Intracranial and extracranial arterial dissection presenting with ischemic stroke: Lesion location and stroke mechanism

Abstract

Background and purpose Although cervicocranial artery dissections (CADs) are common causes of ischemic stroke in young individuals, anatomical locations and mechanisms of ischemic strokes are still unclear. We evaluate the prevalence, location, and pathogenic mechanisms of ischemic stroke caused by CADs.

Methods: We reviewed CAD patients who presented with acute (<7days) ischemic events and who had undergone diffusion weighted magnetic resonance imaging (MRI) and appropriate vascular imagings (MR angiography, computed tomography angiography, digital subtraction angiography, and high-resolution MRI). Stroke mechanisms were categorized as artery-to-artery (AA) embolism, local branch occlusion, in situ thrombotic occlusion and hemodynamic impairment.

Results: One hundred and thirty-five patients with cerebral infarcts (n=125) or transient ischemic attacks (n=10) were included. The locations of 159 dissected vessels were: 77 vertebral, 29 internal carotid, 24 middle cerebral, 12 basilar, eight posterior inferior cerebellar, five anterior cerebral, and four posterior cerebral arteries. Among stroke mechanisms, A-A embolism (n=70, 55.5%) was the most common followed by local branch occlusions (n=40, 31.7%) and in situ thrombotic occlusions (n=8, 6.3%). Intracranial CADs were more common (89 vs. 44), less often associated with trauma (21.3% vs. 40.9%, p=0.018) and A-A embolism (32.9% vs. 97.6%, p<0.001), and more often treated with intravenous thrombolysis (15.7% vs. 2.3%. p=0.021) than extracranial CADs.

Conclusions: In our cohort, intracranial CADs are more common than extracranial CADs, and the vertebral artery is the most frequently involved site. Although A-A embolism is the main stroke mechanism, local branch occlusion is another important stroke mechanism.

Keywords: Dissection; Ischemic stroke; Location; Pathogenesis; Stroke mechanism; Transient ischemic attack.