Postmortem Changes as Documented in Postmortem Computed Tomography Scans

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.

CT analysis of skull contents in naturally mummified human corpses, a multicentric study

INTRODUCTION

This study aimed to assess skull contents, brain appearance, and density on postmortem computed tomography in naturally mummified corpses.

MATERIAL AND METHODS

For this purpose, a retrospective multicentric study, including mummified corpses from two French centers (Brest and Nantes) and from the New Mexico Decedent Image Database (USA), was performed by analyzing postmortem computed tomography (PMCT) focused on the head and neck of partially or fully mummified corpses discovered between 2011 and 2022. The PMCT analysis provided data on the CT appearance of brains, allowing them to be classified into four different categories (desiccation, liquefaction, dura mater only (DMO), and absence), and to measure densities (HU) of the brain remains. In addition, data on postmortem intervals (PMI) from Nantes and Brest centers were collected and analyzed to test the link between brain densities and PMIs.

RESULTS

54 cases of naturally mummified corpses were included. The brains were classified as liquefied (56%), desiccated (17 %), DMO (20 %), and absent (7 %) based on their CT appearance. Dehydrated brains were significantly (p < 0.004) denser (median 102 HU, interquartile range (IQR) 41) than either liquefied brains (median 39.5 HU, IQR 9) or brains with DMO (median -25 HU, IQR 57). However, the density of brain remains was not significantly affected by where the bodies were found (p = 0,41). Analysis of PMI and brain densities was performed on 22 cases. The results showed that brain remains were significantly (p = 0.039) denser when they were found after a PMI of more than six months.

CONCLUSION

Brain desiccation was the aspect with the highest densities on PMCT, and for which we were able to highlight great preservation of anatomical structures observable in living organisms.

Post mortem computed tomography is highly sensitive for pyelonephritis. A radiologic-pathologic correlation series

Pyelonephritis is a potentially lethal disease occasionally encountered in the forensic setting. Post mortem computed tomography (PMCT) is an important investigative tool for the forensic pathologist. In particular, it may be used to document and screen disease prior to traditional autopsy methods. While the sensitivity and specificity of computed tomography for pyelonephritis is well studied in the antemortem clinical setting, the test characteristics of PMCT are not yet described in the forensic pathology literature. A series of all cases of fatal pyelonephritis identified at the Ontario Forensic Pathology Service, over the course of 1 year was studied. Radiologic, clinical and pathologic findings were reviewed. A fulsome autopsy, including histopathologic examination, was considered the gold standard for sensitivity and specificity calculations. A control group consisting of 16 cases without pyelonephritis (ex: opiate toxicity) in which both PMCT and histologic data were available by way of comparison. Sixteen cases of pyelonephritis were identified. Post mortem computed tomographical signs of pyelonephritis included asymmetric renal enlargement, perinephric fat stranding, and ectopic renal air. The most (57%) individually sensitive of these findings was perinephric fat stranding but sensitivity increased to 100% if any of the three signs were present. The control group analysis revealed the specificity of air asymmetry (81%), asymmetric renal enlargement (81%), and fat stranding (69%). PMCT findings may rule in a diagnosis of pyelonephritis, and should prompt the pathologist to grossly and microscopically examine the kidneys.

Postmortem computed tomography differentiation between intraperitoneal decomposition gas and pneumoperitoneum

PURPOSE

The aim of this study is to investigate the ability of postmortem computed tomography (PMCT) to distinguish intraperitoneal decomposition gas from pneumoperitoneum due to intestinal perforation.

METHODS

This retrospective study investigated the factors affecting intraperitoneal gas in two groups of 14 decedents as detected by postmortem CT performed in the Department of Legal Medicine of Hamburg University. The first group died with a cause of death associated with intestinal perforation, and the second group with other different natural causes of death. These factors include postmortem interval, gas volume, gas distribution, radiology alteration index (RAI), and pneumoperitoneum-associated pathology.

RESULTS

The findings of this study showed the appearance of specific gas distribution patterns and a significant increase in gas volumes in the cases of intestinal perforation. Moreover, postmortem interval and the pneumoperitoneum-associated pathology could help distinguish postmortem-generated gas from pneumoperitoneum.

CONCLUSION

Based on the findings of this study, we propose that these findings can improve the proper detection of intestinal perforation cases in the future.

Head and Brain Postmortem Computed Tomography-Autopsy Correlation in Hospital Deaths

The use of postmortem computed tomography (PMCT) to support autopsy pathology has increased in recent decades. To some extent, PMCT has also been contemplated as a potential alternative to conventional postmortem examination. The purpose of this study was to investigate the ability of PMCT to detect specific pathologic findings in the head and brain in natural hospital deaths.We examined postmortem CT images and autopsy data from 31 subjects who died at SUNY (State University of New York) Upstate University Hospital between 2013 and 2018. Each subject underwent a noncontrast PMCT and a traditional autopsy. A neuroradiologist analyzed PMCT images for head and brain abnormalities. The autopsies were performed by pathologists who were aware of the radiology results.In our series, PMCT was able to detect the majority of the significant space-occupying lesions, although it was not always reliable in ascertaining their nature. Postmortem computed tomography revealed findings usually challenging to detect at autopsy. Unfortunately, there were also situations in which PMCT was misleading, showing changes that were difficult to interpret, or that could be related to postmortem events. Therefore, we conclude PMCT should be used as an adjunct rather than a substitute to autopsy.