Plaque Steepness is Associated with Hemodynamics in Patients with Atherosclerotic Middle Cerebral Artery Stenosis.

OBJECTIVE: To evaluate the relationship between plaque steepness and hemodynamics in middle cerebral artery (MCA) stenosis based on high-resolution magnetic resonance imaging and computational fluid dynamics. METHODS: Eighty consecutive patients accompanying with unilateral atherosclerotic MCA stenosis (50%-99%) were prospectively recruited. All patients underwent a cross-sectional scan of the stenotic MCA vessel wall. The parameters and features of the plaque, vessel wall, translesional wall shear stress ratio (WSSR), wall shear stress in stenosis (WSSs), and translesional pressure ratio (RP) were obtained. The patients were divided into the DWI-positive group and the DWI-negative group. The differences in plaque, vessel wall, and hemodynamics were compared between the two groups. Correlations between the plaque steepness and hemodynamics were calculated. RESULTS: The DWI-positive group (31 cases) had a smaller lumen area (LA) (P = 0.024), larger plaque area (PA) (P < 0.001) and normal wall index (NWI) (P = 0.009), higher WSSR (P = 0.009) and WSSs (P = 0.018), and larger plaques' height (P = 0.039) and radio of height/width (P = 0.014) at the most stenotic site. The DWI-positive group had more enhanced plaques (24 vs 13, P = 0.03), positive remodeling patients (23 vs 20, P < 0.001) than the DWI-negative group (49 cases). The height of plaque (r = 0.805, P < 0.001) and ratio of height/width (r = 0.879, P < 0.001) showed positive correlation with WSSR, respectively. CONCLUSION: Steepness is an important feature of atherosclerotic plaques; individuals with steep plaques might be more prone to stroke.