Internal carotid artery dissection

Case contributed by Assoc Prof Frank Gaillard


Acute left sided neck pain and unequal pupils.

Patient Data

Age: 30 years
Gender: Male

CT brain

Ventricles and sulci within normal limits. No acute intracranial abnormality, including hemorrhage identified. No CT evidence of acute ischemic event, with preserved grey white differentiation. The left internal carotid artery below the base of skull is enlarged and has higher density, particularly medially suggesting mural hemorrhage and dissection. 

T1 fat sat images demonstrate increased signal in the left internal carotid artery from the level of the bifurcation to the cavernous ICA. Superior to the bifurcation, there is a flow void demonstrated extending superiorly which represents a narrowed patent lumen with a prominent high T1 signal crescent in the wall of the carotid artery. The narrow caliber of the lumen extends to the supraclinoid portion. 

There is no evidence of high signal within the sulci or ventricular system on the FLAIR or T1 weighted imaging to suggest subarachnoid hemorrhage. No intra or extra axial collection, mass, or region of restricted diffusion identified.

DSA (angiography)


A tapered stenosis of the proximal left ICA is evident consistent with dissection.  There is trickle flow in antegrade direction however the petrous left ICA fills via ECA collaterals more rapidly than the antegrade flow. The petrous left ICA is smooth but narrowed (possibly secondary to underfilling).  

Case Discussion

This case demonstrates typical appearances of arterial dissection of the cervical internal carotid artery with a large crescent sign. It is an example of a finding on CT which would be difficult to see if the history was not helpful.  In this case the combination of pain and a Horner's syndrome is very telling. 

This patient was treated conservatively and improved without infarction. 

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Case information

rID: 22195
Published: 18th Mar 2013
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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