Proposed imaging assessment score for aneurysmal subarachnoid hemorrhage correlated with prognosis: Shinshu Aneurysmal subarachnoid hemorrhage score.

BACKGROUND

Aneurysmal subarachnoid hemorrhage (aSAH) imaging has been shown to correlate with prognosis. However, no numerical index of bleeding severity has been established. This study aimed to propose a new simple scoring system for computed tomography imaging of aSAH and to confirm its effectiveness in retrospective and prospective studies.

METHODS

We devised an image evaluation system as an objective index. This system was established by scoring six items, with a maximum total of 19 points. Using this score, named the Shinshu Aneurysmal Subarachnoid Hemorrhage Score (S-score), we performed a retrospective study of 210 patients with aSAH at a single institution to confirm its efficacy. Age and World Federation of Neurosurgical Societies grades were adopted as other verification items, and the modified Rankin Scale was used for prognostic evaluation. A multicenter prospective study was then conducted to examine the function of the score by examining 214 patients with aSAH.

RESULTS

In the retrospective study, the threshold of the S-score between good and poor prognoses was 9/19 points. The area under the curve by receiver operating characteristic analysis of the S-score was 0.819, suggesting efficacy, with an odds ratio (OR) of 1.291 (1.077-1.547). In the prospective study, the judgment capability of the S-score was evaluated with a sensitivity of 0.674, specificity of 0.881, positive predictive value of 0.789, negative predictive value of 0.804, false-positive ratio of 0.119, false-negative ratio of 0.325, positive likelihood ratio of 6.072, and negative likelihood ratio of 1.369. S-score showed a significant difference in prognosis. The OR was 1.183 (1.009-1.388).

CONCLUSIONS

The scoring system could contribute to patient prognosis assessment. S-score and its prognostic formulas may serve as an objective source of information in the development of clinical medicine.