The value of computerized tomography in aneurysmal subarachnoid hemorrhage. The concept of the CT score.

Of 256 patients with aneurysmal subarachnoid hemorrhage, 131 underwent computerized tomographic (CT) scanning within 7 days of the ictus. These scans were analyzed in order to assess the quantity of blood in the main subarachnoid cisterns and cerebral fissures. The method of quantification used recognized the horizontal and vertical components of the largest clot visible on the CT scan and expressed this as the "CT score." Angiographic vasospasm was assessed and graded, based on reduction in the caliber of the major cerebral vessels. The CT score was then compared to 1) the incidence of angiographic vasospasm, 2) the clinical course, and 3) the eventual outcome. Of the patients who showed no blood on the initial CT scan, 87% were admitted in good clinical grades, whereas among patients with higher CT scores the number admitted in poor clinical grades increased. The degree of angiographic vasospasm did not relate as closely as the CT score to the clinical grade on admission or to the subsequent clinical course. The final outcome was assessed on follow-up review, and those acquiring neurological deficits from ischemic neurological dysfunction (IND) were identified. Ninety percent of patients with no blood on the CT scan (CT score 0) had a good outcome, while 5% sustained the effects of IND. The incidence of IND gradually increased with a rise in the CT score until, with scores of 8 and above, 90% of patients suffered the ill effects of IND. The CT score proved to be a simple yet accurate prognostic indicator of the outcome of IND.