应用膝关节MRI T_2加权脂肪抑制像推断活体年龄

目的探索膝关节MRI T2加权脂肪抑制像(T2-FS)在法医年龄推断中的应用价值,建立安全可靠的四川汉族年龄推断方法。方法收集膝关节MRI 324例(男性170例,女性154例),年龄范围为10~30岁。采用西门子1.5T磁共振仪摄片,MRI参数:T2-FS TSE序列,矢状位。将股骨远端、胫骨近端骨骺发育分为6个等级并赋分,分析各指标性别差异及年龄相关性,建立年龄推断回归模型。结果男女性股骨远端、胫骨近端MRI等级与年龄呈正相关性,股骨远端与年龄的相关性男性0.687,女性0.661;胫骨近端与年龄的相关性男性0.684,女性0.488。股骨远端骨骺完全闭合,骺线消失的最小年龄男性18.42岁,女性19.36岁;胫骨近端男性骺线消失的最小年龄为16.93岁,女性为14.68岁。股骨远端等级1~3、5、6和胫骨近端等级1~3、5年龄分布性别差异不显著。分别建立男女年龄推断模型,男性年龄推断平均绝对误差(MAD)=2.90岁;女性年龄推断MAD=3.30岁。结论膝关节MRI T2-FS影像可作为活体年龄推断的指标之一,股骨远端等级6可作为判断18岁的指标之一。

Age estimation in the Living from the knee by using MRI T2 weighting images with fat suppression

Objective The purpose of this study is to estimate the living age by MRI T2-FS images of the knee and to establish a new age estimation method without radiation in Sichuan Hans population. Methods We retrospectively evaluated sagittal T2-weighted, fat-suppression and turbo spin-echo sequence taken upon MRI of 324patients (170 males, 154 females; age 10~30) using a six-stage method. The gender difference was tested by Mann-Whitney U and the correlation between the knee and age height was tested by Spearman correlation coefficient. Regression models were built for age estimation in both genders. Results The correlation between the distal femur and age was 0.687 in males and 0.661in females and was 0.684 in males and 0.488 in females between the proximal tibia and age. Comparison of male and female revealed nonsignificant differences in the ages at the stages 1~3, 5, 6 of the distal femoral epiphysis and stage 1~3, 5 of the proximal tibial epiphysis. The fusion of distal femur commenced at 18.42 years in males and 19.36 years in females. The fusion of proximal tibia commenced at 16.93 years in males and14.68 years in females. The test of accuracy showed MAD=2.90 years in the males and MAD=3.30 years in the females in the compound regression model. Conclusion MRI T2-FS images of the knee can be an indicator for age estimation in the living and stage 6 of the distal femur can be used to determine 18-year limit.