摘要
目的以T2校正MRS为参考,证实多回波Dixon(mDixon)水/脂分离成像定量骨髓脂肪含量的优越性。方法83名绝经后妇女按骨密度T值分为正常骨量组(n=41)、低骨量组(n=26)及骨质疏松组(n=16),受试者同时行T2校正MRS及8回波Dixon扫描获取骨髓质子密度脂肪分数(FF)。随机选取8名受试者做3次mDixon重复扫描,以均方根绝对精度误差及均方根变异系数(CV)评价mDixon定量FF的可重复性。利用组内相关系数(ICC)评估观察者内及观察者间测定mDixonFF值的一致性。采用Linearregression、Bland-Altman分析法及Lin's一致性相关系数法评价mDixon与MRS定量FF的可代替性。结果MRS、mDixon定量83名受试者FF的线性回归分析,相关系数为0.979,Lin's一致性相关系数为0.962。所有的MRSFF与mDixonFF差值的点均落在Bland-Alt-man分析法95%可信区间内。观察者内及观察者间测定受试者mDixonFF均具有实质性的一致性,观察者内ICC=0.993,不同骨密度组观察者间ICC=0.976~0.982。mDixon重复扫描,均方根绝对误差为1.45%。结论mDixon应用多脂峰模型及T2*校正定量骨髓脂肪含量其准确性可等同于MRS,将来可用多回波CSE序列代替MRS对骨髓脂肪进行定量。
Objective To validate mDixon water-fat imaging for quantifying marrow fat fraction ( FF) ,using protonmagnetic resonance spectroscopy ( MRS) as reference. Methods Multiecho T2-corrected MRS and mDixon with eight-echo gradient-echo acquisitions at 3T were performed to calculate marrow FF in 83 subjects,including 41 with normal bonemineral density ( BMD) ,26 with osteopenia,and 16 with osteoporosis. Eight participants were scanned three times with re-positioning to assess the repeatability of mDixon FF map measurements. Pearson correlation coefficient,Bland-Altman 95%limit of agreement,and Lin's concordance correlation coefficient were calculated. Results The pearson correlation coeffi-cient was 0. 979 and Lin's concordance correlation coefficient was 0. 962 between mDixon-based FF and MRS-based FF. Alldata points,calculated using the Bland-Altman method,were within the limits of agreement. The intra-and interrater agree-ment for average mDixon-based FF was excellent ( intrarater,intraclass correlation coefficient [ICC]= 0. 993; interrater,ICC = 0. 976 -0. 982 for different BMD groups) . The repeatability for CSE FF map measurements expressed as absoluteprecision error was 1. 45%. Conclusion mDixon imaging is equally accurate in characterizing marrow fat content asMRS. Given its excellent correlation and concordance with MRS,the mDixon sequence could be used as a potential replace-ment technique for marrow fat quantification.
作者
王明明
李雪峰
李冠武
陶全
李林
周永明
WANG Mingming;LI Xuefeng;LI Guanwu(Department of Radiology,Shanghai Fourth People's Hospital,Shanghai 200080,P. R. China)
出处
《临床放射学杂志》
CSCD
北大核心
2018年第11期1892-1896,共5页
Journal of Clinical Radiology
关键词
化学位移
磁共振波谱成像
骨髓脂肪
骨密度
Chemical shift-encoded
MR
spectroscopy
Marrow fat
Bone mineral density
