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

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.