The benefits and pitfalls of post-mortem computed tomography in forensic external examination: A retrospective study of 145 cases

Machine learning and regression analysis for age estimation from the iliac crest based on computed tomographic explorations in an Indian population

Age estimation constitutes an integral parameter of identification. In children, sub-adults, and young adults, accurate age estimation is vital on various aspects of civil, criminal, and immigration law. The iliac crest presents as a suitable age marker within these age cohorts, and the modified Risser method constitutes a relatively novel and unexplored method for iliac crest age estimation. The present study attempted to ascertain the applicability of this modified method for age estimation in the Indian population, an aspect previously unexplored, through computed tomographic examination of the iliac crest. Computed tomography scans of consenting individuals undergoing routine examinations of the pelvis/ abdomen for various clinically indicated reasons were collected and scored using the modified Risser stages. Computed tomographic examinations of the iliac crest indicate that the recalibrated method accurately depicts the temporal progression of ossification and fusion changes. Different regression and machine learning models were subsequently derived and/or trained to evaluate the accuracy and precision associated with the method. Amongst the ten regression models derived herein, compound regression exhibited the lowest inaccuracy (4.78 years) and root mean squared error values (5.46 years). Machine learning yielded further reduced error rates, with decision tree regression achieving inaccuracy and root mean squared error values of 1.88 years and 2.28 years, respectively. A comparative evaluation of error computations obtained from regression analysis and machine learning illustrates the statistical superiority of machine learning for forensic age estimation. Error computations obtained with machine learning suggest that the modified Risser method is capable of permitting reliable age estimation within criminal and civil proceedings.

False-Positive Rate for Suspected Drug-Related Deaths Following Full Autopsy

ABSTRACT

The sharp increase in drug-related deaths has tempted medical examiner/coroner offices to perform external examinations with comprehensive toxicology testing instead of performing a standard autopsy. Compounding the problem of an increasing workload has been the decrease in available forensic pathologists. Opting for external examinations on suspected drug-related fatalities, however, is antithetical to current best practices. The purpose of this study was to review case files, autopsy reports, and toxicologic results of all deaths that were autopsied at the authors' facility and decide whether significant disease processes or injuries that would supersede the results of toxicologic testing and external examination findings alone were being missed.

Knowledge and attitudes of Polish prosecutors and general Polish population in regard to post-mortem computed tomography in 2019

Post-mortem computer tomography (PMCT) is an imaging technique that is gaining popularity both worldwide and in Poland. It provides certain benefits in death investigation that a conventional autopsy is not able to, however, it has significant limitations. As PMCT and post-mortem computed angiography (PMCTA) continue to develop in this country, it is critical to become aware what people know and think about these imaging techniques, especially the prosecutors who officially order such examinations to be performed. In 2019, two concurrent surveys were administered to Polish prosecutors and general Polish population, respectively, regarding their current knowledge and opinions on PMCT. The results were collected both online and on paper, and then subjected to analysis. In total, 92 prosecutors and 227 non-prosecutors responded to the survey. The present authors observed that while prosecutors were more likely to have heard of this examination than the general public, their knowledge was often inadequate or incorrect. Conventional autopsy was still held as the gold standard in death investigation. However, a good popular sentiment towards PMCT was shown, and a desire to learn more about it - not just among prosecutors, but among the general public as well. The present authors' recommendation is that more courses and training should be organised for Polish prosecutors to compensate this knowledge gap.

Comparison of findings identified at traditional invasive autopsy and postmortem computed tomography in suicidal hangings

Cases of suicidal hanging are a common death referred for medico-legal autopsy throughout the world. Although some advocate using postmortem computed tomography (PMCT) without traditional invasive autopsy (TIA) to investigate such deaths, others reject this approach. There is currently limited evidence to guide practice. In this context, the TIA reports and PMCT images of 50 cases of suspected suicidal hanging during an 11-month period were reviewed. The reviewers were blinded to the findings of the other modality. A Cohen’s Kappa coefficient (K) was calculated to assess agreement between TIA and PMCT across a range of pertinent findings. This analysis demonstrated perfect agreement for identification of a ligature (K = 1.00) and a strong level of agreement for identification of a ligature suspension point (K = 0.832) but only a minimal level of agreement for overall ligature mark (K = 0.223). PMCT demonstrated a weak level of agreement for fractures of hyoid bone (K = 0.555) and thyroid cartilage (K = 0.538). Three probable fractures not identified at TIA were identified on PMCT. TIA was shown to be superior in the identification of intramuscular and laryngeal fracture–related haemorrhage/bruising whereas PMCT was superior to TIA in identifying body gas deposition. There was overall good correlation between the natural disease and trauma identified elsewhere in the body during the TIA and PMCT. The study demonstrates that PMCT can assist the investigation of suspected suicidal hangings. However, the accuracy of many findings is limited, and if it is used as an alternative to the TIA, potentially pertinent findings, such as fractures of the laryngeal cartilages, could be missed.

