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Background and Purpose: The development of high-resolution magnetic resonance imaging (HR-MRI) has enabled submillimeter-level evaluation of intracranial artery plaque and luminal thrombus. We sought to investigate the value of HR-MRI in assessing the pathogenesis of acute intracranial artery thrombus., Methods: We examined the presence of intracranial thrombus on three-dimensional T1-weighted HR-MRI in acute ischemic stroke patients with intracranial artery occlusion on magnetic resonance angiography. We defined two thrombus-related HR-MRI features (peri-thrombus plaque and distal residual flow beyond the thrombus) and analyzed their association with potential embolic sources., Results: Luminal thrombus and a shrunken artery without luminal thrombus were detected in 162 (96.4%) and six (3.6%) of 168 patients with intracranial artery occlusion, respectively. Among 111 patients with culprit major artery thrombus, peri-thrombus plaques were observed in 46.8% and distal residual flow beyond the thrombus in 64.0%. Patients with peri-thrombus plaque had a higher prevalence of diabetes (44.2% vs. 25.4%; p = 0.037), a lower prevalence of potential sources of cardioembolism (0% vs. 16.9%; p = 0.002), and a nonsignificantly lower prevalence of potential embolic sources from extracranial arteries (9.6% vs. 20.3%; p = 0.186) than those without. Patients with distal residual flow beyond the thrombus had a lower prevalence of potential sources of cardioembolism (1.4% vs. 22.5%; p < 0.001) and smaller infarct volumes (5.0 [1.4-12.7] mL vs. 16.6 [2.4-94.6] mL; p = 0.012) than those without., Conclusions: Our study showed that HR-MRI helps clarify the pathogenesis of acute intracranial artery thrombus. The presence of peri-thrombus plaque and distal residual flow beyond the thrombus favor the stroke mechanism of atherosclerosis rather than cardioembolism., (© 2023 European Academy of Neurology.)

Background: We aimed to quantitatively assess the vessel morphology of middle cerebral artery (MCA) atherosclerosis and explore its value in discriminating plaque types., Methods: Patients were selected from a high-resolution magnetic resonance imaging (HRMRI) study from January 2007 to December 2015. One hundred and three patients with acute cerebral infarcts due to MCA stenosis (>50%) and eighty-nine patients with asymptomatic MCA stenosis (>50%) were included. Quantitative measurements of MCA morphology, including lumen area, outer-wall and wall area at stenotic site and reference site, stenotic degree, plaque length, remodeling index and plaque eccentricity, were performed on HRMRI with observers blinded to clinical presentations. Firth's penalized logistic regression analysis was used to construct a symptomatic plaque score (SPS) model. Then, the HRMRI data of 39 patients prospectively enrolled from January 2016 to January 2017 were used to validate the SPS model., Results: The HRMRI data of 103 patients with symptomatic MCA stenosis and 89 patients with asymptomatic MCA stenosis in the construction cohort were analyzed. Four main factors were found to be associated with symptomatic plaques: stenotic lumen area ≥ 2.28 mm 2 , stenotic wall area ≥ 8.88 mm 2 , plaque length and presence of an eccentric plaque. Summation of each logistic regression coefficient multiplying the corresponding score produced the SPS with an area under curve (AUC) of 0.890 on receiver operating characteristics analysis. Validation of the score of 39 plaques (19 symptomatic and 20 asymptomatic) revealed an AUC of 0.862, confirming the continued diagnostic ability. When the data were pooled in all 235 plaques, the optimal cutoff score of discriminating symptomatic and asymptomatic plaques was 2.79 (SPS ≥ 2.79 indicating a symptomatic plaque) with AUC = 0.886, sensitivity 81.1% and specificity 80.5%., Conclusions: The quantitative analysis of MCA morphology can independently and accurately discriminate plaque types, suggesting its close association with the underlying pathophysiology. Further prospective studies are required to verify whether the SPS model is clinically valuable in monitoring plaque progression and assessing the vulnerability., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Objective: We aimed to investigate the geometric features of the middle cerebral artery (MCA) and their relevance to plaque distribution and ischemic stroke., Methods: We reviewed our institutional vessel wall imaging database. Patients with symptomatic MCA atherosclerosis, asymptomatic MCA atherosclerosis, or without MCA atherosclerosis were included. The MCA geometric features, including M1 segment shape and M1 curve orientation, were defined on magnetic resonance angiography. Plaque distribution and other plaque parameters were identified on vessel wall imaging. The association among MCA geometric features, plaque distribution, and ischemic stroke were analyzed., Results: A total of 977 MCAs were analyzed (87 atherosclerotic symptomatic MCAs, 459 atherosclerotic asymptomatic MCAs, and 431 plaque-free MCAs). Overall, curved M1 segments were the predominant shape across all groups. In 91.1% of curved atherosclerotic MCAs, the plaque involved the inner wall of the curve. Plaque not involving the inner wall was shorter ( p < 0.0001) and thinner ( p = 0.005) compared to plaque involving the inner wall. Inferior plaque was observed in 39.9% of inferior-oriented M1 curves compared to 21.7% in non-inferior-oriented M1 curves ( p < 0.0001). The absence of an inferior-oriented M1 curve (odds ratio 0.45, 95% confidence interval 0.27-0.77) and presence of superior plaque (odds ratio 2.67, 95% confidence interval 1.52-4.67) were independently associated with stroke after adjusting for plaque length and thickness, degree of stenosis, and remodeling ratio., Conclusions: MCA geometric features are associated with plaque distribution and stroke. Our findings provide insight into the vascular pathophysiology of MCA atherosclerosis., (© 2018 American Academy of Neurology.)

