Basilar artery occlusion

Case contributed by Prof Peter Mitchell

Presentation

Initial presentation with speech difficulty and unsteady gait. Progressed to acute onset hemiparesis and slurred speech.

Patient Data

Age: 60
Gender: Male
CT

The distal basilar artery is hyperdense compared to the adjacent segments, and the middle cerebral arteries. No early vertebrobasilar territory infarct, although there is subtle hypodensity of the mid pons. Mild ventriculomegaly.  No intracranial haemorrhage.

CT

Coronal CTA confirms occlusion of the basilar artery from just distal to the anterior inferior cerebellar arteries. Fetal right and large conventional left PCA.

DSA (angiography)

Basilar artery occlusion at the level of AICA.  Antegrade flow after stent retriever placement and clot retrieval, but with persistent left PCA distal occlusion. After stent retrieval of thrombus, an underlying resistant stenosis was identified in the mid basilar artery treated with angioplasty.

MRI

 

Diffusion restriction consistent with ischaemia involves almost the entirety of the pons, the entire left posterior cerebral artery territory, and a moderate-sized wedge-shaped portion of the right posterior inferior cerebellar artery territory. Smaller foci of diffusion restriction elsewhere in the cerebellar hemispheres compatible with embolic infarction.

The TOF MRI demonstrates flow along the length of the basilar artery with a 3mm segment of persistent basilar artery stenosis at the site of angioplasty.

Case Discussion

The initial diagnosis is often delayed as not identified on the non contrast CT. The so called "stuttering" onset is seen in at least 30% of patients with basilar artery occlusion, but can lead to diagnoses other than vertebrobasilar ischemia being considered. With appropriate suspicion, hyperdense basilar artery sign can be identified, prompting the diagnosis and confirmation with  immediate CTA.

Basilar artery occlusion is associated with up to 85% mortality untreated, is often diagnosed outside accepted time windows for IV tPA, but success with intra-arterial therapy can be achieved out to 24 hours post onset.  Increasingly the stent retrievers are being used over IA lytic therapy, and offer more rapid and more complete recanalisation and reperfusion. This works particularly well for embolic occlusions seem for example in AF - if atherothrombosis with high grade underlying intracranial atherosclerosis and stenosis is found angioplasty or stent assisted angioplasty can be performed.

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Case information

rID: 33570
Case created: 16th Jan 2015
Last edited: 5th Sep 2017
Inclusion in quiz mode: Included

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