Anthropological and Radiographic Comparison of Vertebrae for Identification of Decomposed Human Remains

The potential of facial nevi in personal identification

Forensic anthropologists dealing with personal identification (PI) of human remains have recently stressed the need to explore the potential of "secondary identifiers" for identifying victims who died in particular events for whom images often represent the main antemortem data available. Being the face the part most exposed in images, characteristics as pigmented skin lesions (PSLs), can be crucial if combined with other input. Since no data is available on frequencies and distribution of facial PSLs in the general population, this study aims at systematically collecting such data to verify their potential in PI and to open a debate on the aid that "secondary identifiers", regardless of their specific nature, can give to the identification of the deceased in specific forensic contexts. A retrospective analysis on three-dimensional facial models of 1039 Italian subjects (from 4 to 84 years old) was conducted to examine the incidence of PSLs discriminated according to size and position in well-defined facial areas. From the collected data we developed a probabilistic approach providing the likelihood ratio (LR) for two settings: (1) the relative frequencies of nevi in the various facial areas, providing the deriving compound probability of owning a certain facial PSLs pattern; and (2) codes describing the facial nevi pattern of each individual of our population, thus testing their uniqueness and so their potential in PI. The calculated LRs mostly proved high identifying strength, particularly when provided by the compound probability-based approach. Data on incidence and position of facial nevi, their generated codes, and the probabilistic approach here presented, all constitute a starting point for advancing secondary identifiers. Nonetheless, although this preliminary study proved facial PSLs as valuable and potentially useful for identification, their significance and validity should be interpreted with caution as we are still at the first theoretical step clearly based on ideal conditions, and thus further investigations are due on the limitations of their use in practical identifying settings. Therefore, being this systematic study only a preliminary one in its nature, it is recommended not to use this kind of approach until further studies will test its validity in several practical conditions.

Technical Note: Individuals identified by radiographic comparison: A sample of demographics and the region of body used for identification in Clark County, Nevada, USA (2017-2020)

Radiographs regularly aid in identifications by comparing antemortem and postmortem images. The forensic community has widely accepted this method because radiographic images are low in cost, easily transferable, and generally believed to be uncomplicated to assess. However, there is a dearth of diverse, modern radiographic datasets as well as a deficiency in assessing population frequencies of nonmetric traits via radiographs. Further, radiographic comparisons, although typically required as a core competency of practicing forensic anthropologists, do not have standard training and education requirements. To understand the diversity and representation within an opportunistic dataset, we provide a case study of the demographics of decedents identified via radiographic comparison at the Clark County Office of the Coroner/Medical Examiner (CCOCME) in Las Vegas, NV, USA from 2017 to 2020. Additionally, we examined each region of the body used to make radiographic identifications. The sample was majority Caucasian and male, with a mean and median age at death of 64.9 years and 67.0 years, respectively. Our results indicated that this sample was not representative of the greater Clark County population. The most common body region used for comparisons was the chest, followed by the head and neck, pelvis, dentition, and the extremities. Thus, large generalizations made from these types of datasets must be implemented with caution due to the relative lack of diversity and representation. As well, current discussions regarding training and education of forensic anthropologists as they relate to radiographic comparisons are explored.

A novel method to estimate adult age from the lumbar vertebral body using 3D PMCT images in Japanese

This study evaluated the age-related changes in the vertebral body using 3D Postmortem CT (PMCT) images and proposed an alternative age estimation formula. The PMCT images of 200 deceased individuals aged 25 to 99 years (126 males, 74 females) were retrospectively reviewed and included in the study. Using the open-source software ITK-SNAP and MeshLab, a 3D surface mesh of the fourth lumbar vertebral body (L4) and its convex hull models were created from the PMCT data. Using their inbuilt tools, volumes (in mm3) of the L4 surface mesh and convex hull models were subsequently computed. We derived VD, defined as the difference in volumes between the convex hull and L4 surface mesh normalized by L4 mesh volume, and VR, defined as the ratio of L4 mesh volume to convex hull volume based on individual L4. Correlation and regression analyses were performed between VD, VR, and chronological age. A statistically significant positive correlation (P < 0.001) between chronological age and VD, (r_s = 0.764, males; r_s = 0.725, females), and a significant negative correlation between chronological age and VR (r_s = -0.764, males; r_s = -0.725, females) was obtained in both sexes. The lowest standard error of the estimate was demonstrated by the VR at 11.9 years and 12.5 years for males and females, respectively. As such, their regression models to estimate adult age were Age = 248.9-2.5VR years, males; Age = 258.1-2.5VR years, females. These regression equations may be useful for estimating age in Japanese adults in forensic settings.

