Left PCA partially thrombosed dissecting aneurysm

Case contributed by Prof Peter Mitchell


Severe headache prompting imaging. No neurological findings. No history of trauma.

Patient Data

Age: 70 years
Partially thrombosed aneurysm of Left PCA. No subarachnoid hemorrhage.
Partially thrombosed left posterior cerebral artery (P1/P2 junction) aneurysm. Aneurysm wall enhancement and surrounding vasogenic edema are in keeping with inflammatory change secondary to thrombosis.
DSA (angiography)

Superior and laterally directed irregular wall aneurysm arising from P1 and P2 junction of left posterior cerebral artery measuring 7.8mm(height)x 8.3mm (body ) x 3.6mm (neck ) . The CT angiogram shows a large sac containing thrombus external to the patent portion of the aneurysm. No high-grade stenosis is shown. The left vertebral artery is dominant, the right very small caliber. Normal aortic arch configuration without significant atherosclerotic disease involving extracranial or intracranial vessels. Partially thrombosed aneurysm arising from the P1, P2 junction of left posterior cerebral artery. Site and morphology strongly suggest a dissecting etiology. Assessment with MRI and MRA would also be valuable as a baseline for followup.

Balloon assist coiling followed by LVIS 2.5*17 stent placement.

Coiled left P1/P2 junction aneurysm with probable recurrent neck. Signal at the dome is more likely evolving thrombus than flow, particularly given decreased overall size.

Case Discussion

Site and morphology of PCA P1/2 aneurysm suggests likely dissecting aneurysm and thrombosis. Enhancing wall raises concern over infective - but no underlying infection identified and the progress was not in keeping with mycotic aneurysm. So called inflammatory aneurysms, with enhancing wall, in our experience are more likely to be associated with headache, and to have a higher chance of recanalization despite combined coil and stent treatment hence early follow up. In the presence of edema, thrombus, coils, stent and neck remnant - MRI can be hard to make a firm diagnosis of the degree of recanalization vs new thrombus. IV DSA on the newer platforms - in this case a 2016 Siemens unit - can give more definitive imaging.
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Case information

rID: 45761
Published: 17th Aug 2016
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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