T1-weighted fluid-attenuated inversion recovery and T1-weighted fast spin-echo contrast-enhanced imaging: a comparison in 20 patients with brain lesions.

T1-weighted fluid-attenuated inversion recovery (FLAIR) sequence is a relatively new pulse sequence for intracranial MR imaging. This study was performed to compare the image quality of T1-weighted FLAIR with the T1-weighted FSE sequence. Twenty patients with brain lesions underwent T1-weighted fast spin-echo (FSE) and T1-weighted FLAIR during the same imaging session. Four quantitative and three qualitative criteria were used to compare the two sequences after contrast. Two of four quantitative criteria pertained to lesion characteristics: lesion to white matter (WM) contrast-to-noise ratio (CNR) and lesion to cerebrospinal fluid (CSF) CNR, and two related to signals from normal tissue: grey matter to WM CNR and WM to CSF CNR. The three qualitative criteria were conspicuousness of the lesion, the presence of image artefacts and the overall image contrast. Both T1-weighted FSE and FLAIR images were effective in demonstrating lesions. Image contrast was superior in T1-weighted FLAIR images with significantly improved grey matter-WM CNRs and CSF-WM CNRs. The overall image contrast was judged to be superior on T1-weighted FLAIR images compared with T1-weighted FSE images by all neuroradiologists. Two of three reviewers considered that the FLAIR images had slightly increased imaging artefacts that, however, did not interfere with image interpretation. T1-weighted FLAIR imaging provides improved lesion-to-background and grey to WM contrast-to-noise ratios. Superior conspicuity of lesions and overall image contrast is obtained in comparable acquisition times. These indicate an important role for T1-weighted FLAIR in intracranial imaging and highlight its advantage over the more widely practiced T1-weighted FSE sequence.