Postmortem chest computed tomography for the diagnosis of drowning:a feasibility study

It may be difficult to distinguish the cause of death in drowning cases without specific findings. The aim of this study was to explore the forensic value of thoracic postmortem computed tomography (PMCT) using routine images and three-dimensional (3D) image reconstructions. The imaging data of PMCT examinations of six drowning cadavers, aged 21–54 years, were analyzed. Twelve victims of sudden death from coronary artery disease (CAD) were chosen as a control group. After 3D bilateral lung images were reconstructed using image processing software, an interactive medical image control system was used to measure and analyze parameters including lung volume, lung volume ratio, mean CT value of the whole lung, and lung CT value distribution curves. Lung volume and lung volume ratio were used to assess the shape changes of the lung. Lung CT value distribution curves showed the corresponding number of pixels of the different CT values in the lung image. Lung volume was not significantly larger in drowning cases (mean 2 958 cm³) than in controls (mean 2 342 cm³). Lung volume ratio values in the drowning group (mean 0.3156) were greater than those in the control group (mean 0.2763); (P = 0.02). There was no significant difference between the drowning and control group in the mean CT value of the whole lung. There were differences between lung CT value distribution curves in drowning victims and controls, with drowning victims showing a single peak and CAD cases showing a bimodal distribution. Thoracic PMCT is helpful for the forensic medical diagnosis of drowning. Lung volume ratio and lung CT value distribution are potential indicators to distinguish between drowning and CAD.     

Forensic toxicological study on adipocere formation in submerged cadavers of female albino rats intoxicated with cadmium

There is a dearth of information on the mutual interaction between metal intoxication and adipocere formation. Herein, 40 adult female albino rats were distributed into two equal groups, one used as control while the other orally administered single dose of cadmium chloride (CdCl₂) 225 mg/kg·bw (LD_min). Control group was killed by cervical dislocation. Half of dead rats of both groups were subjected for determination of iodine value and estimation of cadmium (Cd) residues while the other half of both groups were submerged in opened glass container previously filled with 4 L dechlorinated tap water kept in closed room with an open air access (one cadaver/container). Gross morphological changes of submerged cadavers were recorded weekly along the experiment. At the end of the experiment, after 3 months, samples were collected again for iodine value determination and estimation of Cd residues. The obtained results revealed the depressant effect of Cd toxicity on development of adipocere. Cd residues were found in different tissues of cadavers at time of death with the highest amount in the intestines followed by the liver and kidneys, then lungs, adipose tissue, muscles, and finally the bones. After 3 months of water submersion, tissues exhibited significant decrease in the amount of Cd residues but to a limit that was still detected. This study concluded the possibility of detection of Cd residues even after adipocere formation. Additionally, it shed light on the possibility of the interference of environmental pollution with the natural rate of decomposition especially adipocere formation.     

多层螺旋CT检查在尸体颈椎损伤中的应用

对需要在尸体检验时进行颈椎多层螺旋CT(MSCT)检查的情形进行讨论,研究利用MSCT对疑有颈椎损伤的尸体进行颈椎检查的方法,并对一例疑似颈椎损伤尸体的颈椎提取后进行MSCT检查。发现对疑似有颈椎骨折尸体提取颈椎进行MSCT检查,可以快速精确地显示颈椎的细微骨折及骨折的空间分布,从而推断致伤方式。解决了传统尸检中费时费力,容易漏诊和误诊的问题。     

Significant Differences in PostMortem Heart Weight Before and After Dissection Using the Short-Axis Dissecting Method

Correctly assessing heart weight can be critical at postmortem examination. The current international guidelines advocate using the short-axis method in dissecting the heart and the heart weighed when the blood is emptied. However, it did not specify at what point the heart should be weighed or how the blood should be emptied. This study compared heart weights at three different time points during the heart examination (immediately after dissecting out of the pericardial sac with blood still in chambers, blood washed/removed from heart chambers without the heart opened, and the heart completely opened, blood emptied, and pad dried). This was to illustrate the variation in measurement and potential errors when the heart is weighed at different time of dissection. The results show that there were statistical and clinical significant differences between the heart weights at each weighing points. We recommend the heart to be completely dissected with any blood and residual washing/rinsing water emptied before being weighed. Although performed in this study, the effect of pad drying the heart on heart weight was not explored and was a limitation in this study.     

Postmortem Computed Tomography in Firearm Homicides: A Retrospective Case Series,

Postmortem computed tomography (PMCT) is integrated into the evaluation of decedents in several American medical examiner offices and medicolegal death investigative centers in many other countries. We retrospectively investigated the value of PMCT in a series of firearm homicide cases from a statewide centralized medical examiner’s office that occurred during 2016. Autopsies were performed or supervised by board-certified forensic pathologists who reviewed the PMCT scans prior to autopsy. PMCT scans were re-evaluated by a forensic radiologist blinded to the autopsy findings and scored by body region (head–neck, thoracoabdominal, and extremities). Injury discrepancies were scored using a modified Goldman classification and analyzed with McNemar’s test. We included 60 males and 20 females (median age 31 years, range 3–73). Based on PMCT, 56 (79.1%) cases had injuries relevant to the cause of death in a single body region (24 head–neck region, 32 thoracoabdominal region). Out of these 56 cases, 9 had a missed major diagnosis by PMCT outside that region, including 6 extremity injuries visible during standard external examination. Yet all had evident lethal firearm injury. We showed that PMCT identifies major firearm injuries in homicide victims and excludes injuries related to the cause of death in other regions when a single body region is injured. Although PMCT has a known limited sensitivity for soft tissue and vascular pathology, it can be combined with external examination to potentially reduce or focus dissections in some of these cases depending on the circumstances and medicolegal needs.     

