Association of Intraplaque Hemorrhage and Acute Infarction in Patients With Basilar Artery Plaque

Abstract

Background and Purpose-High-resolution magnetic resonance imaging (HRMRI) is ideal for serial examination of diseased arterial walls because it is noninvasive and has superior capability of discriminating tissue characteristics. The aim of this study is to evaluate the prevalence and clinical relevance of intraplaque hemorrhage (IPH) in patients with basilar artery (BA) atherosclerosis using HRMRI. Methods-We analyzed HRMRI and clinical data from 74 patients (45 symptomatic and 29 asymptomatic), all of whom had >50% BA stenosis. High-signal intensity within a BA plaque on magnetization-prepared rapid acquisition with gradientecho was defined as an area with an intensity that was >150% of the signal from the adjacent muscle. The relationship between IPH within a BA plaque region and clinical presentation was analyzed. Results-Thirty patients were positive for IPH on HRMRI (42.3%, 24 symptomatic and 6 asymptomatic). Symptomatic lesions in the MR-positive IPH group were significantly more prevalent than in the MR-negative group (80.0% versus 48.8%; P<0.01). Also, MR-predicted IPH was significantly more prevalent in the high-grade stenosis group (P<0.001) than in the low-grade group. The relative risk of an acute focal stroke event among patients who were magnetizationprepared rapid acquisition with gradient-echo-positive for IPH compared with patients who were magnetization-prepared rapid acquisition with gradient-echo-negative was 1.64. Conclusions--IPH within a BA plaque region on HRMRI is highly prevalent and is associated with acute stroke.

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

“…Several previous intracranial VWI studies have related HST1 to IPH because of the fact that the major substance of IPH, methemoglobin, has a relatively short T1 relaxation time and, thus, appears hyperintense on T1‐weighted imaging 13, 16. In their work, HST1 was highly associated with ischemic symptoms 13, 16. In another study by Natori et al,18 HST1 was believed to indicate the presence of lipid components in addition to IPH.…”

“…Xu et al13 reported HST1 in 19.6% of culprit lesions, and Yu et al16 reported HST1 in 53.3% of culprit lesions. Note that our definition of HST1 is based on whether plaque‐wall CR is >150%, whereas previous studies used different criteria.…”

“…The degree of vasa vasorum invading from the adventitia is increased in ruptured plaques compared with stable plaques, and microvascular incompetence is a plausible explanation for the occurrence of IPH 22, 25. Several previous intracranial VWI studies have related HST1 to IPH because of the fact that the major substance of IPH, methemoglobin, has a relatively short T1 relaxation time and, thus, appears hyperintense on T1‐weighted imaging 13, 16. In their work, HST1 was highly associated with ischemic symptoms 13, 16.…”

“…The advent of 3‐dimensional VWI techniques in the past few years also makes it possible to simultaneously assess atherosclerotic plaques presenting in multiple arterial segments 11, 12. Using VWI, several plaque features have been intimately associated with symptomatic or asymptomatic lesions, such as high signal on T1‐weighted images (HST1), wall thickening pattern, and postcontrast enhancement 7, 13, 14, 15, 16, 17, 18. However, most of previous studies were limited to one feature only, a local arterial segment, or a cohort with heterogeneous time periods after symptom onset.…”

Intracranial vessel wall MRI: a review of current indications and future applications

“…For example, T1, T2 and PD weighted IVWM hyperintensity was found to be more common among symptomatic (57.1 %) vs. asymptomatic (22 %) MCA plaques [42], a finding which has been replicated in several studies [43,44]. In the posterior circulation, a study of 73 patients with >50 % BA stenosis found that IPH, detected on the nonblood suppressed 3D magnetization-prepared rapid gradient-echo (MP-RAGE) sequence, was associated with a 1.64 relative risk of a focal stroke event on DWI (p < 0.01), with a sensitivity of 80.0 % and specificity of 46.5 % [45].…”