Vertebrobasilar insufficiency: correlation of clinical and radiologic findings.

Radiological and clinical findings of 20 cases with angiographically proven stenosis or occlusion of the vertebrobasilar system and with clinical signs and symptoms attributable to posterior circulation disorder were studied. A simplified classification of vertebrobasilar arterial disease was presented; type I refers to stenosis of the vertebrobasilar system or subclavian artery, type II refers to vertebrobasilar occlusion, and type III refers to vertebrobasilar branch disease. Type I lesions were further subdivided into types Ia and Ib; type Ia cases showed no infarction in the posterior territory, whereas type Ib cases showed one or more infarctions on computed tomography or magnetic resonance imaging. This angiographic classification is based on treatment options that can be adopted to specific types of lesion. In type I cases, lesions are usually amenable to surgical or angiographic intervention. In type II cases, short-term anticoagulation is the treatment of choice. In type III cases, treatment is primarily aimed at prevention of complication and further stroke.