Early Prediction of Delayed Ischemia and Functional Outcome in Acute Subarachnoid Hemorrhage: Role of Diffusion Tensor Imaging

Abstract

Background and Purpose-Diffusion tensor imaging (DTI) parameters are markers of cerebral lesion in some diseases. In patients with acute subarachnoid hemorrhage (SAH), we investigated whether DTI parameters measured at <72 hours might be associated with delayed cerebral ischemia (DCI) and with poor functional outcome at 3 months (modified Rankin Scale score ≥3). Methods-DTI was performed in a prospective cohort of 60 patients with nontraumatic SAH at <72 hours. Association of fractional anisotropy and apparent diffusion coefficient values at <72 hours with the occurrence of DCI and outcome at 3 months was evaluated with logistic regression models, adjusting for known predictors of prognosis. Results-At <72 hours after SAH, fractional anisotropy values at the cerebellum were associated with DCI occurrence (78% less odds of DCI for each 0.1 increase in fractional anisotropy; P=0.019). Early apparent diffusion coefficient values were not associated with DCI. After adjusting for confounding variables, an increase of 10 U in apparent diffusion coefficient at the frontal centrum semiovale corresponded to 15% increased odds of poor outcome (P=0.061). Conclusions-DTI parameters at <72 hours post-SAH are independently associated with the occurrence of DCI and functional outcome. These preliminary results suggest the role of DTI parameters as surrogate markers of prognosis in nontraumatic SAH.