摘要
目的:探讨T_2-mapping和磁共振化学位移成像(CSI)定量观察健康志愿者多裂肌内少量脂肪含量的价值。方法:对56名健康志愿者(年龄22～59岁)进行腰椎常规MRI检查及T_2-mapping和CSI。根据Goutallier分级系统,在常规MRI图像上进行脂肪浸润分级。用T_2-mapping非抑脂序列图像测得的T_2值(非抑脂)减去抑脂序列测得的T_2值(抑脂)得到T_2值(脂肪)。CSI采用非对称回波的最小二程估算法迭代水脂分离(IDEAL)技术,并在IDEAL图像上计算得到脂肪分数η。采用多元回归分析和pearson相关分析评价年龄、性别、身高体重指数(BMI)与T_2值(非抑脂)、T_2值(脂肪)和脂肪分数η的相关性。结果:56名志愿者的平均T_2值(脂肪)为(6.1±1.58) ms(95%置信区间:5.7 ms,6.6 ms);T_2值(非抑脂)为(44.9±4.66) ms(95%置信区间:43.8 ms,46.2 ms)。T_2值(脂肪)与年龄、BMI均具有相关性(P均<0.001),脂肪分数η与年龄、BMI亦具有相关性(P均<0.05),T_2值(脂肪)与脂肪分数η呈显著相关性(r=0.794,P<0.001)。结论:T_2-mapping和CSI能识别正常成人肌肉内少量脂肪的差异,所测参数显示出与健康志愿者体格特征的相关性。
Objective:To explore the value of quantitative observation of the variation of fat content in the multifidus muscle of healthy volunteers by T_2-mapping and magnetic resonance chemical shift imaging(CSI).Methods:Fifty-six healthy volunteers,age range from 22 to 59 years,were evaluated multifidus muscles with routine MRI examinations,T_2-mapping and CSI.According to the Goutallier grading system,fat infiltration grading was performed on conventional MRI images.T_2 values of fat tissue were obtained by subtracting T_2-mapping images with fat suppression from T_2-mapping images with non-fat suppression.Iterative decomposition of water and fat with echo asymmetric and least-squares estimation(IDEAL) was used in CSI.Fat fraction of η was obtained in IDEAL images.Multiple regression analysis and Pearson correlation were used to assess relationships between among age,sex,BMI,T_2(non-fat suppression),T_2(fat) and fat fraction.Results:The mean T_2(fat) value of the 56 volunteers was(6.1±1.58)ms(95% confidence interval:5.7 ms,6.6 ms).The T_2(non-fat suppression) value was(44.9±4.66)ms(95% confidence interval:43.8 ms,46.2 ms).There was a correlation between among age,BMI,and T_2(fat) values(P<0.001),and between among age,BMI and fat fraction(P<0.05).There was a strong correlation between T_2(fat) values and fat fraction η(r=0.794,P<0.001).Conclusion:T_2-mapping and CSI might enable detection of minimal variation of fat content in healthy volunteers' multifidus muscles,and quantitative parameters showed correlations with physical characteristics of healthy volunteers.
引文
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