Usefulness of a tissue optical clearing technique for forensic autopsy

Forensic pathologists are required to investigate lethal trauma or disease at autopsy. In addition to massive contusions of various organs, a number of small features with potentially fatal implications also need to be sought. Since such lesions may need microscopic examinations for detailed evaluation, it is important to select suitable anatomic locations for tissue sampling. For practical screening of small lesions, we have developed a tissue optical clearing (TOC) technique for forensic autopsy. The technique involves clearing with a non-toxic organic solvent, ethyl cinnamate, which renders excised organs transparent, while hemorrhages or blood-containing vessels remain opaque. Using this technique, tiny hemorrhages in the spinal cord were able to be identified by gross examination, allowing proper selection of locations for tissue sampling. Subsequent histopathological evaluation was successfully performed with no apparent artifacts related with the TOC procedure. In addition, a combination of TOC and targeted CT angiography allowed feasible examination of the arterial occlusive lesion in the superior mesenteric artery, and when combined with micro-CT scanning it was useful for evaluating the lumen of the coronary artery with stent implantation. The results obtained so far indicated that TOC could complement routine forensic autopsy procedures when detailed evaluation of small lesions is required.

Thermal bone injuries: postmortem computed tomography findings in 25 cases

INTRODUCTION

Fire death investigations attempt to determine whether a subject was alive or dead before the fire started. Therefore, it is essential to assess if the bone damage is traumatic or the result of exposure to heat. This observational study aims to expose the specific CT semiology of thermal bone lesions to allow the forensic radiologist to identify and distinguish them from traumatic lesions that would have preceded death.

MATERIALS AND METHODS

We retrospectively reviewed the CT findings of 25 bodies with thermal bone lesions for which a postmortem computed tomography (PMCT) was performed prior to an autopsy. Imaging findings were correlated to the autopsy data to identify the specific features of thermal bone lesions.

RESULTS

Specific signs of thermal injuries to bone were identified on PMCT on all deceased cases. Thermal damages predominated in areas directly exposed to flames (rib cage, distal extremities) with less soft tissue coverage ("soft tissue shielding"). The mottled appearance of bone marrow was a constant sign of burned bones. Heat fractures such as trans-diploic fractures of flat bones and beveled ("flute-mouthpiece") fractures of extremities seemed specifically related to thermal mechanism. In addition, we provided a better description of superficial cortical fissures of flat bones ("ancient Chinese porcelain") and observed a "stair step" fracture of a long bone until now undescribed in radiological literature.

CONCLUSION

Thermal bone lesions have specific CT findings, different on several points from traumatic injuries. Their knowledge is essential for radiologists and forensic physicians to provide an accurate report of injury and conclusions.

The Importance of Autopsy in a Case of Digestive Perforation Undetected by Postmortem Computed Tomography

ABSTRACT

Cases of foreign body ingestion in the forensic literature are mainly described in children or psychiatric patients. Postmortem imaging can detect most foreign bodies, but its sensitivity depends, among other things, on the type of item and its location. In some cases, the ingestion of foreign bodies can remain unnoticed and have serious consequences for the patient. We describe the case of a patient who died in a psychiatric seclusion room with no obvious cause and for whom a forensic autopsy was requested. Further investigations showed the existence of a subdural hematoma associated with a midline shift, secondary to a skull fracture that was considered to be the cause of death. Toxicological analyses identified in blood several drugs, including diazepam (24 ng/mL) and its major metabolite nordazepam (24 ng/mL), propranolol (57 ng/mL), paliperidone (9 ng/mL), and loxapine (620 ng/mL). The forensic autopsy revealed the existence of a gastrointestinal perforation after the ingestion of a plastic teaspoon, which the postmortem CT scan had failed to detect. Although technological advances continue to assist the forensic pathologist in his diagnosis, autopsy still has a leading role in forensic investigations and does not yet seem to be replaceable by imaging techniques alone.

