Forensic relevance of post-mortem CT imaging of the haemopericardium in determining the cause of death

Application of postmortem imaging modalities in cases of sudden death due to cardiovascular diseases-current achievements and limitations from a pathology perspective : Endorsed by the Association for European Cardiovascular Pathology and by the International Society of Forensic Radiology and Imaging

Postmortem imaging (PMI) is increasingly used in postmortem practice and is considered a potential alternative to a conventional autopsy, particularly in case of sudden cardiac deaths (SCD). In 2017, the Association for European Cardiovascular Pathology (AECVP) published guidelines on how to perform an autopsy in such cases, which is still considered the gold standard, but the diagnostic value of PMI herein was not analyzed in detail. At present, significant progress has been made in the PMI diagnosis of acute ischemic heart disease, the most important cause of SCD, while the introduction of postmortem CT angiography (PMCTA) has improved the visualization of several parameters of coronary artery pathology that can support a diagnosis of SCD. Postmortem magnetic resonance (PMMR) allows the detection of acute myocardial injury-related edema. However, PMI has limitations when compared to clinical imaging, which severely impacts the postmortem diagnosis of myocardial injuries (ischemic versus non-ischemic), the age-dating of coronary occlusion (acute versus old), other potentially SCD-related cardiac lesions (e.g., the distinctive morphologies of cardiomyopathies), aortic diseases underlying dissection or rupture, or pulmonary embolism. In these instances, PMI cannot replace a histopathological examination for a final diagnosis. Emerging minimally invasive techniques at PMI such as image-guided biopsies of the myocardium or the aorta, provide promising results that warrant further investigations. The rapid developments in the field of postmortem imaging imply that the diagnosis of sudden death due to cardiovascular diseases will soon require detailed knowledge of both postmortem radiology and of pathology.

Analysis of the role of PMCT during the COVID-19 pandemic: a systematic review

Objectives

During COVID-19 pandemic PMCT has been proposed as a forensic investigation method. This systematic review is aimed to systematize evidence and peer-reviewed opinions reported during the first two years of pandemic, to evaluate the role of PMCT during the COVID-19 pandemic.

Materials and methods

An online literature search was performed to identify publications on PMCT during the COVID-19 pandemic between December 2019 and March 2022. For each publication included, the following data were collected: title and abstract, year of publication, type of article, number and type of individuals examined. The selected publications were also categorized based on PMCT findings, histopathological results, the comparison between PMCT and histopathological findings, cause of death and proposed role of PMCT during the pandemic.

Results

A total of 20 publications were included, mostly case reports (9/20). All cases examined included adults. The most frequent PMCT pattern in positive cases was diffuse mixed densities with prevalence of consolidations (pattern 1) (54%). In 97% of the cases where a comparison between PMCT and histological results was performed, a correspondence was found. In 82% of the cases the principal cause of death was COVID-19 pneumonia. PMCT has been proposed as a pre-autopsy screening tool in 62%, and as a method for augmenting post-mortem data in 50% of the papers reporting this issue.

Conclusion

This systematic review suggests that PMCT should be regarded as a highly valuable investigative technique for the forensic evaluation of deaths with ascertained or suspected COVID-19 pneumonia.

Milk of calcium pericardial effusion confirmed with postmortem computed tomography and autopsy findings: A case report

We present the postmortem computed tomography and autopsy findings of a 60-year-old man who developed milk of calcium pericardial effusion and died of constrictive epicarditis. He experienced out-of-hospital cardiopulmonary arrest, and spontaneous circulation returned at the hospital. However, 7 h after recovery, the patient died. He had a swollen neck, had been experiencing coughing from 4 to 5 days earlier, and had no significant medical or surgical history. On computed tomography (CT), highly dense pericardial fluid (CT value: 130-150 Hounsfield units) and multiple calcifications along the epicardium and pericardium were visualized. The epicardium and pericardium were thick, hard, rough, and widely calcified with mild adhesions on autopsy. The pericardial cavity contained a pale, reddish brown, turbid, and highly viscous liquid. Bacteriological tests of pericardial fluid cultures revealed the presence of group G β-hemolytic streptococci. Hence, we diagnosed the patient's cause of death as heart failure due to constrictive epicarditis. We believe that this case of milk of calcium pericardial effusion is the first case confirmed with postmortem CT and autopsy findings.

Role of Postmortem CT in the Forensic Evaluation of Hemopericardium

Hemopericardium (HP) is defined as the accumulation of blood in the pericardial sack. In a clinical setting, prompt identification of the presence of HP is of huge importance, because HP can result in pericardial tamponade. While echocardiography remains the most appropriate method for the evaluation of pericardial effusions in the clinical setting, postmortem imaging computed tomography (PMCT) is a valuable instrument for detecting the presence of HP and in evaluating its significance in causing mechanical impairment of cardiac activity and finally death. In this article, the actual knowledge on PMCT imaging findings related to HP are reported, with particular attention to the assessment of its significance with relation to the forensic diagnosis of the cause of death. According to the present work, the diagnosis of pericardial tamponade due to HP might be considered one of the critical fields of investigation where classical autopsy may fail and where PMCT imaging may offer its most important aids.

