Postmortem whole-body MRI in traumatic causes of death

The aim of this study was to determine the sensitivity and specificity of postmortem whole-body MRI for typical injuries resulting from traumatic causes of death.

Reduction of postmortem angiography-induced tissue edema by using polyethylene glycol as a contrast agent dissolver

Postmortem investigation is increasingly supported by computed tomography (CT) and magnetic resonance imaging, in which postmortem minimal invasive angiography has become important. The newly introduced approach using an aqueous contrast agent solution provided excellent vessel visualization but was suspected to possibly cause tissue edema artifacts in histological investigations. The aim of this study was to investigate on a porcine heart model whether it is possible to influence the contrast agent distribution within the soft tissue by changing its viscosity by dissolving the contrast agent in polyethylene glycol (PEG) as a matrix medium. High-resolution CT scans after injection showed that viscosities above c. 15 mPa s (65% PEG) prevented a contrast agent distribution within the capillary bed of the left ventricular myocardium. Thereby, the precondition of edema artifacts could be reduced. Its minimal invasive application on human corpses needs to be further adapted as the flow resistance is expected to differ between different tissues.

Postmortem unenhanced magnetic resonance imaging of myocardial infarction in correlation to histological infarction age characterization

AIMS: Postmortem magnetic resonance (MRI) imaging is currently evaluated as alternative to traditional autopsy and myocardial infarction plays a key role therein. The aim of this study is to determine the suitability of postmortem MRI in infarction age staging. METHODS AND RESULTS: In eight human forensic corpses presenting with a total of 11 myocardial infarcted areas, short-axis, transversal, and longitudinal long-axis images (T1, T2, stir, flair) were acquired in situ on a 1.5 T system. During subsequent autopsy, the section technique was adapted to short-axis images. Histological investigations were performed along the entire circumference of the left ventricle to correlate the signal alteration in MR to the histological appearance. Two peracute infarctions were not detected in MRI and autopsy. Four acute infarcted areas presented with decreased signal in necrotic centres and increased signal in marginal myocardial regions (T2-weighted). T1-weighted images showed local hyperintensities when intramyocardial haemorrhage occurred. Four cases showed subacute infarctions with hyperintense regions in T2-weighted images and no signal alteration in T1-weighted images. Four chronic myocardial infarctions showed distinctively decreased signals in all applied sequences. CONCLUSION: Postmortem MRI demonstrates myocardial infarction in situ and allows for an infarction age estimation based on the signal behaviour.

Postmortem radiology of fatal hemorrhage: measurements of cross-sectional areas of major blood vessels and volumes of aorta and spleen on MDCT and volumes of heart chambers on MRI

OBJECTIVE: Autopsy determination of fatal hemorrhage as the cause of death is often a difficult diagnosis in forensic medicine. No quantitative system for accurately measuring the blood volume in a corpse has been developed. MATERIALS AND METHODS: This article describes the measurement and evaluation of the cross-sectional areas of major blood vessels, of the diameter of the right pulmonary artery, of the volumes of thoracic aorta and spleen on MDCT, and of the volumes of heart chambers on MRI in 65 autopsy-verified cases of fatal hemorrhage or no fatal hemorrhage. RESULTS: Most cases with a cause of death of "fatal hemorrhage" had collapsed vessels. The finding of a collapsed superior vena cava, main pulmonary artery, or right pulmonary artery was 100% specific for fatal hemorrhage. The mean volumes of the thoracic aorta and of each of the heart chambers and the mean cross-sectional areas of all vessels except the inferior vena cava and abdominal aorta were significantly smaller in fatal hemorrhage than in no fatal hemorrhage. CONCLUSION: For the quantitative differentiation of fatal hemorrhage from other causes of death, we propose a three-step algorithm with measurements of the diameter of the right pulmonary artery, the cross-sectional area of the main pulmonary artery, and the volume of the right atrium (specificity, 100%; sensitivity, 95%). However, this algorithm must be corroborated in a prospective study, which would eliminate the limitations of this study. Quantitative postmortem cross-sectional imaging might become a reliable objective method to assess the question of fatal hemorrhage in forensic medicine.

Noninvasive estimation of organ weights by postmortem magnetic resonance imaging and multislice computed tomography

OBJECTIVE: Computed tomography (CT) and magnetic resonance imaging (MRI) are introduced as an alternative to traditional autopsy. The purpose of this study was to investigate their accuracy in mass estimation of liver and spleen. METHODS: In 44 cases, the weights of spleen and liver were estimated based on MRI and CT data using a volume-analysis software and a postmortem tissue-specific density factor. In a blinded approach, the results were compared with the weights noted at autopsy. RESULTS: Excellent correlation between estimated and real weights (r = 0.997 for MRI, r = 0.997 for CT) was found. Putrefaction gas and venous air embolism led to an overestimation. Venous congestion and drowning caused higher estimated weights. CONCLUSION: Postmortem weights of liver and spleen can accurately be assessed by nondestructive imaging. Multislice CT overcomes the limitation of putrefaction and venous air embolism by the possibility to exclude gas. Congestion seems to be even better assessed.

