自制米袋在3.0T MRI颈部弥散序列扫描中的价值

目的:探讨自制米袋在3.0T MRI颈部弥散加权成像(Diffusion weighted imaging,DWI)序列扫描中的应用价值。方法:通过常规及米袋序列,用相同参数对50名志愿者颈部进行DWI扫描,对所得图像进行主观四级法及客观测量法评价,并比较分析。结果:50例志愿者主观评价法中,DWI图像质量分级在常规组和米袋组分别为30例和0例(1级)、15例和0例(2级)、5例和4例(3级)、0例和46例(4级),P均<0.05。客观评价法中,DWI图像在b值为200、400、600、800 s/mm^2时相位编码方向变形率平均值在常规组和米袋组分别为80.51±25.31和11.41±4.31、81.92±23.27和12.23±5.25、82.89±19.63和12.52±9.67,83.41±30.44和13.22±11.32,P均<0.05;结论:在3.0T MRI颈部DWI序列扫描中,应用米袋辅助扫描可明显提高成像质量,减少变形率,并且操作简单,易于推广。

The application of customized rice bags during neck 3.0T MRI scanning with diffusion weighted imaging

Objective:To investigate the value of using customized rice bags during the neck 3.0 T MRI scanning with diffusion weighted imaging(DWI)pulse sequences.Methods:Fifty healthy volunteers were scanned with the DWI sequences using the same parameter settings,one group with customized rice bags placed on the neck and upper chest and the other group without.The resultant images were compared using a four-level observer-grading system(Levels 1~4 for image effect from the worst to the best)for subjective evaluation as well as via quantitative measurements of deformation rate in different regions of interest for objective evaluation.Statistical significance for the comparison between the conventional(no rice bag)group and the rice-bag group or between the observers was analysed by the Mann-Whitney test and the Wilcoxon test,or the Kappa test.Results:Using the four-level observer-grading system for the DWI,the 50 cases were classified as followed in the conventional group vs.the rice-bag group:30 vs.0(Level 1),15 vs.0(Level 2),5 vs.4(Level 3),and 0 vs.46(Level 4),with P<0.05 for all levels.For the quantitative comparison,the deformation rate for the conventional group vs.the rice-bag group in the average deformation rate of phase encoding direction when the b=200,400,600 and 800 s/mm^2 were 80.51±25.31 and 11.41±4.31,81.92±23.27 and 12.23±5.25,82.89±19.63 and 12.52±9.67,83.41±30.44 and 13.22±11.32.Conclusion:In neck 3.0 T MR DWI scans,the use of customized rice bags can significantly improve the imaging quality and reduce the deformation rate.It is simple to implement and hence broadly applicable.