Distribution and morphological characteristics of symptomatic atherosclerotic plaques in the middle cerebral artery using high?resolution magnetic resonance imaging / 中华神经科杂志

ABSTRACT

Objective To observe distribution and morphological characteristics of symptomatic atherosclerotic plaques in the middle cerebral artery (MCA) using high?resolution magnetic resonance imaging (HR?MRI), and to investigate HR?MRI characteristics of atherosclerotic plaques in the MCA in patients with acute cerebral infarction. Methods A total of 57 symptomatic patients with MCA atherosclerotic plaques recruited in the Affiliated Hospital of Yangzhou University from January 2014 to January 2016 were imaged with diffusion weighted imaging (DWI), three dimensional time of flight magnetic resonance angiography (3D TOF?MRA) and HR?MRI scanning for plaque on a 3.0 T MRI scanner. According to the results of DWI examination, the 57 patients were divided into transient ischemic attack (TIA) group (27 cases) and acute cerebral infarction group (30 cases). The distribution of the narrowest lumen plaque was evaluated by cross?section division into four equal arcs (superior, inferior, ventral, dorsal arcs). For quantitative analysis, lumen area (LAMLN), vessel area (VAMLN) at maximal lumen narrow (MLN) and LAreference, VAreference were measured, then wall area (WA), plaque area (PA), percentage of plaque burden, rate of lumen stenosis and remodeling index (RI) were calculated. The data of each group were compared and analyzed. Results The location and morphological analysis of the 57 patients with symptomatic MCA atherosclerotic plaques revealed that plaques were located in the ventral wall in 19 cases (33.3%), the upper wall in 15 cases (26.3%), the dorsal wall in 10 cases (17.5%), and the lower wall in 13 cases (22.8%). For the location variations in ventral wall, upper wall, dorsal wall and lower wall, the TIA group was shown as six cases (22.2%), five cases (18.5%), seven cases (25.9%) and nine cases (33.3%), and the acute cerebral infarction group was shown as 13 cases (43.3%), 10 cases (33.3%), three cases (10.0%) and four cases (13.3%), respectively. There was no statistically significant difference in the distribution of each side wall between the two groups (P>0.05). VAreference, LAreference, VAMLN and RI of the TIA group and the acute cerebral infarction group were (19.89 ± 1.34) mm2, (15.19 ± 2.04) mm2, (20.78 ± 1.78) mm2, 1.09 ± 0.11 and (19.70 ± 1.34) mm2, (14.60 ± 2.33) mm2, (21.53 ± 2.34) mm2, 1.10 ± 0.11, respectively. There was no statistically significant difference between the two groups (P>0.05). The remodeling patterns of both groups were mainly positive remodeling, with a total of 44 cases (77.2%). In the TIA group and the acute cerebral infarction group, the WAMLN, PA, stenosis rate and plaque load percentages were (8.85±1.92) mm2, (4.00±3.00) mm2, 20.92%± 9.18%, 19.05% ± 14.93% and (11.10 ± 1.88) mm2, (6.00 ± 2.25) mm2, 28.56% ± 8.67%, 27.30% ± 7.69%, respectively. The differences between the two groups were statistically significant (t=-4.466, t=-2.865, t=-3.231, t=-2.580, P<0.01). There were eight patients (29.6%) with unsmooth plaque surface in the TIA group and 19 patients (63.3%) in the acute cerebral infarction group. The differences between the two groups were statistically significant (χ2=6.475, P<0.05). LAMLN in the TIA group and the acute cerebral infarction group was (11.93±1.59) mm2 and (10.43±2.08) mm2 respectively, and the difference between the two groups was statistically significant (t=3.033, P<0.01). Conclusions Symptomatic atherosclerotic plaques in MCA in the acute cerebral infarction group have higher plaque load, thicker vascular wall at the maximum stenosis and more unsmooth plaque surface. This indicates the characteristics of high?risk plaques to a certain extent.