Virtopsy hemorrhage of the posterior cricoarytenoid muscle by blunt force to the neck in postmortem multislice computed tomography and magnetic resonance imaging

In forensic autopsies, one of the most important and common signs of violence to the neck is hemorrhages of the soft tissues. The Institute of Forensic Medicine in Bern evaluates the usefulness of postmortem multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) of forensic cases prior to autopsy. The aim of this study was to prove the sensitivity of postmortem MSCT and MRI in the detection of hemorrhages of the neck muscles. A full body scan prior to and a detailed scan of the explanted larynx after autopsy were performed. MSCT detected multiple fractures of the larynx. Detailed MRI was able to demonstrate the hemorrhage of the left posterior cricoarytenoid muscle. The minor hemorrhage of the right posterior cricoarytenoid muscle could not be detected with certainty. Although more experience is required, we conclude that combined MRI and MSCT examination is a useful tool for documentation and examination of neck muscle hemorrhages in forensic cases.

Postmortem imaging of blood and its characteristics using MSCT and MRI

The rapid development of computed tomography (CT) and magnetic resonance imaging (MRI) led to the introduction and establishment in postmortem investigations. The objectives of this preliminary study were to describe the imaging appearances of the early postmortem changes of blood after cessation of the circulation, such as sedimentation, postmortem clotting, and internal livores, and to give a few first suggestions on how to differentiate them from other forensic findings. In the Virtopsy project, 95 human corpses underwent postmortem imaging by CT and MRI prior to traditional autopsy and therefore 44 cases have been investigated in this study. Postmortem alterations as well as the forensic relevant findings of the blood, such as internal or subcutaneous bleedings, are presented on the basis of their imaging appearances in multislice CT and MRI.

Intrahepatic gas at postmortem computed tomography: forensic experience as a potential guide for in vivo trauma imaging

BACKGROUND: Until August 2004 there were 106 forensic cases examined with postmortem multislice computed tomography (MSCT) and magnetic resonance (MR) imaging before traditional autopsy within the Virtopsy project. Intrahepatic gas (IHG) was a frequent finding in postmortem MSCT examinations. The aim of this study was to investigate its cause and significance. METHODS: There were 84 virtopsy cases retrospectively investigated concerning the occurrence, location, and volume of IHG in postmortem MSCT imaging (1.25 mm collimation, 1.25 mm thickness). We assessed and noted the occurrence of intestinal distention, putrefaction, and systemic gas embolisms and the cause of death, possible open trauma, possible artificial respiration, and the postmortem interval. We investigated the relations between the findings using the contingency table (chi2 test) and the comparison of the postmortem intervals in both groups was performed using the t test in 79 nonputrefied corpses. RESULTS: IHG was found in 47 cases (59.5%). In five of the cases, the IHG was caused or influenced by putrefaction. Gas distribution within the liver of the remaining 42 cases was as follows: hepatic arteries in 21 cases, hepatic veins in 35 cases, and portal vein branches in 13 cases; among which combinations also occurred in 20 cases. The presence of IHG was strongly related to open trauma with systemic gas. Pulmonary barotrauma as occurring under artificial respiration or in drowning also caused IHG. Putrefaction did not seem to influence the occurrence of IHG until macroscopic signs of putrefaction were noticeable. CONCLUSIONS: IHG is a frequent finding in traumatic causes of death and requires a systemic gas embolism. Exceptions are putrefied or burned corpses. Common clinical causes such as necrotic bowel diseases appear rarely as a cause of IHG in our forensic case material.

Postmortem noninvasive virtual autopsy: extrapleural hemorrhage after blunt thoracic trauma

A 19-year-old man speeding recklessly along a highway caused a left-frontal crash with another car. After his vehicle came to a standstill, he climbed out of the wreck and crawled across the tarmac to the other side of the road, where he died several minutes after the accident and before the arrival of an ambulance. Postmortem multislice computed tomography (MSCT) demonstrated fractures of the first, second, and third ribs and scapula on the left, an extrapleural hemorrhage in the apical region of the left thorax, as well as a large amount of blood in the left thoracic cavity. These radiologic findings were indicative of a delayed rupture of a traumatic extrapleural hematoma into the pleural space. A traditional autopsy confirmed the very rare diagnosis of a traumatic extrapleural hemorrhage with a delayed rupture.

