Estimation of sex in Japanese cadavers based on sternal measurements using multidetector computed tomography

Estimation of ancestry from cranial measurements based on MDCT data acquired in a Japanese and Western Australian population

The estimation of ancestry is important not only towards establishing identity but also as a required precursor to facilitating the accurate estimation of other attributes such as sex, age at death, and stature. The present study aims to analyze morphological variation in the crania of Japanese and Western Australian individuals and test predictive models based on machine learning for their potential forensic application. The Japanese and Western Australian samples comprise computed tomography (CT) scans of 230 (111 female; 119 male) and 225 adult individuals (112 female; 113 male), respectively. A total of 18 measurements were calculated, and machine learning methods (random forest modeling, RFM; support vector machine, SVM) were used to classify ancestry. The two-way unisex model achieved an overall accuracy of 93.2% for RFM and 97.1% for SVM, respectively. The four-way sex and ancestry model demonstrated an overall classification accuracy of 84.0% for RFM and 93.0% for SVM. The sex-specific models were most accurate in the female samples (♀ 95.1% for RFM and 100% for SVM; ♂91.4% for RFM and 97.4% for SVM). Our findings suggest that cranial measurements acquired in CT images can be used to accurately classify Japanese and Western Australian individuals into their respective population. This is the first study to assess the feasibility of ancestry estimation using three-dimensional CT images of the skull.

[Morphology of sternum for formation of the biological profile of unidentified individual]

Identification of a person by general group characteristics does not lose its relevance over a long period. An analysis of publications (2000-2023) devoted to the possibilities of using the sternum to determine gender and age showed a fairly large amount of work on this topic, with very promising results. The trend in the development of this area is the use of modern methods of medical imaging. This becomes the starting point for conducting such studies on the territory of the Russian Federation and developing a methodology that includes the Russian population, taking into account their population characteristics.

Statistical analysis of biomechanical properties and size of the sternum and its fracture risk in a Japanese sample

OBJECTIVE

Sternal fractures can have life-threatening complications. To understand chest injury mechanisms, sufficient data regarding the mechanical properties and structure of the sternum are required. The aim of this study was to examine the mechanical properties and size of the sternum in a Japanese forensic sample.

MATERIALS AND METHODS

Sterna were obtained from 120 Japanese dead bodies of known age and sex. The sample thickness (ST) and the sample width (SW) were measured using a computed tomographic image. Three-point-bending tests were conducted using a three-point-bending apparatus to assess the fracture load (FL) of the sample. Then, the flexural strength (FS) was calculated and the natural logarithm of FL (ln FL) and FS (ln FS) were also calculated.

RESULTS

The values of ST, ln FL, and ln FS for male samples were significantly greater than those for female samples. Both ln FL and ln FS had significant negative correlations with age regardless of sex; the Pearson product-moment correlation coefficients were larger for female samples than for male samples. Although age was significantly negatively correlated with SW in female samples, there was no significant correlation between age and SW in male samples. No significant correlations were found between age and ST regardless of sex.

CONCLUSION

This is the first study to present quantitative data on the biomechanical properties of the sternum. Because of the smaller sternal strength of elderly women, it is especially important for them to avoid the risk of sternal fractures.

Stature estimation by semi-automatic measurements of 3D CT images of the femur

Stature estimation is one of the most basic and important methods of personal identification. The long bones of the limbs provide the most accurate stature estimation, with the femur being one of the most useful. In all the previously reported methods of stature estimation using computed tomography (CT) images of the femur, laborious manual measurement was necessary. A semi-automatic bone measuring method can simplify this process, so we firstly reported a stature estimation process using semi-automatic bone measurement software equipped with artificial intelligence. Multiple measurements of femurs of adult Japanese cadavers were performed using automatic three-dimensional reconstructed CT images of femurs. After manually setting four points on the femur, an automatic measurement was acquired. The relationships between stature and five femoral measurements, with acceptable intraobserver and interobserver errors, were analyzed with single regression analysis using the standard error of the estimate (SEE) and the coefficient of determination (R²). The maximum length of the femur (MLF) provided the lowest SEE and the highest R²; the SEE and R² in all cadavers, males and females, respectively, were 3.913 cm (R² = 0.842), 3.664 cm (R² = 0.705), and 3.456 cm (R² = 0.686) for MLF on the right femur, and 3.837 cm (R² = 0.848), 3.667 cm (R² = 0.705), and 3.384 cm (R² = 0.699) for MLF on the left femur. These results were non-inferior to those of previous reports regarding stature estimation using the MLF. Stature estimation with this simple and time-saving method would be useful in forensic medical practice.

