Symptomatic Middle Cerebral Artery Research Articles

Multiple intracranial arterial stenosis influences the long-term prognosis of symptomatic middle cerebral artery occlusion.

BackgroundLarge intracranial occlusive vascular disease is a major contributor to the incidence of stroke worldwide, especially when it involves the middle cerebral artery (MCA). The data on the prognosis of symptomatic atherosclerotic MCA occlusions (MCAO) with concomitant intracranial arterial disease (MCAO-AIS) are limited. MCAO-AIS may reflect the extent of the atherosclerotic intracranial disease, we hypotheses that coexisting intracranial arterial disease influenced the prognosis of MCAO.MethodsPatients having survived at least one month after the initial ischemic stroke who suffered from atherosclerotic occlusion of the MCA were enrolled. According to their concomitant atherosclerotic intracranial arterial disease, the patients were assigned to one of two groups: the MCAO or the MCAO-AIS. All of the patients’ cerebrovascular risk factors were recorded. Recurrent ischemic stroke and death were the end-point events during the follow-up.ResultsA total of 232 patients (mean age 57.68 ± 9.50 years; 69% male) were analyzed. The mean follow-up time was 17.65 months. The end-point events occurred in 35 (15.09%) patients, resulting in an annual rate of 10.26%. The presence of MCAO- AIS was an independent risk factor associated with the patient’s prognosis in the cohort (OR = 3.426, 95% CI 1.261 to 9.308; p = 0.016), as well as gender and diabetes mellitus. The MCAO-AIS were more likely to experience ipsilateral ischemic strokes, but the difference was not statistically significant.ConclusionConcomitant intracranial arterial disease may influence the prognosis of patients with atherosclerotic MCAO. The result warrants further research in larger sample population.

High-resolution MRI of the vessel wall in patients with symptomatic atherosclerotic stenosis of the middle cerebral artery

Intracranial atherosclerosis is associated with recurrent ischemic stroke. High-resolution MRI (HR MRI) can provide information about atheroma in vivo. We aimed to analyze and compare vascular wall imaging characteristics between patients with symptomatic and asymptomatic atherosclerotic stenosis of the middle cerebral artery (MCA) using 3.0 Tesla HR MRI. The HR MRI protocol included four different scans: black blood T1-weighted, T2-weighted and proton density-weighted MRI, as well as three-dimensional turbo spin echo imaging techniques with multiplanar reconstruction. Plaque characteristics, including location, morphology, and signal intensity, were analyzed in 51 patients (29 symptomatic, 22 asymptomatic) with atherosclerotic stenosis of the middle cerebral artery. The vessel wall area, lumen area, and plaque area (PA) were also calculated and compared between the symptomatic and asymptomatic groups. We found that PA, remodeling index (RI), and positive remodeling (PR) prevalence were significantly greater in the symptomatic group than in the asymptomatic group (PA: p=0.033; RI: p=0.020; PR: p=0.032). Plaque location in the superior aspect of the vessel wall and irregular plaque surface were more frequently observed in the symptomatic group than in the asymptomatic group (superior location: p=0.031; irregular surface: p=0.036). Moreover, multivariate logistic regression identified plaque location on the superior wall as an independent predictor of symptomatic MCA stenosis (odds ratio: 4.471; p=0.039). Therefore, we can conclude that patients with symptomatic atherosclerotic stenosis of the MCA are more likely to have larger plaques, PR, superiorly located plaques, and irregular plaque surface. These characteristics are promising factors for stratifying stroke risk.

Abstract T P174: Intra-Arterial Signal on Arterial Spin Labeling Perfusion MRI Can Identify Stagnant Flow in Patients with Acute Middle Cerebral Artery Occlusion

