Intracranial versus extracranial artery dissection cases presenting with ischemic stroke

To compare the clinical and radiologic characteristics, possible stroke mechanisms, and prognosis of intracranial artery dissections (IADs) with those of extracranial artery dissections (EADs) presenting with cerebral infarction.

Among 3250 adult patients with acute ischemic stroke (cerebral infarction), we prospectively recruited and categorized patients with cerebral infarction secondary to spontaneous cerebral artery dissection into IAD or EAD groups. The clinical and radiologic characteristics, possible stroke mechanisms according to the distributions of the infarctions based on diffusion-weighted imaging, and prognosis were analyzed for both groups.

There were 48 and 50 patients experiencing IAD and EAD, accounting for 1.5% and 1.5% of all ischemic stroke patients, respectively. Compression of the perforating artery was the most common possible stroke mechanism (33.3%) in IADs; thromboembolism was more common in EADs than that in IADs (36 of 50 versus 12 of 48; P < .001). Magnetic resonance imaging and angiography were used to investigate the arterial dissections in all IAD patients and 46 EAD patients. Based on magnetic resonance imaging and angiography, the IADs more frequently displayed dissecting aneurysm (6 of 48 versus 0 of 46; P = .027) and intimal flap or double lumen (21 of 48 versus 4 of 46; P < .001) than EADs. For the clinical characteristics and prognosis, there was no significant difference between the 2 groups.

These results indicate that IAD is an important cause of ischemic stroke, and it displays unique radiologic characteristics and specific stroke mechanisms compared with EAD.