Differentiation of antemortem pulmonary thromboembolism and postmortem clot with unenhanced MRI: a case report

Cadaver clots: a systematic review of the literature

Cadaveric blood is ubiquitous, and observed in various forms-liquid, coagulated, and clot-like-during autopsies. Understanding its state in postmortem vessels is essential for both scientific research and forensic investigations. Pulmonary thromboembolism (PT) is a leading cause of sudden death, often requiring medicolegal evaluation. While thrombus formation is primarily explained by Virchow's triad, the distinction between antemortem, agonal, and postmortem clot (PMC) pathogenesis remains debated. This study aims to systematically review the literature to clarify the morphological and pathological differences among these entities in forensic practice. A systematic review of PubMed, Science Direct, Scopus, and Web of Science was conducted using predefined key terms: "clot," "thrombus," "chicken-fat," "agonal," "postmortem," and "autopsy." Articles were screened for relevance, and 11 studies meeting the inclusion criteria were analyzed. The review highlights a significant gap in comparative studies addressing antemortem versus postmortem clots. The literature lacks a consensus regarding their definitions, macroscopic and microscopic characteristics, pathogenesis, and relevance to determining the cause and timing of death. Existing studies present conflicting interpretations, limiting the reliability of forensic differentiation. The current understanding of antemortem, agonal, and postmortem clots remains incomplete. Our findings underscore the need for further research to establish standardized criteria for distinguishing clot types, which is crucial for forensic pathology and medicolegal evaluations.

Investigating the Source of Fatal Pulmonary Thromboembolism in a Coronial Postmortem Population

ABSTRACT

The incidence of how often a deep vein thrombosis is found in the calves of the legs at coronial postmortem examination is unclear. This study retrospectively examined postmortem examination reports from Australian Coronial investigations of sudden death resulting from pulmonary thromboembolism to determine the likelihood of dissection of the deep veins of calves of the legs revealing the source of a pulmonary thromboembolism. From 450 cases taken from the National Coronial Information System (NCIS) for 2016, the postmortem reports of 327 cases were reviewed to provide demographic details of victims of sudden death from pulmonary thromboembolism. In 235 cases, it was possible to determine in 76.6% a thrombus had been found in the deep veins of the calves of the legs after dissection. In 141 cases, it was documented that both sides had been examined. From these, it was determined there was no statistically significant difference in the prevalence of thrombus in either side. However, it was shown that the presence of an abnormality of a lower limb (such as leg or hip infection, burns, surgery and nonoperated fractures, or a larger circumference) increased the likelihood that a deep vein thrombus would be found on that side.

Block-like and cast-like hyperdense areas in the right heart cavities on post-mortem CT strongly suggest the presence of intracardiac blood clots at autopsy

OBJECTIVE

To classify the types of hyperdense areas in the heart cavities on post-mortem CT (PMCT) and compare them according to the presence of blood clots in the heart cavities at forensic autopsy.

METHODS

One hundred and twelve cases with CT images taken before forensic autopsy were evaluated. The presence and shape of hyperdense areas in the right or left heart cavities were retrospectively evaluated on PMCT images and were classified into four types (block-like, cast-like, fluid level-like, and unclear). The presence of blood clots was confirmed when there were clots in the heart cavities at forensic autopsy.

RESULTS

Of the 112 cases, 57 exhibited blood clots in the heart cavities at forensic autopsy. The hyperdense areas in the right heart cavities on PMCT in 57 cases exhibiting blood clots at forensic autopsy were classified as follows: block-like, 32; fluid level-like, 4; cast-like, 17; and unclear, 4. The sensitivity of block-like and cast-like hyperdense areas in the right heart cavities on PMCT for the presence of clots in the heart cavities at forensic autopsy was 86% (95% confidence interval [CI]: 74-94%); the corresponding specificity, PPV, and NPV were 95% (95% CI: 85-99%), 94% (95% CI: 84-99%), and 87% (95% CI: 75-94%), respectively.

CONCLUSION

Block-like and cast-like hyperdense areas in the right heart cavities on PMCT predicted the presence of intracardiac blood clots at forensic autopsy.

KEY POINTS

• Clinical radiologists likely have no experience of interpreting findings of blood clots on post-mortem CT (PMCT). • The appearance of blood clots on PMCT provides important clues for diagnosing the cause and process of death. • The shapes of the hyperdense areas in the heart cavities were classified into four types, and two of these types could be used to predict the presence of blood clots in the heart cavities at forensic autopsy.

Pulmonary PMCT angiography by right ventricle cardiac puncture: a novel, promising approach for investigating pulmonary thromboembolism

Forensic scholars are paying more attention to postmortem computed tomography (PMCT) and PMCT angiography (PMCTA), which are gradually becoming effective and practical methods in forensic practice. However, few studies have focused on the application of PMCTA to cardiac ventricular puncture-especially of the right ventricle. In this article, we introduce a pulmonary PMCTA approach by right ventricle cardiac puncture and its potential value in fatalities from pulmonary thromboembolism (PTE). The procedure was performed on 11 males and 6 females. PMCT was performed first; then a biopsy core needle was used for percutaneous puncture of the right ventricle under CT guidance. About 400 mL of contrast media was injected at a rate of 50 mL/8 s, followed by CT scanning. Visualization of the pulmonary artery contrast filling was complete in 9 cadavers, and the pulmonary arteries showed significant filling defects in 8 subjects. Unlike in clinical practice, the phenomenon of postmortem coagulation sometimes occurs in the vascular lumina after death. Therefore, the results of these 8 cases can only suggest or be highly suspicious of death from PTE. Then autopsy and histopathological examination confirmed that 4 of the above 8 patients were diagnosed with PTE; the remaining 4 had postmortem clot including chicken fat clot in the pulmonary artery. Pulmonary PMCTA approach is a simple, convenient, and effective method for the visualization of the pulmonary artery, which can be used as an effective auxiliary tool to identify PTE in forensic practice. It will also provide technical support to further investigate PTE imaging characteristics.

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.