The Stability of 4-Chloromethcathinone in Blood and Vitreous Humor

We present results of our study on the stability of 4-chloromethcathinone (4-CMC) in authentic postmortem peripheral blood and vitreous humor samples. The stability of 4-CMC was determined in postmortem blood samples (for a period of 90 days) and vitreous humor (30 days) at three different temperatures: −15°C, +4°C, and + 23°C. The analyses were carried out using ultra-high-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS). In both materials, the lowest 4-CMC stability was demonstrated at room temperature. The blood samples stored in a freezer (−15°C) showed stability for the entire study period (90 days), while in the case of the vitreous humor sample stored at the same temperature the concentration of the substance decreased by 53% after 30 days. The study carried out in authentic postmortem blood and vitreous humor samples confirms the previous reports of 4-CMC instability in biological material. Authors suggest that the biological material should be stored frozen until analyses are carried out as soon as possible after collection of the material.     

Detection of Mitragynine in Mitragyna Speciosa (Kratom) Using Surface-Enhanced Raman Spectroscopy with Handheld Devices

A simple, quick, selective, sensitive, and effective field-friendly method capable of being used by nonexperts has been developed for detecting mitragynine in Mitragyna speciosa (kratom) using surface-enhanced Raman spectroscopy (SERS). Over 100 samples and blanks (known to be either positive or negative for the presence of mitragynine) were examined in duplicate using five identical handheld Raman spectrometers, which provided a data set of over 1,000 examinations. Based on the results of these analyses, the method yielded a true-positive rate of 99.3%, a true-negative rate of 97.9%, a false-positive rate of 2.1%, and a false-negative rate of 0.7%. The average minimum detectable concentration (C_m) of mitragynine that reproducibly yielded a match for one of the library spectra on all five instruments was determined to be 342 ng/mL (ppb). This C_m value is a conservative estimate considering that the extraction process was not fully optimized by this study, which was not necessary since the C_m value achieved was well below typical mitragynine concentrations in kratom (1.3–2.3%). The method is ideal (i) for prioritizing samples for additional testing using other more time-consuming laboratory-based techniques needed to detect and quantify mitragynine and (ii) for field use at international mail facility (IMF) satellite laboratories to help interdict kratom and prevent this dangerous product from reaching the U.S. supply chain.     

Postmortem Changes of Female External Genitalia and Their Importance in Suspected Sexual Abuse

Examination of the female external genitalia to assess for sexual abuse is performed in living individuals, and the interpretation of the findings is based on evidence-based studies. However, in the deceased, no such studies are available, and postmortem changes could present as suspicious findings that can be mistaken for trauma. Patches of discoloration in the hymen were reported previously in one case as hypostasis (i.e., livor and lividity), and based on this finding, it was listed as a finding that is not associated with trauma. This was a retrospective study that was conducted in the Center of Forensic and Legal Medicine in Dammam, Saudi Arabia over a 4-year period. The study included 30 deceased women in whom photographic documentation of their external genitalia was assessed for postmortem changes. The postmortem interval ranged from less than 24 h to more than 100 days, and the ages of these deceased women were in the 20–40 year-old age group. In cases where the hymen, vagina, and/or fossa navicularis were clearly visible, none of these areas showed any hypostatic discoloration. A comparison between antemortem and postmortem appearance of the hymen in one case clearly showed the absence of hypostatic changes in the hymen. In conclusion, any discoloration of the external genitalia that is detected in a female decedent requires serious consideration.     

The Accuracy and Repeatability of Reconstructing Single Bullet Impacts Using the 2D Ellipse Method

When a bullet punctures a surface, it leaves behind a bullet impact, which can be analyzed in order to determine the origin and trajectory path from which a bullet was discharged using many different scientific methods to reconstruct a shooting scene. The purpose of the research was to test the accuracy and repeatability of reconstructing the impact angle of single bullet impacts using the ellipse method. The research was conducted by firing various calibers of ammunition into drywall panels positioned at varying angles of incidence from 88° until ricochet occurred. This was done in order to determine which caliber type and angle of incidence are most accurate and precise for reconstructing a shooting scene. The study examined four caliber types fired into drywall panels, with 5 repeated shots for each of the 11 angles of incidence (n = 220). Furthermore, 31 participants partook in the study to estimate a bullet impact angle of incidence utilizing the ellipse method. The results show that the best performance (accuracy and repeatability) is seen with the measurements of the 0.45 caliber ammunition. When angle of incidences is low (<64°), the performance (accuracy and repeatability) was seen to be better in all caliber ammunitions. Overall, the data provided for single bullet impacts deposited in drywall show that the ellipse method is useful in providing measurements for most crime scene reconstruction purposes and has also demonstrated that results vary depending on the type of ammunition, firearm, and angle of incidence being examined.