Middle cerebral artery intraplaque hemorrhage: Prevalence and Clinical Relevance

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.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.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).HST1 within MCA plaque on HR-MRI is associated with ipsilateral stroke. Our results provide new insight into the vascular biology of MCA atherosclerosis.