The role of radiology in fatality investigations

Cervicothoracic junction in disaster victim identification: Idiosyncrasies and relevance of body position for advanced chest radiograph comparisons

Standard plain film medical radiographs often form a valuable line of evidence to identify individuals in large-scale fatality events. While commonly available, chest radiographs present a challenge that their analysis is somewhat more involved and complex than radiographic records of other body regions. For example, chest radiographs concern subtler morphological varieties of smaller anatomical features across a larger number of skeletal elements in contrast to frontal sinus comparisons that concern a large, (often) single, highly variable void within one bone. This does not detract from or discount chest radiographs as useful identification aids, but it does demand additional prerequisite skills in radiographic interpretation to ensure valid conclusions are attained. When subjects deviate from standardized antemortem (AM) radiographic positions and/or the image quality decreases, the complexity of a chest radiograph comparison is elevated. Generally, the current body of forensic radiographic comparison literature infrequently addresses these more complex circumstances. In this paper, we use real-world radiographic comparison reference images from a military DVI repatriation context to illustrate these factors and outline some procedures that enable these complexities to be easily recognized and appropriately addressed at case examination. A report for an exemplar case that concurrently highlights multiple factors is presented. For novices learning radiographic comparison methods, this case review saliently demonstrates: (1) why the AM reference radiograph(s) drive(s) the radiographic comparison procedure; (2) why care should be taken for correct positioning of the cervicothoracic junction in postmortem radiography of chest elements.

Post-mortem CT in the investigation of homicides

AIM

To investigate the reliability of post-mortem computed tomography (PMCT) in a case series of homicides involving blunt-force, sharp-force, and ballistic trauma.

MATERIALS AND METHODS

The study investigates 16 homicide cases that underwent PMCT before autopsy. Two radiologists assessed the PMCT examinations and the data were compared to the forensic pathology findings. Data were organised in broad categories: foreign bodies, external injuries, soft-tissue and organ injuries, fractures, air in cavities, fluid collections, random pathology, and wound track. Findings were organised by systems: head and neck, thorax, abdomen and pelvis, extremities. Cohen's kappa statistics were used to assess observer agreement.

RESULTS

Six gunshot-related homicides (37.5%), seven sharp-force-related homicides (43.75%), two blunt-force-related deaths (12.5%), and one homicide due to mechanical asphyxia (1.25%) were analysed. A total of 64 fractures were reported by the pathologists, 67 by radiologist 1 and 68 by radiologist 2. Agreement was deemed substantial in all cases. Pathologists failed to report gas in cavities while radiologists underreported superficial injuries.

CONCLUSION

An overall observation was that less accurate findings were produced by the blinded radiologist in comparison to the non-blinded one. The extremeness of homicides obscured the interpretation of PMCT leading to the observed discrepancies. The combination of PMCT and autopsies is deemed optimal when investigating homicidal events.

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.

Forensic Radiology: A Primer

RATIONALE AND OBJECTIVE

Forensic radiology is a relatively unknown subspecialty which is becoming increasingly more important. The field incorporates antemortem and postmortem imaging for the detection and documentation of various pathologies for medicolegal purposes. Postmortem imaging is increasingly used in conjunction with the traditional autopsy in a process called a "virtual" autopsy. Radiography has been a staple of forensic investigations for over a century, first used in 1896. Advanced imaging techniques such as postmortem computed tomography and postmortem magnetic resonance imaging have only recently gained acceptance in the forensic science community. Postmortem computed tomography and postmortem magnetic resonance imaging methods are now widely used in some parts of the world, while other countries including the United States have been slower to adopt these methods into their daily practice. Advanced forensic imaging is increasingly used in the courts where juries have responded positively to such presentation of forensic data. For these reasons, advanced postmortem imaging is becoming a regular part of forensic investigations. The increase in the use of forensic imaging presents a unique opportunity for radiologists to collaborate with pathologists and law enforcement officials. This paper provides an overview of forensic radiology and identifies potential challenges and opportunities.

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

This case study demonstrates the importance of involving an anthropologist in forensic situations with decomposed remains. Anthropological consultation was used in conjunction with the comparison of antemortem and postmortem radiographs to establish positive identification of unknown, decomposed remains. The remains had no traditional identifying features such as fingerprints or dental. Through anthropological analysis, it was determined the decedent was male, between 20 and 23 years at time of death and c. 5'2'' tall. This information allowed for a presumptive identification and a request for antemortem radiographs. The missing person was identified comparing the spinous processes of the cervical and thoracic vertebrae between ante- and postmortem radiographs.

Forensic implications of the foot and ankle

To clinicians, forensic medicine and the foot and ankle complex may appear to have little connection. However, if decomposed, burned, fragmented, or skeletonized human remains are recovered, the foot and ankle can provide information leading to identification and incident analysis. Furthermore, analysis of data collected at accidents can lead to safety modifications. This article reviews common elements of forensic medicine applied to the foot and ankle in 2 areas: establishing positive identification by using radiographic comparisons and analyzing aviation incidents. An understanding of these cases will enhance clinicians' awareness of the potential forensic value of the foot and ankle.

[Role of radiology in forensic dentistry]

There are various methods for the identification of human remains; most of them are based on comparisons between available ante- and post-mortem data. Although fingerprinting is the most accurate and precise method, in many cases, such as in mutilated, decomposed, burned or fragmented bodies, it cannot be used, and the dental methods become of the utmost importance, since teeth and dental restorations are very resistant to destruction by fire--they keep numerous characteristics, which are quite unique, and offer the possibility of accurate and legally acceptable identification of remains. This brief review describes the progress of forensic dentistry during the last 25 years, regarding the procedures and techniques that use ante-mortem and post-mortem radiographs. Among the discussed progresses one can point out: a specially designed self-supporting film holder that retains intra-oral films in the mouths of deceased persons whose mandibular musculature has been fixed in rigor mortis; positioning devices suitable for reproducing the geometry of ante-mortem radiographic images; methods involving digital radiographs, which can be easily stored in a central archive, retrieved and transmitted, via modem, to mass casualty sites; age estimation procedures; identification of edentulous individuals comparing radiographs of the maxilla; and studies of validation of dental radiographs taken with ante-mortem and post-mortem intervals of up to 30 years.

Radiology in forensic identification: the Mt Erebus disaster

Although radiology has exceptional discriminatory power in the identification of individuals, it is not often used for this purpose. This under-utilization stems in part from insufficient appreciation of its potential, and in part from a lack of agreed operational protocols. Descriptions of criteria used for radiological identification are scattered in individual reports and have not been collated. The circumstances in which identification is required are various and pose different problems for which guidelines have not been established. The areas in which radiology has a high capacity for identification of age, sex or identity are reviewed and their strengths and limitations are discussed. A survey of the literature identified three different circumstances in which cadaver identification is needed, and a protocol is suggested to meet the differing requirements of these three situations. The use of these protocols and techniques in the identification of bodies recovered from the Mt Erebus disaster is described. Postmortem radiographs established the identity of 11 bodies not identified by other techniques. There is a need for greater awareness in police and forensic circles of the identifying power of radiology.