Ischemic heart disease in postmortem CT and CT angiography

Objective: Postmortem radiology had in recent years appeared in the field of forensic medicine and is now considered by some authors as a good replacement for conventional autopsy and by others as a complementary examination. Although postmortem CT radiological imaging is very useful in demonstrating traumatic lesions, its utility is still quite limited in the cardiovascular field. This limitation could be minimized by the introduction of postmortem angiography. At the University Center of Legal Medicine of Lausanne, CT scans and postmortem multiphase CTangiography are used in cases with a suspicion of ischemic heart disease.Method: The goal of this presentation is to demonstrate some correlations between postmortem CT, CTangiography and conventional autopsy examination in cases of ischemic heart disease.Results: We observed that the native CT scan can show only some pathological findings as cardiac tamponade and calcifications of coronary arteries. However, postmortem angiography allows a better visualization of coronary arteries and evaluation of stenosis and occlusion as well as better imaging of soft tissue.Conclusion: The interpretation of postmortem modern radiology is a new field for both forensic pathologists and radiologists who have to learn to read the postmortem modified images. The information obtained from both parties can help to further the understanding of CT and CT angiography in postmortem cases.

Innovative method for carbon dioxide determination in human postmortem cardiac gas samples using headspace-gas chromatography-mass spectrometry and stable labeled isotope as internal standard.

A novel approach to measure carbon dioxide (CO2) in gaseous samples, based on a precise and accurate quantification by (13)CO2 internal standard generated in situ is presented. The main goal of this study was to provide an innovative headspace-gas chromatography-mass spectrometry (HS-GC-MS) method applicable in the routine determination of CO2. The main drawback of the GC methods discussed in the literature for CO2 measurement is the lack of a specific internal standard necessary to perform quantification. CO2 measurement is still quantified by external calibration without taking into account analytical problems which can often occur considering gaseous samples. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in situ an internal labeled standard gas ((13)CO2) on the basis of the stoichiometric formation of CO2 by the reaction of hydrochloric acid (HCl) with sodium hydrogen carbonate (NaH(13)CO3). This method allows a precise measurement of CO2 concentration and was validated on various human postmortem gas samples in order to study its efficiency.

Investigation of Postmortem Gases: A Forensic Imaging and Analytical Chemistry Approach

Background: Distinguishing postmortem gas accumulations in the body due to natural decomposition and other phenomena such as gas embolism can prove a difficult task using purely Multi-Detector Computed Tomography (MDCT). The Radiological Alteration Index (RAI) was created with the intention to be able to identify bodies undergoing the putrefaction process based on the quantity of gas detected within the body. The flaw in this approach is the inability to absolutely determine putrefaction as the origin of gas volumes in cases of moderate alteration. The aim of the current study is to identify percentage compositions of O2, N2, CO2 and the presence of gases such as H2 and H2S within these sampling sites in order to resolve this complication. Materials and methods: All cases investigated in our University Center of Legal Medicine are undergoing a Post-Mortem Computed Tomography (PMCT)-scan before external examination or autopsy as a routine investigation. In the obtained images, areas of gas were characterized as 0, I, II or III based on the amount of gas present according to the RAI (1). The criteria for these characterizations were dependent of the site of gas, for example thoracic and abdominal cavities were graded as I (1 - 3cm gas), II (3 - 5cm gas) and III (>5cm gas). Cases showing gaseous sites with grade II or III were selected for this study. The sampling was performed under CT-guidance to target the regions to be punctured. Luer-lock PTFE syringes equipped with a three-way valve and needles were used to sample the gas directly (2). Gaseous samples were then analysed using gas chromatography coupled to a thermal conductivity detector (GC-TCD). The components present in the samples were expressed as a percentage of the overall gas present. Results: Up to now, we have investigated more than 40 cases using our standardized procedure for sampling and analysis of gas. O2, N2 and CO2 were present in most samples. The following distributions were found to correlate to gas origins of gas embolism/scuba diving accidents, trauma and putrefaction: ? Putrefaction → O2 = 1 - 5%; CO2 > 15%; N2 = 10 - 70%; H2 / H2S / CH4 variable presence ? Gas embolism/Scuba diving accidents → O2 and N2= varying percentages; CO2 > 20% ? Trauma → O2 = small percentage; CO2 < 15%; N2 > 65% H2 and H2S indicated levels of putrefaction along with methane which can also gauge environmental conditions or conditions of body storage/burial. Many cases showing large RAI values (advanced alteration) did reveal a radiological diagnosis which was in concordance with the interpretation of the gas composition. However, in certain cases (gas embolism, scuba divers) radiological interpretation was not possible and only chemical gas analysis was found to lead to the correct diagnosis, meaning that it provided complementary information to the radiological diagnosis. Conclusion: Investigation of postmortem gases is a useful tool to determine origin of gas generation which can aid the diagnosis of the cause of death. Levels of gas can provide information on stage of putrefaction and help to perform essential medico-legal diagnosis such as vital gas embolism.