The pseudo-SAH sign: an imaging pitfall in postmortem computed tomography

Postmortem computed tomography (PMCT) of the brain has an important role in detection of subarachnoid hemorrhage (SAH), which has a high mortality rate. However, a phenomenon known as "pseudo-SAH," or high-attenuation areas along the cisterns mimicking SAH, may be seen on CT. The aim of this study was to evaluate the diagnostic accuracy of brain PMCT for SAH and to identify the characteristics of pseudo-SAH. Findings on PMCT (sulcal effacement, asymmetry, maximum thickness of SAH signs, presence of acute/subacute intraventricular/intraparenchymal hemorrhage) and clinical history (left ventricular assist device [LVAD] implantation, anticoagulation therapy/coagulation disorder, global ischemia) were compared between subjects with true SAH and those with pseudo-SAH. Twenty eight of 128 enrolled subjects had positive signs of SAH on PMCT, 20 (71.4%) had SAH on autopsy, and 8 (28.6%) did not. The sensitivity, specificity, positive predictive value, and negative predictive value of SAH signs seen on PMCT were 95.2, 94.6, 71.4, and 99.3%, respectively. Asymmetry of SAH signs and acute/subacute intraventricular and intraparenchymal hemorrhage were significantly more common in true SAH cases than in pseudo-SAH cases. The maximum thickness of SAH signs was significantly greater in true SAH cases. A history of LVAD implantation, anticoagulation therapy, and/or a coagulation disorder were more common in true SAH cases but not significantly so. A history of global ischemia was significantly more common in pseudo-SAH cases. If signs of SAH are observed on PMCT, it is important to look for other signs on PMCT and carefully review the clinical history to avoid a diagnostic error.

State of the art in post-mortem forensic imaging in China

The autopsy and histopathologic examination are traditional and classic approaches in forensic pathology. In recent years, with the tremendous progresses of computer technology and medical imaging technology, the developed post-mortem computer tomography, post-mortem magnetic resonance imaging and other new methods provide non-invasive, intuitive, high-precision examining methods and research tools for the forensic pathology. As a result, the reconstruction of the injury as well as the analysis of injury mechanism has been essentially achieved. Such methods have become popular in the research field of forensic science and related work has also been carried out in China. This paper reviews the development and application of abovementioned post-mortem forensic imaging methods in China based on the relevant literature.

Cardiac dilatation index as an indicator of terminal central congestion evaluated using postmortem CT and forensic autopsy data

Previous studies demonstrated possible application of postmortem quantitative CT data analysis of the heart and lung in situ to investigate terminal cardiopulmonary pathophysiology. The present study analyzed virtual CT morphometric and autopsy data of the heart to investigate terminal central congestion in forensic autopsy cases (n=113, within 3 days postmortem); the virtual total heart weight in situ was estimated using CT morphometry, and the difference from and ratio to the measured weight at autopsy were calculated as indicators of heart blood pooling and the cardiac dilatation index (CDI) before dissection, respectively. There were substantial differences between the estimated heart blood pooling in situ and volume recovered at autopsy, including a characteristic decrease in drowning, alcohol/sedative-hypnotic intoxication and sudden cardiac death (SCD), possibly due to blood redistribution after thoracic dissection. The estimated in situ heart blood pool and CDI values were higher in SCD but lower in fatal hemorrhage and hemopericardium, as well as in acute mechanical asphyxiation and hyperthermia (heatstroke). In addition, there was a significant difference in heart blood pooling between mechanical asphyxiation or drowning and SCD. The CDI was significantly lower in fatal hyperthermia (heatstroke) than in drowning, fatal methamphetamine abuse, alcohol/sedative-hypnotic intoxication and SCD. These findings suggest the usefulness of applying the CDI and postmortem heart blood volume in situ as supplementary indicators of terminal central congestion, especially for investigating deaths from hemorrhage, hemopericardium, hyperthermia (heatstroke) and SCD.

Virtopsy Computed Tomography in Trauma: Normal Postmortem Changes and Pathologic Spectrum of Findings

Virtopsy or virtual autopsy is an emerging technique, developed to supplement traditional forensic autopsy. Virtopsy can be done by using imaging techniques such as computed tomography (CT) and magnetic resonance imaging. Virtopsy CT comprises a pan-body noncontrast CT scan obtained after death. Virtopsy CT is useful in trauma cases as it can provide an overview of injuries sustained by the victim; detect craniofacial, cerebral, thoracic, and osseous injuries; and suggest putative causes of death. This can reduce the time taken for forensic autopsy and sometimes obviate the need for a forensic autopsy. However, virtopsy CT reporting is not exactly synonymous with interpreting antemortem contrast-enhanced CT images as postmortem decompositional changes also occur. Awareness of imaging appearances of both postmortem putrefactive changes and pathologic findings is essential to avoid errors in interpretation and enable estimation of cause of death in patients with trauma.

Imaging for homicide investigations

The authors present the opportunities of the application of post-mortem imaging, focusing on post-mortem computed tomography and post-mortem computed tomography angiography in modern forensic investigation of homicide cases. The paper is based on scientific publications related to the subject from ca. the past 10 years, supplemented by the authors' own experiences. The article is illustrated with reconstructions based on the authors' own cases related to homicide due to ballistic/sharp/blunt trauma. As is shown, the results of evaluation of post-mortem computed tomography allow better diagnosis, documentation and visualisation of forensic examinations.