Background: The plaques at the dorsal or lateral wall of basilar artery (BA) are associated with pontine infarcts. We sought to explore the correlations between vertebrobasilar artery geometry and BA plaque locations., Methods: We retrospectively analyzed the imaging and clinical data of 84 patients with BA atherosclerosis. On three-dimensional time-of-flight images, a side to side diameter difference of bilateral vertebral artery (VA) and BA bending were assessed. The vertebrobasilar artery geometry was qualitatively classified into four basic configurations: Walking, Tuning Fork, Dominant-Lambda, and Hypoplasia-Lambda. On high-resolution magnetic resonance imaging, the plaques were categorized based on the involvement of the ventral, dorsal, or lateral sides of BA wall. The relationships between vertebrobasilar artery geometry parameters and plaque locations were analyzed., Results: Left VA dominance was identified in 28(33%) patients, and right VA dominance in 22(26%) patients. BA bending were detected in 49 patients. There were no significant correlations between the diameter difference/ratio of VA diameters and plaque locations, or between BA bending and plaque locations. BA plaques were evenly distributed in the vertebrobasilar arteries with Tuning Fork and Dominant-Lambda configurations. In Hypoplasia-Lambda group, however, plaques were more frequently located at the dorsal wall (58.57%) than at the ventral (14.43%) and lateral wall (26.71%; P = 0.001). In Walking group, the plaques more likely occurred at the lateral (49.79%) and dorsal (35.07%) wall than at the ventral wall (14.86%, P = 0.02)., Conclusions: The geometric configurations of vertebrobasilar artery strongly influence the BA plaque locations. Further prospective studies are warranted to testify whether Hypoplasia-Lambda and Walking configurations are independent risk factors for pontine infarcts.

