Diverse Pattern and Postmortem Changes of Hemorrhage on Postmortem Computed Tomography: An Integrated Analysis with Autopsy

Postmortem computed tomography (PMCT) is a non-invasive imaging modality used to assess injuries, pathological lesions, and postmortem changes before autopsy. Accurate interpretation of PMCT findings is crucial to avoid misinterpretation owing to postmortem changes. In this case, PMCT was performed before autopsy of a decedent who died from multiple injuries to identify various hemorrhagic findings in the torso, including those in the thoracic cavity and pericardium, which were confirmed through autopsy. PMCT revealed horizontally layered and droplet-shaped hyperdense areas along the lateral right thoracic wall, a crescent-shaped homogeneous hyperdensity in the pericardium, and obliquely layered hyperdensity in the left pulmonary artery. Lower layers of blood had >70 Hounsfield unit (HU), whereas the upper layers measured 30-40 HU. Integrated analysis with subsequent autopsy confirmed that these imaging findings reflected blood sedimentation and coagulation reactions, suggesting misinterpretation of atypical hemothorax patterns resulting from anatomical characteristics as hematomas or tumors. This approach enabled the precise determination of hemorrhage location and coagulation status, facilitating the estimation of circulatory conditions at death and timing of injury. PMCT provides valuable information for event reconstruction and autopsy guidance by visualizing hemorrhage location, morphology, density, and sedimentation. However, PMCT alone cannot definitively determine the coagulation status or distinguish antemortem from postmortem bleeding, necessitating a combined interpretation with autopsy and histopathology. This case demonstrates the use of PMCT combined with autopsy for evaluating hemorrhage, injury mechanisms, and death circumstances, thereby enhancing the objectivity and accuracy of forensic assessments.