Postmortem computed tomography angiography, contrast medium administration and toxicological analyses in urine.

Postmortem angiography methods that use water soluble or lipid soluble liquid contrast compounds may potentially modify the composition of fluid-based biological samples and thus influence toxicological findings. In this study, we investigated whether toxicological investigations performed in urine collected prior to and post angiography using Angiofil? mixed with paraffin oil are characterized by different qualitative or quantitative results. In addition, we studied whether diluting samples with 1% and 3% contrast medium solution may modify molecule concentration. A postmortem angiography group consisting of 50 cases and a postmortem group without angiography consisting of 50 cases were formed. In the first group, toxicological investigations were performed in urine samples collected prior to and post angiography as well as in undiluted and diluted samples. In the second group, analyses were performed in undiluted and diluted urine, bile, gastric content, cerebrospinal and pericardial fluids collected during autopsy. The preliminary results indicate that differences may be observed between urine samples collected prior to and post angiography in the number of identified molecules in relation to specific cases. Analyses performed in diluted samples failed to reveal differences that might potentially alter the interpretation of toxicological results in all analyzed specimens for nearly all molecules, except for tetrahydrocannabinol and its metabolites. Though these findings suggest that toxicology might be effectively performed, in very special cases and for a large number of molecules, in biological samples collected after angiography, it remains recommendable to collect biological fluids for toxicology prior to contrast medium injection.

Postmortem computed tomography angiography vs. conventional autopsy: advantages and inconveniences of each method.

PURPOSE: Postmortem computed tomography angiography (PMCTA) was introduced into forensic investigations a few years ago. It provides reliable images that can be consulted at any time. Conventional autopsy remains the reference standard for defining the cause of death, but provides only limited possibility of a second examination. This study compares these two procedures and discusses findings that can be detected exclusively using each method. MATERIALS AND METHODS: This retrospective study compared radiological reports from PMCTA to reports from conventional autopsy for 50 forensic autopsy cases. Reported findings from autopsy and PMCTA were extracted and compared to each other. PMCTA was performed using a modified heart-lung machine and the oily contrast agent Angiofil® (Fumedica AG, Muri, Switzerland). RESULTS: PMCTA and conventional autopsy would have drawn similar conclusions regarding causes of death. Nearly 60 % of all findings were visualized with both techniques. PMCTA demonstrates a higher sensitivity for identifying skeletal and vascular lesions. However, vascular occlusions due to postmortem blood clots could be falsely assumed to be vascular lesions. In contrast, conventional autopsy does not detect all bone fractures or the exact source of bleeding. Conventional autopsy provides important information about organ morphology and remains the only way to diagnose a vital vascular occlusion with certitude. CONCLUSION: Overall, PMCTA and conventional autopsy provide comparable findings. However, each technique presents advantages and disadvantages for detecting specific findings. To correctly interpret findings and clearly define the indications for PMCTA, these differences must be understood.

Evaluation of postmortem MDCT and MDCT-angiography for the investigation of sudden cardiac death related to atherosclerotic coronary artery disease.

