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Silke Grabherr - One of the best experts on this subject based on the ideXlab platform.
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Post-Mortem Forensic Imaging
P5 Medicine and Justice, 2017Co-Authors: Fabrice Dedouit, Lorenzo Campana, Tanya Uldin, Silke GrabherrAbstract:For autopsies, in addition to classical non-enhanced post-mortem computed tomographies, (PMCT), an innovative technique consists in post-mortem vascular opacification. It is called post-mortem computed tomography angiography (PMCTA) and the most widespread method is multiphase PMCTA (MPMCTA). It permits the diagnosis and characterization of vascular lesions. Another radiological technique is the post-mortem magnetic resonance Imaging (PMMR). Its great advantage is the optimal spontaneous inter-tissular contrast. The development of PMMR angiography (PMMRA) seems to be promising for post-mortem cardio-vascular explorations. 3D surface scanning combined with photogrammetry permits the documentation of information such as texture and colour, which may be combined with PMCT reconstructions, the surface scanning of objects or the environment of a deceased person, to perform virtual reconstitutions of the events. In Forensic anthropology, PMCT is also very useful for identification purposes (comparative, reconstructive and lesional identification).
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How to Create a Functional Imaging Team
Atlas of Postmortem Angiography, 2016Co-Authors: Jochen Grimm, Silke GrabherrAbstract:When considering starting a Forensic Imaging department, two things are indispensable: Imaging equipment and the personnel to perform the Imaging and interpret the images. Both may prove more or less difficult to obtain. This chapter will focus on the creation of a well-working postmortem Imaging team (Fig. 35.1).
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Future Prospects of Forensic Imaging
Atlas of Postmortem Angiography, 2016Co-Authors: Jochen Grimm, Silke GrabherrAbstract:Postmortem radiology has experienced a recent surge of interest in the last decade, primarily from those engaged in Forensic pathology. The technology most frequently applied is postmortem computed tomography (PMCT). Technologies and ideas have been emerging ever since, aiming at overcoming PMCT’s principal drawbacks: low soft tissue contrast and lack of vascular visualization. These efforts are likely to continue, and promising approaches are at hand.
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virtual versus real Forensic Imaging procedures application fields advantages and limits virtuelle vs reale forensische bildgebende verfahren einsatzgebiete vorteile und limits
Rechtsmedizin, 2015Co-Authors: Silke Grabherr, Patrice Mangin, P. Baumann, Stella Fahrni, J GrimmAbstract:Bildgebende Verfahren haben einen steigenden, wenn auch umstrittenen Stellenwert in der Rechtsmedizin. Dies liegt v. a. an uneinheitlichen und unklaren Definitionen, die derzeit im Umlauf sind. Ziel dieses Beitrags ist es, die in der forensischen Medizin eingesetzten bildgebenden Verfahren genau zu beleuchten und die verschiedenen ihr zugehorigen Techniken zu erlautern. Im Wesentlichen sind dies radiologische Methoden wie konventionelles Rontgen, Computertomographie und Magnetresonanztomographie, aber auch andere Techniken, wie das 3D-Oberflachen-Scanning. Diese Basismethoden konnen durch die Kombination mit minimalinvasiven Eingriffen erweitert werden. Beispiele hierfur sind die postmortale Angiographie und die bildgesteuerte Probenentnahme. Jede dieser Methoden hat ihre Vor- und Nachteile. Die Aussagekraft der jeweiligen Untersuchung hangt davon ab, welche Technik(en) angewendet wurde(n), und von der Ausbildung bzw. Erfahrung der Personen, die sie durchfuhren und die Bilder interpretieren.
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Investigation of Postmortem Gases: A Forensic Imaging and Analytical Chemistry Approach
2014Co-Authors: N. Giuliani, Silke Grabherr, Alejandro Dominguez, Coraline Egger, Christine Chevallier, Vincent VarletAbstract: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 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.
Michael J. Thali - One of the best experts on this subject based on the ideXlab platform.
