Abstract 57: Arterial Dissection as a Cause of Intracranial Stenosis in East Asians: A High-resolution Magnetic Resonance Imaging Study of 558 Patients

Abstract

Background: Intracranial occlusive disease is a common cause of stroke worldwide, and is more prevalent in Asians. We hypothesized that non-traumatic intracranial artery dissection (ICAD) may be a common hidden cause of large intracranial occlusive disease in Asian patients with ischemic stroke, and that many patients with ICAD may be misclassified as having intracranial atherosclerotic stenosis (ICAS). Methods: We prospectively recruited patients with acute symptomatic infarcts due to intracranial occlusive disease between January 2011 and October 2016. High-resolution magnetic resonance imaging (HR-MRI) was performed when vascular studies yielded ambiguous results for the diagnosis of ICAS, ICAD, or other causes. Clinical, laboratory, and HR-MRI findings were compared between the ICAS and ICAD groups. Results: Among 937 patients who showed intracranial stenosis on time-of-flight magnetic resonance angiography, HR-MRI was performed in 558. According to HR-MRI features, 123 were classified as ICAD and 252 as ICAS. Male sex, older age, hypertension, and diabetes were more frequent in the HR-confirmed ICAS group. Anterior circulation location, and the presence of vascular calcification and tandem stenosis were also more common in the ICAS group. However, clinical and radiological characteristics did not differ between patients with typical luminal changes of ICAD (n=69) and those with ICAD documented by HR-MRI but no typical luminal changes (n=123). Conclusion: Almost two thirds of ICAD patients in an Asian population were misclassified as having ICAS by standard luminal imaging techniques. Considering the different therapeutic and prognostic approaches in ICAD and ICAS, HR-MRI may be a useful diagnostic tool in this population.