Evaluation of optimized inversion‐recovery fat‐suppression techniques for T2‐weighted abdominal MR imaging

Abstract

Purpose To test the theoretical benefits of a spectral attenuated inversion‐recovery (SPAIR) fat‐suppression (FS) technique in clinical abdominal MRI by comparison to conventional inversion‐recovery (IR) FS combined with T2‐weighted (T2W) partial Fourier single shot fast spin echo (SSFSE). Materials and Methods 1.5T MRI studies of the abdomen were performed in 28 patients with liver lesions (hemangiomas n = 14; metastases n = 14). T2W sequences were acquired using IR and SPAIR SSFSE. Measurements included retroperitoneal and mesenteric fat signal‐to‐noise (SNR) to evaluate FS; liver lesion contrast‐to‐noise (CNR) to evaluate bulk water signal recovery effects; and bowel wall delineation to evaluate susceptibility and physiological motion effects. Results SPAIR‐SSFSE images produce significantly improved FS and liver lesion CNR. The mean SNR of the retroperitoneal and mesenteric fat for SPAIR SSFSE was 20.5 ± 10.2 (±1 SD) and 12.7 ± 6.2, compared to 43.2 ± 24.1 (P = 0.000006) and 29.3 ± 16.8 (P = 0.0000005) for IR‐SSFSE. SPAIR‐SSFSE images produced higher CNR for both hemangiomas CNR = 164 ± 88 vs. 126 ± 83 (P = 0.00005) and metastases CNR = 75 ± 27 vs. 53 ± 19 (P = 0.007). Bowel wall visualization was significantly improved using SPAIR‐SSFSE (P = 0.002). Conclusion The theoretical benefits of SPAIR over conventional IR FS translate into significant multiple improvements that can be measured on clinical abdominal MRI scans. J. Magn. Reson. Imaging 2008;27:1448–1454.