Introduction: T2*-weighted imaging (T2*WI) can detect acute endovascular clots by the susceptibility vessel sign (SVS). Stagnant flow in front of middle cerebral artery (MCA) occlusion sites may contribute to intra-arterial high-intensity signal on arterial spin labeling (ASL) magnetic resonance imaging (MRI), making it another potential marker of MCA occlusion. We compared intra-arterial high-intensity signal and SVS in patients with symptomatic and asymptomatic MCA occlusion and patients without major vessel occlusion. Methods: We identified transient ischemic attack or ischemic stroke patients by (a) 3-T MRI, diffusion-weighted imaging, ASL, T2*WI, and magnetic resonance angiography (MRA) performed within 24 h after stroke onset and (b) the presence of MCA occlusion (n=34 patients) or the absence of major vessel occlusion (n=24 patients). We included asymptomatic patients with MCA occlusion (n=6). The presence or absence of intra-arterial high-intensity signal and SVS was recorded as was its coincidence with the presence of MCA occlusion on MRA. Results: In patients with acute ischemic stroke the sensitivity of intra-arterial high-intensity signal was significantly higher than of the SVS (88% vs 50%; p<0.05). The accuracy of intra-arterial high-intensity signal was also higher than of the SVS (93% vs 71%; p<0.05). Neither the intra-arterial high-intensity signal nor the SVS was observed in patients without major vessel occlusion. The presence or absence of intra-arterial high-intensity signal was highly consistent with the presence or absence of MCA occlusion on MRA (κ=0.74). Positivity for the intra-arterial high signal was higher in symptomatic than asymptomatic patients with MCA occlusion (88% vs 17%; p<0.05), suggesting that acute rather than chronic arterial occlusion contributes to the visibility of the intra-arterial high-intensity signal. Conclusions: The intra-arterial high-intensity signal on ASL could identify stagnant flow in front of occlusion sites due to acute arterial occlusion.

Abstract T P110: Impact Of Systolic Blood Pressure On Cerebral Hemoynamics Measure By Computational Fluid Dynamics In Patients With Intracranial Atherosclerosis

Background: Success in clinical trials of intracranial atherosclerosis (ICAS) hinges upon the definition of high-risk patients. Noninvasive computational fluid dynamics (CFD) of stenotic lesions may enhance therapeutic decision-making, yet the wide hemodynamic variation may limit the snapshot data of CFD. We determined whether different physiologic parameters may change downstream cerebral hemodynamics in patients with ICAS. Methods: Based on degree of stenosis, patients were divided into a moderate (50-69%) and severe group (70-99%). CFD models were made using CTA source images of patients with symptomatic middle cerebral artery stenosis. Inlet boundary conditions were defined using three ranges (2.5, 50, and 97.5 percentiles) of systolic BP (109.2, 158, and 225 mmHg) and hematocrit (27.3, 40.2, and 48.8). According to systolic BP and hematocrit, 9 distinct scenarios were simulated. Ratio of pressure was calculated using the simulated pressure at pre- and post-stenotic segments. Ratio of shear strain rate (SSR) and velocity were assessed between throat and proximal normal segment. A linear mixed model was used for the statistical analysis of repeated simulations. Results: Among the 56 patients, 32 (57.1%) patients had moderate stenosis and 24 (42.9%) had severe stenosis. Patients with severe stenosis showed unfavorable hemodynamics in terms of ratio of pressure, velocity, and SSR comparing with moderate stenosis group. A linear mixed model revealed that ratio of pressure was predicted by systolic BP X stenosis group interaction (p = 0.036). These pressure drops were associated with systolic BP (p<0.001), and stenosis group (p<0.001), not with hematocrit (p = 0.337). Ratios of SSR and velocity were only associated with stenosis group. Conclusions: Downstream blood flow may be significantly altered by systolic BP along with severity of stenosis. As individual patient’s specific anatomy influences hemodynamics, physiologic conditions may superimpose further changes in post-stenotic blood flow in patients with ICAS.

Reappraisal of primary balloon angioplasty without stenting for patients with symptomatic middle cerebral artery stenosis.

There is a controversy regarding the safety and efficacy of intracranial stenting. We describe our experience with primary balloon angioplasty without stenting for symptomatic middle cerebral artery (MCA) stenosis. All patients who underwent balloon angioplasty without stenting for MCA stenosis between 1996 and 2010 were retrospectively reviewed. We evaluated technical success rates, degrees of stenosis, and stroke or death within 30 days. Among patients who were followed-up for > 1 year we evaluated latest functional outcomes, stroke recurrence at 1 year, and restenosis. In total 45/47 patients (95.7%) were successfully treated. Average pre- and postprocedure stenosis rates were 79.9% and 39.5%, respectively. Three neurological complications occurred within 30 days: one thromboembolism during the procedure; one lacunar infarction; and one fatal intraparenchymal hemorrhage after the procedure. Stroke or death rate within 30 days was 6.4%. Thirty-three patients were available for follow-up analysis with a mean period of 51.5 months. The combined rate of stroke or death within 30 days and ipsilateral ischemic stroke of the followed-up patients within 1 year beyond 30 days was 9.4%. Restenosis was observed in 26.9% of patients and all remained asymptomatic. In our retrospective series, balloon angioplasty without stenting was a safe, effective modality for symptomatic MCA stenosis. For patients refractory to medical therapy, primary balloon angioplasty may offer a better supplemental treatment option.

