benefits of monitoring cerebral blood flow (CBF) in patients with subarachnoid hemorrhage, severe hemispheric stroke and head injury are apparent. To date a suitable method for bedside CBF measurement, able to detect smaller areas of ischemia and easy to perform at the bedside is still lacking. New techniques combining near infrared spectroscopy (NIRS) and indocyanine green (ICG) dye dilutions to estimate cerebral hemodynamics are available. Objective: To develop a new intraparenchymatous probe for combined monitoring of intracranial pressure (ICP), cerebral blood flow (CBF) and cerebral blood volume (CBV) with near infrared spectroscopy (NIRS) and indocyanine green (ICG) dye dilution. Mtehods: For NIRS, conventional intraparenchymatous probes for ICP monitoring are supplied with two fiber bundles. The light is coupled out into the brain tissue via a metalized conical mirror and, after absorption and scattering, photons are collected with a 2cm distant photodiode. Central venous injections of 0.5mg/bw ICG are performed. Regional values for the mean transit time of ICG (mttICG), CBF and CBV are calculated according to published algorithms [1]. Results: With prototypes of a subdural probe in two patients with intracerebral haemorrhage 9 measurements were performed. Mean values obtained by the subdural probe were in mean for mttICG 9.2 sec, CBF 16.2 ml/100g/min and CBV 2.4 ml/100g. Conclusion: Optical imaging allows the determination of multiple parameters synchronously and will deliver an overall picture of brain oxygenation, hemodynamics, metabolism and function. Based on these results the method can be further developed regarding different measurement scenarios and additional measurement probe types leading to a conclusive informative picture of the entire brain condition of brain injured patients. 1. Keller E et al., Neuroimage, 20:828-39

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
CAN ONE-TIME MULTIDETECTOR RAW COMPUTERIZED TOMOGRAPHY ACCURATELY CLASSIFY STROKE ACCORDING TO TOAST CRITERIA ?
S. CAKMAK    L. BOUSSEL    N. NIGHOGHOSSIAN     R. LOFFROY     L. DEREX    P. TROUILLAS     P. DOUEK                     
 
GHE, Lyon, France Université Claude Bernard , Lyon I Creatis UMR 5515, INSERM U630

FRANCE

Background: Multidetector raw CT is a powerful tool, allowing one time morphological examination of the heart, the cervical arteries and coronary arteries. In the setting of stroke, it may be helpful in order to simplify etiological screening and save time and money by avoiding multiples scans. Objectives: to evaluate the ability of a one-time comprehensive cardiac, supraaortic and cerebrovascular CT in the setting of ischemic stroke, according to TOAST criteria, in comparison with the usual aetiological setting, including doppler ultrasound and/or magnetic resonance angiography of cervical arteries and transoesophageal echocardiography. Methods: Ischemic stroke patients were prospectiveley recruited at the Lyon (France) Stroke Unit. The study was approved by the local Ethical Committee. Each patient underwent 2 strategies for the etiological screening of stroke: a classical multi-exams approach vs a novel single exam multidetector raw CT strategy. Etiology of stroke was determined according to the TOAST criteria for each method in all patients. Results: 47 patients were recruited between 06/2006 and 10/2007. TOAST classification was correctly determined by CT in 42/47 cases. Multidetector raw CT exploration exhibited similar results compared with classical methods regarding atheromatous causes of stroke (carotid stenosis 11/12 cases, aortic atheroma 3/4 cases). No intracardiac thrombus or tumors were detected at this stage. Detection of minor cardiac sources remained difficult at this stage, but the clinical meaning of these abnormalities is still debated. The study is going on. Final results will be shown during the congress. Conclusions: Multidetector raw CT is a promising tool in the etiological screening of ischemic stroke. Preliminary results are encouraging regarding the detection of atheromatous sources of stroke, in comparison of usual techniques. These results need confirmation in more patients, especially to better evaluate the diagnostic performance of CT for the detection of cardiac sources of stroke.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Comparison of intracranial hemodynamic indices obtained by transcranial Doppler and by transcranial color-coded imaging
N. Venketasubramanian    M.P.Yumul    S.J.Agustin     B.C.Teo     J. Eng    W.C.Koh     R. Gan                     
 
