Reliability and correlation of in vivo heptic shimming of liver and water suppression with 3.0T proton MRS / 中国医学影像技术

ABSTRACT

Objective To assess the reliability of auto-shimming line width (LW) and water suppression rate (WS), and the correlation between them. Methods GE Signa Excite HD 3.0T system and eight-channel torso phased-array coils with PRESS sequence were performed in 38 volunteers. Liver spectra were collected with TR of 1500 ms, TE of 30 ms, VOI of 2 cm×2 cm×2 cm, NSA of 64 times. Spectroscopy routine auto-shimming pre-scanning program was executed and the values of LW and WS were recorded. Then another spectroscopy routine auto-shimming pre-scanning program was performed repeatedly and 38 groups of data were obtained totally. Intra-class correlation coefficients (ICC), coefficient of variation (CV) and significance test were conduced on 38 groups of LW and WS data. Spearman rank correlation analysis was used to assess the correlation of LW and WS. Results ①The ICC of LW and WS was 0.862 and 0.961 (both P＜0.0001), respectively, while the value of CV was 0.20, 0.18, 0.09 and 0.08, respectively. Significant difference was not observed; ②The value of correlation coefficient was -0.659, -0.485 (both P＜0.0001), respectively. Conclusion ①The reliability is excellent for in vivo liver 3.0T 1H-MRS and WS appears relatively stable; ②Indexes of LW correlate with WS moderately, and it seems the smaller the value of LW is, the easier to achieve higher WS.