Novel Approaches in Evaluating and Predicting the Potential Benefit of Middle Cerebral Artery Angioplasty & Stenting.

Our aim was to investigate a novel approach to perform preoperative evaluation patients who underwent middle cerebral artery (MCA) percutaneous transluminal angioplasty and stenting (PTAS). Sixty-five patients with symptomatic MCA stenosis of at least >70% who underwent MCA PTAS were enrolled. The multimodal stroke assessment using CT (MOSAIC) score was used to evaluate the preoperative condition. The Alberta Stroke Program Early Computed Tomography Scoring (ASPECTS) was used to assess the time-to-peak (TTP) parameter of Computer tomography perfusion (CTP). The factors potentially improving TTP following stenting were investigated. The prognostic value of the MOSAIC scores to predict TTP improvement was analyzed and compared. The MOSAIC score was a reliable prognostic tool for the degree of improvement of TTP (odds ratio 1.89 [1.08-2.07], P < .01) in patients with PTAS. The MOSAIC score had a higher prognostic accuracy than the degree of CBF deficit, the degree of stenosis, and the amount of tissue infarction. During 1-year follow-up, the stroke and death rate of was 8.1%, the in-stent restenosis rate was 6.5%, and good final outcome (modified Rankin Scale ≤ 2) was observed in 76.9%. The MOSAIC score can be reliably used in selecting patients with MCA stenosis for PTAS.

Intra-Arterial Signal on Arterial Spin Labeling Perfusion MRI to Identify the Presence of Acute Middle Cerebral Artery Occlusion

Background: The susceptibility vessel sign on gradient echo-type-T2*-weighted imaging is a well-known marker of arterial occlusion. Stagnant flow in front of the middle cerebral artery (MCA) occlusion sites may contribute to the intra-arterial, high-intensity signal on arterial spin labeling magnetic resonance imaging (MRI), making it another potential marker of MCA occlusion. We compared the intra-arterial, high-intensity signal and susceptibility vessel sign in patients with symptomatic MCA occlusion and patients without major vessel occlusion. Methods: We identified transient ischemic attack or ischemic stroke patients with (1) 3-T MRI performed within 24 h after clinical onset including arterial spin labeling, T2*-weighted imaging, and magnetic resonance angiography (MRA) and (2) either having MCA occlusion (n = 34 patients) or without major vessel occlusion (n = 24 patients). The intra-arterial, high-intensity signal was defined as an enlarged circular or linear bright hyperintensity within the artery. The susceptibility vessel sign was defined as an enlarged spot of hypointensity within the MCA, in which the diameter of the hypointense signal within the vessel exceeded the contralateral vessel diameter. The presence or absence of the intra-arterial, high-intensity signal and susceptibility vessel sign were assessed, along with their inter-rater agreement and consistency with the presence of MCA occlusion on MRA. Results: The intra-arterial, high-intensity signal was detectable in 30 patients (52%), and susceptibility vessel sign was observed in 17 patients (29%). The sensitivity of the intra-arterial high-intensity signal was significantly higher than that of the susceptibility vessel sign (88% vs. 50%; p < 0.05). The accuracy of the intra-arterial high-intensity signal was also higher than that of the susceptibility vessel sign (93% vs. 71%; p < 0.05). The intra-arterial high-intensity signal was situated in the proximal regions of the susceptibility vessel sign on T2*WI within the MCA. Neither the intra-arterial high-intensity signal nor the susceptibility vessel sign was observed in patients without major vessel occlusion. Inter-rater agreement was good for intra-arterial high-intensity signal detection (κ = 0.73) and moderate for susceptibility vessel sign detection (κ = 0.47). The presence or absence of the intra-arterial high-intensity signal was highly consistent with that of MCA occlusion on MRA (κ = 0.74). Conclusions: The intra-arterial high-intensity signal on arterial spin labeling appears to be useful to identify the presence of acute MCA occlusion and may be associated with stagnant flow in front of occlusion sites. The intra-arterial high-intensity signal may also be used to identify the occlusion site.

