Distribution patterns of postmortem intravascular gas on PMCT in natural deaths

Postmortem intravascular gas is a frequent PMCT finding, yet its forensic interpretation remains uncertain. This study investigated whether early postmortem intravascular gas distribution demonstrates reproducible systemic distribution patterns or is associated with the postmortem interval.

This retrospective observational study analyzed 247 autopsy-confirmed natural deaths. Cases with trauma, visible putrefaction, or invasive airway management were excluded to prevent artifacts. Intravascular gas was graded (0-3) in hepatic, coronary, and cerebral vessels on pre-autopsy Postmortem Computed Tomography (PMCT). Statistical analyses evaluated associations with PMI and systemic association.

Gas frequently appeared in hepatic (50.6%) and coronary (51.4%) vessels, but rarely in the cerebral vasculature (9.7%). No significant linear correlation existed between gas grade and PMI across any territory. Instead, distribution demonstrated a strong systemic association between the hepatic and coronary systems (ρ = 0.765). Cerebral gas was observed only in conjunction with hepatic and coronary gas, while isolated cerebral gas was not identified.

During the early postmortem interval, intravascular gas did not demonstrate a reliable association with PMI. Instead, it follows a predictable systemic association between the hepatic, coronary, and cerebral vascular systems. Deviations from this systemic pattern, specifically isolated cerebral gas on PMCT, lead us to hypothesize that such findings may indicate antemortem etiologies such as air embolism or barotrauma, warranting future validation.