Estimation of sex based on metrics of the sternum in a contemporary Jordanian population: A computed tomographic study

There is a paucity of osteometric standards for sex estimation from unknown skeletal remains in Jordan and the sexual dimorphism of the sternum has not yet been investigated. The aim of this study was to evaluate the sexual dimorphism in sternal measurements using 3D multidetector computed tomography (MDCT), and to assess their reliability for sex estimation in a Jordanian population. A total of 600 MDCT scans (300 males and 300 females) were used and a total of 8 sternal measurements were studied (manubrium length, sternal body length, combined length of manubrium and body, corpus sterni width at 1st and 3rd sternebrae, sternal index and area). Sexual dimorphism was evaluated by means of discriminant function analyses. Significant sexual dimorphism was found mainly in middle-aged and older adults. Including all subjects, multivariate, and stepwise functions gave an overall accuracy of 83.0% and 84.0%, respectively. Additionally, multivariate and stepwise analyses were conducted separately for each age group. The accuracy of sex estimation in multivariate analysis (all variables) varied from 63.2% in the young, and 83.7% in the middle adults to 84.9% for older adults. In stepwise analysis, the highest accuracy rates were provided by only sternal area in young adults (81.6%), and sternal area combined with sternal body length in middle-aged and older adults (84.2% and 85.3%, respectively). The best sex discriminator using univariate analysis (single variable) was sternal area followed by sternal body length (84.0% and 80.8% respectively). Notably, univariate analyses for most variables gave relatively higher classification accuracies in females but were poor at predicting males in the sample (sex bias ranged between -6.4% and -20%). Our data suggest that dimorphism in the human sternum increases with advancing age and separate discriminant functions are needed for each age group in Jordanians. In addition, multivariate and stepwise analyses using sternum gave higher classification accuracies with comparatively lower sex biases compared to univariate analyses.

State of the art in post-mortem computed tomography: a review of current literature

Computed tomography (CT) and other advanced diagnostic imaging techniques are gaining popularity in forensic pathology. This paper aims to define and offer complete and easily accessible "state of the art" for post-mortem computed tomography (PMCT), by reviewing the latest international literature. The proposed format answers the "five Ws" that follows: (1) What: We report the different kinds of CT scan and settings generally used in post-mortem imaging. The machine most employed is a 8/16-slice spiral CT, usually without contrast enhancement. The introduction of some variables, such as CT-guided biopsies, post-mortem ventilation, and PMCT angiography is becoming increasingly useful. (2) Why: Literature highlights the many advantages of PMCT. Limitations can be partly overcome by modern imaging techniques and combined evaluation with traditional autopsy. (3) Who: Most authors agree that collaboration between different specialists, i.e., radiologists and pathologists, is the best scenario, since radiologic, anatomic, and forensic skills are needed simultaneously. The most important human factor is "teamwork". (4) When: Literature provides no absolute limits for performing PMCT. Some authors have tested PMCT as a replacement for conventional autopsy but found some limitations. Others evaluated PMCT as a guide or screening tool for traditional autopsy. (5) Where: Many research groups around the world have performed studies on the use of PMCT. Although few countries adopt PMCT in routine practice, its use is rapidly spreading.

Determining gender by taking measurements from magnetic resonance images of the patella

BACKGROUND

A key step in making a positive identification in forensic medicine is the establishment of a biological profile, which involves determining factors such as gender, age, ancestry, and stature. The goal of this study was to determine if gender could be established by taking various measurements of the patella taken from magnetic resonance imaging (MRI) images and analyzing the variations by gender.

METHODS

The sample group consisted of 220 patients (110 male and 110 female) whose patella were measured using MRI images of their left knee. Reasons for exclusion were any previous surgery, patella bipartite variation, any fracture in the patella due to trauma or findings of mass or infection. Three measurements - transverse length (TP), craniocaudal length (CC) and anteroposterior length (APP) - were taken off T2-weighted axial and sagittal MRI scans. The program SPSS (Version 21.0) was used to make a descriptive analysis, independent t-test and discriminative analysis.

RESULTS

It was found possible to determine gender with an accuracy rate of 91% for females and 87% for males. Since measurements were made individually the accuracy for gender estimation is lower than that seen in other methods.

CONCLUSION

The findings are important in that they show that it is possible to determine gender with a high degree of accuracy using just a few measurements taken from the patella.

Estimation of stature from sternum - Exploring the quadratic models

Identification of the dead is significant in examination of unknown, decomposed and mutilated human remains. Establishing the biological profile is the central issue in such a scenario, and stature estimation remains one of the important criteria in this regard. The present study was undertaken to estimate stature from different parts of the sternum. A sample of 100 sterna was obtained from individuals during the medicolegal autopsies. Length of the deceased and various measurements of the sternum were measured. Student's t-test was performed to find the sex differences in stature and sternal measurements included in the study. Correlation between stature and sternal measurements were analysed using Karl Pearson's correlation, and linear and quadratic regression models were derived. All the measurements were found to be significantly larger in males than females. Stature correlated best with the combined length of sternum, among males (R = 0.894), females (R = 0.859), and for the total sample (R = 0.891). The study showed that the models derived for stature estimation from combined length of sternum are likely to give the most accurate estimates of stature in forensic case work when compared to manubrium and mesosternum. Accuracy of stature estimation further increased with quadratic models derived for the mesosternum among males and combined length of sternum among males and females when compared to linear regression models. Future studies in different geographical locations and a larger sample size are proposed to confirm the study observations.

