In the practice of forensic pathology, fat embolism is one of the common causes of death, which can be divided into two categories: traumatic and non-traumatic. Non-traumatic fat embolism refers to the blockage of small blood vessels by fat droplets in the circulatory blood flow caused by non-traumatic factors such as underlying diseases, stress, poisoning and lipid metabolism disorders. At present, it is believed that the production of non-traumatic fat embolism is related to the disturbance of lipid metabolism, C-reactive protein-related cascade reaction, the agglutination of chylomicron and very low-density lipoprotein. The forensic identification of the cause of death of non-traumatic fat embolism is mainly based on the case, systematic autopsy, HE staining and fat staining, but it is often missed or misdiagnosed by forensic examiners because of its unknown risk factors, hidden onset, the difficulty of HE staining observation and irregular implementation of fat staining. In view of the lack of attention to non-traumatic fat embolism in forensic identification, this paper reviews the concepts, pathophysiological mechanism, research progress, existing problems and countermeasures of non-traumatic fat embolism, providing reference for forensic scholars.
Autopsy ; Embolism, Fat/pathology* ; Forensic Medicine ; Forensic Pathology ; Humans ; Pulmonary Embolism/pathology*

This study was done to demonstrate the computed tomography (CT) and pathologic findings of the sequential changes for experimental pulmonary fat embolism (PFE), and to correlate the CT and pathologic findings of rabbit lung. PFE was induced by an intravenous injection of 0.2 mL linoleic acid in 24 rabbits. The rabbits were divided into 4 groups of 6 rabbits each. CT scans were obtained sequentially at 2 hr (n= 24), day 1 (n=18), day 3 (n=12) and day 7 (n=6) after fat embolization. The pathologic findings were analyzed and CT-pathologic correlation was done. CT scans showed bilateral ground-glass opacity (GGO), consolidation and nodule in all cases. The findings of PFE at 2 hr after fat embolization were areas of decreased attenuation, GGO, consolidation and nodule. These findings were aggravated on the follow- up CT after 1 day and 3 days. The follow-up CT revealed linear density in the subpleural lungs after 7 days. On CT-pathology correlation, wedge-shaped ischemic necrosis in the subpleural lungs correlated with nodule at 2 hr. GGO and consolidation at day 1 on CT correlated with congestion and edema, and these findings at day 3 were correlated with inflammation and hemorrhagic edema. The linear density in the subpleural lungs correlated with interstitial fibrosis and pleural contraction at day 7. In conclusion, PFE was caused by using linoleic acid which is kind of free fatty acid and this study served as one model of the occurrence of nontraumatic PFE. CT accurately depicted the natural evolution of PFE in the serial followup, and this correlated well with the pathologic findings.
Animals ; Embolism, Fat/*pathology/*radiography ; Pulmonary Embolism/*pathology/*radiography ; Rabbits ; *Tomography, X-Ray Computed

BACKGROUNDThe experimental studies of venous thromboembolism (VTE) as an entity and the response of the pulmonary arterial endothelium after VTE are still rare. The objective of this study was to observe changes in the pulmonary arterial endothelium using a novel rat model of VTE.

METHODSRats were allocated to the VTE (n = 54) or control groups (n = 9). The left femoral vein was blocked using a microvessel clip to form deep vein thrombosis (DVT). One, four or seven-day-old thrombi were injected into the right femoral vein to induce DVT-pulmonary thromboembolism (DVT-PTE). The rats were sacrificed 1, 4 or 7 days later (D(n(1,4,7)) P(n(1,4,7)) subgroups (n = 6)), and the lungs were examined using light and electron microscopy.

RESULTSOn gross dissection, the rate of DVT formation was higher on day 1 (D(1)P(n): 100%, 18/18) than day 4 (D(4)P(n): 83%, 15/18; χ(2) = 5.900, P = 0.015) or day 7 (D(7)P(n): 44%, 8/18; χ(2) = 13.846, P = 0.000). On gross dissection, the positive emboli residue rate in the pulmonary arteries was lower in the D(1)P(n) subgroup (39%, 7/18) than the D(4)P(n) (73%, 11/15; χ(2) = 3.915, P = 0.048) and D(7)P(n) subgroups (100%, 8/8; χ(2) = 8.474, P = 0.004); however, light microscopy indicated the residual emboli rate was similar in all subgroups. Hyperplasia of the pulmonary arterial endothelium was observed 4 and 7 days after the injection of one-day-old or four-day-old thrombi. However, regions without pulmonary arterial endothelial cells and intra-elastic layers were observed one day after injection of seven-day-old thrombi.

CONCLUSIONSThis novel model closely simulates the clinical situations of thrombus formation and is ideal to study pulmonary endothelial cell activation. The outcome of emboli and pulmonary arterial endothelial alterations are related to the age and nature of the thrombi.