Background: The underlying pathophysiology of BA distribution is unclear and intriguing. Using high-resolution magnetic resonance imaging (HR-MRI), we sought to explore the plaque distribution of low-grade basilar artery (BA) atherosclerosis and its clinical relevance., Methods: We retrospectively analyzed the imaging and clinical data of 61 patients with low-grade atherosclerotic BA stenosis (<50%). On HR-MRI, the plaques were categorized based on the involvement of the ventral, dorsal, or lateral sides of BA wall. A culprit plaque was defined if it was on the same slice or neighboring slices of symptomatic pontine infarcts and played a probable causal role (dorsal plaques with median pontine infarcts or lateral plaques with ipsilateral pontine infarcts). The relationships between plaque distribution and clinical presentations were analyzed., Results: Twenty-five symptomatic and thirty-six asymptomatic BAs with 752 HR-MRI image slices were studied. The average length of BA atherosclerosis plaques was 12.16 ± 5.61mm (10.30 ± 6.44mm in symptomatic and 13.46 ± 7.03mm in asymptomatic patients, p = 0.079). The plaque distribution was similar at ventral (29.0%), dorsal (37.6%) and lateral walls (33.1%). The BA plaques in symptomatic patients were more frequently located at the dorsal (42.5%) and lateral (41.2%) walls than at the ventral walls (16.1%; P < 0.05). Compared with symptomatic patients, asymptomatic patients more likely had their plaques distributed at the ventral walls (P = 0.022). Culprit plaques were observed in 85.0% (17/20) pontine infarcts in symptomatic patients and only 14.3% (2/14) silent pontine infarcts in asymptomatic patients (p < 0.001)., Conclusions: Low-grade BA atherosclerosis has a long distribution and evenly involves ventral, dorsal and lateral walls. The plaques at dorsal and lateral walls are associated with symptomatic pontine infarcts but not with silent infarcts.

Background and Aims: Using high-resolution magnetic resonance imaging (HR-MRI), we aimed to investigate the abnormalities of intracranial artery in relation to cerebral small-vessel diseases (SVD)-related ischemic stroke and white matter lesions (WMLs)., Methods: Routine cranial MRI and HR-MRI were performed on consecutive patients with a SVD-related acute deep brain infarct (DBI) in the territory of middle cerebral artery (MCA), patients with SVD-related WMLs, and age-matched controls. The presence and distribution of MCA plaque and the area of MCA lumen and wall were comparatively analyzed among the groups., Results: A total of 2340 image slices of 260 vessels in 130 subjects (57 with an acute DBI, 28 with WMLs, and 45 control subjects) were analyzed. In the patients with a DBI, eccentric plaques were identified in 26 vessels ipsilateral and 24 vessels contralateral to the ischemic lesions. Superior-wall plaques of MCA were observed more frequently ipsilateral than contralateral to the infarcts (69.2% vs. 37.5%, P = 0.025). Compared to the controls, larger outer-wall boundary area (P ≤ 0.017) and wall area (P < 0.001) were observed in the patients, while larger lumen was only observed in the WMLs group (P < 0.001)., Conclusions: Middle cerebral artery superior-wall plaques are associated with acute DBIs, while MCA lumen dilation is associated with WMLs., (© 2014 John Wiley & Sons Ltd.)

Purpose: Even after comprehensive evaluations, the etiology of 25-39% ischemic stroke remains unknown, and such a stroke often labeled as cryptogenic. Herein, we report a young patient with "cryptogenic stroke" caused by an intracranial atheroma, which was only visible on high-resolution magnetic resonance imaging (HR-MRI)., Case Report: A 22-year-old male presented with acute right limb weakness. He was a smoker and had been in good health without hypertension, diabetes, hyperlipidemia or cardiac diseases. Diffusionweighted imaging revealed ischemic lesions at left basal ganglia and left centrum semiovale. Magnetic resonance angiography (MRA) showed left middle cerebral artery (MCA) stenosis (>50%). Six days later, this stenosis disappeared on repeated MRA and digital subtraction angiography. HRMRI suggested a superior-wall atheroma at the location where the stenosis previously existed. We hypothesize heavy thrombosis formation at the surface of atheroma may have caused a stenosis, while the subsequent spontaneous fibrinolysis may gradually eliminate this thrombosis and make the stenosis invisible., Conclusion: Intracranial non-stenotic atheroma is a potential cause of a stroke. Our observation support HR-MRI as a tool for the etiology evaluation in young patients with cryptogenic stroke.

