Comparison of plaque characteristics of small and large subcortical infarctions in the middle cerebral artery territory using high-resolution magnetic resonance vessel wall imaging

Abstract

Background: The characteristics of plaque that ultimately lead to different subcortical infarctions remain unclear. We explored the differences in plaque characteristics between patients with small subcortical infarction (SSI) and large subcortical infarction (LSI) of the middle cerebral artery (MCA) using high-resolution magnetic resonance vessel wall imaging (HR-MRVWI).

Methods: The study group comprised 71 patients (mean age, 47.49±11.5 years; 55 male) with MCA territory ischemic stroke. Whole-brain HR-MRVWI was performed using a three-dimensional T1-weighted variable-flip-angle turbo spin echo (SPACE) sequence. Patients were divided into SSI and LSI groups based on routine MRI images. Plaque distribution was classified as the superior, inferior, ventral, or dorsal wall of the MCA. The number of quadrants with plaque formation, location of plaque, plaque burden (PB), arterial remodeling pattern (positive or negative), and degree of stenosis were analyzed and compared between groups.

Results: Of the 71 patients, 43 (60.6%) and 28 (39.4%) were identified as the SSI and LSI groups, respectively. The proportion of plaques involving only one quadrant was significantly higher in the SSI group, and these plaques were located in the superior or dorsal MCA vessel wall. There was no significant difference between groups in the proportion of plaques involving two or more quadrants, plaque distribution, or PB. Most plaques in both groups showed positive remodeling, and the percentage of remodeling pattern was similar. A significantly higher incidence of low-grade stenosis (<50%) was observed in the SSI group.

Conclusions: Both SSI and LSI may be associated with major intracranial artery atherosclerosis, but patients with SSI showed relatively fewer quadrants with plaque formation and a lesser degree of stenosis.

Keywords: Atherosclerotic plaque; ischemic stroke; magnetic resonance vessel wall imaging (MRVWI); subcortical infarction.

Figure 1

Representative MR images for a patient with SSI (A,B,C,D) and another with LSI (E,F,G,H). T2-FLAIR images (A,E) show a subcortical infarction of the right middle cerebral artery (MCA) territory (arrows). Plaque (arrows) was detected in the ipsilateral MCA on HR-MRVWI images (B,C,F,G) for each patient. The cross-sectional images (D,H) of the plaques (arrows) of both patients show involvement in only one quadrant, specifically ventral for SSI (D) and superior for LSI (H). FLAIR, fluid-attenuated inversion recovery; HR-MRVWI, high-resolution magnetic resonance vessel wall imaging; LSI, large subcortical infarction; SSI, small subcortical infarction.

Figure 2

Frequency of positive, intermediate, and negative remodeling patterns and frequency of <50% and ≥50% stenosis. LSI, large subcortical infarction; SSI, small subcortical infarction.

Figure 3

Representative MR images for a patient with SSI (A,B,C,D) and another with LSI (E,F,G,H), respectively. T2-FLAIR images (A,E) show a subcortical infarction of the left middle cerebral artery (MCA) territory (arrows). Plaque (arrows) was detected in the ipsilateral MCA on HR-MRVWI images (B,C,F,G) for each patient. The cross-sectional images (D,H) of the plaques (arrows) of both patients show involvement of three quadrants, but the plaque in the patient with LSI (H) caused more stenosis than in the patient with SSI (D). FLAIR, fluid-attenuated inversion recovery; HR-MRVWI, high-resolution magnetic resonance vessel wall imaging; LSI, large subcortical infarction; SSI, small subcortical infarction.