Stent-assisted coil embolization of a symptomatic middle cerebral artery aneurysm in an infant.

Pediatric intracranial aneurysms are rare and challenging to treat. Achieving efficacy and durability of aneurysmal occlusion while maintaining parent vessel patency requires innovative treatment strategies, especially in cases in which aneurysmal location or morphology pose substantial morbidity associated with microsurgical treatment. In the last 3 decades, endovascular treatments have had a remarkable evolution and are currently considered safe and effective therapeutic options for cerebral aneurysms. While endovascular techniques are well described in the English literature, the endovascular management of pediatric aneurysms continues to pose a challenge. In this report, the authors describe the case of a 9-month-old infant who presented with a 1-day history of acute-onset left-sided hemiparesis and left facial droop. Imaging revealed a large symptomatic saccular middle cerebral artery aneurysm. Treatment included successful stent-assisted aneurysm coiling. At follow-up, the patient continued to fare well and MR angiography confirmed complete occlusion of the aneurysm dome. This case features the youngest patient in the English literature to harbor an intracranial aneurysm successfully treated with stent-assisted coiling. Based on this experience, endovascular intervention with vascular reconstruction can be safe and effective for the treatment of infants and could further improve prognosis; however, further studies are necessary to confirm these findings.

Luminal thrombosis in middle cerebral artery occlusions: a high-resolution MRI study.

High signals within occluded vessels on T1-weighted fat-suppressed images (HST1) are highly suggestive of luminal thrombosis. We sought to investigate the feasibility of in vivo identification of luminal thrombosis in middle cerebral artery (MCA) occlusions using high-resolution magnetic resonance imaging (HR-MRI). We retrospectively reviewed the HR-MRI data of 25 patients with unilateral symptomatic MCA occlusion. HST1 were defined as an area of high signal within the cross-section of occluded MCA, the intensity of which was >150% of the signal of adjacent muscles. The prevalence of HST1 and their relationship to infarct sizes and infarct patterns were analyzed. The average time from stroke onset to HR-MRI examination was 9±6 days. There were 18 (72%) occluded vessels with HST1 on HR-MRI. HST1 were observed in 5/7 patients with a large territory infarct (≥1/3 MCA distribution) and 13/18 patients without (P=0.37). In the patients with non-large territory infarcts, the presence of HST1 was similar in those with and without border zone infarcts (9/13 vs. 4/5, P=0.42). It's feasible to in vivo identify luminal thrombosis in occluded MCA. HR-MRI is a potentially powerful tool for investigating the mechanisms of stroke due to MCA occlusions.

Safety and efficacy of the treatment for symptomatic atherosclerotic high-grade stenosis in middle cerebral artery with Wingspan stent

Objective To assess the safety and efficacy of the treatment for symptomatic atherosclerotic high-grade stenosis in middle cerebral artery with Wingspan stent.Methods The medical records of Wingspan stenting for 102 cases with symptomatic middle cerebral artery high-grade stenosis from February 2008 to May 2012 in our hospital were reviewed retrospectively.All of the patients suffered from ischemic stroke or transient ischemic attack ( TIA ) attributed to the atherosclerotic high-grade stenosis in middle cerebral artery and the stenosis of 70%to 99%was confirmed by DSA before the stenting procedure.All the stroke, death, TIA within 30 days after the stenting procedure or during the follow-up beyond 30 days were observed and recorded.In-stent restenosis were recorded after DSA or CTA was performed 6 months later.χ2 test or Fisher exact test was used to compare in-stent restenosis rate among patients with different clinical and pathological conditions.Results Stenting procedure were successfully performed in 100 patients (98.0%,100/102).The mean degree of stenosis was reduced from (81.0 ±8.4)% to (15.3 ±6.7)%right after surgery.Eight adverse cardiovascular events (7.8 %, 8/102) occured within 30 days ,including seven stroke or death ( 6.9%, 7/102 ) and 1 TIA.The mean clinical follow-up duration was ( 29 ± 15) months in 82 patients, and 9 ischemic events were documented (4 cases of ipsilateral recurrent stroke , 3 cases of ipsilateral TIA, and 2 cases of contralateral ischemic stroke ).The mean radiological follow-up duration was (11 ±9) months in 55 patients.Among them, 8 patients (14.3%) had in-stent restenosis and 3 patients had symptomatic restenosis.The restenosis rate in patients with age ≤49 years.(25.0%,7/28) was higher than those with age >49 years ( 3.7%,1/27 ) ( P>0.05 ).The restenosis rate in patients with lesion size>7.5 mm(25.0%,7/28) was higher than those with lesion size ≤7.5 mm (3.7%,1/27)(P>0.05).Conclusions The treatment of symptomatic middle cerebral artery high-grade stenosis with Wingspan system was relatively safe and associated with a low perioperative complication rate.The long-term efficacy of the treatment for symptomatic atherosclerotic high-grade stenosis in middle cerebral artery with Wingspan stent is prominent. Key words: Atherosclerosis ; Middle cerebral artery ; Stent ; Radiology,interventional ;