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Value of monoenergetic dual-energy CT (DECT) for artefact reduction from metallic orthopedic implants in post-mortem studies
Skeletal Radiology, 2015Co-Authors: Laura Filograna, Michael J. Thali, Nicola Magarelli, Antonio Leone, Roman Guggenberger, Sebastian Winklhofer, Lorenzo BonomoAbstract:Objectives The aim of this ex vivo study was to assess the performance of monoenergetic dual-energy CT (DECT) reconstructions to reduce metal artefacts in bodies with orthopedic devices in comparison with standard single-energy CT (SECT) examinations in Forensic Imaging. Forensic and clinical impacts of this study are also discussed. Materials and methods Thirty metallic implants in 20 consecutive cadavers with metallic implants underwent both SECT and DECT with a clinically suitable scanning protocol. Extrapolated monoenergetic DECT images at 64, 69, 88, 105, 120, and 130 keV and individually adjusted monoenergy for optimized image quality (OPTkeV) were generated. Image quality of the seven monoenergetic images and of the corresponding SECT image was assessed qualitatively and quantitatively by visual rating and measurements of attenuation changes induced by streak artefact. Results Qualitative and quantitative analyses showed statistically significant differences between monoenergetic DECT extrapolated images and SECT, with improvements in diagnostic assessment in monoenergetic DECT at higher monoenergies. The mean value of OPTkeV was 137.6 ± 4.9 with a range of 130 to 148 keV. Conclusions This study demonstrates that monoenergetic DECT images extrapolated at high energy levels significantly reduce metallic artefacts from orthopedic implants and improve image quality compared to SECT examination in Forensic Imaging.
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Forensic Imaging in an unusual postmortem case of sigmoid volvulus
Journal of forensic radiology and imaging, 2015Co-Authors: Rilana Baumeister, Michael J. Thali, Stephan A Bolliger, Saskia Gauthier, Steffen RossAbstract:Sigmoid volvulus (SV) is the most common form of intestinal volvulus. It results from a twist at the base of the sigmoid mesentery. The twist causes obstruction of the large bowel and ischemia of the affected portion of the intestine, resulting in necrosis of the intestinal wall, acidosis and subsequent death. While clinical symptoms may vary, they usually include typical signs of a small bowel obstruction, such as nausea, vomiting, and constipation. Some cases of sigmoid volvulus can be more or less clinically silent. Typical radiologic signs of SV are the so-called split-wall sign, the coffee bean sign and the whirlpool sign. In this report, we present the diagnosis of SV in a deceased 52-year-old female, who presented none of the aforementioned clinical key symptoms, using post-mortem computed tomography (PMCT). PMCT examination showed the typical radiologic signs of SV. The findings from the cross-sectional Imaging were validated with a traditional autopsy.
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Forensic Imaging findings by post mortem computed tomography after manual versus mechanical chest compression
Journal of forensic radiology and imaging, 2015Co-Authors: Rilana Baumeister, Patricia M. Flach, Michael J. Thali, Ulrike Held, Steffen RossAbstract:Abstract Objectives The aim of this study was to compare the injuries observed after cardiopulmonary resuscitation ( 1 CPR) by means of standard or assisted chest compression by the Lund University Cardiopulmonary Assist System ( 2 LUCAS™2) device visualized by post-mortem computed tomography ( 3 PMCT). Materials and methods A retrospective study was conducted that included 44 cases delivered to our institution following CPR before death. All bodies underwent PMCT. The case group was divided into two groups: one group that underwent manual and one group that underwent mechanical CPR with the LUCAS™2 device. The main traumatic findings associated with CPR were reported, and a statistical evaluation was performed. Results The LUCAS group comprised 24 cases, the manual group 20 cases. Rib fractures were the most frequent injury in both groups. A mean of 10.38 rib fractures per case was observed in the LUCAS group, and 10.40 fractures were observed in the manual group ( p =0.999). Subcutaneous pre-sternal hematomas were described in 15/24 patients in the LUCAS group and in 6/20 patients in the manual group. The frequency of sternal factures was similar in both groups. A few trauma injuries to internal organs (i.e., retrosternal, perihepatic, and retroperitoneal hematomas and lung contusion) were recorded in both groups. Conclusion PMCT is useful for evaluating injuries related to CPR. LUCAS™2-CPR has a greater association with subcutaneous pre-sternal hematomas than standard CPR. There is no further significant difference in the incidence of injuries between mechanical and manual chest compression. From a Forensic point of view, it is important to identify CPR-related injuries.
