Relation Between Clinic And High-resolution Magnetic Resonance Image Of Distal Vessel Of Occluded M1 Segment Of Middle Cerebral Artery

Background and purpose:To investigate prevalence, distribution and possible mechanism of “distal patency of middle cerebral artery M1 segment occlusion”(DP-MCAMO). Materials and methods:We retrospectively reviewed the magnetic resonance angiography, diffusion weighted imaging and high resolution magnetic resonance imaging(HR-MRI) data of 49 patients with unilateral middle cerebral artery occlusion, and collected the information of age, sex category, hypertension, diabetes, hypercholesterolemia, smoke history and symptoms. The presence of DP-MCAMO, defined as normal or low-grade(<30%) stenotic lumen distal to the middle cerebral artery M1 segment occlusion on HR-MRI. According to the above definition, found patients with DP-MCAMO by searching images in database. The relationship between DP-MCAMO and clinical presentations was analyzed. Also, we investigated the relationship between DP-MCAMO and large territorial infarct and eccentric plaque distal to middle cerebral artery occlusion. Results:DP-MCAMO were identified in 12/49(24.49%) patients(8 symptomatic, 4 asymptomatic, P=0.21), and DP-MCAMO didn’t show relation with large territorial infarct(P=1.00) and deep tiny flow voids(P=0.72). DP-MCAMO tend to relate to the occurrence of eccentric plaque distal to middle cerebral artery occlusion(P=0.02). Conclusions:Distal lumen patency is quite common in patients with middle cerebral artery M1 segment occlusion. Possible mechanism of DP-MCAMO may associate with collateral circulation. Further exploration is still needed in the future.