Approaching pulmonary fat embolism on postmortem computed tomography.

Area of Science:

• Forensic pathology
• Radiology
• Pulmonary medicine

Background:

• Pulmonary fat embolism (PFE) is a critical diagnosis in forensic pathology, serving as a sign of vitality or cause of death.
• Histological grading systems, such as Falzi, are used to assess PFE severity.
• Unenhanced postmortem computed tomography (PMCT) is increasingly utilized in forensic investigations.

Purpose of the Study:

• To evaluate the diagnostic utility of unenhanced PMCT for pulmonary fat embolism (PFE).
• To assess the ability of PMCT to detect fat layers indicative of PFE.
• To correlate PMCT findings with histological grading of PFE severity.

Main Methods:

• Retrospective analysis of consecutive cases with both PMCT and autopsy.
• Inclusion of PFE-positive and PFE-negative cases.
• Independent assessment of PMCT data by three observers for fat layers in the pulmonary artery system.

Main Results:

• 830 cases were analyzed (366 PFE positive, 464 PFE negative).
• Fat layers were identified on PMCT in 18 cases (16 PFE positive, 2 controls).
• PMCT demonstrated low sensitivity but high specificity for PFE diagnosis, with fat layers typically located in the pulmonary trunk near the pulmonary valve.

Conclusions:

• Detection of fat layers on PMCT is a rare but significant finding for PFE diagnosis.
• The presence of fat layers on PMCT correlates with severe histological grades of PFE.
• The typical location of these fat layers in the pulmonary trunk is a key diagnostic feature.