Use of spiral computerized tomography angiography in patients with subarachnoid hemorrhage in whom subtraction angiography did not reveal cerebral aneurysms

Object. Patients with subarachnoid hemorrhage (SAH) in whom angiography doe s nor demonstrate diagnostic findings sometimes suffer recurrent disease an d actually harbor undetected cerebral aneurysms. The management strategy fu r such cases remains controversial, but technological advances in spiral co mputerized tomography (CT) angiography are changing the picture. The purpos e of this prospective study was to examine how spiral CT angiography can co ntribute to the detection of cerebral aneurysms that cannot be visualized o n angiography. Methods. In 134 consecutive patients with SAH, a prospective search for the source of bleeding was performed using digital subtraction (DS) and spiral CT angiography. In 21 patients in whom initial DS angiography yielded no d iagnostic findings, spiral CT angiography was performed within 3 days. Pati ents in whom CT angiography provided no diagnostic results underwent second and third DS angiography sessions after approximately 2 weeks and 6 months , respectively. Six patients with primesencephalic SAH were included in the 21 cases. Six o f the other 15 patients had small cerebral aneurysms detectable by spiral C T angiography. five involving the anterior communicating cutely and one the middle cerebral artery. Two patients in whom initial angiograms did not de monstrate diagnostic findings proved to have a ruptured dissecting aneurysm of the vertebral artery; in one case this was revealed at autopsy and in t he other during the second DS angiography session. A third DS angiography s ession revealed no diagnostic results in 13 patients. Conclusions. Spiral CT angiography was useful in the: detection of cerebral aneurysms in patients with SAH in whom angiography revealed no diagnostic findings. Anterior communicating artery aneurysms are generally well hidden in these types of SAH cases. A repeated angiography session was warranted in patients with nonperimesencephalic SAH and in whom initial angiography r evealed no diagnostic findings, although a third session was thought to be superfluous.