Virtual computed tomography morphometry of the patella for estimation of sex using postmortem Japanese adult data in forensic identification

In forensic anthropological identification of human remains and single bones, computed tomography (CT) data analysis facilitates volumetric and radiographic density analyses, and a recently developed automated analysis system markedly improved the performance, accuracy, and reproducibility of three-dimensional (3-D) reconstruction. The present study aimed to investigate virtual CT morphometry of the patella for the estimation of sex using postmortem CT data of forensic autopsy cases of Japanese individuals aged ≥18 years (total n=220; 110 males and 110 females; estimated postmortem interval <88h), especially with regard to the efficacy of 3-D bone volumetry. Sex-related differences were detected for all parameters (males>females; p<0.0001), but the differences were the most notable for bone mass volume; the estimated cut-off values (cm³) for discriminating males and females were 20.35 with a sensitivity and specificity of 0.85 and 0.91 for the left side and 19.96 with a sensitivity and specificity of 0.83 and 0.92 for the right side, respectively. The mean CT value showed an age-dependent decrease and was particularly low in females aged >60years. These findings indicate the efficacy of virtual CT morphometry of the patella using an automated analyzer for sex estimation.

Determination of sex on the basis of hyoid bone measurements in a Japanese population using multidetector computed tomography

Sex determination for unidentified human remains is important because the determined sex is usually used as a foundation for the estimation of other biological profiles. This study investigated the sexual dimorphism of the adult hyoid bone and developed discriminant equations to accurately estimate sex in a contemporary Japanese population using measurements on two-dimensional computed tomography (CT) images. The study sample comprised 280 cadavers (140 males, 140 females) of known age and sex that underwent postmortem CT and subsequent forensic autopsy. In accordance with previous studies, seven measurements were performed using two-dimensional CT reconstructed images. Most measurements of males were significantly greater than those of females. The perpendicular length from the most anterior edge of the hyoid body to the line that connects the most distal points of the greater horns of the hyoid and the linear distance between the most lateral edges of the hyoid body most significantly contributed to sex determination. This study demonstrated that discriminant functions on the basis of three measurements provided higher rates of accurate sex classification (93.3-94.6%) than univariate functions. Therefore, the hyoid bone is highly sexually dimorphic in the contemporary Japanese population and may be useful in forensic contexts for sex determination with a high level of accuracy.

Virtual anthropology - a brief review of the literature and history of computed tomography

Computed tomography (CT) has influenced numerous fields since its inception in the 1970s. The field of palaeoanthropology significantly benefited from this efficient and non-invasive medium in terms of the conservation, reconstruction and analysis of fossil human remains. Over the past decade, there has been a steady increase in the number of forensic anthropological studies incorporating virtual osteological analyses. Because of the increasing importance of these modern cross-sectional imaging techniques and the requirement for standardized parameters in forensic science, we deemed it important to outline the history and development of CT applications in these related academic areas. The present paper outlines the history of “virtual anthropology” and osteological multi-detector CT in the context of palaeoanthropology and forensic anthropology.

Sexual determination based on multidetector computed tomographic measurements of the second cervical vertebra in a contemporary Japanese population

Accurate sex estimation is important in forensic investigation to determine the identity of unknown individuals. The aim of this study was to investigate the accuracy of sex assessment based on measurements of the second cervical vertebra (C2) using computed tomographic (CT) images in a Japanese population and to develop discriminant function formulae. The data were collected from 224 Japanese cadavers (112 male subjects, 112 female subjects) on which postmortem CT scanning and subsequent forensic autopsy were performed. Nine CT measurements of the C2 were performed for CT images of each subject. The measurements were assessed using descriptive statistics and discriminant function analyses (DFA). All of the measurements demonstrated significant sexual dimorphism. Multiple DFA with stepwise variable selection resulted in multivariable models; a five-variable model reached an accuracy rate of 92.9%. Our results suggest that metric analysis based on CT images of the C2 can accurately determine the sex from the human skeletal remains in a contemporary Japanese population and may be useful for sex estimation in forensic anthropology.

Sex estimation based on scapula analysis in a Japanese population using multidetector computed tomography

Accurate sex estimation based on measurements of dimorphic dimensions in human unknown remains is important as the first step toward making individual identification. The purpose of this study was to assess the sexual dimorphism of the scapula and to quantify the accuracy of sex estimation in a contemporary Japanese forensic sample using scapular measurements based on three-dimensional (3D) computed tomographic (CT) images. A total of 218 cadavers (109 males, 109 females) that underwent postmortem CT and subsequent forensic autopsy were used. Ten scapular measurements were performed on 3D CT reconstructed images that extracted only bone data, and were analyzed using descriptive statistics and discriminant function analyses (DFA). All measurements were dimorphic in terms of sex differences. Univariate DFA provided sex classification accuracy rates of 75.7-91.3%. Stepwise DFA yielded sex prediction accuracy rates of 93.1-94.5%. In conclusion, the scapular measurements using 3D CT images of a contemporary Japanese population may be useful for the estimation of skeletal sex in the field of forensic anthropology.