Exploring the functionality of mesh-to-mesh value comparison in pair-matching and its application to fragmentary remains

SIMPLE SUMMARY: Forensic anthropologists often face the task of analysing a mixed group of skeletal remains or matching a solitary bone with the rest of a skeleton to determine if it belongs to the same individual. One of the best ways to do this is by pair-matching left and right bones of the same type. Common pair-matching methods experience issues such as high levels of subjectivity, lack of reliability, or expensive cost of implementation. This study explores the application of the relatively new method, mesh-to-mesh value comparison (MVC), which matches paired bones based on morphological shape to determine the likelihood that they derive from the same individual. This study sought to expand on the success found in past publications using MVC and to see how well it performed on a sample of clavicles, a bone known for having a high degree of bilateral variability, of 80 modern Turkish individuals. This study also explored whether MVC can reliably match fragmented bones to their intact counterpart. Results show MVC successfully matched 88.8% of paired clavicles and suggest the method continues to be a promising avenue for pair-matching that is not affected by ancestry and may be applicable to fragmented remains with further study. ABSTRACT: Many cases encountered by forensic anthropologists involve commingled remains or isolated elements. Common methods for analysing these contexts are characterised by limitations such as high degrees of subjectivity, high cost of application, or low proven accuracy. This study sought to test mesh-to-mesh value comparison (MCV), a relatively new method for pair-matching skeletal elements, to validate the claims that the technique is unaffected by age, sex and pathology. The sample consisted of 160 three-dimensional clavicle models created from computed tomography (CT) scans of a contemporary Turkish population. Additionally, this research explored the application of MVC to match fragmented elements to their intact counterparts by creating a sample of 480 simulated fragments, consisting of three different types based on the region of the bone they originate from. For comparing whole clavicles, this resulted in a sensitivity value of 87.6% and specificity of 90.9% using ROC analysis comparing clavicles. For the fragment comparisons, each type was compared to the entire clavicles of the opposite side. The results included a range of sensitivity values from 81.3% to 87.6%. Overall results are promising and the MVC technique seems to be a useful technique for matching paired elements that can be accurately applied to a Modern Turkish sample

Sex estimation in a Turkish population using Purkait’s triangle: a virtual approach by 3-dimensional computed tomography (3D-CT)

Sex estimation is considered one of the first steps in the forensic identification process. Morphological and morphometrical differences between males and females have been used as means for morphoscopic and metric methods on both cranial and postcranial skeletal elements. When dry skeletal elements are not available, virtual data can be used as a substitute. The present research explores 3-dimensional (3D) scans from a Turkish population to test a sex estimation method developed by Purkait (2005). Overall, 296 individuals were used in this study (158 males and 138 females). Purkait’s triangle parameters were measured on computed tomography (CT) scans obtained from both right and left femora of each patient at the Bakirkoy Dr. Sadi Konuk Training Research Hospital (Istanbul, Turkey). Intra- and inter-observer errors were assessed for all variables through technical error of measurements analysis. Bilateral asymmetry and sex differences were evaluated using parametric and non-parametric statistical approaches. Univariate and multivariate discriminant function analyses were then conducted. Observer errors demonstrated an overall agreement within and between experts, as indicated by technical error of measurement (TEM) results. No bilateral asymmetries were reported, and all parameters demonstrated a statistically significant difference between males and females. Fourteen discriminant models were generated by applying single and combined parameters, producing a total correct sex classification ranging from 78.4% to 92.6%. In addition, over 67% of the total sample was accurately classified, with 95% or greater posterior probabilities. Our study demonstrates the feasibility of 3D sex estimation using Purkait’s triangle on a Turkish population, with accuracy rates comparable to those reported in other populations. This is the first attempt to apply this method on virtual data and although further validation and standardisation are recommended for its application on dry bone, this research constitutes a significant contribution to the development of population-specific standards when only virtual data are available

Virtual morphometric method using seven cervical vertebrae for sex estimation on the Turkish population