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postmortem ventilation a new method for improved detection of pulmonary pathologies in Forensic Imaging
Legal Medicine, 2012Co-Authors: Tanja Germerott, Steffen Ross, Patricia M. Flach, Ulrich Preiss, Michael J. ThaliAbstract:Abstract Postmortem Imaging has gained prominence in the field of Forensic pathology. Even with experience in this procedure, difficulties arise in evaluating pathologies of the postmortem lung. The effect of postmortem ventilation with applied pressures of 10, 20, 30 and 40mbar was evaluated in 10 corpses using simultaneous postmortem computed tomography (pmCT) scans. Ventilation was performed via a continuous positive airway pressure mask ( n =5), an endotracheal tube ( n =4) and a laryngeal mask ( n =1) using a portable home care ventilator. The lung volumes were measured and evaluated by a segmentation technique based on reconstructed CT data. The resulting changes to the lungs were analyzed. Postmortem ventilation at 40mbar induced a significant ( p p In conclusion, postmortem ventilation is a feasible method for improving evaluation of the lungs and detection of small lung pathologies. This is because of the volume increase in the air-filled portions of the lung and reduced appearance of inner livores.
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postmortem ventilation a new method for improved detection of pulmonary pathologies in Forensic Imaging
Legal Medicine, 2012Co-Authors: Tanja Germerott, Steffen Ross, Patricia M. Flach, Ulrich Preiss, Michael J. ThaliAbstract:Postmortem Imaging has gained prominence in the field of Forensic pathology. Even with experience in this procedure, difficulties arise in evaluating pathologies of the postmortem lung. The effect of postmortem ventilation with applied pressures of 10, 20, 30 and 40 mbar was evaluated in 10 corpses using simultaneous postmortem computed tomography (pmCT) scans. Ventilation was performed via a continuous positive airway pressure mask (n=5), an endotracheal tube (n=4) and a laryngeal mask (n=1) using a portable home care ventilator. The lung volumes were measured and evaluated by a segmentation technique based on reconstructed CT data. The resulting changes to the lungs were analyzed. Postmortem ventilation at 40 mbar induced a significant (p<0.05) unfolding of the lungs, with a mean volume increase of 1.32 l. Small pathologies of the lung such as scarring and pulmonary nodules as well as emphysema were revealed, while inner livores were reduced. Even though lower ventilation pressures resulted in a significant (p<0.05) volume increase, pathologies were best evaluated when a pressure of 40 mbar was applied, due to the greater reduction of the inner livores. With the ventilation-induced expansion of the lungs, a decrease in the heart diameter and gaseous distension of the stomach was recognized. In conclusion, postmortem ventilation is a feasible method for improving evaluation of the lungs and detection of small lung pathologies. This is because of the volume increase in the air-filled portions of the lung and reduced appearance of inner livores.
Steffen Ross - One of the best experts on this subject based on the ideXlab platform.
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Forensic Imaging in an unusual postmortem case of sigmoid volvulus
Journal of forensic radiology and imaging, 2015Co-Authors: Rilana Baumeister, Michael J. Thali, Stephan A Bolliger, Saskia Gauthier, Steffen RossAbstract:Sigmoid volvulus (SV) is the most common form of intestinal volvulus. It results from a twist at the base of the sigmoid mesentery. The twist causes obstruction of the large bowel and ischemia of the affected portion of the intestine, resulting in necrosis of the intestinal wall, acidosis and subsequent death. While clinical symptoms may vary, they usually include typical signs of a small bowel obstruction, such as nausea, vomiting, and constipation. Some cases of sigmoid volvulus can be more or less clinically silent. Typical radiologic signs of SV are the so-called split-wall sign, the coffee bean sign and the whirlpool sign. In this report, we present the diagnosis of SV in a deceased 52-year-old female, who presented none of the aforementioned clinical key symptoms, using post-mortem computed tomography (PMCT). PMCT examination showed the typical radiologic signs of SV. The findings from the cross-sectional Imaging were validated with a traditional autopsy.
