Contrast-enhanced multi-shot echo-planar FLAIR in the depiction of metastatic tumors of the brain: comparison with contrast-enhanced spin-echo T1-weighted imaging

Abstract

Background: The usefulness of fast fluid-attenuated inversion-recovery (FLAIR) sequences after administration of contrast medium (f-FLAIR (+)) has been shown in depicting brain tumors including metastases and meningeal carcinomatosis. Contrast-enhanced multi-shot echo-planar FLAIR (Ms-EPI-FLAIR (+)), comprising combined sequences of f-FLAIR (+) and Ms-EPI, may provide the advantages of f-FLAIR (+) along with rapid acquisition. Purpose: To compare Ms-EPI-FLAIR (+) with post-contrast spin-echo T1-weighted imaging (SE-T1WI (+)) in the depiction of brain metastases. Material and Methods: In 14 patients with metastatic tumors of the brain, spin-echo precontrast T1-weighted imaging (SE-T1WI (−)), fast spin-echo T2-weighted imaging (FSE-T2WI), fast-FLAIR, SE-T1WI (+), and Ms-EPI-FLAIR (+) were acquired. For qualitative evaluation of SE-T1WI (+) and Ms-EPI-FLAIR (+), receiver operating characteristic (ROC) analysis was performed in two different readers. For quantitative analysis, the intensity ratios (intensity of tumor divided by intensity of peritumoral region) in SE-T1WI (+) and Ms-EPI-FLAIR (+) were compared. Results: Although pre-contrast f-FLAIR detected 84 of 106 tumors, Ms-EPI-FLAIR (+) detected 98 of 106 tumors. In the ROC analysis for observers A and B, Az values in SE-T1WI (+) did not differ from values in Ms-EPI-FLAIR (+). Quantitatively, the intensity ratio in Ms-EPI-FLAIR (+) also did not differ from that in SE-T1WI (+). Conclusion: Detectability of brain metastases with Ms-EPI-FLAIR (+) is almost similar to that with SE-T1WI (+). Ms-EPI-FLAIR (+) could be an alternative to SE-T1WI (+) in the depiction of brain metastases.