Vertebrobasilar Dolichoectasia

KEY FACTS

TERMINOLOGY

• Extensive ectatic, elongated vertebrobasilar artery (VBA)

• Usually associated with decreased blood flow velocity

IMAGING

• General findings

○ Irregular, elongated, tortuous VBA

○ Usually 6-12 mm, can be giant (> 2.5 cm)

○ Focal arterial dilatation = fusiform aneurysm

• CT

○ Hyperdense tortuous enlarged vessel, Ca++ common

○ Enlarged lumen enhances, intramural thrombus does

not

• MR

○ Signal varies with flow, presence/age of thrombus

○ Dynamic CE MRA best

○ 3D TOF inadequate (slow flow saturation effects)

TOP DIFFERENTIAL DIAGNOSES

• Fusiform aneurysm, ASVD

• Giant serpentine aneurysm

• Nonatherosclerotic fusiform vasculopathy

• Dissecting aneurysm

CLINICAL ISSUES

• Peak age = 7th, 8th decades

• Often asymptomatic

○ Vertebrobasilar TIAs

○ Progressive cranial nerve compression less common

– CN5, 7; hemifacial spasm

○ Rare: Hemorrhage, hydrocephalus

DIAGNOSTIC CHECKLIST

• Slow complex flow → heterogeneous signal, TOF artifact

• Dynamic contrast-enhanced CTA/MRA or DSA necessary to

delineate true lumen

(Left) Autopsied brain seen

from below shows ectatic,

very tortuous basilar artery ﬊

with extensive yellow plaques

of atherosclerosis. No focal

areas of dilatation are seen, so

this is vertebrobasilar

dolichoectasia, a relatively

common finding in elderly

patients. (Courtesy R. Hewlett,

MD.) (Right) Sagittal T1WI MR

in a 76-year-old man with

headaches shows a very

elongated, unusually ectatic

basilar artery ſt. The basilar

tip elevates and indents the

3rd ventricle ﬇.

(Left) Axial T1 C+ FS MR shows

the strongly enhancing basilar

bifurcation ﬇ as it indents

the inferior 3rd ventricle.

(Right) Coronal T1 C+ MR

shows the extremely ectatic,

elongated basilar artery ſt

characteristic of typical

vertebrobasilar dolichoectasia.

Brain: Pathology-Based Diagnoses: Malformations,

Trauma, and Stroke

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