Imaging Characteristics of Persistent Carotid‐Vertebrobasilar Anastomoses Detected by Ultrasound

In this case series, we aimed to evaluate the ultrasonic characteristics of 35 patients with persistent carotid-vertebrobasilar anastomoses (PCVBA), a rare variant between the anterior and posterior cerebral circulation. Ultrasound detected seven (30.4%, 7/23) primitive trigeminal arteries (PTA), eight (100%, 8/8) primitive hypoglossal arteries (PHA), and four (100%, 4/4) proatlantal intersegmental arteries (PIA). PHA and PIA can be observed as abnormal branches arising from the internal or external carotid artery, most likely accompanied by hypoplastic vertebral arteries with low velocities and high resistances. Still, the basilar arteries had normal blood flows in stark contrast to the vertebral arteries.