The goal of this study was to evaluate the diagnostic value of postmortem multi-computed tomography (MDCT) and MDCT-angiography for sudden cardiac deaths related to ischemic heart disease. Twenty three cases were selected based on clinical history and the results of native MDCT, multiphase post-mortem CT-angiography and conventional autopsy were compared. Radiological examination showed calcification of coronary arteries in 78% of the cases, most of which were not detailed at autopsy. MDCT-angiography allowed better visualization of the coronary arteries than MDCT and permitted the evaluation of stenoses and occlusions. Of the 14 cases of coronary thrombosis detected at conventional autopsy, 11 were visible as stop of perfusion with CT-angiography and three were found to be partly perfused. One case had an old thrombosis with collateral circulation. One case had a coronary artery postmortem clot found with MDCT-angiography. Coronary artery calcifications are more easily detected and documented with radiological examination than with conventional autopsy. MDCT is of limited diagnostic value for ischemic heart disease. MDCT-angiography, when correctly interpreted, is a reasonable tool to view the morphology of coronary arteries, rule out significant coronary artery stenoses, identify occlusions and direct sampling for histological examination.

Usefulness of postmortem biochemistry in forensic pathology: illustrative case reports.

The aim of this work is to present some practical, postmortem biochemistry applications to illustrate the usefulness of this discipline and reassert the importance of carrying out biochemical investigations as an integral part of the autopsy process. Five case reports are presented pertaining to diabetic ketoacidosis in an adult who was not known to suffer from diabetes and in presence of multiple psychotropic substances; fatal flecainide intoxication in a poor metabolizer also presenting an impaired renal function; diabetic ketoacidosis showing severe postmortem changes; primary aldosteronism presented with intracranial hemorrhage and hypothermia showing severe postmortem changes. The cases herein presented can be considered representative examples of the importance of postmortem biochemistry investigations, which may provide significant information useful in determining the cause of death in routine forensic casework or contribute to understanding the pathophysiological mechanisms involved in the death process.

Postmortem findings in bone cement implantation syndrome-related deaths.

Several mechanisms have been postulated as potentially involved in life-threatening complications during cemented surgery. In this study, we evaluated the role of anaphylaxis and pulmonary fat embolism in the pathophysiology of bone cement implantation syndrome in a series of fatal cases that underwent medicolegal investigations. Postmortem findings in these cases were compared with those obtained from individuals who died after other injuries and/or interventions and in which activated mast cells and pulmonary fat embolism were involved in the pathogenesis of death. Fifty subjects were selected including 6 individuals who had undergone cemented total hip arthroplasty and died intraoperatively, 32 subjects who died shortly after being involved in traffic accidents, 8 individuals who died shortly after the injection of contrast material, and 4 subjects who had undergone orthopedic surgery and died postoperatively. Massive pulmonary fat embolism was determined to be the cause of death in all the 6 subjects who died intraoperatively as well as the main cause of death in traffic-road victims with rapid respiratory function deterioration. Mast cell activation was identified exclusively in the group of subjects who died shortly after contrast material administration. Massive pulmonary fat embolism appears to be the most important factor responsible for severe cardiorespiratory function deterioration during cemented arthroplasty. Cardiac comorbidities can also significantly influence the severity of intraoperative complications, thus corroborating the hypothesis of a multifactorial model in the pathogenesis of bone cement implantation syndrome.

Diagnostic value of soluble CD14 subtype (sCD14-ST) presepsin for the postmortem diagnosis of sepsis-related fatalities.

The first aim of this study was to assess the diagnostic performance of presepsin (sCD14-ST) in postmortem serum from femoral blood compared to procalcitonin (PCT) to detect sepsis-related fatalities. The second aim was to compare sCD14-ST levels found in postmortem serum to the values in pericardial fluid to investigate the usefulness of the latter as an alternative biological fluid. Two study groups were formed, a sepsis-related fatalities group and a control group. Radiology (unenhanced CT scans and postmortem angiographies), autopsies, histology, neuropathology, and toxicology as well as other postmortem biochemistry investigations were performed in all cases. Microbiological investigations on right cardiac blood were carried out exclusively in septic cases. The results of this study indicated that postmortem serum PCT and sCD14-ST levels, individually considered, allowed septic cases to be identified. Even though increases in both PCT and sCD14-ST concentrations were observed in the control cases, coherent PCT and sCD14-ST results in cases with suspected sepsis allowed the diagnosis to be confirmed. Conversely, no relevant correlation was identified between postmortem serum and pericardial fluid sCD14-ST levels in either the septic or control groups.

Increased α2- and β1-adrenoceptor densities in postmortem brain of subjects with depression: differential effect of antidepressant treatment.

