Contrast-enhanced FLAIR imaging in combination with pre- and postcontrast magnetization transfer T1-weighted imaging: Usefulness in the evaluation of brain metastases

Purpose To assess whether the use of postcontrast fluid‐attenuated inversion recovery (FLAIR) imaging in combination with pre‐ and postcontrast magnetization transfer (MT) T1‐weighted imaging (T1WI) can increase diagnostic confidence in the evaluation of brain metastases. Materials and Methods Brain MR images from 41 patients with suspected brain metastases were reviewed. Two radiologists viewed pre‐ and postcontrast MT‐T1W images for the presence of metastatic tumors and rated the possible enhanced lesions using a five‐point confidence scale (session 1). The postcontrast FLAIR images were then viewed together with pre‐ and postcontrast MT‐T1W images, and the presence of metastasis was rated again (session 2). Results A total of 240 possible enhanced lesions were detected in session 1. Judging by follow‐up MR examinations, 196 were considered to be nonmetastatic findings and 44 were determined to be metastasis. In session 2 the confidence rating for nonmetastasis increased significantly in the subset of nonmetastatic findings (P < 0.001), and the confidence rating for metastasis increased significantly in the subset of metastases (P < 0.05). Conclusion The addition of postcontrast FLAIR imaging to pre‐ and postcontrast MT‐T1WI improves diagnostic confidence in evaluation of brain metastases. J. Magn. Reson. Imaging 2007;25:479–487. © 2007 Wiley‐Liss, Inc.