Postmortem computed tomography lung findings in fatal of hypothermia

To identify lung findings specific to fatal hypothermia on postmortem computed tomography (CT) imaging. Whole body CT scans were performed followed by full autopsy to investigate causes of death. There were 13 fatal hypothermia cases (group A) and 118 with other causes of death (group B). The chest cavity (CC), dead space including fluid/pneumothorax (DS), aerated lung volume (ALV), percentage aerated lung (%ALV), and tracheal aerated volume (ATV) were measured. Autopsy findings of groups A and B were compared. Receiver operating characteristics (ROC) curves were used to identify factors specific to fatal hypothermia. There were no differences in age, sex, number with emphysema, or time from death to CT examination between the 2 groups. CC, DS, ALV, %ALV, and ATV were 2601.0±247.4 (mL), 281.1±136.5 (mL), 1564.5±281.1 (mL), 62.1±6.2(%), and 21.8±2.7 (mL) in group A and 2339.2±67.7 (mL), 241.1±38.0 (mL), 739.9±67.0 (mL), 31.4±2.3(%), and 15.9±0.8 (mL) in group B, respectively. There were statistically significant differences between groups A and B in ALV, %ALV and ATV. The multiple comparison procedure revealed that ALV and %ALV differed significantly between fatal hypothermia and other causes of death (p<0.05). Using ROC evaluation, %ALV had the largest area under the curve (0.819). This study demonstrates that the %ALV is greater in fatal hypothermia cases than in those with other causes of death on postmortem CT chest imaging. Based on CT, hypothermia is very likely to be the cause of death if the %ALV is >70%.