MR Imaging with FLAIR Pulse Sequence in Various Cerebral Lesions: Comparison with T2-Weighted Imaging

ABSTRACT

PURPOSE: To evaluate the utility of fluid-attenuated inversion recovery(FLAIR) sequence by comparing thesignal intensities in various cerebral lesions with those on T2-weighted MR imaging. MATERIALS & METHODS: In 41patients who showed different signal intensities between T2-weighted images and FLAIR sequences, we reviewed theVirchow-Robin space(VRS), acute or chronic infarctions including lacunar cavities, and postoperativeencephalomalacia. In all patients, the location, shape and size of abnormal signal intensities were evaluated. RESULTS: The hyperintensities of VRS and lacunar infarctions on T2-weighted imaging appeared as hypointensitieson FLAIR imaging. The hyperintense rims or crescents around lacunar cavities were only detected on FLAIR imaging.The extent of acute and chronic infarctions with homogenous hyperintensities seen on T2-weighted images was welldelineated on FLAIR imaging. Postoperative encephalomalacia and adjacent lesions showed low and high signalintensities, respectively, on FLAIR imaging, though they were hyperintense on T2-weighted images. CONCLUSION: ForVRS, infarction and encephalomalacia, FLAIR provides images that are superior to T2-weighted images, and may thusbe useful as an additional MR sequence in various cerebral lesions.