Microembolic Signals Detected with Transcranial Doppler Sonography Differ between Symptomatic and Asymptomatic Middle Cerebral Artery Stenoses in Northeast China

Although microembolus monitoring has been widely used for ischemic cerebrovascular disease, the clinical significance of microembolic signal (MES) in asymptomatic middle cerebral artery (MCA) stenosis remains unclear. We aim to investigate the frequency of MES and the value of MES in predicting ischemic stroke secondary to asymptomatic MCA stenosis. From June 2011 to December 2012, microembolus monitoring was performed in 83 asymptomatic and 126 symptomatic subjects. By comparing the demographics and risk factors between the symptomatic and asymptomatic subjects, we found that the ratio of male sexuality and smoking history differed (101/126 vs 43/83, and 88/126 vs 38/83, respectively, p<0.01). The frequency of MES was significantly higher in the symptomatic group than in the asymptomatic group (49/126 vs 2/108, p<0.01). Specifically, the frequency of MES in the symptomatic and asymptomatic groups with mild stenosis, moderate stenosis, severe stenosis and occlusion groups was 4/18 (22.22%) vs 0/30 (0), 13/31 (41.94%) vs 1/28 (3.57%), 30/62 (48.39%) vs 1/39 (2.56%), 2/15 (13.33%) vs 0/11 (0), respectively. Except for the occlusive group, the frequency of MES is correlated with stenosis degree and symptom. Two patients in the asymptomatic group were found positive for MES, and the MES number was 1 for both. During the one-year follow-up, neither of them developed ischemic stroke. In conclusion, MES detected with TCD differs between symptomatic and asymptomatic MCA stenoses. Due to the low frequency, the value of MES as a predictor of subsequent ischemic stroke in patients with asymptomatic MCA stenosis might be limited.

Mechanism of Acute Ischemic Stroke in Patients with Severe Middle Cerebral Artery Atherosclerotic Disease

Intracranial atherosclerotic disease (ICAD) is one of the most common causes of ischemic stroke worldwide. Although the pathogenesis of cerebral infarct in ICAD has been reported from autopsy series, the mechanism of stroke is not well known. This study used baseline perfusion imaging and diffusion-weighted imaging (DWI) or computerized tomography (CT) imaging to help identify the mechanism of stroke in ICAD involving the middle cerebral artery (MCA). We retrospectively reviewed baseline CT or magnetic resonance (MR) perfusion studies and diffusion-weighted MR imaging or CT scans in patients with severe symptomatic MCA stenosis. Perfusion scans were classified according to stage of perfusion deficit, and the acute stroke patterns were categorized as borderzone, cortical, or perforating artery infarcts according to DWI or noncontrast CT. Fifteen patients were included in this analysis. All 15 patients had some type of borderzone infarct. Six had borderzone infarct only, 4 had borderzone and cortical infarcts, and 5 had borderzone, cortical, and perforating artery infarcts. Thirteen of the 15 patients had baseline perfusion deficits. In patients with severe MCA ICAD, the mechanism of stroke is multifactorial, but hemodynamic insufficiency plays a significant role. This finding is important in selecting a subgroup of patients who may benefit from revascularization.

Primary angioplasty for symptomatic atherosclerotic middle cerebral artery stenosis.

