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

Abbreviated injury scale-guided assessment of traumatic deaths: postmortem CT versus autopsy

Objective

This study aimed to evaluate the diagnostic agreement between postmortem computed tomography (PMCT) and conventional autopsy in assessing injury severity and determining the cause of death using the Abbreviated Injury Scale (AIS).

Materials and methods

A retrospective analysis was conducted on 65 trauma-related fatalities that underwent both PMCT and autopsy. Injuries were classified by anatomical region and scored using AIS. Severity was categorized as minor (AIS 0-3) or major (AIS 4-6). The cause of death was determined based on either expert opinion or the highest AIS score per region. Agreement between PMCT and autopsy was analyzed using kappa statistics, correlation coefficients, and chi-square tests.

Results

Moderate agreement in AIS scoring was observed across most anatomical regions (36 %-52 %). Agreement improved substantially when classifying injuries as minor or major (78 %-86 %). The overall concordance for determining the cause of death was 33.85 % using expert opinion (κ = 0.23) and 55.38 % using AIS scoring (κ = 0.41). PMCT showed high sensitivity in detecting skeletal injuries but was limited in identifying soft tissue damage and vascular lesions, particularly in the abdomen and external surface regions.

Conclusion

PMCT demonstrates substantial agreement with autopsy in classifying injury severity, especially when guided by AIS scoring. While PMCT alone may not replace autopsy in all cases, its utility is enhanced through standardized injury scoring. PMCT may serve as a reliable adjunct or alternative in select forensic contexts, particularly where autopsy is declined or unavailable.

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.

Gray-white matter contrast reversal on T1-weighted spin-echo in postmortem brain

PURPOSE

The image contrast of postmortem magnetic resonance imaging (MRI) may differ from that of antemortem MRI because of circulator arrest, changes in postmortem tissue, and low-body-temperature scanning conditions. In fact, we have found that the signal intensity of white matter (WM) on T1-weighted spin-echo (T1WSE) images of the postmortem brain was lower than that of gray matter (GM), which resulted in image contrast reversal between GM and WM relative to the living brain. However, the reason for this phenomenon is unclear. Therefore, the aim of this study is to clarify the reason why image contrast reversal occurs between GM and WM of the postmortem brain.

MATERIALS AND METHODS

Twenty-three corpses were included in the study (mean age, 60.6 years; range: 19-60 years; mean rectal temperature at scan, 6.9℃; range: 4-11℃). On a 1.5 T MRI system, postmortem T1W-SE MRI of the brain was conducted in the 23 corpses prior to medico-legal autopsy. Next, T1 and T2 of the GM and WM at the level of the basal ganglia were determined in the same participants using inversion recovery and multiple SE sequences, respectively. The proton density (PD) was also calculated from the T1 and T2 images (in the same slice).

RESULTS

T1W-SE image contrast between the GM and WM of all postmortem brains was inverted relative to the living brain. T1 (579 ms in GM and 307 ms in WM) and PD (64 in GM and 44 in WM) of the postmortem brain decreased compared with the living brain. While T1 of WM/GM remained below 1 even postmortem, the PD of WM/GM decreased. T2 (110 ms in GM and 98 ms in WM) of the postmortem brain did not differ from the living brain.

CONCLUSION

The decrease in PD of WM/GM in the postmortem brain may be the major driver of contrast reversal between the GM and WM relative to the living brain.

Acute subdural hematoma caused by rupture of a mycotic aneurysm due to meningitis associated with infectious endocarditis: comparison of autopsy findings with postmortem computed tomography

Forensic pathologists often encounter cases of acute subdural hematoma (SDH) due to trauma, whereas those attributable to endogenous causes are rare. Here, we report a case of the latter type in a 42-year-old man who was found dead at home after several months of fever and malaise. Postmortem computed tomography (PMCT) and autopsy were undertaken to clarify the cause of death. PMCT images revealed a fatal SDH and a localized hyper-density area in the right parietal lobe; macroscopic and microscopic examinations revealed SDH due to rupture of a mycotic aneurysm (MA) associated with meningitis. The PMCT images also indicated thickening and calcification of the mitral valve, while autopsy demonstrated infective endocarditis (IE). In addition, PMCT demonstrated a low-density area in the spleen, which was shown to be a splenic abscess at autopsy. PMCT also demonstrated tooth cavities. Based on the findings of autopsy, the cause of death was considered to be SDH due to rupture of the MA resulting from meningitis with IE and splenic abscess. Although PMCT was unable to clarify the significance of any individual feature, a retrospective review of the PMCT images might have suggested IE, bacteremia, or ruptured MA leading to SDH. This case suggests that, instead of interpreting individual features demonstrated on PMCT images, integrated interpretation of overall PMCT findings might provide clues for identifying causes of death, despite the fact that PMCT lacks diagnostic accuracy for infectious diseases such as IE and meningitis.

A clear presentation of intracranial hypostasis on PMCT

Intracranial hypostasis is a common postmortem change evident on postmortem CT (PMCT), but can be readily misinterpreted as subdural hematoma by inexperienced physicians. Although PMCT is necessarily lacking contrast enhancement, we reconstructed hypostatic sinuses into three-dimensional images resembling the results of in vivo venography. This simple methodology facilitates easy recognition of intracranial hypostasis.

Perimortem Skeletal Sharp Force Trauma: Detection Reliability on CT Data, Demographics and Anatomical Patterns from a Forensic Dataset

Simple Summary

The increased use of computed tomography images in forensic anthropology is easily explained with a variety of benefits: among other reasons they are digitally stored, they can easily be shared and they are non-invasive. However, it is not clear how suitable these images are for forensic anthropologists to detect sharp force trauma. Therefore, we analyzed computed tomography images, by observing digital images of 41 forensic cases in different viewing modalities. In addition, we looked for anatomical injury patterns in the soft- and hard-tissues and any significant correlations between the manner of death (suicide or homicide) with different parameters. Our findings indicated a superiority of viewing the images in 2D, but not all bone lesions were detected. The manner of death was significantly correlated to some of the parameters, which could be extrapolated to future forensic anthropological cases. We promote the inclusion of imaging training into the anthropological curricula.

Abstract

The increasing importance of trauma analysis by means of postmortem computed tomography (PMCT) is insufficiently reflected in forensic curricula, nor are best practice manuals available. We attempt to detect sharp force bone lesions on PMCT of closed forensic cases with the aims of assessing errors and pointing out patterns in anatomical location and manner of death (MOD). We investigated 41 closed sharp force fatality cases, with available PMCT and forensic reports. Two observers with different radiological training assessed the lesions on PMCT scans (2D and 3D) for comparison with the reports. Between 3% (suicides) and 15.3% (homicides) of sharp force injuries caused visible bone lesions. While our observations were repeatable, each forensic investigation left a similar number of bone lesions undetected. Injury patterns differed between MOD, with thoracic bone lesions being most frequent overall. Soft tissue injury location varied between the MOD. Associations between MOD and age as well as number of injuries were significant. The detection of bone lesions on PMCT for untrained forensic specialists is challenging, curricula and pertinent manuals are desirable. With the low frequency of bone lesions compared to soft tissue injuries, we should be aware when analyzing decomposed bodies.