Feasibility of diffusion-weighted imaging under split breath-hold acquisition and postprocessing (DWI-SBAP). An attempt to suppress hepatic pseudo-anisotropy

The purpose of this study was to suppress hepatic pseudo-anisotropy, which is a specific artifact in diffusion-weighted imaging (DWI) of the liver obtained under respiratory triggering, the authors developed a novel acquisition technique for DWI that we termed ''diffusion-weighted imaging under split breath-hold acquisition and postprocessing'' (DWI-SBAP). We evaluated its feasibility in this study. Of 113 patients whose hepatic DWI under respiratory triggering (RT-DWI) showed prominent hepatic pseudo-anisotropy, 35 were included in the study. DWI-SBAP was additionally performed in these patients. Two radiologists visually evaluated the RT-DWI and DWI-SBAP from the viewpoints of the degree of pseudo-anisotropy and the image quality of trace images of both sequences. During evaluation of the image quality of trace images, both pseudo-anisotropy and slice misregistration artifacts were taken into consideration. The pseudo-anisotropy seen was significantly lower in DWI-SBAP than that in RT-DWI. Regarding visual evaluation of the trace images, the image quality of DWI-SBAP was superior to that of RT-DWI, although misregistration artifacts were observed in DWI-SBAP trace images of two patients. DWI-SBAP is a feasible technique for obtaining fine abdominal DWI and is effective in suppressing hepatic pseudo-anisotropy. To use this sequence in the clinical scenario, we believe it is necessary to develop a method of generating apparent diffusion coefficient maps and simultaneous use of slice tracking techniques. (author)