Optimization of Gray/White Matter Contrast with Fast Inversion Recovery for Myelin Suppression: A Comparison of Fast Spin-Echo and Echo-Planar MR Imaging Sequences

Summary: We compared two MR imaging sequences, fast inversion recovery for myelin suppression (FIRMS) and echo-planar FIRMS (EP-FIRMS), for depicting gray/white matter contrast. In 18 patients, the frequency bandwidth (BW) was optimized for each sequence; in nine patients, the BW was held constant. In the BW-optimized group, the mean contrast-to-noise ratio (C/N) was three times higher with the FIRMS sequence. In the BW-constant group, the mean C/N was 27 % higher with the EP-FIRMS sequence; however, geometric distortion degraded the EP-FIRMS im-ages excessively. For optimal gray/white contrast, FIRMS appears to be the superior pulse sequence. In an earlier study (1), a fast inversion recovery for myelin suppression (FIRMS) sequence with a TI of 250 was found to generate gray/white matte