多体素~1H-MRS推断不同温度下死亡时间的研究

目的利用多体素质子磁共振波谱(1H-MRS)技术推断不同温度下的死亡时间。方法选取24只白兔,分为两组,利用多体素质子磁共振波谱测定死后30m in、1h、2h、4h、6h、8h、12h、16h、24h脑内N-乙酰天门冬氨酸、胆碱复合物、磷酸肌酸和肌酸各代谢物之间峰下面积的比值。结果死后24h内N-乙酰天门冬氨酸与磷酸肌酸和肌酸的比值随死亡时间的延长而降低,胆碱复合物与磷酸肌酸和肌酸的比值随死亡时间的延长而升高。Naa/Cr、Ch/Cr与PM I进行回归分析:自变量为Naa/Cr的二次多项式方程为:y=0.0020x2-0.0815x+1.4532(R2=0.971);自变量为Ch/Cr的二次多项式方程为:y=-0.0024x2+0.0870x+1.1876(R2=0.962)。用Naa/Cr的方程推测PM I,当PM I<24h时,平均偏离时间为1.70~50.27m in,用Ch/Cr的方程推测PM I,当PM I<24h时,平均偏离时间为1.12~98.11m in。结论Naa/Cr、Ch/Cr的死后变化与时间呈强相关性,可用于死亡时间推断。

The study on estimation of time since death with muitivoxel-voxel proton 1 H-MR spectroscopy at different temperatures

ObjectiveTo investigate a method for estimation of time since death with multivoxes-voxel proton 1H-MR spectroscopy at different tmperatures.MethodsMetabolite peak area ratios of Nacetylaspartate(Naa) or choline(ch) to creatine(Cr) were dtermined by 1H-MR spectroscopy(1H-MRS) in the brain in 24 rabbits 30min,1h,2h,4h,6h,8h,12h,16h and 24h after death respectively.ResultsNaa/Cr ratia was decreased,while Ch/Cr increased with the extension of postmortem interval within 24 hours.Having Naa/Cr as the independent variable,the quadratic polynomial regression equation was expressed as y=-0.0024x2+0.0870x+1.1876(R2=0.962,Equation 1);having Ch/Cr as the independent variable,the quadratic polynomial regression equation was expressed as y=-0.0024x2+0.0870x+1.1876(R2=0.962,Equation 2).When PMI was estimated by Equation 1,the average deviation was approxiamtely 1.70～50.27min,and when by Equation 2,the average deviations was approxiamtely 1.12～98.11min.ConclusionThere is a definite relationship between Naa/Cr,or Ch/Cr and PMI,which may be used for estimation of time since death.