Role of Diffusion-weighted Imaging in Detecting Early Ischemic Brain Injury Following Aneurysmal Subarachnoid Hemorrhage

BACKGROUND: Aneurysmal SAH is the significant cause of morbidity and mortality in stroke patients. Early brain injury and delayed cerebral ischemia are the two main responsible pathophysiologic processes. Cerebral ischemia needs to be detected early so that early aggressive therapy could be started. Although Diffusion weighted imaging (DWI) has often been utilized for the measurement of acute ischemic strokes, its role in the detection of early cerebral ischemia due to aneurysmal subarachnoid hemorrhage has not been extensively investigated. This study is being carried out to describe the role of DWI in detecting early ischemic brain injury and outcome after aneurysmal SAH. AIM: Efficacy of DWI in detecting ischemic injury and predicting outcome after aneurysmal SAH. MATERIAL AND METHODS: In this prospective study 44 consecutive patients who had aneurysmal SAH; admitted within 7 days of their ictus were included. Hunt and Hess grade on admission and modified Fisher grade of SAH were noted. Plain CT brain and MR DWI was done on day before surgery. Diffusion restriction on DWI was correlated with postoperative neurological deficit, postoperative CT finding and outcome of the patient at 1 month follow-up. RESULTS: DWI revealed restricted diffusion in 12 patients, out of which 1 patient was having infarction in preoperative CT scan, 6 patients were having postoperative deficit in the form of disorientation, hemiparesis and aphasia, and all patients were having infarction in postoperative CT scan. When DWI findings were compared on the basis of postoperative neurological deficit, postoperative CT finding and modified Rankin outcome score at 1month follow-up, results were statistically significant. CONCLUSION: DWI shows cerebral ischemia much earlier than CT scan in cases of aneurysmal SAH. It has significant correlation with postoperative neurological status and outcome of the patient.