Re-examining so-called 'secondary identifiers' in Disaster Victim Identification (DVI): Why and how are they used?

Disaster victim identification (DVI) refers to the identification of multiple deceased persons following an event that has a catastrophic effect on human lives and living conditions. Identification methods in DVI are typically described as either being primary, which include nuclear genetic markers (DNA), dental radiograph comparisons, and fingerprint comparisons, or secondary, which are all other identifiers and are ordinarily considered insufficient as a sole means of identification. The aim of this paper is to review the concept and definition of so-called 'secondary identifiers" and draw on personal experiences to provide practical recommendations for improved consideration and use. Initially, the concept of secondary identifiers is defined and examples of publications where such identifiers have been used in human rights violation cases and humanitarian emergencies are reviewed. While typically not investigated under a strict DVI framework, the review highlights the idea that non-primary identifiers have proven useful on their own for identifying individuals killed as a result of political, religious, and/or ethnic violence. The use of non-primary identifiers in DVI operations in the published literature is then reviewed. Because there is a plethora of different ways in which secondary identifiers are referenced it was not possible to identify useful search terms. Consequently, a broad literature search (rather than a systematic review) was undertaken. The reviews highlight the potential value of so-called secondary identifiers but more importantly show the need to scrutinise the implied inferior value of non-primary methods which is suggested by the terms "primary" and "secondary". The investigative and evaluative phases of the identification process are examined, and the concept of "uniqueness" is critiqued. The authors suggest that non-primary identifiers may play an important role in providing leads to formulating an identification hypothesis and, using the Bayesian approach of evidence interpretation, may assist in establishing the value of the evidence in guiding the identification effort. A summary of contributions non-primary identifiers may make to DVI efforts is provided. In conclusion, the authors argue that all lines of evidence should be considered because the value of an identifier will depend on the context and the victim population. A series of recommendations are provided for consideration for the use of non-primary identifiers in DVI scenarios.

Frontal Sinus Morphological and Dimensional Variation as Seen on Computed Tomography Scans

Frontal sinus variation has been used in forensic anthropology to aid in positive identification since the 1920s. As imaging technology has evolved, so has the quality and quantity of data that practitioners can collect. This study examined frontal sinus morphological and dimensional variation on computed tomography (CT) scans in 325 individuals for assigned sex females and males from African-, Asian-, European-, and Latin American-derived groups. Full coronal sinus outlines from medically derived CT images were transferred into SHAPE v1.3 for elliptical Fourier analysis (EFA). The dimensional data were measured directly from the images using the MicroDicom viewer. Statistical analyses—Pearson’s chi-square, ANOVA, and Tukey post hoc tests—were run in R Studio. Results indicated that 3.7% lacked a frontal sinus and 12.0% had a unilateral sinus, usually on the left (74.3%). Additionally, no statistically significant morphological clustering using EFA was found based on assigned sex and/or population affinity. However, there were statistically significant differences dimensionally (height and depth) when tested against assigned sex and population affinity, indicating that the interactive effects of sexual dimorphism and adaptive population histories influence the dimensions but not the shape of the frontal sinus.

Infracranial radiographic comparison for human identification: A study of image quality and tissue shielding effects

In this study, we explore how image resolution and tissue shielding can impact correct classification rates (CCRs) of infracranial radiographic comparisons undertaken using small field-of-view radiographs. Thirty-six identification arrays (using clavicles and seventh cervical vertebra) were constructed with each array comprised of five radiographs: one X-ray of a single dry bone (postmortem [PM] skeletal image) and four simulated antemortem [AM] radiographs (radiographs taken pre-skeletization). One AM radiograph in each array represented the ground truth match to the PM radiograph (=25% rate of randomly selecting the correct match). Radiographs were digitally manipulated, so that four varieties of decreasing blur (Gaussian blur = 12-0 pr across 24 arrays), and, for PM clavicles, four varieties of decreasing hard tissue shielding (opacity of 40-0% across 12 arrays) existed. Arrays were evaluated, for their correct PM/AM pair, by 8 anthropologists trained in chest radiograph comparison (CXR; either currently or formerly competency certified by the Defense POW/MIA Accounting Agency CXR training program), 28 current American Board of Forensic Anthropology (ABFA) diplomates and 30 novices. Analysts' CCRs substantially improved when Gaussian blur was <10 pr (55% CCR at >10 pr vs. 89% for <10 pr). Tissue shielding effects increased CCRs on average by +10% for each -10% opacity step (between 40-0% opacity). The CXR anthropologists were the most tolerant of the more challenging identification contexts (highest blur and opacity), reconfirming that analyst training and expertise is an important factor, especially when poorer quality radiographic images are the subject of analysis.

