Postmortem computed tomography findings in the thorax – Experimental evaluation

• Four fatal models were prepared to investigate the time-related course of lung changes and appearance of pleural space fluid collection.
• The lung hypostasis showed a different time course pattern according to the postmortem time, and also according to the causes of death.
• The alveolar space fluid transudated the visceral pleura into the pleural space, and consequently the alveolar space fluid decreased and lung aeration increased.
• The consideration of postmortem time course is essential in evaluating postmortem lung CT.

ObjectiveExperimental fatal models were prepared to investigate the time-related course of lung changes using postmortem CT (PMCT). This study was approved by our institutional animal ethics committee.Materials and methodsTwenty-four NZW rabbits (female 24, 2.30–4.30 (mean 3.10) kg) were divided into 4 fatal groups; drowning, hypothermia, bag suffocation, and Potassium Chloride intravenous (control) group. All individuals were examined by CT (Aquilion CX, Toshiba, Japan) on postmortem time course until detection of putrefaction air. The percent of aerated lung volume (%ALV = 100 * (ALV/total lung volume)) was measured and the pleural space fluid was investigated by axial imaging. A paired t-test and Bonferroni/Dunn study were employed for statistical evaluation.ResultsIn intra-group analysis, the %ALV showed statistically different periods compared with each pre-image: 4–48 h in control, 1–24 h in drowning, 5–6 h in hypothermia, and 1–4 h in bag suffocation. In inter-group comparison (compared with control group), the %ALV increased in suffocation and decreased in drowning within 12 h. The %ALV remained significantly high in hypothermia until 24 h. The earliest detection times of pleural space fluid collection were different in each group: control (20 h), drowning (18 h), suffocation (36 h), and hypothermia (95 h).ConclusionThe lung hypostasis and the appearance of pleural space fluid collection presented differently in individual causes of death and depending on the postmortem time.

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