gms | German Medical Science

Objective: In 95% of patients with a typical distribution of blood in CT scan classified as perimesencephalic subarachnoid haemorrhage (PSAH) no ruptured aneurysm willl be detected. Cinical course of these patients is better than in patients with detected ruptured aneurysm. Although possible reasons for PSAH are discussed in literature, no definitive clarification exists. Vessel variants may influence the risk of PSAH. Therefore, the aim of this study was to evaluate 3D-CTA images in patients with PSAH regarding the frequency of vessel variants compared to the literature.

Methods: In patients with diagnosed perimesencephalic SAH 3D-CTA was performed and evaluated. 3D-CTA findings were analysed for vessel configuration in the posterior circulation with special focus on vessel variants. Analysis was done in the axial acquisition images as well as in the multiplanar reconstruction.

Results: 24 patients with diagnosed PSAH had D-CTA. In 4 patients the vertebral artery (VA) was hypoplastic whereas in one patientt aplasia of the vertebral artery occurred. In 5 patients the posterior inferior cerebral artery (PICA) was hypoplastic. In one patient a dublicate Pica was present and in another patient the vessel originated extradurally. In 10 patients the anterior inferior cerebral artery (Aica) was hypoplastic. In one patient a dublicate Aica was present and in two patients the Aica's origin was in the VA. In four patients the superior cerebellar artery (SCA) was hypoplastic and in two patients a dublicate SCA was present. In three patients the posterior cerebral artery was hypoplastic. In five patients a persistent fetal origin of the posterior cerebral artery was present.

Conclusions: The appearance of a persistent fetal origin of the posterior cerebral artery was higher in this study compared to the literature, whereas no increase frequency of other vessel variations could be observed.