Differences in plaque curvature in middle cerebral artery stenosis between acute stroke and non-acute stroke

The characteristics of plaques have a significant effect on the occurrence of stroke. This study aimed to examine the potential value of high-resolution magnetic resonance imaging (HR-MRI) in identifying symptomatic patients with middle cerebral artery (MCA) atherosclerotic plaques using plaque curvature.

In total, 107 patients with transient ischemic attack or ischemic stroke caused by unilateral MCA stenosis ranging from 50-99% were enrolled in this retrospective cross-sectional study from January 2020 to May 2024. The parameters of the plaques, including the vessel area (VA), lumen area (LA), wall area (WA), normalized wall index (NWI), plaque area (PA), remodeling index (RI), degree of stenosis, and enhancement, were obtained. The height of the plaques (H₂) at the most stenotic site, midpoint (H₁) from the beginning of the plaques to H₂, and the midpoint (H₃) from H₂ to the ending of the plaques were measured. R₁₂ and R₃₂, the ratios of H₁/H₂ and H₃/H₂, respectively, were also calculated. The above parameters were compared between groups. Multivariate logistic regression analyses were performed to assess the optimal predictive model. All the above factors and location features of plaques were compared between the patients with artery-to-artery embolism (AAE) and those with local branch occlusion (LBO).

Of the 107 patients, 43 were allocated to the asymptomatic group, and 64 were allocated to the symptomatic group (of whom 31 had AAE, 25 had LBO, and 8 had mixed mechanisms). The symptomatic group had a larger PA (5.79±2.16 vs. 4.74±1.58, P=0.007), a larger RI (1.08±0.10 vs. 0.94±0.10, P<0.001), more enhanced plaques (52 vs. 14, P=0.001), and a smaller H₁ (1.42±0.33 vs. 1.96±0.49, P<0.001), H₃ (1.57±0.36 vs. 1.95±0.42, P<0.001), R₁₂ (P<0.001), and R₃₂ (P<0.001) than the asymptomatic group. The model that included the above statistically significant factors had the best predictive value [area under the curve (AUC) =0.961, P<0.001]. The AAE group had more superior/posterior plaques than the LBO group (P=0.018).

An association was found between plaque curvature and ischemic stroke, such that the larger plaque curvature the more likely the occurrence of acute ischemic stroke.