Sex estimation from skeletal remains is crucial for the estimation of the biological profile of an individual. Although the most commonly used bones for means of sex estimation are the pelvis and the skull, research has shown that acceptable accuracy rates might be achieved by using other skeletal elements such as vertebrae. This study aims to contribute to the development of sex estimation standards from a Turkish population through the examination of CT scans from the seven cervical vertebrae. A total of 294 individuals were included in this study. The CT scans were obtained from patients attending the Bakirkoy Training and Research Hospital (Turkey) and the data was collected retrospectively by virtually taking measurements from each cervical vertebrae. The full database was divided into a training set (N = 210) and a validation set (N = 84) to test the fit of the models. Observer error was assessed through technical error of measurement and sex differences were explored using parametric and non-parametric approaches. Logistic regression was applied in order to explore different combinations of vertebral parameters. The results showed low intra- and inter-observer errors. All parameters presented statistically significant differences between the sexes and a total of 15 univariate and multivariate models were generated producing accuracies ranging from a minimum of 83.30% to a maximum of 91.40% for a model including three parameters collected from four vertebrae. This study presents a virtual method using cervical vertebrae for sex estimation on the Turkish population providing error rates comparable to other metric studies conducted on the postcranial skeleton. The presented results contribute not only to the development of population-specific standards but also to the generation of virtual methods that can be tested, validated, and further examined in future forensic cases

Metric variation of the tibia in the Mediterranean: implications in forensic identification

Ancestry estimation from skeletal remains is a challenging task, but essential for the creation of a complete biological profile. As such, the study of human variation between populations is important for the fields of biological and forensic anthropology, as well as medicine. Cranial and dental morphological variation have traditionally been linked to geographic affinity resulting in several methods of ancestry estimation, while the postcranial skeleton has been systematically neglected. The current study explores metric variation of the tibia in six Mediterranean populations and its validity in estimating ancestry in the Mediterranean. The study sample includes 909 individuals (470 males and 439 females) from Cyprus, Greece, Italy, Spain, Portugal and Turkey. The sample was divided in two subsamples: a reference and a validation sample. Multinomial regression models were created based on the reference sample and then applied to validation sample. The first model used three variables and resulted in 57% and 56% accuracy for the two samples respectively, while the second model (6 variables) resulted in 80% and 74% respectively. Classification between groups ranged from 28% to 95% for the reference sample and from 15% to 91% for the validation sample. The highest classification accuracy was noted for the Greek sample (95% and 90% for the reference and validation sample respectively), followed by the Turkish sample (74% and 78% respectively). The Spanish, Portuguese and Italian samples presented greater morphological overlap which resulted in lower classification accuracies. The results indicate that although the tibia presents considerable variation amongst neighbour populations is not suitable as a sole skeletal element to separate all groups successfully. A combination of different skeletal elements may be required in order to achieve the levels of reliability required for forensic applications

Sex estimation in a contemporary Turkish population based on CT scans of the calcaneus

Building a reliable biological profile from decomposed remains depends heavily on the accurate estimation of sex. A variety of methods based on every single skeletal element have been developed over the years for different populations employing both osteological and virtual methods. The latter seem to be a reasonable alternative in countries lacking osteological reference collections. The current study used 3D virtual models of calcanei from CT scans of living adults to develop a sex estimation method for contemporary Turkish. Four hundred and twenty eight calcanei CT scans were analysed. The sample was divided in two subsamples: an original (N = 348) and a validation sample (N = 80) with similar distribution of males and females. Nine classical measurements were taken using the 3D models of the calcanei and two different statistical methods (Discriminant function analysis and Binary logistic regression) were used. Classification accuracy ranged from 82% to 98% for the validation sample and it was consistently high using any of the two methods. Sex bias seems to be lower for most of the logistic regression equations compared to the discriminant functions. These results, however, need further testing to be verified. Based on the results of this study we recommend the use of both methods for sex estimation from the measurements of the calcaneus bone in a Turkish population. (C) 2017 Elsevier B.V. All rights reserved

