Imaging meningiomas: Is there a need for post-contrast FLAIR?

The aim of this study was to compare post-contrast fluid-attenuated inversion recovery (FLAIR) imaging with post-contrast T1-weighted images (T1WI) in depicting meningiomas. Twenty-nine patients with 46 meningiomas were included in this study. FLAIR and T1WI were obtained before and after intravenous administration of gadopentetate dimeglumine. The contrast enhancement degree, contrast enhancement pattern, lesion conspicuity, and the detection of the dural sign were compared between post-contrast FLAIR images and post-contrast T1WI. The enhencement degree on FLAIR was equal or less than T1WI for all meningiomas. Among 46 meningiomas 38 (83%) enhanced homogeneously and eight (17%) inhomogeneously on T1WI. On contrast-enhanced FLAIR images, of the total 46 meningiomas 22 (48%) enhanced homogeneously, eight (17%) inhomogeneously, whereas 14 (30%) meningiomas showed a peripheral rim enhancement not observed on T1WI. Two (5%) meningiomas showed no contrast enhancement on post-contrast FLAIR images. Among the 14 meningiomas showing rim enhancement using FLAIR imaging, 12 (85%) were measured to be 2 cm or more in diameter. A dural tail sign was found in 16 (35%) and 23 (50%) meningiomas on post-contrast T1WI and FLAIR images, respectively. In contrast to other extra-axial diseases, post-contrast FLAIR sequence was not found to be a valuable adjunct to contrast-enhanced T1WI in the depiction of meningiomas.