Multimodality MR imaging depiction of hemodynamic changes and cerebral ischemia in subarachnoid hemorrhage

BACKGROUND AND PURPOSE: Subarachnoid hemorrhage (SAH) is a common and serio us neurologic emergent condition. We tested the hypothesis that multimodali ty MR imaging depicts changes in cerebral blood flow SAH, before any surgic al or endovascular intervention, and that the frequency of these changes in creases with time after ictus. METHODS: We prospectively examined 37 patients with suspected SAH and three with symptoms of acute stroke but who subsequently had SAH. Routine CT and multimodality MR imaging were performed within 18 h of presentation. Stand ard MR imaging, diffusion-weighted MR imaging, time-of-flight MR angiograph y, and dynamic first-pass gadolinium-enhanced MR perfusion imaging were per formed. Images were reviewed for abnormalities in cerebral blood flow, isch emia, and infarction. Nine patients did not have SAH at CT and CSF investig ations. Of 31 patients with proved SAH, 13 were examined during the acute s tage (within 4 d of ictus) and 18, during the subacute stage (4-14 d after ictus). RESULTS: MR imaging showed alteration in cerebral blood flow parameters in 16 of 31 patients before surgery or endovascular treatment. The frequency o f blood flow changes and associated complications increased with worsening clinical grade and increasing time after ictus. CONCLUSION: Multimodality MR imaging provides information not available fro m CT in patients with SAH. MR imaging shows oligemic and ischemic areas in SAH before surgery or endovascular treatment. MR imaging is a simple noninv asive method of assessing cerebral blood flow and its complications in SAH. It can be performed in a clinical environment.