Integrated slice-specific dynamic shimming for whole-body diffusion-weighted MR imaging at 1.5 T

• Published in: Magma (New York, N.Y.) N.Y.), 2021-08, Vol.34 (4), p.513-521
• Main Authors: McElroy, Sarah, Winfield, Jessica M., Westerland, Olwen, Charles-Edwards, Geoff, Bell, Joanna, Neji, Radhouene, Stemmer, Alto, Kiefer, Berthold, Streetly, Matthew, Goh, Vicky
• Format: Article
• Language: English
• Subjects: Biomedical Engineering and Bioengineering; Clinical Applications - Oncology; Computer Appl. in Life Sciences; Health Informatics; Imaging; Medicine; Medicine & Public Health; Radiology; Research Article; Solid State Physics
• ISSN: 0968-5243; 1352-8661
• DOI: 10.1007/s10334-020-00898-6

Objective To compare integrated slice-specific dynamic shim (iShim) with distortion correction post-processing to conventional 3D volume shim for the reduction of artefacts and signal loss in 1.5 T whole-body diffusion-weighted imaging (WB-DWI). Methods Ten volunteers underwent WB-DWI using conventional 3D volume shim and iShim. Forty-eight consecutive patients underwent WB-DWI with either volume shim ( n  = 24) or iShim ( n  = 24) only. For all subjects, displacement of the spinal cord at imaging station interfaces was measured on composed b  = 900 s/mm 2 images. The signal intensity ratios, computed as the average signal intensity in a region of high susceptibility gradient (sternum) divided by the average signal intensity in a region of low susceptibility gradient (vertebral body), were compared in volunteers. For patients, image quality was graded from 1 to 5 (1 = Poor, 5 = Excellent). Signal intensity discontinuity scores were recorded from 1 to 4 (1 = 2 + steps, 4 = 0 steps). A p value of