Two Different Morphologies of Chronic Unilateral Middle Cerebral Artery Occlusion: Evaluation using High-Resolution MRI

INTRODUCTION Characterizing the morphologies of occluded artery segments may help elucidate the etiology of chronic intracranial artery occlusion. We acquired high-resolution MRI (HR-MRI) of the middle cerebral artery (MCA) in patients with chronic unilateral MCA occlusion and evaluated the MRI and clinical findings. METHODS We selected 20 consecutive patients who presented with unilateral MCA occlusion. Proton-density weighted HR-MRI of the occluded MCA was acquired using a 3.0 Tesla MRI. We surveyed the morphology of the MCA at the occluded segment. Symptoms, the presence of other stenotic arteries, and atherosclerosis risk factors were compared for patients grouped by different findings on HR-MRI. RESULTS MCA occlusions were classified into the following two groups: plugged MCA (13/20) with a clear view of the MCA trunk or vanishing MCA (7/20) with no MCA trunk visible in the Sylvian cistern. The presence of other stenotic arteries was more frequent in the plugged MCA group than in the vanishing MCA group. CONCLUSIONS HR-MRI can characterize the morphology of pathologic segments of chronic unilateral MCA occlusions in vivo. In chronic MCA occlusion, morphological analysis using HR-MRI may enhance the effort to assess the etiology in company with the angiographic finding.