MATERIAL and METHODS: In this prospective study ,16 patients within 5 days of their ictus were included. Preoperative CT scan excluded an intracerebral infarct; an angiogram determined the extent of vasospasm; MR studies were done to detect cerebral ischemia and the diffusion coefficient (ADC) was calculated. Patients underwent surgery (n=12) or endovascular coiling (n=4). Postintervention CT scan within 24 hours and on day 5 determined radiological outcome as good or poor depending on the absence or presence of infarction. Clinical outcome at follow up (2-6 months) was regarded as good or poor when the patient was independent or dependent regarding daily activities, respectively,.

RESULTS: Restricted diffusion occurred in 8 (80%) of poor and in 1 (16.6%) of good grade patients (p<0.05). In patients with good radiological outcome (n=8), DWI restriction occurred in 2 (25%) patients. In patients with poor radiological outcome(n=8), DWI restriction occurred in 7 (87.5%) patients . At 2-6 month follow-up, 7 (77.8%) of 9 patients with restricted diffusion and 2 of 7 patients with no DWI abnormality showed a poor clinical outcome

CONCLUSION: Clinical and radiological outcome at follow-up is related to the preoperative DWI Keywords : Apparent diffusion, Radiological outcome, Subarachnoid hemorrhage