Virtual CT morphometry of lower limb long bones for estimation of the sex and stature using postmortem Japanese adult data in forensic identification

How reliable is stature estimation by dental means? Systematic review and meta-analysis

Dental measurements have been proposed as parameters for stature estimation for at least 85 years. The scientific literature on the topic, however, is controversial regarding the performance of the method. This systematic literature review of observational cross-sectional studies aimed to compile evidence to support decisions in the forensic practice regarding the use of dental measurements for stature estimation. Embase, LILACS, MedLine (via PubMed), SciELO, Scopus, Web of Science, DansEasy and Open Access Thesis and Dissertations (OATD) were searched. Data regarding the rate of correct stature classifications were extracted. A meta-analysis with a Random Intercept Logistic Regression model and a Logit Transformation was conducted. The search led to 10.803 entries, out of which 15 were considered eligible (n = 1486 individuals). The studies were published between 1990 and 2020 and were authored by South American (n = 7) and Asian (n = 8) research teams. Dental measurements were predominantly (93.34 %) performed on dental casts or via intraoral inspection. The overall rate of correct classifications based on stature was 68 %. Excluding outliers, the overall accuracy of the method decreased to 64 % (95 %CI: 54-73 %). Significant heterogeneity was detected (I² = 72.4 %, τ2 = 0.24, H = 1.91, p < 0.001). Egger's test (p = 0.94) and the funnel plot did not reveal publication bias. Dental measurements are not reliable for stature estimation in the forensic field.

Stature estimation from the scapula measurements using 3D-volume rendering technique by regression equations in the Northern Indian population

The present study assessed the correlation between the stature and scapular measurements from both sides in order to develop population-specific regression equations to estimate the stature from measurements of the scapula in a contemporary Northern Indian population individually for the left and right sides. A total of 597 cadavers underwent postmortem multidetector computed tomography and subsequent medicolegal autopsy in our department between August 2021 and August 2022. Two hundred samples (100 males and 100 females) were randomly collected based on inclusion and exclusion criteria. Six linear anthropometric measurements of the scapula from either side were measured using the 3D volume-rendered technique by an electronic cursor. Each anthropometric measurement showed a significant difference between males and females (p < 0.05). Regression analysis was applied to match the taken measurements against stature. The accuracy to predict stature ranged from 3.99 to 4.94 cm for males and from 4.49 to 5.27 cm for females, respectively. Left-sided measurements were better predictors of stature than the right side in both genders. The results of this study indicate that scapular measurements could be useful to estimate the stature of Northern Indian individuals, particularly in scenarios of disaster victim identification lacking long bones, which are considered to be better predictors to date.

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.

Study of Sexual Dimorphism in Metatarsal Bones: Geometric and Inertial Analysis of the Three-Dimensional Reconstructed Models

The aim of the present paper is to determine the sex of the individual using three-dimensional geometric and inertial analyses of metatarsal bones. Metatarsals of 60 adult Chinese subjects of both sexes were scanned using Aquilion One 320 Slice CT Scanner. The three-dimensional models of the metatarsals were reconstructed, and thereafter, a novel software using the center of mass set as the origin and the three principal axes of inertia was employed for model alignment. Eight geometric and inertial variables were assessed: the bone length, bone width, bone height, surface-area-to-volume ratio, bone density, and principal moments of inertia around the x, y, and z axes. Furthermore, the discriminant functions were established using stepwise discriminant function analysis. A cross-validation procedure was performed to evaluate the discriminant accuracy of functions. The results indicated that inertial variables exhibit significant sexual dimorphism, especially principal moments of inertia around the z axis. The highest dimorphic values were found in the surface-area-to-volume ratio, principal moments of inertia around the z axis, and bone height. The accuracy rate of the discriminant functions for sex determination ranged from 88.3% to 98.3% (88.3%-98.3% cross-validated). The highest accuracy of function was established based on the third metatarsal bone. This study showed for the first time that the principal moment of inertia of the human bone may be successfully implemented for sex estimation. In conclusion, the sex of the individual can be accurately estimated using a combination of geometric and inertial variables of the metatarsal bones. The accuracy should be further confirmed in a larger sample size and be tested or independently developed for distinct population/age groups before the functions are widely applied in unidentified skeletons in forensic and bioarcheological contexts.

Scapular length estimation from anatomical landmarks: an osteometry and radiographic evaluation using regression equations

Estimation of body length has been achieved from the measurements of the scapular with relative accuracy by researches in recent times. This research hypothesized that the landmarks on the scapular and on the x-ray radiographs could be used to predict scapular length and elucidated the landmarks that best estimate the scapular length. A total of 600 scapulae and 600 anterior-posterior x-ray radiographs were used for the study. Positive correlation was observed between the measured variables and the scapular length with the males showing significantly higher mean length compared to females. The length of axillary boarder of the scapula was the best predictor of the scapular length. No significant difference (P>0.05) existed in the mean length derived from the scapular and the x-ray radiographs of scapular. We therefore conclude that measurements from the radiographs of scapular were as reliable in estimating scapular length as those from the scapular bones.

Estimation of sex based on patella measurements in a contemporary Chinese population using multidetector computed tomography: An automatic measurement method

Sex estimation is an important part of creating a biological profile, and ultimately assisting in creating a presumptive identification of unidentified skeletal remains. However, manual methods of anthropometric are time-consuming and prone to observer variability. The present study is an attempt to estimation of sex from automatic measurement of patella by multidetector computed tomography (MDCT) in a contemporary Chinese population. Four measurements for every patella, including maximum height (MAXH), maximum breadth (MAXB), maximum thickness (MAXT) and patellar volume (PV), were automatically provided by the software from CT image of 300 Chinese. The sample is composed of 156 males and 144 females with an average age of 41.44 and 45.68 years, respectively. The statistical analyses showed that all variables were sexually dimorphic. Receiver operating characteristic (ROC) analysis was performed to estimate sex from patella. The univariate analysis of each patellar parameter yielded a sex classification accuracy rate of 73.1% to 85.7%. The classification accuracy rates of sex estimation using the combination of the patellar parameters are 81.9% to 91.6%. This paper provides indications that the patella is important bone for sex estimation and it may be used as an alternative in forensic cases when the skull and pelvis are unavailable.

