Postmortem computed tomography findings in cases of bath-related death: Applicability and limitation in forensic practice.

Purpose: Bath-related deaths occur frequently in Japan, and many of these deaths are diagnosed as death from disease without autopsy in the current Japanese death-investigation system. Therefore, we aimed to examine the postmortem computed tomography (PMCT) findings of bath-related deaths to determine if PMCT can differentiate between real cases of drowning and sudden deaths not related to drowning.

Methods: Bath-related deaths were sampled from all autopsies conducted at the Tokyo Medical Examiner's Office from September 2015 to August 2016. A total of 90 bath-related deaths (77 drowning cases and 13 non-drowning cases) and 50 controls (sudden cardiac deaths non-related to bathing) were included in this study. We investigated factors contributing to drowning and measured PMCT parameters (presence/density of fluid in the maxillary sinus/trachea, distance between the lungs, lung patterns [ground glass opacities, consolidation], position of the right diaphragmatic dome, density in the right atrium, stomach volume, and density of the gastric/duodenal contents).

Results: The analysis of the factors contributing to drowning showed that alcohol intoxication was the most frequent (n=25), followed by cardiac pathology (n=22), and psychotropic drug intoxication (n=6). Radiological evaluation showed that measurements of all parameters differed significantly between the drowning group and the controls. In addition, significant differences were observed between drowning and non-drowning cases in three radiological parameters (i.e., distance between lungs, stomach volume, and density of gastric contents).

Conclusions: Majority of bath-related deaths in this study showed signs of drowning at autopsy, and we observed a range of factors that contributed to drowning. By using several radiological parameters (e.g., the distance between the lungs, stomach volume, and the density of the gastric contents), PMCT for the investigation of bath-related deaths might indicate that drowning as opposed to other factors unrelated to drowning (e.g., sudden cardiac death) was the cause of death. This might allow for calculation of accurate mortality statistics on bath-related deaths.