Animals ; Disease Models, Animal ; Endothelium, Vascular ; pathology ; Pulmonary Artery ; pathology ; Pulmonary Embolism ; pathology ; Rats ; Rats, Sprague-Dawley ; Venous Thromboembolism ; pathology

Air embolism, a life-threatening complication of medical procedure, is a frequently encountered challenge in the forensic practices. It can be easily missed due to ignorance by forensic examiner or it could be difficult to be identified due to prolonged storage of the cadaver. This article reviews the etiological factors, pathophysiological changes, clinical manifestation, diagnosis, and the medicolegal identification of air embolism. The authors suggest that modern imaging techniques including echocardiogram, computer tomography, and magnetic resonance imaging play animportant role in the clinical diagnosis and forensic identification of air embolism.
Cause of Death ; Echocardiography ; Embolism, Air/pathology* ; Forensic Pathology ; Humans ; Postmortem Changes ; Pulmonary Embolism/etiology* ; Tomography, X-Ray Computed

PURPOSE: To evaluate the low attenuation of mosaic pattern in pulmonary embolism, as observed on HRCT, and to correlate the findings with the pathologic features of resected lung. MATERIALS AND METHODS: Using permanent embolic materials, pulmonary embolism was induced in eight Yorkshire pigs. Pre-and post-embolic pulmonary angiography was performed and after 6 weeks, the incidence and pattern of parenchymal change in low attenuation (mosaic pattern), as seen on HRCT, was evaluated. The animals were then sacrified and contact radiography of the lung was performed. Thirty-eight segments of pathology were taken from the area in which the presence of embolism had been suggested. Pathologic and HRCT findings were then correlated. RESULTS: On HRCT, low attenuation was seen in 23 of 36 segments (64%) and showed variable patterns : crescent peripheral hyperlucency (61%, n=14), heterogeneous mottled hyperlucency (17%, n=4), lobular hyperlucency (13%, n=3), and homogeneous segmental hyperlucency (9%, n=2). Parenchymal low attenuation was seen on HRCT in 10 of 11 segments (91%) in which large segmental arterial occlusion occurred, and in 3 of 16 segments (19%) in which there was small segmental arterial occlusion. Abnormal pathologic findings were pulmonary congestion, dilatation of pulmonary arteries, interlobular septal thickening, and thrombus formation. Among the 38 pathologic segmental specimens, 29 were from the area in which HRCT findings were positive, and in which pulmonary embolism subsequently occurred. In only four of nine segments (44%) in the area in which HRCT fingings were negative was pulmonary embolism subsequently. CONCLUSION: HRCT findings of pulmonary embolism at six weeks after embolization showed variable patterns of low attenuation, diminished diameter of pulmonary arteries, and normal diameter of bronchi. In cases with large segmental arterial occlusion, the finding of low attenuation was more common ; this may be due to reduced blood flow to the embolic area, in combination with bronchiolar spasm. For the early diagnosis of pulmonary embolism, these findings may be useful.
Angiography ; Animals ; Bronchi ; Dilatation ; Early Diagnosis ; Embolism ; Estrogens, Conjugated (USP) ; Incidence ; Lung ; Pathology ; Pulmonary Artery ; Pulmonary Embolism* ; Radiography ; Spasm ; Swine ; Thrombosis

The development of thrombus on the tricuspid valve is very rare. This report describes a case of acute pulmonary embolism (PE) with a mass on the tricuspid valve in a normal heart, detected by bedside transthoracic echocardiography (TTE). After successful surgical management, the histopathological examination revealed the mass from the tricuspid valve to be mixed thrombus. The early use of bedside TTE can facilitate the prompt diagnosis and aggressive therapy when PE is suspected.
Female ; Humans ; Middle Aged ; Pulmonary Embolism ; diagnosis ; Thrombosis ; diagnosis ; Tricuspid Valve ; pathology

Female ; Humans ; Middle Aged ; Multiple Myeloma ; complications ; Pulmonary Embolism ; etiology ; pathology ; Venous Thrombosis ; etiology

Popliteal venous aneurysms can be a cause of fatal pulmonary thromboembolism. We report a case of a 47-year-old woman who suddenly died of fatal pulmonary thromboembolism. Deep vein thrombosis was not observed, but a venous aneurysm with intraluminal thrombi formation was identified on the left popliteal vein. This case illustrates that venous aneurysms can be presented as fatal pulmonary thromboembolism, and that they should be considered as a rare cause of pulmonary thromboembolism.
Aneurysm ; Female ; Forensic Pathology ; Humans ; Middle Aged ; Popliteal Vein ; Pulmonary Embolism ; Venous Thrombosis

Pulmonary thromboembolism （PTE）, which is caused by detachment of venous thrombosis, is a common cause of sudden death in forensic practice. In the cases which die of PTE after trauma or die of PTE during non-thrombosis disease hospitalization, forensic pathologists are required to analyze the time sequence between trauma or medical practice and venous thrombosis, and then analyze their causal relationship. This review summarizes the history of thrombus age estimation and recent advances in forensic medicine, and then gives a brief outlook for future research to provide reference for forensic identification of PTE and guide follow-up studies.
Age Determination by Skeleton ; Death, Sudden ; Forensic Medicine ; Forensic Pathology/trends* ; Humans ; Pulmonary Embolism ; Venous Thrombosis

Optical coherence tomography (OCT) is a new imaging technique capable of obtaining high-resolution intravascular images and has been used in interventional cardiology. However, an application of OCT in pulmonary arteries had seldom been documented. In this case, OCT imaging is performed in peripheral pulmonary arteries and shows mural red thrombi. Subsequently, the red thrombi are aspirated and confirmed by a histological examination. These findings suggest that OCT may be a useful tool to depict peripheral pulmonary artery thrombi.
Adult ; Angiography ; Humans ; Male ; Pulmonary Artery/*pathology/radiography ; Pulmonary Embolism/*diagnosis ; Tomography, Optical Coherence/*methods ; Tomography, X-Ray Computed