Long-Term Natural History of Intracranial Arterial Stenosis: An MRA Follow-Up Study

Abstract

Background: Intracranial arterial stenosis (ICAS) is a major cause of ischemic stroke in Asians. Despite the clinical importance of ICAS, the literature on the natural history of ICAS has been less enlightening. The aims of our study were to evaluate a long-term natural course of symptomatic and asymptomatic ICAS. Methods: 102 subjects (37 symptomatic and 65 asymptomatic) underwent follow-up MR angiography (MRA) with a median time interval between initial and follow-up MRA of 5.7 years (range 3.6-8.5 years). For each patient, the extent of stenosis of five arteries (both middle cerebral arteries, both intracranial internal carotid arteries, and basilar artery) was classified according to five grades, by consensus: normal, mild (signal reduction <50%), moderate (signal reduction ≥50%), severe (focal signal loss with the presence of a distal signal), and occlusion. Because the sample size was too small to adjust for multiple confounders, we applied the propensity score. Results: Mean (Standard deviation) age at initial MRA was 63.5 (9.6) and 54% were men. The progression rate of ICAS differed significantly between symptomatic and asymptomatic patients (22 vs. 8%, p < 0.01), indicating a 3-fold risk of progression for symptomatic stenosis compared with asymptomatic stenosis [odds ratio (OR) 3.27, 95% confidence interval (CI) 1.08-9.95]. After adjustment for propensity score, the OR was 4.84 (95% CI, 1.40-16.7). In the matched cohort, the relative risk of stenosis progression was 5.20 for symptomatic stenosis (95% CI 1.00-27.23) compared with asymptomatic stenosis. Conclusion: We found a greater risk of progression for symptomatic stenosis compared with asymptomatic stenosis.

Evaluation of Encephaloduroarteriosynangiosis Efficacy Using Probabilistic Independent Component Analysis Applied to Dynamic Susceptibility Contrast Perfusion MRI

“…This has been reported in cases of intensive medical management alone, which is maintained in all patients undergoing EDAS in this study. 11,33 While this observation supports the notion that the decrease in the venous probability derived from probabilistic ICA acts as a surrogate for revascularization, it raises a second interesting question: one might inquire whether the observed relationship between increased venous probability and post-operative revascularization might qualify as a marker for patient selection and/or a valuable tool for surgical planning and monitoring. While this is beyond the scope of this initial study, it is well worth following up in a systematic study of a larger size.…”

Intracranial artery stenosis magnetic resonance imaging aetiology and progression study: Rationale and design

“…Ryu et al. () studied 102 subjects with ICAS and found that symptomatic ICAS subjects had greater risk of stenosis progression than asymptomatic ones. In carotid arteries, a number of studies have shown that presence of intraplaque hemorrhage (Sun et al., ; Takaya et al., ), maximum wall thickness (Xu et al., ), maximum lipid‐rich necrotic core percentage (Xu et al., ), and negative remodeling (Bianda et al., ) determined by MR vessel wall imaging are effective predictors for carotid plaque progression.…”

“…For subjects who were diagnosed with ICAD ( n > 200), the clinical follow‐up will be conducted at 3, 6, 12, and 24 months and the MR imaging follow‐up will be performed at 12 and 24 months, respectively. Previous studies reported that the progression rate of ICAS was 3.86% per year (Ryu et al., ) and the intra‐reader and inter‐scan variation in measuring maximum wall thickness of intracranial plaques was 6.67% (Zhang et al., ). Therefore, it might be reasonable to detect the 2 years’ progression of intracranial atherosclerosis disease (7.72%) which is greater than the variation of quantitative measurement by MRI.…”

“…It has been shown that the progression of intracranial atherosclerotic disease (ICAD) will subsequently increase the risk of ischemic cerebrovascular events (Arenillas et al., ; Wong, Li, Lam, Chan, & Kay, ). Previous studies have shown that baseline symptomatic ICAD (Ryu et al., ), diabetes (Miyazawa, Akiyama, & Yamagata, ), smoking (Miyazawa et al., ), and treatment of statin (Kim, Kim, Kwon, Kim, & Kang, ) and cilostazol (Kwon et al., ) were associated with ICAS progression. Shimizu et al.…”

Management of Intracranial Incidental Findings on Brain MRI

“…Opinions regarding the management of intracranial stenoses are varied [34]. There should be further clarification of the stenosis (Category II) if the stenosis is > 50 % or extensive WMH is ascertained (Fazekas Grade II/III) [35], since stenosis progression or the risk of a cerebrovascular event is raised [33].…”