ObjectiveThe objective of this study is to evaluate the clinical and angiographic outcomes after primary balloon angioplasty in patients with symptomatic middle cerebral artery (MCA, M1 segment) stenosis refractory to medical therapy.Materials and MethodsEleven patients with intracranial stenosis were treated with primary balloon angioplasty. All patients had MCA stenosis with recurrent transient ischemic attack (TIA). The indication for balloon angioplasty was patients with significant MCA stenosis: 1) age older than 18 years with recurrent or progressive TIA or infarction despite optimal medical therapy, including anti-coagulation, dual anti-platelet, and anti-lipid medication; 2) previous ischemic events or asymptomatic severe stenosis (more than 50%) with poor collateral cerebral circulation, or diminished cerebral perfusion on single photon emission computed tomography before and after administration of the intravenous dosage of acetazolamide.ResultsThe median age of patients was 53 years (range 44-79). The technical success rate was 100%. Mean pretreatment stenosis degree was 83.63 ± 9.53% and 29.1 ± 15.4% before and after angioplasty, respectively. Procedural-related complications occurred in four of 11 patients (36%), but none of the patients had permanent neurological deficit. All patients were available for an average follow-up period of 19.4 ± 5.1 months. One patient had a stroke in the territory of angioplasty at two months after angioplasty. The stroke free survival rate at 30 days and 12 months was 100% and 91%, respectively. Restenosis over 50% was observed in three of 11 patients (27%); all were asymptomatic.ConclusionIntracranial angioplasty for symptomatic MCA stenosis refractory to medical therapy can be a treatment option to reduce the risk of further TIA or stroke.

Tissue Kallikrein Preventing the Restenosis after Stenting of Symptomatic MCA Atherosclerotic Stenosis (KPRASS)

Many recent studies suggest that the kallikrein-kinin system play a protective role in the impairment of vascular smooth muscle cells and vascular endothelial cell. The study aims to determine whether tissue kallikrein is efficacy for preventing the long-term in-stent restenosis after stenting of symptomatic atherosclerotic stenosis of the middle cerebral artery M1 segment. This is a Phase II, randomized, single-blinded, controlled trial. In line with SAMMPRIS stenting indications, patients (n = 90) with the symptomatic the middle cerebral artery M1 segment stenosis ≥ 70% and successfully treated with stent will be enrolled. Eligible patients will be randomized using computer generated numbers, and allocated to receive tissue kallikrein treatment or not. Patients in tissue kallikrein treatment group will be prescribed with intravenous infusion of tissue kallikrein (0.15 PNAU/d, dissolved in 100 ml saline) for 7 days after stenting and then oral administration of pancreatic kallikrein enteric-coated tablet (240 U, 3/d) to the end of study. As the foundation treatment, all the enrolled patients will receive aspirin (100 mg/d), clopidogrel (75 mg/d), and atorvastatin (20 mg/d) for the first 6 months and continue with the combination of aspirin and atorvastatin at the previous dosage. Patients will be evaluated at 1, 6 and 12 months after stenting. The primary outcomes are the in-stent restenosis rate, new stroke or aggravation of the previous ischemic stroke ipsilateral to the severe stenotic artery. Secondary outcomes include stroke of other artery territories, myocardial infarction and vascular death. Modification of stroke knowledge, exercise and diet habit, smoking cessation and available laboratory data will also be recorded. As our pilot study, tissue kallikrein would be expected to prevent the long-term in-stent restenosis after stenting of the symptomatic middle cerebral artery dramatically.

Arterial Spin Labeling Perfusion MRI in Children and Young Adults with Previous Ischemic Stroke and Unilateral Intracranial Arteriopathy

