集成MR序列T1、T2弛豫定量的可重复性研究

Reproducibility of quantitative relaxation study of synthetic MRI

目的:探讨集成磁共振成像(SyMRI)T 1、T 2弛豫定量的可重复性。方法:纳入8例正常志愿者,在两台相同的1.5T MR扫描仪上分别进行前后两次SyMRI扫描,生成组织T 1-mapping和T 2-mapping。基于体素分析测量四个灰质区及四个白质区的T 1、T 2值,采用组内相关系数(ICC)评价同一MR前后(组内)及不同MR之间(组间)测量的可重复性,同时采用Bland-Altman散点图显示组内及组间测量结果的一致性。使用配对样本t检验对比组内及组间T 1、T 2值的差异。结果:ICC结果显示8个特征性脑区的组内及组间测量的ICC值均在0.75以上,表现为很好的稳定性及可重复性。Bland-Altman散点图显示测量结果基本均在95%的可信区间内,表明组内及组间测量结果具有很好的一致性。组内及组间的测量的值进行配对t检验,差异均无统计学意义(P>0.05)。结论:集成MRI测量的组织T 1及T 2值有很好的稳定性,可作为长期随访研究或多中心研究的有效指标。

Objective:The purpose of this study was to evaluate the multi-center reproducibility and test-retest variability of synthetic MRI(SyMRI)in brain.Methods:Eight volunteers were enrolled and scanned twice on two 1.5T MRI scanners using SyMRI with identical scan parameters.T 1-mapping and T 2-mapping were generated and T 1,T 2 values for eight major grey matter and white matter areas were calculated by voxel based analysis.The intra-and inter-scanner reliability and reproducibility were assessed with intraclass correlation coefficients(ICCs).Bland-Altman method was used to show the level of agreement between two measurement types.Paired t-test was also used to compare the difference between inter-and intra-scanner,respectively.Results:In the eight grey matter and white matter areas,all ICC values exceeded 0.75,which indicated high intra-and inter-scanner measurement reliability and reproducibility.The Bland-Altman plots together with 95%confidence interval(CI)across all ROIs in the eight volunteers also demonstrated good repeatability.No significant differences between inter-and intra-scanner were found in Paired t-test with all P>0.05.Conclusion:There are good inter-and intra-scanner reliability and reproducibility of T 1 and T 2 values generated by SyMRI measurements,it can be used as biomarkers in longitudinal and multicenter studies.