Isolated MCA Disease in Patients Without Significant Atherosclerotic Risk Factors

Background and Purpose— Diagnosis of intracranial artery atherosclerosis remains often uncertain. The high-resolution magnetic resonance imaging (HR-MRI) enables vessel wall assessment for more precise diagnoses. The aim of the present study was to investigate the etiologies of middle cerebral artery steno-occlusive disease in young adult patients with few atherosclerotic risk factors using HR-MRI. Methods— We prospectively studied patients who visited a tertiary hospital in Seoul, Korea, and had (1) unilateral middle cerebral artery disease (≥50% stenosis or occlusion), (2) were ≤55 years old and had no or minimal (≤1) atherosclerotic risk factors. We excluded patients with a confirmed diagnosis of Moyamoya disease, vasculitis, or dissection and those having emboligenic sources. A presumptive diagnosis was made based on HR-MRI findings, and patients were categorized as HR-athero (atherosclerotic disease), HR-MMD (Moyamoya disease), HR-dissection, or HR-vasculitis. Results— Among 95 patients analyzed, 26 (27.4%) had HR-athero who were more often male (P =0.004), smokers (P =0.018), and had focal stenosis (P =0.003) than others. As compared with the HR-athero patients, 29 HR-MMD patients were more often female (P <0.001) and more often had occlusive lesions (P =0.001) and nonfocal stenosis (P <0.001). The 22 HR-dissection patients tended to have hypertension less often, and the 13 HR-vasculitis patients were younger (P =0.004) and tended to have nonfocal stenosis.Conclusions— In our cohort of young patients with minimal risk factors, atherosclerosis seems to be an uncommon pathology of middle cerebral artery stenosis. HR-MRI aids us to make a more reliable diagnosis.