Background: Little is known about cerebral blood flow (CBF) in young patients with ischemic stroke caused by an intracranial arteriopathy. Arterial spin labeling (ASL) perfusion is a noninvasive technique for measuring CBF. We aimed to investigate whether, in young patients with unilateral intracranial arteriopathy and previous ischemic stroke, CBF is compromised in noninfarcted brain areas of the symptomatic hemisphere and whether this is related to the severity of the arteriopathy. Methods: Patients aged 5-50 years, with previous middle cerebral artery (MCA) territory infarction and a unilateral intracranial arteriopathy, underwent magnetic resonance imaging (MRI), MR angiography and pseudocontinuous ASL perfusion MRI. We assessed the severity of stenosis of arteries that fed the symptomatic MCA territory, quantified CBF in the noninfarcted cortex of both MCA territories and generated CBF maps for visual CBF interpretation. Results: A total of 17 patients were included (median age 29 years, range 5-49, 29% male). We found a similar median quantified CBF in the symptomatic and asymptomatic MCA territories (86 ml·100 g^-1·min^-1). CBF maps showed hypoperfusion in the symptomatic MCA territory in 59% of patients compared to 18% based on quantified CBF. Patients with a severe arteriopathy more often showed hypoperfusion on CBF maps than patients with a mild arteriopathy. In 53% of patients, small foci of increased signal intensity were visible on CBF maps around an area of hypoperfusion, indicating vascular artifacts. In these patients, we found large intraindividual variation in the quantified CBF in the symptomatic hemisphere. In 47% of patients, the visual interpretation of perfusion did not correspond with the quantified CBF. Conclusions: This study shows that more than half of young patients with previous ischemic stroke in the MCA territory and a unilateral intracranial arteriopathy have hypoperfusion in the noninfarcted cortex of the symptomatic hemisphere when CBF is visually assessed using a CBF map, in particular in patients with a severe arteriopathy. In the same patients, quantification of CBF shows hypoperfusion in the symptomatic hemisphere in only 18%. This discrepancy is caused by labeled blood within the arteries that has not yet reached the tissue at the time of imaging. Visual assessment can show hypoperfusion, while the quantified CBF in a similar region appears higher when the intravascular labeled blood is included in the region of interest. Further research should focus on elucidating whether cerebral perfusion deficits in young stroke patients with intracranial arteriopathy might help to identify patients who are at risk of poor outcome or stroke recurrence.

Prognostic effect of posterior cerebral artery laterality on middle cerebral artery occlusion

To explore the prognostic value of posterior cerebral artery (PCA) laterality in patients with symptomatic middle cerebral artery (MCA) occlusion on standard medical therapy. Forty consecutive patients with first onset isolated atherosclerotic occlusion in M1 segment of MCA received medication from June 2009 to March 2013. All patients underwent magnetic resonance angiography (MRA) for assessment of PCA laterality. Clinical data and modified Rankin Scale (mRS) at 3 months were compared between PCA positive and negative patients. Retrospective analysis was performed on their clinical and imaging data. Among them, 20 patients (50%) showed PCA laterality on MRA and 32 patients (80%) completed a 3-month follow-up. No significant difference existed between PCA laterality positive and negative groups in a favorable outcome of mRS = 0-1 at 3 months (P = 0.433). The presence of PCA laterality showed no prognostic effect on patients with symptomatic MCA occlusion on standard medical therapy.

Evaluation of cerebrovascular reserve using xenon-enhanced CT scanning in patients with symptomatic middle cerebral artery stenosis

Cerebrovascular reserve (CVR) is an important prognostic factor in patients with major cerebral arterial steno-occlusive disease. However, few studies have examined CVR in symptomatic intracranial stenosis without ipsilateral extracranial internal carotid artery stenosis. This study sought to evaluate CVR in patients with symptomatic middle cerebral artery (MCA) stenosis using xenon-enhanced computed tomography (Xe/CT) with acetazolamide (ACZ) challenge. Twelve patients with symptomatic MCA stenosis were recruited. All patients were examined by Xe/CT to quantitatively measure resting cerebral blood flow (CBF) and received ACZ challenge to evaluate CVR. For resting CBF, no significant differences were found between the sides in four regions of interest. After the ACZ challenge test, the CVR was significantly different between hemispheres (ipsilateral versus contralateral CVR: 12.9±24.3% versus 28.0±16.8%, respectively; p=0.005) and in the MCA territory (ipsilateral versus contralateral CVR: 8.7±24.7% versus 29.3±24%, respectively; p=0.003). However, no significant differences in CVR were detected between cortical comparisons and white matter comparisons from the two sides. Thus, ACZ-challenge Xe/CT is useful for the measurement of CBF and CVR in these patients. Impaired CVR is an important characteristic of patients with symptomatic MCA stenosis.

