Usefulness of computed tomography angiography for initial diagnosis of ruptured basilar perforator aneurysm: a case report

We report a rare case of ruptured basilar perforator aneurysm that computed tomography angiography (CTA) was useful to diagnose. A 69-year-old man presented with a sudden headache and vomiting, and computed tomography (CT) revealed subarachnoid hemorrhage in the posterior cranial fossa and CTA showed an aneurysm on the right side of the upper basilar artery, although digital subtraction angiography (DSA) revealed no aneurysm. On day 4, we performed DSA that revealed a perforator aneurysm with a diameter of 2 mm at the site, which we diagnosed as basilar perforator aneurysm ruptured. Conservative therapy and rehabilitation were performed, and eventually, he had just mild motor impairments. One year after onset, DSA demonstrated that the aneurysm disappeared. For the initial diagnosis of small aneurysms, CTA might be useful because the scanning time of CTA is longer than that of DSA.