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

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 ISSFSE 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.