Forensic Sex And Age Estimation Based On Pelvic Measurements Using Multidetector Computed Tomography In Modern Chinese

Part Ⅰ The application of pelvic measurements using multidetector computed tomography for sex estimationObjective To explore sex differences of pelvis in contemporary Jiaodong Peninsula Han adults using multi-slice computed tomography(MSCT),and to establish equations for sex estimation.Methods CT imaging data of 154 patients including 72 males and 82 females in the Affiliated Hospital of Qingdao University from August 2017 to August 2019 were retrospectively collected and analyzed.20 measurements were measured by multi-planar reconstruction(MPR).Paired sample t-test was used to determine whether the differences between the two measurements were statistically significant.Independent sample t-test or Mann-Whitney test was used to explore meaningful variables.Fisher discriminant analysis was used to establish the equations,and the accuracy of the equation was verified by leave a cross validation method.Results In addition to the width of the sacrum,the rest of the variables had statistical significance.The accuracy rates of univariate discriminant equations were 59.7%-90.3%,and the equation which based on the subpubic angle with the highest accuracy was 90.3%.The accuracy rates of multivariable discriminant function were 72.7% ~ 98.7%.Among all the discriminant equations,the stepwise discriminant equation consisting of iliac crest height,subpubic angle,pubic length and the width of the greater ischium notch had the highest accuracy,reaching 98.7%.Conclusion The pelvic measurements obtained from the MPR images of the pelvis could provide high accuracy of sex estimation,which provided useful information and more options for forensic workers in sex estimation.Part Ⅱ Image analysis of trabecular bone changes of the iliac bone for age estimation in a computed tomography sampleObjective To explore the value of trabecular bone changes in the auricular surface of the ilium of computed tomography(CT)transverse sections of the auricular surface,and establish an adult age estimation model.Methods The CT samples consisted of 680 hospital Digital Imaging of known sex and age from January 2017 to September 2020 were retrospectively collected and analyzed in our hospital,of which 50 samples(25 males and 25 females)were randomly selected as a test sample.The transverse axial image of the iliac crest in front of the opposite edges of the first and second sacral vertebrae was observed,the change of the trabecular density of a single slice was observed and measured.Wilcoxon rank sum test was used to determine whether the differences in bilateral measurements were statistically significant.Spearman rank correlation was used to evaluate the correlation between the trabecular bone changes and ages,and regression equations were established.Mean error(ME)and Mean absolute error(MAE)were used to evaluate prediction error between estimated age and actual age respectively.Results There were positive correlations between ages and trabecular bone changes.The calculated multiple regression models showed the coefficient of determination(adjusted R squared)of 0.621 for males and 0.615 for females.The results showed that the ME were 5.02 years in males and 3.87 years in females,the MAE was 9.56 years in males and 9.84 years in females.Conclusion It was feasible to estimate the age of adults by using pelvic multi-slice spiral CT imaging technology,which had a certain potential and guiding significance in age estimation,and provided a new idea for the prediction of adult age.