National Neuroscience Institute (Singapore)

SINGAPORE

BACKGROUND: Two methods of transcranial ultrasonography are available: Transcranial Doppler (TCD) and Transcranial Color-Coded Imaging (TCCI). Very few studies have directly compared these two modalities in the same patient population. OBJECTIVE: To correlate the hemodynamic indices as measured by TCD and by TCCI METHODS: Data from all patients referred to the Neurodiagnostic Laboratory for transcranial ultrasound and underwent both TCD and TCCI from Jan 2006 to Aug 2007 were analyzed. TCD was performed using DWL Multi Dop x4 with a 2 MHz probe. TCCI was performed using GE Vingmed System-5 with a 2.5 MHz probe. The highest peak systolic (PSV) and mean flow velocities (MV) detected from each insonated artery and corresponding pulsatility indices (PI) were recorded. No angle correction was performed on TCCI. Correlations of PSV, MV, and PI between TCD and TCCI were assessed by linear regression. This study was approved by the IRB. RESULTS: Two hundred ninety three patients (mean age 61 ± 15 years; females 46%; Chinese 80%, Malay 6%, Indian 9%) with 410 paired TCD and TCCI studies were analysed. Indications for the studies were SAH 37%, ischemic stroke 16%, TIA 12%, VBI 3%, and others 32%. A total of 2,068 vessels were insonated by both TCD and TCCI: MCA 587, ACA 434, PCA 378, BA 192, VA 477. Rates of insonation failure were not statistically different between TCD and TCCI, and between left and right windows. Overall, there was good correlation (R=0.88) between TCD and TCCI for PSV, best observed in MCA (R=0.89), followed by VA (R=0.83), BA (R=0.76), ACA (R=0.69), then PCA (R=0.59). Likewise, overall correlation for MV was 0.87 with the best correlation observed in MCA (R=0.88), followed by VA (R=0.84), BA (R=0.72), ACA (R=0.66), then PCA (R=0.55). Overall correlation for PI was fair (R=0.57) between TCD and TCCI. CONCLUSIONS: There is good correlation between TCD and TCCI in measuring flow velocities, particularly in the MCA and VA. Rates of failure of vessel insonation are comparable between the two modalities.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
One year follow-up study of redistribution of vascular parameters in young patient after MCA stroke using MR perfusion with local arterial flow calculation
G.V.Vucurevic    K. Bruehl    G. Kutschke     P. Stoeter                                            
 
Institute of Neuroradiology Mainz

GERMANY

Introduction: Perfusion parameter images in standard magnetic resonance dynamic contrast enhancement techniques are depend on selection of arterial input function (AIF).. Newly proposed technique (Gruener,MRM,55,805-815,2006) offers calculation of AIF in every voxel, which significantly iproves perfusion evaluation and gives new information about vascular ,,distribution“ in the brain. Patient and Method 12 year old girl was examined 6 times within a year starting from 8th day after MCA infarction. Apart from standard MR examination protocol, 50 EPI 3D volumes (15 slices, matrix 128x128, FOV 210 mm, TR=1500 ms, TE=54 ms, thicknes 6 mm) for evaluation of perfusion using 1.5 T MR scanner with 8 channel array coil. For perfusion data postprocessing made we used in house developed software with: motion correction, slice time acquisiton correction, noise reduction with nonlinear filtering, ,,global vascular transport function“ evaluation to adequately calculate recirculation effects. With dynamic factor analysis we made methodological improvement to previously published model. Results: . MR angiography have shown significant colateral artery development within whole 1y period. „Dynamc continuous angiography“ using local AIF calculation have shown continuous trend towards normalisation of blood distribution during the whole year resulting in uniform blood distribution at the last measurement (one year after). Conclusion: Advances in diagnostics: more robust measurements ( higher S/N), multichanel coils faster measurements, PP-acquisition, scanning that covers whole brain, and new perfusion methodology gives new modality that clearly depicts development of vascular system after stroke. To our knowledge this is the first case that is so thoroughly examined and evaluated.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Patients with persistent decrease of flow velocities in the symptomatic middle cerebral artery - Radiological findings
C. Kremer    K. Abul-Kasim    A. Siennicki-Lantz     J. Petersson                                            
 
