Detection of Acute Subarachnoid Hemorrhage: Comparison of FLAIR MR Imaging with Unenhanced CT

ABSTRACT

PURPOSE: Our aim was to evaluate the usefulness of fluid-attenuated inversion recovery (FLAIR) MR imaging for detection of acute subarachnoid hemorrhage (SAH) compared with unenhanced CT. MATERIALS AND METHODS: We compared FLAIR MR images with unenhanced CT scans in 28 patients with acute SAH. Findings of SAH on CT and MR images were graded as 0 (absence), 1 (suspicious), 2 (definite) in the cerebral sulci, sylvian fissure, basal cistern, and cisterns of the posterior fossa. We also compared FLAIR MR images of 28 patients with those of 35 normal subjects, and then the sensitivity, specificity, and diagnostic accuracy of FLAIR MR image for detection of acute SAH were calculated. RESULTS: FLAIR MR image was superior to CT in detecting SAH in the posterior fossa (1.41+/-.74 vs 0.78+/-.80; p<0.05) and cortical sulci(1.11+/-.80 vs 0.70+/-.83; p<0.05). There was no significant difference between FLAIR MR image and CT in detecting SAH in the basal cistern and sylvian fissure. The sensitivity, specificity, and diagnostic accuracy of FLAIR MR image for detection of SAH were 100% in all. CONCLUSION: FLAIR MR image is useful in detecting acute SAH, especially in patients with small amount of SAH or SAH in the posterior fossa.