Evaluation of reparative cartilage after autologous chondrocyte implantation for osteochondritis dissecans: histology, biochemistry, and MR imaging

BACKGROUND: The aim of this study was to investigate the biochemical properties, histological and immunohistochemical appearance, and magnetic resonance (MR) imaging findings of reparative cartilage after autologous chondrocyte implantation (ACI) for osteochondritis dissecans (OCD). METHODS: Six patients (mean age 20.2 +/- 8.8 years; 13-35 years) who underwent ACI for full-thickness cartilage defects of the femoral condyle were studied. One year after the procedure, a second-look arthroscopic operation was performed with biopsy of reparative tissue. The International Cartilage Repair Society (ICRS) visual histological assessment scale was used for histological assessment. Biopsied tissue was immunohistochemically analyzed with the use of monoclonal antihuman collagen type I and monoclonal antihuman collagen type II primary antibodies. Glycosaminoglycan (GAG) concentrations in biopsied reparative cartilage samples were measured by high performance liquid chromatography (HPLC). MR imaging was performed with T1- and T2-weighted imaging and three-dimensional spoiled gradient-recalled (3D-SPGR) MR imaging. RESULTS: Four tissue samples were graded as having a mixed morphology of hyaline and fibrocartilage while the other two were graded as fibrocartilage. Average ICRS scores for each criterion were (I) 1.0 +/- 1.5; (II) 1.7 +/- 0.5; (III) 0.6 +/- 1.0; (IV) 3.0 +/- 0.0; (V) 1.8 +/- 1.5; and (VI) 2.5 +/- 1.2. Average total score was 10.7 +/- 2.8. On immunohistochemical analysis, the matrix from deep and middle layers of reparative cartilage stained positive for type II collagen; however, the surface layer did not stain well. The average GAG concentration in reparative cartilage was 76.6 +/- 4.2 microg/mg whereas that in normal cartilage was 108 +/- 11.2 microg/mg. Common complications observed on 3D-SPGR MR imaging were hypertrophy of grafted periosteum, edema-like signal in bone marrow, and incomplete repair of subchondral bone at the surgical site. Clinically, patients had significant improvements in Lysholm scores. CONCLUSIONS: In spite of a good clinical course, reparative cartilage after ACI had less GAG concentration and was inferior to healthy hyaline cartilage in histological and immunohistochemical appearance and on MRI findings.

Copper and human health: biochemistry, genetics, and strategies for modeling dose-response relationships

Copper (Cu) and its alloys are used extensively in domestic and industrial applications. Cu is also an essential element in mammalian nutrition. Since both copper deficiency and copper excess produce adverse health effects, the dose-response curve is U-shaped, although the precise form has not yet been well characterized. Many animal and human studies were conducted on copper to provide a rich database from which data suitable for modeling the dose-response relationship for copper may be extracted. Possible dose-response modeling strategies are considered in this review, including those based on the benchmark dose and categorical regression. The usefulness of biologically based dose-response modeling techniques in understanding copper toxicity was difficult to assess at this time since the mechanisms underlying copper-induced toxicity have yet to be fully elucidated. A dose-response modeling strategy for copper toxicity was proposed associated with both deficiency and excess. This modeling strategy was applied to multiple studies of copper-induced toxicity, standardized with respect to severity of adverse health outcomes and selected on the basis of criteria reflecting the quality and relevance of individual studies. The use of a comprehensive database on copper-induced toxicity is essential for dose-response modeling since there is insufficient information in any single study to adequately characterize copper dose-response relationships. The dose-response modeling strategy envisioned here is designed to determine whether the existing toxicity data for copper excess or deficiency may be effectively utilized in defining the limits of the homeostatic range in humans and other species. By considering alternative techniques for determining a point of departure and low-dose extrapolation (including categorical regression, the benchmark dose, and identification of observed no-effect levels) this strategy will identify which techniques are most suitable for this purpose. This analysis also serves to identify areas in which additional data are needed to better define the characteristics of dose-response relationships for copper-induced toxicity in relation to excess or deficiency.

Robust postmortem survival of murine vestibular and cochlear stem cells

Potential treatment strategies of neurodegenerative and other diseases with stem cells derived from nonembryonic tissues are much less subjected to ethical criticism than embryonic stem cell-based approaches. Here we report the isolation of inner ear stem cells, which may be useful in cell replacement therapies for hearing loss, after protracted postmortem intervals. We found that neonatal murine inner ear tissues, including vestibular and cochlear sensory epithelia, display remarkably robust cellular survival, even 10 days postmortem. Similarly, isolation of sphere-forming stem cells was possible up to 10 days postmortem. We detected no difference in the proliferation and differentiation potential between stem cells isolated directly after death and up to 5 days postmortem. At longer postmortem intervals, we observed that the potency of sphere-derived cells to spontaneously differentiate into mature cell types diminishes prior to the cells losing their potential for self-renewal. Three-week-old mice also displayed sphere-forming stem cells in all inner ear tissues investigated up to 5 days postmortem. In summary, our results demonstrate that postmortem murine inner ear tissue is suited for isolation of stem cells.

Postmortem angiography: review of former and current methods

OBJECTIVE: Postmortem investigations are becoming more and more sophisticated. CT and MRI are already being used in pathology and forensic medicine. In this context, the impact of postmortem angiography increases because of the rapid evaluation of organ-specific vascular patterns, vascular alteration under pathologic and physiologic conditions, and tissue changes induced by artificial and unnatural causes. CONCLUSION: In this article, the advantages and disadvantages of former and current techniques and contrast agents are reviewed.