Estimation of stature from radiographically determined lower limb bone length in modern Chinese

To develop population - specific stature prediction equations from measurements of the lower limb bone in a contemporary Chinese. 303 individuals of Han group in Western China, including 201 females and 102 males were collected. The study sample was randomly divided into two subgroups. A calibration sample, which consisted of 171 females and 87 males, was used to develop the regression formula. A validation sample comprising the remaining 30 female and 15 male individuals was then used to test the predictive accuracy of the established formula. The regression equations were developed from intact bones and fragments of the femur, tibia and fibula, the maximum lengths of femur, tibia, and fibula were highly correlated with the stature. The maximum length of femur provide the most accurate result with the prediction accuracy of 3.84 cm for unknown sex, 4.00 cm in the male group, 3.45 cm in the female group, 3.61 cm in the group with age no more than 45, 3.45 cm in the group with age above 45. Moreover, the multiple regression equations were developed, and they portray a more accurate stature in instances in which the femur, tibia and fibula are available. This paper provides indications that the femur, tibia and fibula are important bones for stature estimation and they could be effectively used in forensic cases.

Accuracy and reliability of virtual femur measurement from CT scan

BACKGROUND

In the application of scientific human skeletal variation in medico-legal matters, virtual anthropology is the current technique performed to examine skeleton and its body parts. Hence, this study was conducted to assess the accuracy and reliability of virtual femur measurement through intra and inter-observer error analysis, and comparison was made between the virtual and conventional methods.

METHODS

A total of 15 femora were examined with four parameters i.e. maximum length of femur (FeMl), diameter of femoral head (FeHd), transverse diameter of midshaft (FeMd) and condylar breadth (FeCb). Osteometric board and vernier calipers were employed for the conventional method, while CT reconstructed images and Osirix MD software was utilised for the virtual method.

RESULTS

Results exhibited that there were no significant differences in the measurements by conventional and virtual methods. There were also no significant differences in the measurements by the intra or inter-observer error analyses. The intraclass correlation coefficients (ICC) were more than 0.95 by both intra and inter-observer error analyses. Technical error of measurement had displayed values within the acceptable ranges (rTEM <0.08 for intra-observer, <2.25 for inter-observer), and coefficient of reliability (R) indicated small measurement errors (R > 0.95 for intra-observer, R > 0.92 for inter-observer). By parameters, FeMl showed the highest R value (0.99) with the least error in different methods and observers (rTEM = 0.02-0.41%). Bland and Altman plots revealed points scattered close to zero indicating perfect agreement by both virtual and conventional methods. The mean differences for FeMl, FeHd, FeMd and FeCb measurements were 0.01 cm, -0.01 cm, 0.02 cm and 0.01 cm, respectively.

CONCLUSION

This brought to suggest that bone measurement by virtual method was highly accurate and reliable as in the conventional method. It is recommended for implementation in the future anthropological studies especially in countries with limited skeletal collection.

Stature estimation from tibia percutaneous length: New equations derived from a Mediterranean population

Stature is a fundamental anthropometric character to trace the biological profile of a person. In some cases, when dismembered or mutilated bodies are discovered in a forensic context, it is essential to estimate stature from single districts of the body. Nevertheless, to date and worldwide, there are only few population-specific studies on stature estimation from leg length and none of them concerns modern populations in southern Europe. We attempted to fill this gap, focusing on the estimation of stature from the length of the tibia in a Mediterranean population (Italians). We carried out the current study on a sample of 374 Italian university students of both sexes (age range: 19.9-34.4). Both, actual stature and percutaneous length of tibia were measured and new equations were developed for stature estimation. We tested separate regression equations for each sex, as well as an equation for remains, whose sex is unknown. To assess their reliability, the equations were tested on a holdout sample of 30 individuals from the same population. Moreover, results of new specific linear regression equations were compared to others from the literature. We demonstrated that the newly proposed formulae (for males and combined sexes) and the ones by Olivier (for females) provided the most reliable estimations of stature for southern Europeans.

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.

Possible application of CT morphometry of the calcaneus and talus in forensic anthropological identification

Computed tomography (CT) data provide information for volumetric and radiographic density analysis. The present study investigated the application of virtual CT volumetry of the tarsal bones to estimation of the sex, stature, and body weight using postmortem CT (PMCT) data of forensic autopsy cases. Three-dimensional (3D) images of the bilateral foot bones of intact Japanese subjects after adolescence (age ≥ 15 years, n = 179, 100 males and 79 females) were reconstructed on an automated CT image analyzer system. Measured parameters were mass volume, mean CT value (HU), and total CT value of the talus and calcaneus. Mean CT values of these bones showed age-dependent decreases in elderly subjects over 60 years of age for both sexes, with significant sex-related differences especially in the elderly. The mass volumes and total CT values of the talus and calcaneus showed significant sex-related differences, and also moderate correlations with body height and weight for bilateral bones in all cases (r = 0.58-0.78, p < 0.0001); however, the correlations of these parameters of the female talus with body weight were insufficient (r = 0.41-0.61, p < 0.0001). These observations indicate the applicability of virtual CT morphometry of the talus and calcaneus using an automated analyzer to estimate the sex and stature in forensic identification; however, greater variations should be considered in body weight estimations of females.