Machine learning techniques demonstrating individual movement patterns of the vertebral column: the fingerprint of spinal motion

Surface topography systems enable the capture of spinal dynamic movement; however, it is unclear whether vertebral dynamics are unique enough to identify individuals. Therefore, in this study, we investigated whether the identification of individuals is possible based on dynamic spinal data. Three different data representations were compared (automated extracted features using contrastive loss and triplet loss functions, as well as simple descriptive statistics). High accuracies indicated the possible existence of a personal spinal 'fingerprint', therefore enabling subject recognition. The present work forms the basis for an objective comparison of subjects and the transfer of the method to clinical use cases.

Infra-cranial radiographic comparison for human identification: A study of analyst expertise

Radiographic comparison for identification is widely utilized. However, these methods are qualitative and subject to analyst ability to correctly read and interpret radiographs. With regards to infra-cranial radiographs, few studies have been conducted to explore the role of practitioner expertize on correct classification rates (CCRs). Here, we undertake two such studies using forensic anthropologists [American Board of Forensic Anthropology (ABFA) certified, practicing but not board-certified anthropologists, and chest radiograph comparison (CXR) anthropologists trained via the Defense POW/MIA Accounting Agency CXR competency training program] and compare their results to novices. To ensure participants only referred to the same skeletal morphology, we cropped radiographs to single bones. An array of four simulated antemortem radiographs was presented to each assessor with each postmortem radiograph. Assessors evaluated arrays for a correct match, which was always present, yielding a 25% rate for random correct selections. Study 1 used anteroposterior C7, posteroanterior second metacarpal, and lateral calcaneus radiographs (three arrays each for nine arrays total), which yielded 86, 81, 69, and 68% mean CCRs for CXR experts, ABFA anthropologists, non-ABFA anthropologists and novices, respectively. Study 2 used anteroposterior C7 and left clavicles (three arrays each for six arrays total), yielding mean CCRs of 100, 96, and 84% for CXR experts, ABFA anthropologists and novices, respectively. As reflected by the CCRs, expertise is clearly a factor for radiographic comparisons, evident not just between novices and anthropologists, but also between anthropologists. We recommend all radiographic comparison analysts be subject to competency/proficiency tests prior to their engagement for forensic casework.

Strengthening the role of forensic anthropology in personal identification: Position statement by the Board of the Forensic Anthropology Society of Europe (FASE)

In this position statement, the Board members of the Forensic Anthropology Society of Europe (FASE) argue that forensic anthropology methods can be used as means of personal identification, particularly in situations with limited availability of traditional identification methods (i.e. dactyloscopy, odontology, and molecular genetic analysis). This statement has been issued taking into account the international migration crises related to thousands of deaths worldwide, in which the utility of these traditional means of identification has been sporadic to non-existent. The statement is however not limited to deaths related to the migration crises, as similar problems may occur in fatalities en masse such as in natural disasters and armed conflicts, and on a smaller scale in cases of homeless or otherwise socioeconomically disadvantaged persons. The number of reports on personal identification based on sound anthropological methodology is increasing in the scientific literature. However, more research is needed to develop evidence-based standard operating procedures and statistical frameworks. It remains essential to raise awareness among forensic practitioners, law enforcement, and judiciary professionals on the utility of forensic anthropology in cases where it can provide sufficient information for identification.

Automated contour detection in spine radiographs and computed tomography reconstructions for forensic comparative identification

This study was conducted to test an automated method to identify unknown individuals. It relies on a previous radiographic file and uses an edge-based comparison of lumbar CT/PMCT reconstructions and radiographs. The living group was composed of 15 clinical lumbar spine CT scans and 15 paired radiographs belonging to the same patients. The deceased group consisted of 5 lumbar spine PMCT scans and 5 paired antemortem radiographs of deceased individuals plus the 15 unpaired radiographs belonging to the living. An automated method using image filtering (anisotropic diffusion) and edge detection (Canny filter) provided image contours. Cross comparisons of all the exams in each group were performed using similarity measurements under the affine registration hypothesis. The Dice coefficient and Hausdorff distance values were significantly linked (p < 0.001 and p = 0.001 respectively) to the matched examinations in the living group (p < 0.001; pseudo-R2 = 0.70). 12 of the 15 examinations were correctly paired, 2 were wrongly paired and 3 were not paired when they must have been. In the deceased group, the Hausdorff distance was significantly linked (p = 0.018) to the matched examinations (p < 0.001; pseudo-R2 = 0.62; Dice coefficient p = 0.138). The paired examinations were all correctly found, but one was wrongly paired. The negative predictive value was above 98% for both groups. We highlighted the feasibility of comparative radiological identification using automated edge detection in cross-modality (CT/PMCT scan and radiographs) examinations. This method could be of significant help to a radiologist or coroner in identifying unknown cadavers.

