Computed tomography in subarachnoid hemorrhage

CT has becom increasingly important diagnostic method as the inital examination in the diagnosis of subarachnoid hemorrhage with direct detection of extravasated blood inbasal cistern and cortical sulci. Furthermore, CT provides better and exact visualization of the presence, localization, extent and degree of intracerebral, intraventricular and subdural hemorrhage, infarction, hydrocephalus and rebleeding which may be associated wtih subarachnoid hemorrhage, and also could detect the causative lesions with contrast enhancement inmany cases. The purpose of the paper is to describe the CT findings of subarachonid hemorrhage due to various causes and to evalute the diagnostic accuracy of CT in subarachonoid hemorrhage. Authors analysed a total of 153 cases with subarachnoid hemorrhage confirmed by lumbar puncture at Seoul National University Hospital from March 1979 to April 1981, with special emphasis on CT findings.All of the cases took CT scan and 125 cases of the mangiography. The results are as follows; 1. Most prevalent age group was 4th to 6th decades (78%). The ratio ofmale to female was 1.1:1. 2. Of all 125 with angiography, aneurysm was a major cause (68%). Others were arterio-venous malformation (9.6%), Moya-moya disease(4%) and unknown (18.4%). 3. Of all 153 cases with CT scan,hemorrhage was demonstrated in 98 cases (64.1%); SAH in 72 cases (47.1%), ICH in 65 cases (42.5%), IVH in 34 cases(22.2%) and SDH in 1 case(0.7%). SAH combined with ICH was a major group (34.7%) in SAH. Detecton rate of SAH was68.3% within the first 7 days and 5.8% after 7 days. 4. In aneurysms, SAH was detected in 60 of 85 cases (70.6%);88.1% within the first 7 days and 5.6% after 7 days. Anterior communicating artery was the most common site of theaneurysms(40%), in which detection rate of SAH was 100% within the first 7 days. SAH was combined with ICH in38.3%. 5. On CT, SAH of unilateral Sylvian fissure was pathognomonic for ruptured MCA aneurysm and ICH of corpuscallosum for ACA aneurysm. 6. The detection rate of aneurysm itself on CT was 20%(17/85) and its size was variablefrom 5 to 25mm. 7. Infarction was demonstrated in 9 cases (6%) and there was no significant correlation between infarction and angiospasm, 8. Hydrocephalus was detected in 65% cases(42.5%), and 21 cases (32.3%) were demonstrated within the first 3 days.