In vivo high-resolution MR imaging of symptomatic and asymptomatic middle cerebral artery atherosclerotic stenosis

Objective: Recently, the technique of high-resolution magnetic resonance imaging (HR-MRI) has been developed to depict intracranial artery wall. We aimed to compare the vessel wall properties between symptomatic and asymptomatic atherosclerotic middle cerebral arteries (MCA) using HR-MRI.

Methods: We studied 26 patients with symptomatic and 35 patients with asymptomatic MCA stenosis. Routine cranial MRI, magnetic resonance angiography and HR-MRI were performed on each patient. The cross-sectional images of MCA wall on HR-MRI were compared between the two groups.

Results: The degree of MCA stenosis was similar between the two groups (67.9% vs 63.9%, P=0.327). On HR-MRI, eccentric plaques were observed in 26 (100%) symptomatic and 28 (80%) asymptomatic stenosis. In the remaining seven (20%) asymptomatic stenosis, only constrictive remodeling (vessel shrinkage) was observed. Compared with the asymptomatic group, symptomatic MCA stenosis had a larger wall area (P<0.001), greater remodeling ratio (P<0.001), higher prevalence of expansive remodeling (outward expansion of the vessel wall) (P=0.003) and lower prevalence of constrictive remodeling (P=0.008).

Conclusions: Different vessel wall properties on HR-MRI were observed between symptomatic and asymptomatic MCA stenosis. Further prospective studies are required to investigate whether HR-MRI is a helpful tool in stratifying stroke risk in patients with MCA atherosclerotic disease.