Etiologies of symptomatic intracranial arterial stenosis in young patients: a vessel wall MR imaging study

Intracranial arterial stenosis (IAS) is an important cause of ischemic stroke in young patients. The causes of IAS in this population are complex and diverse, yet they have not been extensively studied. We aimed to explore the etiologies of symptomatic IAS in young patients. Young patients (aged 18–45 years) with acute ischemic stroke and symptomatic IAS (≥ 50%) were retrospectively recruited between January 2018 and December 2022. Patients aged 46–55 years with stroke served as the control group. 3D high-resolution magnetic resonance imaging (HR-MRI) was performed within four weeks of symptom onset. Based on HR-MRI findings and clinical data, the etiologies of symptomatic IAS were identified and compared between the two groups. For patients with atherosclerotic stenosis, plaque characteristics on HR-MRI were also compared. A total of 110 patients were included, of whom 56 were young patients. Atherosclerotic stenosis was identified in 74 patients (67.3%), while 36 patients (32.7%) had non-atherosclerotic stenosis. Compared with middle-aged patients, young patients had a significantly lower prevalence of hypertension (44.6% vs. 66.7%, p = 0.02) and a lower frequency of prior stroke or TIA (12.5% vs. 27.8%, p = 0.045). The prevalence of non-atherosclerotic stenosis was significantly higher in young patients than in middle-aged patients (42.9% vs. 22.2%, p = 0.021). Among the non-atherosclerotic etiologies, moyamoya disease was the leading cause in young patients, whereas vasculitis was the primary cause in middle-aged patients. On HR-MRI, young patients exhibited a higher incidence of plaque enhancement compared with middle-aged patients (87.5% vs. 64.3%, p = 0.026). Positive remodeling and intraplaque hemorrhage were more common in the young group, although the differences were not statistically significant. Atherosclerosis is still the leading cause of symptomatic IAS among young Chinese patients. Nevertheless, non-atherosclerotic stenosis is more common in young patients than in middle-aged patients, for which HR-MRI proves valuable in identifying the specific etiologies.