Postmortem CT: Applications in Clinical and Forensic Medicine

Just as radiography has been used in forensic medicine since shortly after the discovery of x-rays in 1895, CT was introduced to postmortem investigation not long after its introduction to medicine in the 1970s. In recent decades, forensic radiology has declared itself as a new subspecialty capable of revolutionizing death investigation and research. A variety of postmortem imaging techniques have emerged. Postmortem CT (PMCT) is widely accepted around the world as a supplementary tool and, in specific cases and settings, an alternative to full autopsy. As its popularity grows, however, it is important for radiologists and pathologists to expand their understanding of the applications, benefits, and limitations of these techniques, as well as the unique nuances of postmortem imaging interpretation. This will ensure high-quality interpretations and avoid potential pitfalls that could result in premature or erroneous conclusions. The authors introduce the reader, particularly the radiologist, to the growing subspecialty of forensic imaging (focusing on imaging of the deceased), specifically focusing on PMCT and its applications in death investigation in both clinical and forensic settings. The authors also discuss the benefits and limitations of PMCT as well as important nuances of PMCT interpretation, emphasizing the similarities and differences between clinical and postmortem studies, the necessity of conducting thorough death investigations, and the importance of pursuing specialized education or training in postmortem imaging interpretation. Applications of more specialized imaging techniques to postmortem and forensic investigations are described, including developing research in this area. ©RSNA, 2025 Supplemental material is available for this article.

The current state of forensic imaging - post mortem imaging

Over the last few decades, forensic imaging has become an essential part of current forensic practice. The aim of this 4-part review is to provide a comprehensive overview of forensic imaging over the first 25 years of this century. After a brief historic review, this first part details the advantages and limitations of post-mortem imaging for the indications most frequently encountered in daily practice.

Post-mortem CT: A Useful Tool to Confirm a Case of Suspected Sudden Cardiac Death

Sudden cardiac death (SCD) is defined as the unexpected death of an individual, not due to any extracardiac cause, occurring within one hour of symptom onset or within 24 hours of last being seen in good health if the death is unwitnessed. Forensic pathologists routinely encounter several SCD cases in their practice. The presentation of such cases can be of two types; firstly, with typical signs and symptoms suggestive of cardiac pathology, and secondly, devoid of any presentation history. This history helps forensic pathologists look for relevant findings during the autopsy examination. The authors intend to explore the feasibility of using advanced radiological techniques like post-mortem CT (PMCT) in determining the cause of death through a minimally invasive approach. In the present case, a 65-year-old male was found unresponsive at his residence on the morning of his death. He had a history of dull chest pain for the past two days, which had resolved after he self-prescribed a few medications. The presenting complaint of chest pain had started the intervening night prior to his death. The deceased was a known case of hypertension and was not compliant with treatment, as stated by the relatives. He was declared as brought dead by the treating emergency medicine physician at the Fortis Flt. Lt. Rajan Dhall Hospital and the body was sent by the authorities to the mortuary of the Department of Forensic Medicine, AIIMS, New Delhi for autopsy examination since an autopsy should be conducted by a government hospital or institute by law. PMCT depicted an alternate hyperdense and hypodense region circumferentially surrounding the heart, indicating hemopericardium. It was followed by a traditional autopsy and histopathology examination, which confirmed the presence of hemopericardium and left ventricular rupture associated with acute coronary insufficiency. Such cases with an indicative history, circumstantial evidence, and PMCT findings can be considered for minimal invasive autopsy. If the external findings indicate the application of physical force, then an explorative dissection could be done. Therefore, we conclude that PMCT can be used as a reliable tool for determining the cause of death in SCDs on a case-to-case basis.

Technical and interpretive pitfalls of postmortem CT: Five examples of errors revealed by autopsy

Image acquisition of dead bodies, particularly using postmortem computed tomography (PMCT), has become common in forensic investigations worldwide. Meanwhile, in countries such as Japan which have an extremely low rate of autopsy, PMCT is being increasingly used in the clinical field to certify the cause of death (COD) without performing an autopsy or toxicological tests, even in cases of unnatural death. Additionally, these PMCT images are predominantly interpreted by clinical personnel such as emergency physicians or clinicians who are not trained in PMCT interpretation and who work for the police, that is, the so-called police doctors. Many potential pitfalls associated with the use of PMCT have been previously described in textbooks and published papers, including the pitfalls of not performing a complete forensic pathology investigation, and the use of physicians without appropriate PMCT training to interpret PMCT and direct death investigation and certification. We describe five examples in which apparent misdiagnosis of COD based on PMCT misinterpretation was revealed by autopsy. Here are the five examples of errors: (1) Postmortem changes were misinterpreted as COD, (2) resuscitation effects were misinterpreted as COD, (3) COD was determined after an incomplete examination, (4) fatal findings caused by external origin were wrongly interpreted as 'of internal origin' based on PMCT, and (5) non-fatal findings on PMCT were wrongly interpreted as fatal. Interpretation of PMCT by appropriately trained physicians and an accompanying complete forensic investigation, including autopsy when indicated, is necessary to prevent significant errors in COD determination and related potential adverse medicolegal consequences.

