Patterns and Implications of Intracranial Arterial Remodeling in Stroke Patients

Abstract

Background and Purpose Preliminary studies suggest ntracranial arteries are capable of accommodating plaque formation by remodeling. We sought to study the ability and extent of intracranial arteries to remodel using 3D high-resolution black blood MRI (BBMRI) and investigate its relation to ischemic events. Methods 42 patients with cerebrovascular ischemic events underwent 3D time-of-flight MRA and contrast-enhanced BBMRI examinations at 3T for intracranial atherosclerotic disease. Each plaque was classified by location (e.g., posterior vs. anterior circulation) and its likelihood to have caused a stroke identified on MRI (culprit, indeterminate, or non-culprit). Lumen area (LA), outer wall area (OWA), and wall area (WA) were measured at the lesion and reference sites. Plaque burden was calculated as WA divided by OWA. The arterial remodeling ratio (RR) was calculated as OWA at the lesion site divided by OWA at the reference site, after adjusting for vessel tapering. Arterial remodeling was categorized as positive if RR >1.05, intermediate if 0.95≤RR ≤ 1.05, and negative if RR <0.95. Results 137 plaques were identified in 42 patients (37% [50] posterior, 63% [87] anterior). Compared with anterior circulation plaques, posterior circulation plaques had a larger plaque burden (77.7±15.7 vs. 69.0±14.0, p=0.008), higher RR (1.14±0.38 vs. 0.95±0.32, p=0.002), and more often exhibited positive remodeling (54.0% vs.29.9%, p=0.011). Positive remodeling was marginally associated with downstream stroke presence when adjusted for plaque burden (OR 1.34, 95% CI: 0.99–1.81). Conclusions Intracranial arteries remodel in response to plaque formation, and posterior circulation arteries have a greater capacity for positive remodeling and, consequently, may more likely elude angiographic detection. Arterial remodeling may provide insight into stroke risk.

Differential Features of Culprit Intracranial Atherosclerotic Lesions: A Whole‐Brain Vessel Wall Imaging Study in Patients With Acute Ischemic Stroke

“…Second, the study recruited patients with strokes in the anterior circulation only. Therefore, our conclusion has to be extrapolated to the posterior circulation with caution, given the reported evidence about the morphological difference in plaques between the 2 vascular sites 8. Last, the features explored in this study are still limited.…”

“…The solution currently available to clinicians heavily relies on luminography imaging, with which the stenotic degree is a primary criterion for defining a culprit or high‐risk lesion. However, extensive research on the atherosclerosis disease has suggested that lumen narrowing may not be a reliable indicator of plaque severity because of positive remodeling of the vessel wall,8 and the features exhibited directly by plaques may provide complementary information 9, 10…”

The Use and Pitfalls of Intracranial Vessel Wall Imaging: How We Do It

“…For optimal CNR, not only suppression of blood signal to depict the inner boundary of the VW, but also suppression of CSF signal to depict the outer boundary is essential, especially when outward vascular remodeling is present (27)(28)(29)(30). At 3 T, the CNR between VW and lumen is superior to the CNR between VW and CSF on most pulse sequences.…”

Identification of high-risk plaque features in intracranial atherosclerosis: initial experience using a radiomic approach

“…Posterior circulation plaques may be particularly underestimated by angiographic means because the basilar artery exhibits a propensity towards positive remodelling and the posterior circulation is predisposed to perforator occlusion [14–16]. Vertebrobasilar artery stenosis confers a significant risk of stroke, myocardial infarction and death [17].…”