Objective: Little is known about the composition of middle cerebral artery (MCA) plaques and how they relate to clinical status. Using high-resolution magnetic resonance imaging (HR-MRI), we aimed to examine the occurrence of high signal on T1-weighted fat-suppressed images (HST1) of MCA plaques, which are highly suggestive of fresh or recent intraplaque hemorrhage., Methods: We retrospectively analyzed the HR-MRI and clinical data of 107 adult patients with high-grade (>70%) MCA stenosis. On HR-MRI, HST1 within an MCA plaque was defined as an area with an intensity >150% of the signal of adjacent muscles. The relationship between HST1 and clinical presentations was analyzed., Results: A total of 109 stenotic MCAs (46 symptomatic and 63 asymptomatic) on 981 image slices were analyzed. HST1 was revealed on HR-MRI in 11 vessels (10.1%, 9 symptomatic and 2 asymptomatic). The occurrence rate of HST1 between symptomatic and asymptomatic MCAs was significantly different (19.6% vs 3.2%, p = 0.01)., Interpretation: HST1 within MCA plaque on HR-MRI is associated with ipsilateral stroke. Our results provide new insight into the vascular biology of MCA atherosclerosis., (Copyright © 2012 American Neurological Association.)

Background and Purpose: Microanatomy studies reveal that most penetrating branches of middle cerebral artery (MCA) arise from the dorsal-superior surface of the trunk. Using high-resolution MRI, we sought to explore the plaque distribution of MCA atherosclerosis and its clinical relevance in relation to the orifices of penetrating arteries., Methods: We retrospectively analyzed the imaging and clinical data of 86 patients with atherosclerotic MCA stenosis. On high-resolution MRI, plaques were categorized based on the involvement of the superior, inferior, ventral, or dorsal MCA wall. The relationship of plaque distribution and clinical presentation was analyzed., Results: A total of 92 stenotic MCAs (40 symptomatic and 52 asymptomatic) on 828 image slices were studied. Overall, of the 251 slices with identified plaques, plaques were more frequently located at the ventral (44.8%) and inferior (31.7%) wall as compared with the superior (14.3%) and dorsal wall (9.0%; P<0.001). Symptomatic MCA stenosis had more superior (P=0.016) and less inferior (P=0.023) wall plaques than asymptomatic stenosis. Within the group of symptomatic MCA stenosis, vessels with penetrating artery infarctions had more superior (P=0.001) but less ventral (P=0.038) and inferior (P=0.024) plaques than without penetrating artery infarctions., Conclusions: MCA plaques tend to locate opposite to the orifices of penetrating arterial branches. Further studies are required to investigate whether MCA plaque distribution is an independent determinant of stroke occurrence and its subtypes.

Background and purpose Methods Results Conclusions Parent artery atherosclerosis is an important aetiology of recent subcortical ischaemic stroke (RSIS). However, comparisons of RSIS with different degrees of parent artery atherosclerosis are lacking.Prospectively collected data from our multicentre cohort (all were tertiary centres) of the Stroke Imaging Package Study between 2015 and 2017 were retrospectively reviewed. The patients with RSIS defined as a single clinically relevant diffusion‐weighted imaging positive lesion in the territory of lenticulostriate arteries were categorized into three subgroups: (1) normal middle cerebral artery (MCA) on magnetic resonance angiography and high‐resolution magnetic resonance imaging (HR‐MRI); (2) low‐grade MCA atherosclerosis (normal or <50% stenosis on magnetic resonance angiography and with MCA plaques on HR‐MRI); (3) steno‐occlusive MCA atherosclerosis (stenosis ≥50% or occlusion). The primary outcome was 90‐day functional dependence (modified Rankin Scale score >2). The clinical and imaging findings were compared between subgroups.A total of 239 patients (median age 60.0 [52.0–67.0] years, 72% male) were enrolled, including 140 with normal MCA, 64 with low‐grade MCA atherosclerosis and 35 with steno‐occlusive MCA atherosclerosis. Patients with steno‐occlusive MCA atherosclerosis had the largest infarct volume. Low‐grade MCA atherosclerosis was independently associated with cerebral microbleeding, more severe perivascular spaces in basal ganglia and higher total cerebral small vessel disease burden. Low‐grade MCA atherosclerosis was an independent determinant of 90‐day functional dependence (odds ratio 3.897; 95% confidence interval 1.309–11.604).Our study suggested RSIS with varying severity of parent artery atherosclerosis exhibits distinctive clinical and neuroimaging characteristics, with low‐grade MCA atherosclerosis associating with higher cerebral small vessel disease burden and worse prognosis. [ABSTRACT FROM AUTHOR]