Brain lesions: When should fluid-attenuated inversion-recovery sequences be used in MR evaluation?

PURPOSE: To compare qualitatively and quantitatively the contrast of brain lesions detected with fluid-attenuated inversion-recovery (FLAIR) and inter mediate-weighted sequences at magnetic resonance (MR) imaging. MATERIALS AND METHODS: In this prospective study, 47 patients suspected of having a brain lesion underwent MR imaging with FLAIR, intermediate-weighte d, and T2-weighted sequences. Qualitative assessment was performed of lesio n conspicuity, detection, overall image artifact, and additional clinical i nformation. Contrast and contrast-to-noise ratio (CNR) were calculated betw een lesions and the normal brain or cerebrospinal fluid (CSF). RESULTS: FLAIR images were equal to intermediate-weighted images for overal l lesion conspicuity and detection but were associated more often with imag e artifacts, Lesion-to-background contrast was significantly higher on FLAI R than on intermediate-weighted images. FLAIR images failed to demonstrate multiple sclerosis (MS) plaques located in the basal ganglia and brain stem . CONCLUSION: Although FLAIR images provided additional information in some c ases, they did not have distinct advantages over intermediate-weighted imag es. When cases of MS are evaluated, intermediate-weighted images are prefer able to FLAIR images. Except in cases of MS, either FLAIR or intermediate-w eighted sequences should be added to T2-weighted sequences at MR imaging.