Plaque distribution of stenotic middle cerebral artery and its clinical relevance.

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.