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Forensic Imaging findings by post mortem computed tomography after manual versus mechanical chest compression
Journal of forensic radiology and imaging, 2015Co-Authors: Rilana Baumeister, Patricia M. Flach, Michael J. Thali, Ulrike Held, Steffen RossAbstract:Abstract Objectives The aim of this study was to compare the injuries observed after cardiopulmonary resuscitation ( 1 CPR) by means of standard or assisted chest compression by the Lund University Cardiopulmonary Assist System ( 2 LUCAS™2) device visualized by post-mortem computed tomography ( 3 PMCT). Materials and methods A retrospective study was conducted that included 44 cases delivered to our institution following CPR before death. All bodies underwent PMCT. The case group was divided into two groups: one group that underwent manual and one group that underwent mechanical CPR with the LUCAS™2 device. The main traumatic findings associated with CPR were reported, and a statistical evaluation was performed. Results The LUCAS group comprised 24 cases, the manual group 20 cases. Rib fractures were the most frequent injury in both groups. A mean of 10.38 rib fractures per case was observed in the LUCAS group, and 10.40 fractures were observed in the manual group ( p =0.999). Subcutaneous pre-sternal hematomas were described in 15/24 patients in the LUCAS group and in 6/20 patients in the manual group. The frequency of sternal factures was similar in both groups. A few trauma injuries to internal organs (i.e., retrosternal, perihepatic, and retroperitoneal hematomas and lung contusion) were recorded in both groups. Conclusion PMCT is useful for evaluating injuries related to CPR. LUCAS™2-CPR has a greater association with subcutaneous pre-sternal hematomas than standard CPR. There is no further significant difference in the incidence of injuries between mechanical and manual chest compression. From a Forensic point of view, it is important to identify CPR-related injuries.
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postmortem ventilation a new method for improved detection of pulmonary pathologies in Forensic Imaging
Legal Medicine, 2012Co-Authors: Tanja Germerott, Steffen Ross, Patricia M. Flach, Ulrich Preiss, Michael J. ThaliAbstract:Abstract Postmortem Imaging has gained prominence in the field of Forensic pathology. Even with experience in this procedure, difficulties arise in evaluating pathologies of the postmortem lung. The effect of postmortem ventilation with applied pressures of 10, 20, 30 and 40mbar was evaluated in 10 corpses using simultaneous postmortem computed tomography (pmCT) scans. Ventilation was performed via a continuous positive airway pressure mask ( n =5), an endotracheal tube ( n =4) and a laryngeal mask ( n =1) using a portable home care ventilator. The lung volumes were measured and evaluated by a segmentation technique based on reconstructed CT data. The resulting changes to the lungs were analyzed. Postmortem ventilation at 40mbar induced a significant ( p p In conclusion, postmortem ventilation is a feasible method for improving evaluation of the lungs and detection of small lung pathologies. This is because of the volume increase in the air-filled portions of the lung and reduced appearance of inner livores.
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postmortem ventilation a new method for improved detection of pulmonary pathologies in Forensic Imaging
Legal Medicine, 2012Co-Authors: Tanja Germerott, Steffen Ross, Patricia M. Flach, Ulrich Preiss, Michael J. ThaliAbstract:Postmortem Imaging has gained prominence in the field of Forensic pathology. Even with experience in this procedure, difficulties arise in evaluating pathologies of the postmortem lung. The effect of postmortem ventilation with applied pressures of 10, 20, 30 and 40 mbar was evaluated in 10 corpses using simultaneous postmortem computed tomography (pmCT) scans. Ventilation was performed via a continuous positive airway pressure mask (n=5), an endotracheal tube (n=4) and a laryngeal mask (n=1) using a portable home care ventilator. The lung volumes were measured and evaluated by a segmentation technique based on reconstructed CT data. The resulting changes to the lungs were analyzed. Postmortem ventilation at 40 mbar induced a significant (p<0.05) unfolding of the lungs, with a mean volume increase of 1.32 l. Small pathologies of the lung such as scarring and pulmonary nodules as well as emphysema were revealed, while inner livores were reduced. Even though lower ventilation pressures resulted in a significant (p<0.05) volume increase, pathologies were best evaluated when a pressure of 40 mbar was applied, due to the greater reduction of the inner livores. With the ventilation-induced expansion of the lungs, a decrease in the heart diameter and gaseous distension of the stomach was recognized. In conclusion, postmortem ventilation is a feasible method for improving evaluation of the lungs and detection of small lung pathologies. This is because of the volume increase in the air-filled portions of the lung and reduced appearance of inner livores.
