ABSTRACT
Approximately 25% of ischemic strokes involve the posterior or vertebrobasilar circulation
(1,2). The anatomy and imaging of this region are important for treatment and have been
extensively reviewed by Cloud and Markus (3). Doppler ultrasound, digital subtraction
angiography (DSA), computed tomography angiography (CTA) and contrast enhanced
magnetic resonance angiography (MRA) can all be used to assess the vertebrobasilar
circulation. Imaging of the posterior circulation should include detailed views of the vertebral
artery origins. In this location, duplex ultrasonography may be limited as this modality is able
to image the origin in only 60% of subjects. CTA and MRA are more accurate in assessment of
the vertebral origins although MRA may over estimate stenosis, and for these reasons the
current gold standard remains DSA.
