label: Vertebrobasilar dolichoectasia
label_lc: vertebrobasilar dolichoectasia
description: "Elongation, dilatation, and/or tortuosity of the vertebrobasilar segment. The definition of VBD includes: (i) diameter of basilar or vertebral artery over 4.5 mm; or (ii) deviation of any portion more than 10 mm from the shortest expected course; and (iii) length of basilar artery over 29.5 mm or length of intracranial vertebral artery over 23.5 mm."