Internal carotid occlusion - MCA & PCA infarcts due to PCA fetal origin

Case contributed by Dr Ian Bickle


Young male presents with left sided hemiparesis. No previous medical history.

Patient Data

Age: 45 years old
Gender: Male

Occlusion of the left internal carotid artery.  Essentially absent doppler waveform.  

** See the normal right internal carotid artery dopple waveform for comparison.

No flow in the left internal carotid artery from just distal to the carotid bulb.

Acute left middle cerebral and posterior cerebral artery territory infarcts.

Although the posterior cerebral artery is not part of the anterior cerebral circulation, a common variant is a fetal origin of posterior cerebral artery is common, in which the posterior communicating artery supplies the majority of blood,  Hence its supply is derived from the internal carotid artery.

MRA of the carotid arteries, showing the almost complete occlusion of the left internal carotid artery at its origin.

Case Discussion

Young patient with an internal carotid artery occlusion resulting in acute MCA and PCA territory infarcts due to a fetal origin of posterior cerebral artery.

Typically the PCA is part of the posterior circulation, so an internal carotid artery occulsion should not result in a PCA territory infarct. However, upto 30% of individuals have a fetal origin of the PCA, in so doing getting the majority of the blood supply from the anterior circulation derived PCOM artery.

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Case information

rID: 26523
Published: 26th Dec 2013
Last edited: 16th Dec 2019
Inclusion in quiz mode: Included

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