The Utility of Skeletal and Surgical Features for the Personal Identification Process: A Pilot Study

This pilot study provides a conceptual framework for the application of the anthropological analysis of skeletal features and surgical interventions for the purpose of identification in cases of unknown deceased individuals with unavailable fingerprint, genetic or odontological antemortem data. The study sample includes 276 individuals with known demographic and clinical information from the Italian CAL Milano Cemetery Skeletal Collection. In the sample, 124 (45%) individuals showed one or more skeletal features that may be potentially individualizing. Of these, 79% showed two and more features, which occurred in a multitude of different combinations. Skeletal findings may provide useful postmortem information that can be compared with antemortem witness statements and clinical imaging. However, more research into the utility of dry bone findings and the availability of comparative material, including imaging, and epidemiological data needs to be undertaken before skeletal features can be implemented into identification protocols and databases.

Personal Identification of Deceased Persons: An Overview of the Current Methods Based on Physical Appearance

The use of the physical appearance of the deceased has become more important because the available antemortem information for comparisons may consist only of a physical description and photographs. Twenty-one articles dealing with the identification based on the physiognomic features of the human body were selected for review and were divided into four sections: (i) visual recognition, (ii) specific facial/body areas, (iii) biometrics, and (iv) dental superimposition. While opinions about the reliability of the visual recognition differ, the search showed that it has been used in mass disasters, even without testing its objectivity and reliability. Specific facial areas being explored for the identification of dead; however, their practical use is questioned, similarly to soft biometrics. The emerging dental superimposition seems to be the only standardized and successfully applied method for identification so far. More research is needed into a potential use of the individualizing features, considering that postmortem changes and technical difficulties may affect the identification.

Application of the Stephan et al. Chest Radiograph Comparison Method to Decomposed Human Remains

This manuscript describes the use of comparative radiography of the chest to facilitate positive identification of human remains in advanced stages of decomposition. The method reported by Stephan et al. for positive identification of dry, disarticulated skeletal elements was used on semifleshed, decomposing remains. Positive identification was established through multiple points of concordance observed in radiographs of the left and right clavicles and the C5-T1 vertebrae. This case study demonstrates the applicability of the Stephan et al.'s method in cases involving decomposing remains.

A Large-Sample Test of a Semi-Automated Clavicle Search Engine to Assist Skeletal Identification by Radiograph Comparison

In 2014, a morphometric capability to search chest radiograph databases by quantified clavicle shape was published to assist skeletal identification. Here, we extend the validation tests conducted by increasing the search universe 18-fold, from 409 to 7361 individuals to determine whether there is any associated decrease in performance under these more challenging circumstances. The number of trials and analysts were also increased, respectively, from 17 to 30 skeletons, and two to four examiners. Elliptical Fourier analysis was conducted on clavicles from each skeleton by each analyst (shadowgrams trimmed from scratch in every instance) and compared to the search universe. Correctly matching individuals were found in shortlists of 10% of the sample 70% of the time. This rate is similar to, although slightly lower than, rates previously found for much smaller samples (80%). Accuracy and reliability are thereby maintained, even when the comparison system is challenged by much larger search universes.

Evolution of Forensic Anthropological Methods of Identification

Forensic identification of human remains has long been a core contribution of forensic anthropologists to death investigations. The array and scientific robusticity of the identification methods employed by the anthropologist has evolved in the last several decades, and as with other nonidentification methods, anthropologists have embraced the progression toward the use of validated and statistically defensible methods for identification. This article presents an overview of the role that the forensic anthropologist plays in the identification of human remains and the evolution of anthropological methods of identification.

