Post-Mortem Computed Tomography (PMCT) is an essential tool in forensic investigations, helping to determine the causes of death with precision. A correct interpretation of PMCT findings is essential for forensic evaluation. The normal post-mortem changes, depending both on the time that has passed since death and on the specific conditions of the body and the surrounding environment, can deceive an inexperienced radiologist. Knowing the specific imaging of these potential pitfalls is essential for a radiologist who wants to approach the forensic field.

Post-mortem changes and decomposition begin to develop immediately upon death. They are generally classified into early changes, which appear within the first 24 hours post-mortem, and late changes that develop over a longer period. In cases of in-hospital deaths, early post-mortem alterations are more commonly observed due to the relatively short time interval between death and imaging. Post-mortem change most commonly refers to livor mortis (or hypostasis), rigor mortis and algor mortis. Decomposition is a multifactorial process that involves cellular autolysis, bacterial fermentation and insect or animal predation. In specific cases, the body can mummify, skeletonize or transform to adipocere rather than decompose.

Livor mortis is the earliest visible post-mortem change. It becomes visible from 20 minutes to 2h after death and reaches its maximum at 8-12 hours. Rigor mortis begins to develop within 1 to 6 hour after death, and it becomes fully developed by 6 to 12 hours; it rarely affects PMCT images. Algor mortis is the equilibration of the body temperature with the surrounding environment after death. Decomposition is the breakdown of dead soft tissues into fluid and gases; it is a multifactorial process involving autolysis and putrefaction.