MR imaging of the liver using an ultrafast 3D multi-shot EPI sequence. Comparison with four other T1-weighted sequences.

Abstract

To compare a 3D echo planar imaging (EPI) sequence with four other T1-weighted sequences for imaging of the liver at 1 T. Twenty volunteers were included in our imaging protocol. Spin-echo (SE), turbo SE (TSE), turbo field echo (TFE) in 2D and 3D acquisition mode, fast field echo (T1-FFE) and 3D EPI sequences were applied. Signal-to-noise (S/N) ratio of the liver, contrast-to-noise (C/N) ratio and relative contrast (ReCon) between the liver and the spleen, scanning time per slice and artifact levels were evaluated. 3D EPI provided a statistically equivalent S/N ratio of the liver with SE and T1-FFE sequences (p>0.05), while it provided a statistically higher S/ N ratio of the liver compared to TFE sequences (p<0.05). The TSE technique provided a statistically higher S/N ratio of the liver compared to 3D EPI (p<0.05). With regard to the liver-spleen C/N ratio, 3D EPI provided statistically equivalent results compared to all sequences except T1-FFE, where 3D EPI was superior. With regard to liver-spleen ReCon, 3D EPI was statistically equivalent to SE, TSE and T1-FFE, while it provided significantly higher liver-spleen ReCon than 3D TFE and significantly lower than 2D TFE. 3D EPI provided sufficient ReCon and C/N ratio and produced motion-free images in one breath-hold period. Further clinical studies are required to estimate the sensitivity, specificity and accuracy of the sequence.