SURGICAL-TREATMENT FOR SUBARACHNOID HEMORRHAGE OF UNKNOWN ETIOLOGY - CONSIDERATION OF RADIOLOGICAL FINDINGS OF DIGITAL SUBTRACTION ANGIOGRAPHY

At present, conventional intra-arterial angiography remains the gold-s tandard for the diagnosis of etiology of subarachnoid hemorrhage (SAH) , but this may change as intra-arterial digital subtraction angiograph y (IA-DSA) or three-dimensional computerized tomography (CT) angiograp hy im prove The purpose of this study is to investigate the reliabilit y of IA-DSA for the diagnosis of SAH of unknown etiology Of 184 patien ts admitted to our unit with proven spontaneous SAH between January, 1 994, and March, 1997, 124 underwent IA-DSA. Ten were diagnosed as havi ng SAH of unknown etiology by initial angiography; therefore, the inci dence of SAH of unknown etiology based on the diagnosis of initial IA- DSA was 8.1 %. Of these 10 patients,sis patients were treated conserva tively in the acute period. Other four went exploratory surgeries in t he acute period due to a great suspicion of the presence of aneurysms. In one patient, no aneurysm was detected: in three patients aneurysms were discovered at surgery and successfully clipped. In two of three patients, aneurysms were not discovered at the suspected site, because radiological findings of a thrombosed aneurysm and infundibular dilat ation of a perforator caused incorrect diagnosis of the aneurysm sites . Although the site of aneurysm diagnosed by IA-DSA is not always corr ect. exploratory aneurysm surgery during the acute period based on the diagnosis by IA-DSA is warranted, and IA-DSA is acceptable for the di agnosis of SAH of unknown etiology.