Basilar artery perforator aneurysm
Basilar artery perforator aneurysms (BAPA) are a rare group of intracranial aneurysms. While for many perimesencephalic subarachnoid hemorrhages no cause is found, BAPA are a possible overlooked cause even with extensive diagnostic workup including CT, MRI, MRA and DSA. They are one of the reasons why in apparently angio-negative SAH, a second DSA and performing 3D angiograms are recommended.
Endovascular treatment options are available including coil occlusion or flow diverter stent implantation. In the literature some cases of larger BAPA have been treated surgically. In small aneurysms there can be technical difficulties for endovascular and surgical approaches (small neck, proximity of basilar perforators or branches at risk of ischemia).
The natural cause of BAPA seems rather benign and therefore conservative treatment often is a viable option (and frequently the only option anyways).
Case imaging courtesy of Prof. R. Chapot and PD Dr. P. Mosimann (Alfried Krupp Krankenhaus Essen, Germany).