University Hospital Malmö UMAS Malmö Stroke Unit

SWEDEN

Background: The aetiology of persistent decrease of flow velocities in the middle cerebral artery (MCA) as measured by transcranial color coded sonography (TCCS) in acute stroke patients (pat.) is unclear. Persistent proximal high grade stenosis or branch occlusion of the symptomatic MCA due to embolism or atherosclerosis have been suggested. Methods: Between June 05 and January 07 consecutive pat. admitted with stroke or TIA to our stroke unit were examined within 12 h by TCCS. All pat. with a decrease of peak systolic velocities (PSV) >50% of the symptomatic MCA compared to contralateral MCA were included and followed-up after 9-18 months by TCCS. Pat. with persistent pathologies defined as PSV MCA asymmetry >20 % were examined by either CT- or MR- angiography > 363 d. Patients with extracranial ipsilateral occlusion of the internal carotid artery (ICA) were excluded. Results: Out of a total 509 pat. examined by TCCS 15 showed a decrease of PSV MCA at admission, three died at follow-up. Nine pat. showed persistent pathologies in the MCA five had an ipsilateral occlusion of the ICA at follow-up. In this ongoing study three patients have been examined. CT angiography after 364 d showed a distal occlusion of the MCA at the level of the bifurcation in one pat. MR angiography (417 d) displayed a moderate stenosis of the MCA at the level of the distal M1 and proximal M2 segment in one case, and an asymmetry of the MCA with a discrete narrowing of the whole M1 segment on the symptomatic side in the other (582 d). Discussion: In acute stroke patients causes of persistent decrease in PSV as measured by TCCS are heterogeneous and must not be due to occlusion or stenosis of the symptomatic MCA.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Middle cerebral artery narrowing: transcranial color-coded duplex sonography versus conventional non-imaging TCD
M.T.Swiat    M. Arkuszewski    G. Opala     J. Krejza                                            
 
Aging, Degenerative and CVD, Medical University of Silesia, Poland

POLAND

Purpose: To prospectively compare accuracies of transcranial color-coded duplex sonography (TCCS) and transcranial Doppler sonography (TCD) in diagnosis of middle cerebral artery (MCA) narrowing in the same population of patients using digital subtraction angiography (DSA) as the reference standard. Methods: Ultrasound studies were performed independently in 81 consecutive patients (mean age 53.9±13.9 years; 48 women, 33 men) routinely referred for DSA. TCCS operators were “blind” to results of TCD, and TCD operators were “blind” to TCD results. The MCA was graded as normal, narrowed ≤ 50% and >50%. The accuracy was estimated by total and partial areas (Az) under ROC curve. McNemar’s test was used to compare sensitivities at mean velocity thresholds of 120cm/s for detection of ≤50%, and 200cm/s for >50% narrowing. Results: DSA was not performed in 17 MCA’s, and 10 were not insonated because of lack of temporal acoustic windows. Angiographic MCA narrowing ≤50% was found in 21, and >50% in 10 out of 135 arteries. TCCS performed better than TCD in detection of ≤50% and >50% narrowing (total Az for mean velocity: 0.83±0.05, 0.77±0.05, and 0.95±0.02, 0.86±0.08, respectively), but the differences were not significant. TCCS outperformed TCD at high sensitivity regions of the ROC curve limited by 80% sensitivity for >50% narrowing: 0.17 versus 0.08, P<0.05, respectively. Sensitivity of TCCS at 120cm/s threshold (55%) was significantly better than sensitivity of TCD (39%) at similar specificity (P=0.038), while at 200cm/s sensitivities and specificities were not different. Conclusion: The overall accuracy of TCCS and TCD is similar, but TCCS is more sensitive than TCD in detection of MCA narrowing.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Vascular assessement of acute posterior circulation cerebral ischemia with power motion Doppler.
G. Tsivgoulis    V.K.Sharma    HT Nguyen     A.Y.Lao     A. Robinson    I. Heliopoulos     C. Bairaktaris     C. Piperidou    A.A.Ardelt   A.V.Alexandrov
 
Comprehensive Stroke Center, University of Alabama at Birmingham Hospital, Birmingham, Alabama