High-resolution Magnetic Resonance Imaging of Symptomatic Middle Cerebral Artery Dissection

Dissection of the middle cerebral artery (MCA) is less frequent compared with dissection of vessels in the vertebrobasilar system or dissection of the carotid artery. High-resolution cross-sectional magnetic resonance imaging (HRMRI) has emerged as a potential technique for atherosclerotic plaque imaging in MCA. We enrolled 3 patients with MCA dissection on whom HRMRI was performed for evaluation of MCA stenosis. Two patients had an embolic infarction in the MCA territory and focal dissection. One patient had a massive infarction in the MCA territory and long-segment dissection of the MCA. On HRMRI, our objectives had an intimal flap with patency of the lumen and 1 had extensive hemorrhaging in the false lumen.

Abstract 159: Symptomatic MCA Plaque Enhancement on High Resolution MRI

Objective High-resolution MRI (HR-MRI) is the useful modality to evaluate the characteristics of intracranial arterial atherosclerotic plaque. The purpose of this study was to evaluate the relationship between the enhancement of middle cerebral artery (MCA) plaque on post-contrast HR-MRI and ischemic stroke. Materials and methods Thirty four patients (19 females, 15 males, mean age: 69.0 years ± 12.1) with isolated MCA stenosis of 50% or more were enrolled in this study. Post-contrast axial 3 dimensional T1-weighted VISTA sequence (TR, 350 ms; TE, 19.51 ms; matrix, 360x299; field of view, 113x180; section thickness, 1 mm; total scan time, 3 min 4 sec) was acquired for assessment of the plaque enhancement. The subjects were divided into two groups (symptomatic or asymptomatic), based on the presence of recent ischemic stroke in the same ipsilateral MCA territory as the MCA stenosis. The signal intensity of plague in the stenotic segment and the CSF were measured by ROI on T1-VISTA. It is subdivided the MCA stenosis into moderate stenosis and severe stenosis by the stenotic degree of 80%. The plaque-to-CSF contrast ratio, the stenotic degree, and the clinical parameters (age, sex, atherosclerotic risk factors, ESR) between two groups were compared. Multivariate logistic regression analysis was used to test for the association of contrast ratio, stenotic degree, and the clinical parameters with ischemic stroke. Results Twenty patients had symptomatic MCA stenosis, and 14 patients had asymptomatic lesion. The plaque-to-CSF contrast ratio was a statistically significant difference between the symptomatic group (mean 5.29 ± 1.78) and asymptomatic group (3.67 ± 1.38). In the multivariate logistic regression analysis, the plaque-to-CSF contrast ratio was the only independent factor for ischemic stroke (OR=7.5, P&lt;0.05). Conclusion The results of our study showed that the enhancement of plaques were significantly higher in symptomatic groups than in asymptomatic groups. It is assumed that the enhancement of symptomatic plaques could be related with the vulnerability.

Persistent middle cerebral artery occlusion associated with lower body temperature on admission

BackgroundLow body temperature is considered neuroprotective in ischemic stroke, yet some studies suggest that low body temperature may also inhibit clot lysis and recanalization. We hypothesized that low body temperature was associated with persistent proximal middle cerebral artery (MCA) occlusion in patients with acute ischemic stroke presenting with symptoms of proximal MCA occlusion, suggesting a possible detrimental effect of low body temperature on recanalization.MethodsAll patients with acute ischemic stroke admitted to our Stroke Unit between February 2006 and August 2012 were prospectively registered in a database. Computed tomography (CT) angiography was performed in patients admitted <6 hours after stroke onset. Based on presenting symptoms, patients were classified according to the Oxford Community Stroke Project classification (OCSP). Patients with symptomatic proximal MCA occlusion were compared to patients with total anterior circulation infarct (TACI) without MCA occlusion on CT angiography.ResultsDuring the study period, 384 patients with acute ischemic stroke were examined with CT angiography. A total of 79 patients had proximal MCA occlusion and 31 patients had TACI without MCA occlusion. Median admission body temperatures were lower in patients with MCA occlusion compared to patients without occlusion (36.3°C versus 36.7°C, P = 0.027). Admission body temperature <36.5°C was independently associated with persistent MCA occlusion when adjusted for confounders in multivariate analyses (odds ratio 3.7, P = 0.007).ConclusionOur study showed that low body temperature on admission was associated with persistent proximal MCA occlusion. These results may support a possible detrimental effect of low body temperature on clot lysis and recanalization.