A case of extravasation from a cerebral aneurysm during 3-dimensional computed tomography angiography

Reports of rebleeding from an aneurysm during 3D-CTA are rare because this imaging method is not widely available. In previous cases, rebleeding of the aneurysm presented with certain imaging features, which were cap-like, corkscrew-like, ribbon-like, and nebulous areas of enhancement. We had a patient whose aneurysm had reruptured during 3D-CTA. This is the sixth report.

The patient came to our hospital with SAH. A 3D-CTA showed a pooling of contrast medium in the temporal parenchyma and an aneurysm with an irregular bleb at the bifurcation of the right MCA. The aneurysm with bleb seemed to have a daughter aneurysm and a granddaughter aneurysm, which attached on the daughter aneurysm. We diagnosed rerupture during 3D-CTA because of a clear difference between the initial CT scan and those used as source data for 3D-CTA. Intraoperatively, we confirmed that a part of the aneurysm invaginated into the temporal lobe and that the possible granddaughter aneurysm was a clot on the daughter aneurysm. The intraparenchymal hematoma was attached to this clot.

We report a patient with rerupture of a cerebral aneurysm during 3D-CTA showing new pattern in the image. When extravasation of blood occurs into the brain parenchyma, 3D-CTA clearly demonstrates its extent because there is little attenuation by CSF. In such cases, extravasated blood can form both a small mass that mimics a granddaughter aneurysm and a pooling of contrast medium.