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Getting in touch--3D printing in Forensic Imaging.
Forensic science international, 2011Co-Authors: Lars Chr Ebert, Michael J. Thali, Steffen RossAbstract:With the increasing use of medical Imaging in Forensics, as well as the technological advances in rapid prototyping, we suggest combining these techniques to generate displays of Forensic findings. We used computed tomography (CT), CT angiography, magnetic resonance Imaging (MRI) and surface scanning with photogrammetry in conjunction with segmentation techniques to generate 3D polygon meshes. Based on these data sets, a 3D printer created colored models of the anatomical structures. Using this technique, we could create models of bone fractures, vessels, cardiac infarctions, ruptured organs as well as bitemark wounds. The final models are anatomically accurate, fully colored representations of bones, vessels and soft tissue, and they demonstrate radiologically visible pathologies. The models are more easily understood by laypersons than volume rendering or 2D reconstructions. Therefore, they are suitable for presentations in courtrooms and for educational purposes.
S. Malbranque - One of the best experts on this subject based on the ideXlab platform.
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Helium poisoning: new procedure for sampling and analysis
International Journal of Legal Medicine, 2019Co-Authors: Vincent Varlet, O. Cordes, V. Dumestre-toulet, Fabien Bévalot, Hilke Andresen-streichert, S. Iwersen-bergmann, Cora Wunder, F. Holz, M Alexandre, S. MalbranqueAbstract:An increasing number of suicidal asphyxiation with a plastic bag with inert gases, and in particular helium (He), have been reported from numerous countries over the last decade. These cases are differently managed and lead to different and variable interpretations. Based on the 12 last cases analysed in the laboratory and on the review of the most recent literature about this topic, updated autopsy guidelines for sampling have been proposed regarding to the samples choice and analytical challenges required by the gaseous state of this substance. Biological samples from airways (lungs lobe) followed by brain and cardiac blood are the best matrices to take during the autopsy to diagnose He exposure. Gaseous samples from trachea, pulmonary bronchi, gastric and cardiac areas are also recommended as alternative samples. The anatomical site of sampling must be carefully detailed, and to this end, Forensic Imaging constitutes a beneficial tool. Even if He detection is sufficient to conclude to He exposure, He concentrations in samples may be related to He exposure conditions (duration, breathing rate, etc.). A quantification in biological samples could be helpful to document more precisely the case. He concentrations in gaseous samples are reported up to 6.0 μmol/mL (tracheal gas), 2.4 μmol/mL (pulmonary gas), 0.64 μmol/mL (cardiac gas) and 12 μmol/mL (gastric gas). He concentrations in solid/liquid samples are reported up to 28 μmol/g (lungs) and 0.03 μmol/g (cardiac blood). The other matrices usually sampled during autopsy such as urine, peripheral blood, liver, fat matter and kidney appear as not relevant.
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Helium poisoning: new procedure for sampling and analysis
International Journal of Legal Medicine, 2019Co-Authors: Vincent Varlet, O. Cordes, V. Dumestre-toulet, Fabien Bévalot, Hilke Andresen-streichert, S. Iwersen-bergmann, Cora Wunder, F. Holz, M Alexandre, S. MalbranqueAbstract:An increasing number of suicidal asphyxiation with a plastic bag with inert gases, and in particular helium (He), have been reported from numerous countries over the last decade. These cases are differently managed and lead to different and variable interpretations. Based on the 12 last cases analysed in the laboratory and on the review of the most recent literature about this topic, updated autopsy guidelines for sampling have been proposed regarding to the samples choice and analytical challenges required by the gaseous state of this substance. Biological samples from airways (lungs lobe) followed by brain and cardiac blood are the best matrices to take during the autopsy to diagnose He exposure. Gaseous samples from trachea, pulmonary bronchi, gastric and cardiac areas are also recommended as alternative samples. The anatomical site of sampling must be carefully detailed, and to this end, Forensic Imaging constitutes a beneficial tool. Even if He detection is sufficient to conclude to He exposure, He concentrations in samples may be related to He exposure conditions (duration, breathing rate, etc.). A quantification in biological samples could be helpful to document more precisely the case. He concentrations in gaseous samples are reported up to 6.0 μmol/mL (tracheal gas), 2.4 μmol/mL (pulmonary gas), 0.64 μmol/mL (cardiac gas) and 12 μmol/mL (gastric gas). He concentrations in solid/liquid samples are reported up to 28 μmol/g (lungs) and 0.03 μmol/g (cardiac blood). The other matrices usually sampled during autopsy such as urine, peripheral blood, liver, fat matter and kidney appear as not relevant.
