Gas, Gaps, and Grayscale: A pattern-based postmortem computed tomography approach in recognizing heat hematoma in charred bodies.

Abstract

Thermal injury produces significant postmortem alterations that may mimic traumatic intracranial haemorrhage, posing a diagnostic challenge during medicolegal investigation. This study aimed to describe a pattern-based approach for recognising heat hematoma on postmortem computed tomography (PMCT) in fatal fire exposure cases by highlighting characteristic imaging features that may assist forensic interpretation. Two cases of fatal fire exposure underwent non-contrast PMCT before conventional medicolegal autopsy. PMCT findings were systematically evaluated for morphology, attenuation, distribution, and associated intracranial features of epidural collections, including intralesional gas, intradiploic gas, dural separation, brain volume changes, and mass effect. PMCT showed diffuse extra-axial collections along the cerebral convexities with an irregular, predominantly crescentic morphology and heterogeneous low attenuation (approximately 30-62 HU), reflecting multiple scattered intralesional air locules and thermally altered blood. The collections were associated with separation of dura mater from the inner table, resulting in widening of the epidural space. Generalised brain volume reduction consistent with thermal shrinkage and dehydration was observed without significant mass effect or features of true pressure-related herniation. Additional findings included intracranial and intradiploic gas producing a mottled calvarial appearance, focal split diploë sign, and soft-tissue gas within the scalp and facial regions. A pattern-based approach to PMCT interpretation is suggested, in which the combined presence of a heterogeneous low attenuation crescentic epidural collection, intralesional and intradiploic gas, dural separation, split diploë sign, and minimal mass effect supports recognition of heat hematoma in charred bodies. These imaging findings may assist medicolegal interpretation when considered in conjunction with the overall postmortem examination.