The Utility of Advanced Imaging in Forensic Anthropology

Imaging technologies play an integral role in forensic anthropology cases. Advances in digital photography allow the anthropologist to photo-document the scene and skeletal remains in exceptional detail. Traditionally, radiographs have been used to document remains, potential trauma, and any individualizing characteristics such as healing trauma and frontal sinus morphology. Given technological advances, some forensic anthropologists have begun to incorporate more advanced imaging methods in their case analyses and research, such as computed tomography and three-dimensional (3D) surface scans. These advanced imaging technologies provide a means to document skeletal remains and trauma, and can be used to create 3D replicas of the elements for archival and illustrative purposes. Researchers have begun to develop novel methods for estimating biological parameters from these 3D virtual models, using new variables such as surface areas and volumes, and advanced statistical methods (e.g., geometric morphometric analyses) to quantitatively analyze skeletal variation for sex and ancestry estimation. The use of these technologies in forensic anthropology remains somewhat limited, however, due to required costs, expertise, and the time involved in collecting and processing the data. Newly developed methods require further validation, and some areas of advanced imaging, such as photogrammetry, remain relatively unexplored in the field. Interdisciplinary collaborations between forensic anthropologists and other medicolegal professionals can help alleviate some of these resource constraints and facilitate advancements in forensic case analysis and research.

Development of a computer-assisted forensic radiographic identification method using the lateral cervical and lumbar spine

Medical examiners and coroners (ME/C) in the United States hold statutory responsibility to identify deceased individuals who fall under their jurisdiction. The computer-assisted decedent identification (CADI) project was designed to modify software used in diagnosis and treatment of spinal injuries into a mathematically validated tool for ME/C identification of fleshed decedents. CADI software analyzes the shapes of targeted vertebral bodies imaged in an array of standard radiographs and quantifies the likelihood that any two of the radiographs contain matching vertebral bodies. Six validation tests measured the repeatability, reliability, and sensitivity of the method, and the effects of age, sex, and number of radiographs in array composition. CADI returned a 92-100% success rate in identifying the true matching pair of vertebrae within arrays of five to 30 radiographs. Further development of CADI is expected to produce a novel identification method for use in ME/C offices that is reliable, timely, and cost-effective.

A radiographic study on the utility of cranial vault outlines for positive identifications

A standard method for positive identification is the use of antemortem and postmortem radiographic comparisons. The purpose of this research is to test the visual accuracy of antemortem and postmortem radiographic comparisons of cranial vault outlines and to evaluate their uniqueness using geometric morphometric methods. A sample of 106 individuals with varying levels of education and forensic case experience participated in a visual accuracy test. Of the 106 individuals, only 42% correctly assigned all of the radiographs, with accuracy rates ranging from 70 to 93% for each radiographic comparison. Vault shape was further examined using elliptic Fourier analysis, and paired t-tests were computed on the first 10 principal components accounting for 100% of the variance, which found no significant differences. The visual accuracy test and elliptic Fourier analysis shows that vault outlines may not be unique enough for positive identifications when used as a sole indicator.

Forensic radiology and personal identification of unidentified bodies: a review

Personal identification of unidentified bodies is crucial for ethical, juridical and civil reasons and is performed through comparison between biological data obtained from the cadaver and antemortem material from one or more missing persons to whom the body may have belonged in life. The increasing applications of forensic radiology and the wide use of conventional radiography and computed tomography (CT) in routine clinical practice demonstrate the potential of these technologies as tools for verifying the correspondence between an unidentified body and an identity suspect. This paper reviews the literature concerning the application of forensic radiology to the difficult issue of personal identification. Despite the increasing importance of the comparison between radiographic and CT findings, numerous limitations still need to be overcome, including the fact that few forensic centres have access to sophisticated X-ray technologies and that the reliability of those technologies for detecting specific morphological traits and bone lesions is a matter of intense debate. In addition, as with other morphological methods for identification, comparisons between antemortem and postmortem data require standardisation and statistical analysis, especially in Europe where there are very few indications concerning the admission in court of evidence obtained by anthropological and radiological methods. In the future, with developments in radiographic technologies and increasing numbers of studies on their application to the forensic setting, radiology will become one of the most useful tools in the field of personal identification.

Manners of killing and rituals in Apulian mafia murders

The Apulian (South of Italy) territory saw the birth of a criminal organization called Sacra Corona Unita (SCU, United Holy Crown) which transformed the rules of traditional mafia organizations. This work examined 83 victims of the SCU between 1980 and 2000. The bodies were mainly of SCU members and in some cases, of police and law enforcement officers and other citizens caught in the crossfire. Some of these were discovered; thanks to the collaboration of "repented" SCU members who became police informers. The condition of the bodies varied in relation to the date and manner of killing. In some cases anthropometric research methods were necessary. In 73% of the cases, lesions of the head were the only marks left on the body. In conclusion, the existence of some social aspects connected with the symbolisms and membership rites that characterized the origin, evolution, and decline of the SCU is stressed.