Vincent Varlet - One of the best experts on this subject based on the ideXlab platform.
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Helium poisoning: new procedure for sampling and analysis
International Journal of Legal Medicine, 2019Co-Authors: Vincent Varlet, O. Cordes, V. Dumestre-toulet, Fabien Bévalot, Hilke Andresen-streichert, S. Iwersen-bergmann, Cora Wunder, F. Holz, M Alexandre, S. MalbranqueAbstract:An increasing number of suicidal asphyxiation with a plastic bag with inert gases, and in particular helium (He), have been reported from numerous countries over the last decade. These cases are differently managed and lead to different and variable interpretations. Based on the 12 last cases analysed in the laboratory and on the review of the most recent literature about this topic, updated autopsy guidelines for sampling have been proposed regarding to the samples choice and analytical challenges required by the gaseous state of this substance. Biological samples from airways (lungs lobe) followed by brain and cardiac blood are the best matrices to take during the autopsy to diagnose He exposure. Gaseous samples from trachea, pulmonary bronchi, gastric and cardiac areas are also recommended as alternative samples. The anatomical site of sampling must be carefully detailed, and to this end, Forensic Imaging constitutes a beneficial tool. Even if He detection is sufficient to conclude to He exposure, He concentrations in samples may be related to He exposure conditions (duration, breathing rate, etc.). A quantification in biological samples could be helpful to document more precisely the case. He concentrations in gaseous samples are reported up to 6.0 μmol/mL (tracheal gas), 2.4 μmol/mL (pulmonary gas), 0.64 μmol/mL (cardiac gas) and 12 μmol/mL (gastric gas). He concentrations in solid/liquid samples are reported up to 28 μmol/g (lungs) and 0.03 μmol/g (cardiac blood). The other matrices usually sampled during autopsy such as urine, peripheral blood, liver, fat matter and kidney appear as not relevant.
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Helium poisoning: new procedure for sampling and analysis
International Journal of Legal Medicine, 2019Co-Authors: Vincent Varlet, O. Cordes, V. Dumestre-toulet, Fabien Bévalot, Hilke Andresen-streichert, S. Iwersen-bergmann, Cora Wunder, F. Holz, M Alexandre, S. MalbranqueAbstract:An increasing number of suicidal asphyxiation with a plastic bag with inert gases, and in particular helium (He), have been reported from numerous countries over the last decade. These cases are differently managed and lead to different and variable interpretations. Based on the 12 last cases analysed in the laboratory and on the review of the most recent literature about this topic, updated autopsy guidelines for sampling have been proposed regarding to the samples choice and analytical challenges required by the gaseous state of this substance. Biological samples from airways (lungs lobe) followed by brain and cardiac blood are the best matrices to take during the autopsy to diagnose He exposure. Gaseous samples from trachea, pulmonary bronchi, gastric and cardiac areas are also recommended as alternative samples. The anatomical site of sampling must be carefully detailed, and to this end, Forensic Imaging constitutes a beneficial tool. Even if He detection is sufficient to conclude to He exposure, He concentrations in samples may be related to He exposure conditions (duration, breathing rate, etc.). A quantification in biological samples could be helpful to document more precisely the case. He concentrations in gaseous samples are reported up to 6.0 μmol/mL (tracheal gas), 2.4 μmol/mL (pulmonary gas), 0.64 μmol/mL (cardiac gas) and 12 μmol/mL (gastric gas). He concentrations in solid/liquid samples are reported up to 28 μmol/g (lungs) and 0.03 μmol/g (cardiac blood). The other matrices usually sampled during autopsy such as urine, peripheral blood, liver, fat matter and kidney appear as not relevant.
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Investigation of Postmortem Gases: A Forensic Imaging and Analytical Chemistry Approach
2014Co-Authors: N. Giuliani, Silke Grabherr, Alejandro Dominguez, Coraline Egger, Christine Chevallier, Vincent VarletAbstract: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 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.