Fatal airway obstruction due to Ludwig's angina from severe odontogenic infection during antipsychotic medication: A case report and a literature review

Ludwig's angina is characterized by inflammation of the sublingual and submandibular spaces and is mainly caused by odontogenic infection, which leads to cellulitis of the soft tissues of the floor of the mouth and the neck. This causes asphyxia due to elevation and posterior deviation of the tissues of the floor of the mouth. We report a fatal case of airway obstruction due to Ludwig's angina. A woman in her forties who had no physical complications, but had a mental illness, was undergoing outpatient dental treatment for caries in the first premolar of the left mandible. She was admitted to a psychiatric hospital because of insomnia caused by pain, where she developed cardiopulmonary arrest while sleeping and died 14 days after onset of the dental infection. Postmortem computed tomography (PMCT) prior to autopsy showed swelling of the soft tissues-from the floor of the mouth to the oropharyngeal cavity, the supraglottic larynx, and the prevertebral tissue. Autopsy revealed a markedly swollen face and neck, an elevated tongue, and a highly edematous epiglottis and laryngopharyngeal mucosa. There was also cellulitis and abscess of the facial, suprahyoid, and neck musculature, which suggested that the cause of death was asphyxiation due to airway obstruction. This was an alarming case, with mental illness leading to risk of severe odontogenic infection, and in which obesity and use of antipsychotic medication might have acted synergistically leading to airway obstruction. This is also a case of Ludwig's angina captured by PMCT, which has rarely been reported.

Diagnostic accuracy of postmortem computed tomography for bleeding source determination in cases with hemoperitoneum

Aim

The aim of this retrospective study was to determine the accuracy of postmortem computed tomography and different radiological signs for the determination of the bleeding source in cases with hemoperitoneum confirmed at autopsy.

Methods

Postmortem computed tomography data of consecutive cases with hemoperitoneum confirmed at autopsy were reviewed by two raters, blinded to the autopsy findings. The determination of possible bleeding sources was based on the presence of the sentinel clot sign, blood or sedimented blood surrounding an organ, intraparenchymal abnormal gas distribution, and parenchymal disruption. The bleeding source and the cause of hemoperitoneum (traumatic, surgical, natural, or resuscitation) as reported in the autopsy report were noted. The survival intervals of the deceased were calculated when information about the time of an incident related to death was available in the autopsy reports.

Results

Eighty-five cases were included in the study. Postmortem computed tomography showed 79% sensitivity and 92.1% specificity for the detection of the bleeding source. The sentinel clot sign was associated with surgical or natural causes of hemoperitoneum and longer survival intervals. Sedimented blood around the bleeding source was associated with resuscitation. Abnormal gas distribution within organs and combination of multiple radiological signs provided higher sensitivity.

Conclusion

Postmortem computed tomography provides moderate sensitivity and high specificity for determining the bleeding source in cases with hemoperitoneum. Different PMCT signs are associated with different causes of hemoperitoneum and survival intervals.

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.

Differentiation of hemopericardium due to ruptured myocardial infarction or aortic dissection on unenhanced postmortem computed tomography

The aim of the study was to evaluate unenhanced postmortem computed tomography (PMCT) in cases of non-traumatic hemopericardium by establishing the sensitivity, specificity and accuracy of diagnostic criteria for the differentiation between aortic dissection and myocardial wall rupture due to infarction. Twenty six cases were identified as suitable for evaluation, of which ruptured aortic dissection could be identified as the underlying cause of hemopericardium in 50% of the cases, and myocardial wall rupture also in 50% of the cases. All cases underwent a PMCT and 24 of the cases also underwent one or more additional examinations: a subsequent autopsy, or a postmortem magnetic resonance (PMMR), or a PMCT angiography (PMCTA), or combinations of the above. Two radiologists evaluated the PMCT images and classified each case as "aortic dissection", "myocardial wall rupture" or "undetermined". Quantification of the pericardial blood was carried out using segmentation techniques. 17 of 26 cases were correctly identified, either as aortic dissections or myocardial ruptures, by both readers. 7 of 13 myocardial wall ruptures were identified by both readers, whereas both readers identified correctly 10 of 13 aortic dissection cases. Taking into account the responses of both readers, specificity was 100% for both causes of hemopericardium and sensitivity as well as accuracy was higher for aortic dissections than myocardial wall ruptures (72.7% and 87.5% vs 53.8% and 75% respectively). Pericardial blood volumes were constantly higher in the aortic dissection group, but a statistical significance of these differences could not be proven, since the small count of cases did not allow for statistical tests. This study showed that diagnostic criteria for the differentiation between ruptured aortic dissection and myocardial wall rupture due to infarction are highly specific and accurate.