Diffusion-weighted MR imaging of upper abdomen : comparison of breath-hold, free-breathing, and respiratory-triggered techniques in image quality and apparent diffusion coefficient (ADC) stability

Abstract

Purpose: To compare the image quality and stability of apparent diffusion coefficient (ADC) in the diffusion-weighted MRI (DWI) of upper abdomen among breath-hold (BH), free-breathing (FB) and respiratory-triggered (RT) techniques.Methods: We analyzed the qualitative and quantitative parameters of 204 consecutive patients who underwent DWI (BH-DWI, FB–DWI or RT-DWI; n=68 in each technique). Qualitative parameters included liver contour, vascular landmarks, intra-slice homogeneity, and inter-slice discontinuity on DWI with a b-factor of 800 mm2/s using a 4-grade scale. Quantitative parameters included inter-slice or intra-slice inhomogeneity of ADC in the spleen.Results: RT-DWI showed better liver contour compared to BH-DWI (P<0.001) or FB-DWI (P=0.001). Regarding the quality of vascular landmarks, BH-DWI had inferior results compared to FB-DWI (P=0.025) and RT-DWI (P<0.001). FB-DWI had the poorest result (P<0.001) for inter-slice discontinuity compared to the other techniques. FB-DWI showed significantly larger inter-slice differences between the highest and the lowest ADCs in the spleen compared with those of RT-DWI (P<0.001). Intra-slice homogeneity was significantly better in RT-DWI and FB-DWI than in BH-DWI (P<0.001).Conclusion: Compared with BH or FB techniques, RT-DWI appears to result in the best imaging by providing better anatomic detail without skipping continuous slices, in addition to more homogeneous ADCs.