An 86-year-old patient presented at the outpatient clinic with headache. Brain CT depicted a left occipital and right cerebellar chronic infarction. The basilar and the left vertebral arteries were enlarged and tortuous.
Figs. 1a and 1b depict an enlarged (>4.5 mm diameter) and tortuous basilar artery, with its top above the level of the sella turca. Fig. 2a and 2b show that the artery bulges into the brain stem anterior surface.
Fig. 3a depicts a small right cerebellar infarction, and Fig. 3b shows a more extensive left occipital infarction.
Vertebrobasilar dolichoectasia (VBDE) is defined as a marked elongation, dilatation and tortuosity of the vertebral (VA) and/or basilar (BA) arteries. The most frequently used diagnostic criteria for VBDE are a diffuse enlargement, with a diameter at the level of the pons greater than 4.5 mm, a position lateral to the clivus or dorsum sellae and a bifurcation above the level of the supraselar cistern. Focal enlargements can also coexist, but in those cases they are called fusiform aneurysms.
Dolichoectasia can affect any intra-cranial vessel, but VA and BA are the most frequently involved. The estimated prevalence ranges from 0.05 to 5%. It occurs mainly in male patients, with a mean age of 65 years old at presentation.
The aetiology is not perfectly established. It can be a congenital non-atherosclerotic vasculopathy but, more often, atherosclerotic plaques are found in the walls of dolichoectasic arteries, suggesting that VBDE is a manifestation of intra-cranial atherosclerosis. Its commonly recognised risk factors are male sex, hypertension, previous myocardial infarction and previous lacunar strokes. There still are some questions about considering VBDE as an independent risk factor for stroke.
Histological features of VBDE consist in fragmentation of internal elastic lamina, intimal hyperplasia and intramural haemorrhage.
Most of the patients (40%) are asymptomatic at the time of diagnosis. Clinical presentations can be related to compression of the brainstem or cranial nerves, most frequently causing visual disturbances, ocular motor abnormalities, trigeminal neuralgia, facial hemispasm, vertigo or pulsating tinnitus. Symptoms of motor or sensory long tracts dysfunction have also been described. Hydrocephalus, as a consequence of aqueductal stenosis, has been reported. Vascular complications are related to thrombosis, dissection or rupture, leading to posterior circulation infarctions or sub-arachnoid haemorrhages.
The natural history of VBDE has been recently evaluated. At a 10 year follow up, 60% of the patients experienced at least one event (stroke, haemorrhage or compression); in 40% of the cases, there was a progression of the imaging findings, and this progression was associated with a higher morbidity and mortality.
The diagnosis was classically established with digital subtraction angiography. Nowadays, CT or MR angiography can easily evaluate the characteristics of the head and neck vessels and depict the most common complications of VBDE. As we demonstrate in this report, non-enhanced CT can also easily establish the diagnosis by showing a hyperdense tortuous vessel, with thickened walls, usually with several calcified areas. Multi-planar reconstructions allow a better anatomical evaluation of the arteries and related structures.
The differential diagnosis includes fusiform aneurysms (usually a focal dilatation), non-atherosclerotic vasculopathies (more frequent in young patients, usually involving the anterior circulation, with the arteries having a more irregular shape) and a dissecting aneurysm (with the presence of a wall thrombus).
The treatment usually is oriented by the symptoms. The asymptomatic patients do not require any kind of intervention.
Differential Diagnosis List