USA

Background: Evaluation of posterior cerebral circulation (PoCC) with single-channel transcranial Doppler (TCD) is technically challenging and less accurate in comparison with anterior circulation. Power Motion-Mode TCD (PMD-TCD) simultaneously displays spectral information, real-time flow signal intensity, and direction over 6 cm of intracranial space. We evaluated the diagnostic accuracy of PMD-TCD compared to angiography in detecting acute PoCC steno-occlusive disease. Methods: Consecutive patients presenting to the emergency room with symptoms of acute (<24 hours) cerebral ischemia underwent emergent (<48 hours) neurovascular evaluation with PMD-TCD and angiography (CTA, MRA or DSA). Previously published diagnostic criteria were prospectively applied to PMD-TCD interpretation independent of angiographic findings. Results: A total of 213 patients (119 men; mean age 65±16years; ischemic stroke 71%, TIA 29%) underwent emergent neurovascular assessment. Compared to angiography, PMD-TCD showed 17 true-positive, 8 false-negative, 6 false-positive and 182 true-negative studies in the PoCC [sensitivity 73% (55%-91%), specificity 96% (93%-99%), PPV 68% (50%-86%), NPV 95% (92%-98%), accuracy 93% (90%-96%)]. In 82% of true positive cases, PMD display showed flow signatures complementary to the spectral display: reverberating or alternating flow, distal basilar artery flow reversal, high-resistance and bruit flow signatures. In 8% of the population, PMD showed findings complementary to CTA/MRA: flow reversal in the distal vertebral artery (VA) with proximal intracranial VA occlusions, real-time embolization distal to a steno-occlusive artery, blunted flow signals throughout the intracranial VA with severe extracranial steno-occlusive disease, and alternating PMD signals indicating subclavian steal phenomenon. Discussion: PMD-TCD has good agreement with angiography in evaluating acute PoCC ischemia. PMD display can depict flow signatures that are complementary to.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Paradoxical arterial embolus via a PFO after DVT - lack of clinical evidence for such a syndrome
F. Cross    Y. Ali    H. Hina                                                    
 
Royal London Hospital

UNITED KINGDOM

Withdrawn!

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Effect of ulcerated carotid plaque in the stroke risk increasement
L. Saba    R. Sanfilippo    R. Montisci     G. Caddeo     G. Mallarini                                    
 
Azienda Ospedaliero Universitaria di Cagliari

ITALY

Purpose: Stroke is a leading cause of serious, long-term disability in the United States and atherosclerosis of the extracranial carotid arteries is its major cause. The purpose of this study was to study the diagnostic efficacy of multi-detector-row spiral CT angiography (MDCTA) in the analysis of patients with carotid plaque complicated by ulceration and to evaluate is relationship with stroke. METHODS: We retrospectively analysed 93 patients for a total of 186 carotid arteries by using MDCTA. We evaluated the following features: degree of the stenosis (on the basis of North American Symptomatic Carotid Endarterectomy Trial Criteria : NACET) the composition of the plaque, course anomalies and particularly the presence of ulcerations. For every patients the axial images, and ANGIO MIP and 3D reconstructions were studied. In a second phase the data have been compared with the surgical results whereas the MDCTA was indicative for the surgical intervention and with our stroke database RESULTS: MDCTA found 23 ulcerations and the surgical confirmation has underlined a 93% sensitivity: concordance between MDCTA ad surgical results was very high We found a positive correlation between presence of ulcerations and stroke presence (p < 0.05), CONCLUSION: Presence of ulcerated carotid plaque is a statistically significant risk factor for ischemic episodes.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Validation of Transcranial Doppler with CT Angiography in cerebral ischaemia: A Preliminary Experience in Singapore
V.K.Sharma    H.L.Teoh    B.KC.Ong     B.PL.Chan                                            
 