Forensic age diagnostics by magnetic resonance imaging of the proximal humeral epiphysis

The most commonly used radiological method for age estimation of living individuals is X-ray. Computed tomography is not commonly used due to high radiation exposure, which raises ethical concerns. This problem can be solved with the use of magnetic resonance imaging (MRI), which avoids the use of ionizing radiation. The purpose of the present study was to evaluate the utility of MRI analysis of the proximal humeral epiphyses for forensic age estimations of living individuals. In this study, 395 left proximal humeral epiphyses (patient age 12-30years) were evaluated with fast-spin-echo proton density-weighted image (FSE PD) sequences in a coronal oblique orientation on shoulder MRI images. A five-stage scoring system was used following the method of Dedouit et al. The intra- and interobserver reliabilities assessed using Cohen's kappa statistic were =0.818 and =0.798, respectively. According to this study, stage five first appeared at 20 and 21years of age in males and females, respectively. These results are not directly comparable to any other published study due to the lack of MRI data on proximal humeral head development. These findings may provide valuable information for legally important age thresholds using shoulder MRI. The current study demonstrates that MRI of the proximal humerus can support forensic age estimation. Further research is needed to establish a standardized protocol that can be applied worldwide

Technical Note: The Forensic Anthropology Society of Europe (FASE) Map of Identified Osteological Collections

Identified (documented) osteological collections represent an important resource in the development of forensic anthropology standards and methods as well as a precious tool for learning and training of practitioners. Even though the number of papers presenting identified collections worldwide increases, many of the collections have still not been divulged to the scientific community in sufficient detail to ascertain their exact number. The Forensic Anthropology Society of Europe (FASE) therefore developed a tool that goes beyond sporadic publications: the FASE Map of Identified Osteological Collections, which is freely accessible and continuously updated and revised. The online map is available at http://forensicanthropology.eu/osteological-collections/. The map of skeletal collections was created in 2017 and currently displays information on 153 identified osteological collections (43 of them categorized as contemporary) located in 41 different countries. This article offers a short analysis of the type, geographical location and content of the collections included in the map. The aim of this article and the map as such is to provide a useful resource to facilitate research planning and teaching in forensic anthropology and related disciplines.info:eu-repo/semantics/publishedVersio

Applicability of T1-weighted MRI in the assessment of forensic age based on the epiphyseal closure of the humeral head

This work investigates the value of magnetic resonance imaging analysis of proximal epiphyseal fusion in research examining the growth and development of the humerus and its potential utility in establishing forensic age estimation. In this study, 428 proximal humeral epiphyses (patient age, 12-30years) were evaluated with T1-weighted turbo spin echo (T1 TSE) sequences in coronal oblique orientation on shoulder MRI images. A scoring system was created following a combination of the Schmeling and Kellinghaus methods. Spearman's rank correlation analysis revealed a significant positive relationship between age and ossification stage of the proximal humeral epiphysis (all subjects: rho=0.664, p<0.001; males: 0.631, p<0.001; females: rho=0.651, p<0.001). The intra- and inter-observer reliability assessed using Cohen's kappa statistic was =0.898 and =0.828, respectively. The earliest age of epiphysis closure was 17years for females and 18years for males. MRI of the proximal humeral epiphysis can be considered advantageous for forensic age estimation of living individuals in a variety of situations, ranging from monitoring public health to estimating the age of illegal immigrants/asylum seekers, minors engaged in criminal activities, and illegal participants in competitive sports, without the danger of radiation exposure

CLINICAL FEATURES OF CANCER ASSOCIATED ISCHEMIC STROKE

Introduction: Cerebrovascular disease is the second most common cause of central nervous system involvement in cancer patients after metastases. Procoagulant substances secreted by tumour cells, cancer therapy, and embolus from tumour have been implicated in ischemic stroke (IS) in cancer patients