Diagnosis of pulmonary infarction in post-mortem computed tomography and post-mortem magnetic resonance imaging-a technical note

Pulmonary thromboembolism may be accompanied by pulmonary infarction. Even though pulmonary thromboembolism (PTE) is a frequently found cause of death at autopsy, pulmonary infarction accompanying PTE is a less common finding and may therefore easily be misinterpreted as infectious or cancerous lung disease. Appearance of pulmonary infarction in post-mortem imaging and acquisition parameters helping to identify pulmonary infarctions are not described yet. Based on a case of a 50-year-old man who died due to PTE and presented pulmonary infarction, we suggest using a pulmonary algorithm in post-mortem computed tomography combined with post-mortem magnetic resonance imaging of the lungs using conventional T1- and T2-weighted sequences.

Neuropsychological autopsy of testamentary capacity: Methodology and issues in the elderly

The forensic assessment of testamentary capacity is a topical issue given the prevalence of dementia illnesses and the increase in the complexity of modern financial and family structures. Although a contemporaneous assessment would be desirable, the majority of situations require a retrospective assessment of the mental state a deceased individual. Neuropsychologists, independently or as part of a board of consultants, are, therefore, frequently requested to give an expert opinion of the competence of cognitively impaired elderly testators.This paper offers a guide for carrying out a neuropsychological autopsy, namely the process of posthumous evaluation, for determining testamentary capacity. Taking into account the recent literature on the assessment of testamentary capacity, we propose a three-phase procedure for carrying out the neuropsychological autopsy in the forensic context. The neuropsychological autopsy of testamentary capacity is based on the meticulous, chronologically structured evaluation of any medical documents, available psychometric data, along with the critical examination of any source of information about the cognitive level of functioning of the deceased person at the time of the will.

Postmortem CT in Trauma: An Overview

As forensic radiology sees an exponential gain in popularity, postmortem computed tomography (PMCT) is increasingly being used in the appropriate setting, either as preautopsy guidance or as part of complementary virtual autopsy protocol. Many articles have expounded the value it adds to forensic pathology in the general setting and the appropriate technical parameters to be used for optimum benefit. We aim to put forth a concise review on the role of PMCT specifically in trauma and the pitfalls to be aware of. Reviews have shown that presumed cause of death in trauma have been proven by autopsy to be wrong in about 30% cases. Radiology applied to postmortem investigation in unnatural deaths and more specifically in trauma shares many semiotic features with emergency radiology. Therefore, in the near future, emergency radiologists might be required to integrate this type of imaging in their regular practice. Although the predominant drawbacks are time-dependent, PMCT also has some difficulty in differentiating antemortem and postmortem events. However, in many such scenarios, PMCT and autopsy play a complementary role in arriving at conclusions, and we believe understanding the benefits and role in trauma is imperative considering the expanding usage of PMCT.

Digital restoration of fragmentary human skeletal remains: Testing the feasibility of virtual reality

Experts in forensic anthropology and medicine have become gradually accustomed to examining components of the human body in the virtual workspace. While the computer-assisted approach offers numerous benefits, the interactions with digital three-dimensional biological objects are often problematic, particularly if conducted with mouse, keyboard and flat-panel screen. The study focusses on feasibility of a virtual reality (VR) system for virtual restoration of fragmentary skeletal remains. The VR system was confronted with three cases of fragmentary remains. The cases were reassembled manually by twenty participants using a HTC Vive headset combined with an in-house application A.R.T. The same task was performed using a CloudCompare software in conjunction with a desktop peripheral. The two systems were compared in terms of time efficiency, the geometric properties of the resulting restorations, and convenience of use. Restoration using the VR system took approximately half the time the desktop set-up did. The VR system also yielded a lower error rate when a severely fragmented skull was reassembled. Ultimately, although the efficiency of the reassembling was shown to be strongly dependent on the operator's experience, the use of the VR system balanced out the uneven levels of proficiency in computer graphics. The current generation of virtual reality headsets has a strong potential to facilitate and improve tasks relating to the virtual restoration of fragmented skeletal remains. A VR system offers an intuitive digital working environment which is less affected by an operator's computer skills and practical understanding of the technology than the desktop systems are.

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.