National University Hospital

SINGAPORE

Background: Transcranial Doppler (TCD) is an established tool for the non-invasive assessment of cerebral blood flow. Since TCD results vary with the skills and experience of the sonographer, it requires validation against contrast angiography. We evaluated the diagnostic accuracy of TCD against CT angiography (CTA) and the feasability of the latter as an additional screening tool in our acute ischaemic stroke patients. Methods: Acute stroke patients admitted to our tertiary care stroke centre undergo TCD for vascular assessment of major arteries of the circle of Willis. Randomly selected acute stroke patients with significant stenosis on TCD underwent high-resolution cranial CTA with multidetector helical scanner. CTA was performed within 24 hours of TCD and images were interpreted by a neuroradiologist blinded to TCD findings. An independent neurosonologist re-evaluated TCD if CTA findings were contradictory. Additional information by either modality was also noted. Results: Thirty two patients (20 men, mean age 56 ± 15years) with cerebral ischaemia and moderate (>50%) stenosis in >/=1 large intracranial arterial segment on routine TCD were evaluated by CTA. Compared with 46 segments of significant stenosis on CTA, TCD showed 35 true-positive, 5 false-positive and 6 false-negative results (sensitivity: 85%, positive predictive value: 88%). In 8 cases, TCD showed findings complementary to CTA (real-time embolisation, collateral flow patterns, evidence of distal M2 branch occlusion). Conclusion: TCD in our neurovascular laboratory shows a satisfactory agreement with cranial CTA in evaluating patients with cerebral ischaemia. TCD provides additional real-time dynamic findings complementary to information provided by CTA.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Leukoaraiosis and stroke risk: are they correlated ? A study by using MR.
L. Saba    R. Sanfilippo    R. Montisci     A. Porcu     G. Mallarini                                    
 
Azienda Ospedaliero Universitaria di Cagliari

ITALY

Background: Cerebral white matter changes, appearing as hypoattenuated areas in CT scans and as hyperintense areas in T2-weighted MR images, are common in elderly subjects and have been termed leukoaraiosis (LA). The purpose of this study was to evaluate if there is a correlation between the presence of leukoaraiosis (identified with MR) and stroke. METHODS: We retrospectively analyzed brain MR of 74 patients with age > 60 years (41 males and 33 females; age range 61-83). All of the examinations were performed on a 1.5T system (Intera, Philips Medical System) equipped with an head coil. After scouts, the examination protocol included axial 3D T1-weighted turbo gradient-echo images and axial T2-weighted images, which were obtained with a FLAIR sequence. We evaluated the FLAIR images of the 51 patients to rate LA extent by using the visual scale proposed by Fazekas. The we compared, by using statistical assessment, stroke data with results about LA RESULTS: We observed 22 patients with LA (average Fazekas Value Scale 2.7; SD 1.1) and 26 patients with stroke. We observed that hypertension and LA are statistically associated (p=0.0038; Odds Ratio 3.67) CONCLUSION: The results of our study indicate that stroke and leukoaraiosis have a statistically significant association.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Desynchronization of intracerebral circulation
Y.D.Volynsky    A.V.Gavrilov     M.G.Kirillov      N.A.Shamalov      V.I.Skvortsova                                    
 
Federal Stroke Center

RUSSIAN FEDERATION

Background: reveal and assessment of circulation (C) disturbances in different vascular segments in serial digital angiograms by the method of time-density-curves (TDCs).Methods. Digital subtraction cerebral angiography (DSCA) was performed in 37 patients with stroke. Cerebral C was assessed by our original program qualitative and semi-quantitative detection of contrast medium propagation through arteries, the capillary system and the venous and using contrast medium as the indicator simultaneously registered TDCs. Results. The shape and time parameters of TDCs reflect dynamics of blood velocity: in arteries the peak was replaced by flat return to an initial level (washout); on the contrary, in veins slow increase in concentration reached peak at the end of record. Time interval between the PC in intracranial part of internal carotid artery and in sinus confluence (SC) or in sinus transversus we assume as a mean time of brain C (mtcb). In control group, the full time of contrast propagation (T1) was 7.3 – 8.5 sec, mtcb was from 4.6 to 6.0 sec (55 – 79% of T1). TDCs in SC or in venous were almost identical and the divergence between the maximum value of curves was no more than 0.7 sec that reflected synchronism of C and venous return. In patients with stenosis, occlusions and kinking, we registered polytypic TDCs with the divergence of mtcb to 1.5 sec that reflected desynchronization of circulation (DC) in different vessel territories in brain hemisphere, as well as between different hemispheres. Conclusion. In the presence of stenosis, artery occlusion and kinking, the DC appears in one vessel territory or between different territories. We believe that the given mechanism plays a certain role in occurrence of an ischemic stroke.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Prediction of Early Risk of Cerebral Infarction by Stiffness Parameter Beta of Common Carotid Artery measured by Ultrasound
H. Mitsumura    K. Inoue    H. Furuhata                                                    
 
