Amide proton transfer imaging of brain tumors using a self‐corrected 3D fast spin‐echo dixon method: Comparison With separate B 0 correction

Purpose To assess the quantitative performance of three‐dimensional (3D) fast spin‐echo (FSE) Dixon amide proton transfer (APT) imaging of brain tumors compared with B 0 correction with separate mapping methods. Methods Twenty‐two patients with brain tumors (54.2 ± 18.7 years old, 12 males and 10 females) were scanned at 3 Tesla (T). Z‐spectra were obtained at seven different frequency offsets at ±3.1 ppm, ± 3.5 ppm, ± 3.9 ppm, and −1560 ppm. The scan was repeated three times at +3.5 ppm with echo shifts for Dixon B 0 mapping. The APT image corrected by a three‐point Dixon‐type B 0 map from the same scan (3D‐Dixon) or a separate B 0 map (2D‐separate and 3D‐separate), and an uncorrected APT image (3D‐uncorrected) were generated. We compared the APT‐weighted signals within a tumor obtained with each 3D method with those obtained with 2D‐separate as a reference standard. Results Excellent agreements and correlations with the 2D‐separate were obtained by the 3D‐Dixon method for both mean (ICC = 0.964, r = 0.93, P  < 0.0001) and 90th‐percentile (ICC = 0.972, r = 0.95, P  < 0.0001) APT‐weighted signals. These agreements and correlations for 3D‐Dixon were better than those obtained by the 3D‐uncorrected and 3D‐separate methods. Conclusion The 3D FSE Dixon APT method with intrinsic B 0 correction offers a quantitative performance that is similar to that of established two‐dimensional (2D) methods. Magn Reson Med 77:2272–2279, 2017. © 2016 International Society for Magnetic Resonance in Medicine