BACKGROUND: Brain α2- and β-adrenoceptor alterations have been suggested in suicide and major depressive disorder. METHODS: The densities of α2-, β1- and β2-adrenoceptors in postmortem prefrontal cortex of 26 subjects with depression were compared with those of age-, gender- and postmortem delay-matched controls. The effect of antidepressant treatment on α2- and β-adrenoceptor densities was also evaluated. α2- and β-adrenoceptor densities were measured by saturation experiments with respective radioligands [(3)H]UK14304 and [(3)H]CGP12177. β1- and β2-adrenoceptor subtype densities were dissected by means of β1-adrenoceptor selective antagonist CGP20712A. RESULTS: Both, α2- and β1-adrenoceptors densities were higher in antidepressant-free depressed subjects (n=14) than those in matched controls (Δ~24%, p=0.013 and Δ~20%, p=0.044, respectively). In antidepressant-treated subjects (n=12), α2-adrenoceptor density remained increased over that in controls (Δ~20%), suggesting a resistance of α2-adrenoceptors to the down-regulatory effect of antidepressants. By contrast, β1-adrenoceptor density in antidepressant-treated depressed subjects was not different from controls, suggesting a possible down-regulation by antidepressants. The down-regulation of β1-adrenoceptor density in antidepressant-treated depressed subjects differs from the unaltered β1-adrenoceptor density observed in citalopram-treated rats and in a group of non-depressed subjects also treated with antidepressants (n=6). β2-adrenoceptor density was not altered in depressed subjects independently of treatment. LIMITATIONS: Antidepressant-treated subjects had been treated with a heterogeneous variety of antidepressant drugs. The results should be understood in the context of suicide victims with depression. CONCLUSIONS: These results show the up-regulation of brain α2- and β1-adrenoceptors in depression and suggest that the regulation induced by chronic antidepressant treatment would be altered in these subjects.

Postmortem circulation: a new model for testing endovascular devices and training clinicians in their use.

The development of new medical devices, such as aortic valves, requires numerous preliminary studies on animals and training of personnel on cadavers before the devices can be used in patients. Postmortem circulation, a technique used for postmortem angiography, allows the vascular system to be reperfused in a way similar to that in living persons. This technique is used for postmortem investigations to visualize the human vascular system and to make vascular diagnoses. Specific material for reperfusing a human body was developed recently. Our aim was to investigate whether postmortem circulation that imitates in vivo conditions allows for the testing of medical materials on cadavers. We did this by delivering an aortic valve using minimally invasive methods. Postmortem circulation was established in eight corpses to recreate an environment as close as possible to in vivo conditions. Mobile fluoroscopy and a percutaneous catheterization technique were used to deliver the material to the correct place. Once the valve was implanted, the heart and primary vessels were extracted to confirm its position. Postmortem circulation proved to be essential in several of the cadavers because it helped the clinicians to deliver the material and improve their implantation techniques. Due to the intravascular circulation, sites with substantial arteriosclerotic stenosis could be bypassed, which would have been impossible without perfusion. Although originally developed for postmortem investigations, this reperfusion technique could be useful for testing new medical devices intended for living patients.

High-mobility group box-1 protein determination in postmortem samples.

The aims of this study were to assess whether high-mobility group box-1 protein can be determined in biological fluids collected during autopsy and evaluate the diagnostic potential of high-mobility group box-1 protein in identifying sepsis-related deaths. High-mobility group box-1 protein was measured in serum collected during hospitalization as well as in undiluted and diluted postmortem serum and pericardial fluid collected during autopsy in a group of sepsis-related deaths and control cases with noninfectious causes of death. Inclusion criteria consisted of full biological sample availability and postmortem interval not exceeding 6h. The preliminary results indicate that high-mobility group box-1 protein levels markedly increase after death. Concentrations beyond the upper limit of the calibration curve were obtained in undiluted postmortem serum in septic and traumatic control cases. In pericardial fluid, concentrations beyond the upper limit of the calibration curve were found in all cases. These findings suggest that the diagnostic potential of high-mobility group box-1 protein in the postmortem setting is extremely limited due to molecule release into the bloodstream after death, rendering antemortem levels difficult or impossible to estimate even after sample dilution.