Improving background suppression in diffusion-weighted imaging of the abdomen and pelvis using STIR with single-axis diffusion encoding

Bowel contents and peripheral nerves often show high signal intensity at diffusion-weighted imaging (DWI) of the abdomen and pelvis, obscuring or mimicking pathology. This study introduced and compared short tau inversion recovery (STIR) with single-axis DWI to the usual combination of spectral fat suppression (SFS) with trace DWI in the suppression of bowel contents and peripheral nerves. Five volunteers underwent both STIR with single-axis DWI and SFS with trace DWI of the abdomen and pelvis. Images were evaluated by two observers with respect to the suppression of signal of bowel contents and peripheral nerves using four-point grading scales (4=poor suppression; 3=moderate suppression; 2=good suppression; 1=excellent suppression). Mean scores (±S.D.) regarding the suppression of bowel contents were 1.60±0.55 and 1.40±0.89 for STIR with single-axis DWI and 3.40±0.55 and 3.00±1.00 for SFS with trace DWI for observers 1 and 2, respectively. Mean scores regarding the suppression of peripheral nerves were 1.20±0.45 and 1.20±0.45 for STIR with single-axis DWI and 2.40±0.89 and 2.80±0.84 for SFS with trace DWI for observers 1 and 2, respectively. In conclusion, STIR with single-axis DWI is superior to SFS with trace DWI in the suppression of bowel signal and peripheral nerves.