Department of Neurology and Medical Engineering Laboratory, Tokyo Jikei University School of Medicine, Tokyo

JAPAN

Background: Stiffness parameter beta (beta value) measured by ultrasound noninvasively can indicate the elastic properties of large arteries. Beta value, which is coefficient of exponential function epxressing the relationship between pressure gradient and arterial diameter change, is useful for evaluating early atherosclerotic change before morphological change. We aimed to evaluate the relationship between this parameter in common carotid artery (CCA) and cerebral infarction (CI). Methods: We used carotid ultrasonography (ALOKA ProSound SSD-alpha10) for examining 31 CI patients (8 female, 23 male, mean age 68.0 +/- 13.7 y.o.) and 38 healthy subjects (11 female, 27 male, mean age 42.5 +/- 19.4 y.o.), and measured beta value of bilateral CCA at 2.0cm proxymal side from bifurcation using echo-tracking method. We analyzed the relationship between beta value and age, and between beta value and max intima-media thickness (IMT) of CCA. Beta value of CI patients were compared statistically with those of healthy subjects in three age groups (A; 20~29y.o. 15 cases, B; 30-59y.o. 19 cases, C; over 60y.o. 35 cases). Results: Beta value showed a reasonable correlation with age in healthy subjects (R=0.72, p<0.0001). On the other hand, no correlation with age in CI patients (R=-0.0008, p=0.9967). Beta value showed no significant correlation with max IMT of CCA in CI patients (R=0.47, p=0.008). In group B, beta value of 8 CI patients was 12.5±3.2, which was significantly higher than 8.09 +/-1.5 in 11 healthy subjects (p=0.0064). However, in group C, there was no significant difference between 23 patients (11.1 +/- 4.7) and 12 healthy subjects (10.8 +/- 2.8). Discussion: Beta value is functional parameter for evaluating atheroscrerotic change of arteries, independently of morphological change of IMT in CI patients. It is anticipated that large beta value is useful for predicting an early risk of CI in middle age.

Session: Poster Session I
Date: Wednesday 14 May 2008  
Time: 12:30 - 14:00
Room: Agora 2

  
Can the vessel tortuosity cause strokes ?
L. Saba    R. Sanfilippo    R. Montisci     A. Porcu     G. Mallarini                                    
 
Azienda Ospedaliero Universitaria di Cagliari

ITALY

OBJECTIVES: Still remain an object of debated whether kinking or coiling of the internal carotid artery simply represents a morphological variation without clinical relevance. The purpose of our work was to evaluate whether the presence of tortuosity carotid arteries (kinking or coiling) is associated with symptomaticity. METHODS: We retrospectively studied 193 consecutive patients by using Multi-Detector-row CT. A total of 386 carotid arteries were assessed for the presence of vessel tortuosity by two experienced radiologists in consensus. Each exam was performed by using a multi-detector-row scanner; contrast material was injected into ante-cubital vein and arterial phase images were obtained by using a delay time variable from 11 to 19 and by using a 4-6 ml\ sec flow rate. Statistic analysis was performed to determine if an independent interaction existed between the presence of vessel tortuosity and symptomaticity. RESULTS: We detected a total of 43 kinkings and 24 coilings. We observed a significant statistical correlation between the presence of kinking and symptomaticity (P value with Yates correction = 0.006 and Odds Ratio 3.14), whereas we did not find a statistical correlation between coiling and symptomaticity (P value with Yates correction = 0.041 and Odds Ratio 1.55). CONCLUSION: Our data suggest that kinking and coiling are a frequent condition (incidence 18 %) and kinking can determine, especially in women and elderly patients, symptoms. Coiling seems not to be associated with symptomaticity. We think that Physician should consider kinking as a significant parameter in the stroke risk stratification.