SUBACUTE AND CHRONIC SUBARACHNOID HEMORRHAGE - DIAGNOSIS WITH FLUID-ATTENUATED INVERSION-RECOVERY MR-IMAGING

PURPOSE: To evaluate fluid-attenuated inversion-recovery (FLAIR) magne tic resonance (MR) imaging in the detection of subacute and chronic su barachnoid hemorrhage. MATERIALS AND METHODS: The authors performed 19 FLAIR MR imaging examinations at 0.5 T in 14 adult patients with suba rachnoid hemorrhage 3-45 days after the ictus and 22 FLAIR examination s in 22 adult control subjects. The detection of subacute and chronic subarachnoid hemorrhage on FLAIR images was compared with the detectio n on conventional spin-echo MR and computed tomographic (CT) images. R ESULTS: In the detection of subacute subarachnoid hemorrhage, FLAIR (1 00% detection) was significantly superior to T1-weighted imaging (36% detection, P < .01), T2-weighted imaging (0% detection, P < .02), and CT (45% detection, P < .02 [Fisher exact test]). Although FLAIR imagin g (63% detection) was superior in chronic subarachnoid hemorrhage dete ction, there were no statistically significant differences between mod alities. FLAIR imaging demonstrated all subarachnoid hemorrhage areas as high-signal-intensity areas within 18 days and up to a maximum of 4 5 days after the ictus. In a blind comparison, no FLAIR images acquire d in control subjects were confused with those acquired in patients. C ONCLUSION: FLAIR diagnostic images are superior to conventional MR or CT images in patients with subacute subarachnoid hemorrhage.