Automated detection of fatal cerebral haemorrhage in postmortem CT data.

During the last years, the detection of different causes of death based on postmortem imaging findings became more and more relevant. Especially postmortem computed tomography (PMCT) as a non-invasive, relatively cheap, and fast technique is progressively used as an important imaging tool for supporting autopsies. Additionally, previous works showed that deep learning applications yielded robust results for in vivo medical imaging interpretation. In this work, we propose a pipeline to identify fatal cerebral haemorrhage on three-dimensional PMCT data. We retrospectively selected 81 PMCT cases from the database of our institute, whereby 36 cases suffered from a fatal cerebral haemorrhage as confirmed by autopsy. The remaining 45 cases were considered as neurologically healthy. Based on these datasets, six machine learning classifiers (k-nearest neighbour, Gaussian naive Bayes, logistic regression, decision tree, linear discriminant analysis, and support vector machine) were executed and two deep learning models, namely a convolutional neural network (CNN) and a densely connected convolutional network (DenseNet), were trained. For all algorithms, 80% of the data was randomly selected for training and 20% for validation purposes and a five-fold cross-validation was executed. The best-performing classification algorithm for fatal cerebral haemorrhage was the artificial neural network CNN, which resulted in an accuracy of 0.94 for all folds. In the future, artificial neural network algorithms may be applied by forensic pathologists as a helpful computer-assisted diagnostics tool supporting PMCT-based evaluation of cause of death.

Longitudinal visibility of MRI findings in living victims of strangulation.

Initial experiences with magnetic resonance imaging (MRI) of living strangulation victims demonstrated additional findings of internal injuries compared to the standard clinical forensic examination. However, existing studies on the use of MRI for this purpose mostly focused on the first 48 h after the incident. The aims of this study were (a) to evaluate the longitudinal visibility of MRI findings after violence against the neck by performing two MRI examinations within 12 days and a minimum of four days between both MRI scans and (b) to assess which MRI sequences were most helpful for the detection of injuries. Twenty strangulation victims participated in this study and underwent one (n = 8) or two (n = 12) MRI scans. The first MRI examination was conducted during the first five days, the second five to 12 days after the incident. Two blinded radiologists assessed the MRI data and looked for lesions in the structures of the neck. In total, 140 findings were reported in the 32 MRI examinations. Most of the findings were detected in the thyroid and the muscles of the neck. T2-weighted SPACE with fat suppression, T1-weighted TSE and T1-weighted MPRAGE were rated as the most helpful MRI sequences. Subjects who showed findings in the initial scan also demonstrated comparable results in the second scan, which was performed on average 8.4 days after the incident. Our results show that even up to 12 days after the incident, the criminal proceeding of strangulation cases may greatly profit from the information provided by an MRI examination of the neck in addition to the standard clinical forensic examination.

Effect of vaporizing cannabis rich in cannabidiol on cannabinoid levels in blood and on driving ability - a randomized clinical trial.

The aim of this prospective, placebo-controlled, double-blind, randomized, cross-over study was to determine cannabinoid levels in blood and driving-related ability after single (S1) and repetitive (S2) vaporization of cannabis rich in cannabidiol (CBD) containing < 1% Δ9-etrahydrocannabinol (THC). Healthy adult volunteers (Nsingle = 27, Nrepetitive = 20) with experience in smoking vapor-inhaled two low-THC/CBD-rich cannabis products both with < 1% THC (product 1: 38 mg CBD, 1.8 mg THC; product 2: 39 mg CBD, 0.6 mg THC) and placebo. Main outcomes were THC- and CBD-levels in whole blood and overall assessment of driving-related ability by computerized tests. Among 74 participants included, 27 (mean age ± SD, 28.9 ± 12.5 years) completed S1, and 20 (25.2 ± 4.0) completed S2. Peak concentrations and duration of detectability depended on the THC-content of the product. After single consumption THC dropped below 1.5 µg/L after 1.5 h, but was detected in some participants up to 5 h. Pairwise comparison of driving-related ability revealed no significant differences between low-THC/CBD-rich products (P1, P2) and placebo. Detection of THC after consumption of low-THC/CBD-rich cannabis might have legal consequences for drivers. Regarding overall driving-related ability, no significant differences were observed between the interventional products. This trial was registered with the German Clinical Trials Register (DRKS00018836) on 25.10.2019 and with the Coordination Office for Human Research (kofam) which is operated by the Federal Office of Public Health (FOPH) (SNCTP000003294).

Investigation of post mortem brain, rectal and forehead temperature relations.

It is well known that magnetic resonance (MR) imaging is temperature sensitive, which is highly relevant for post mortem examinations. Therefore, the determination of the exact temperature of the investigated body site, e.g. the brain, is crucial. However, direct temperature measurements are invasive and inconvenient. Thus, in view of post mortem MR imaging of the brain, this study aims at investigating the relation between the brain and the forehead temperature for modelling the brain temperature based on the non-invasive forehead temperature. In addition, the brain temperature will be compared to the rectal temperature. Brain temperature profiles measured in the longitudinal fissure between the brain hemispheres, as well as rectal and forehead temperature profiles of 16 deceased were acquired continuously. Linear mixed, linear, quadratic and cubic models were fitted to the relation between the longitudinal fissure and the forehead and between the longitudinal fissure and the rectal temperature, respectively. Highest adjusted R2 values were found between the longitudinal fissure and the forehead temperature, as well as between the longitudinal fissure and the rectal temperature using a linear mixed model including the sex, environmental temperature and humidity as fixed effects. The results indicate that the forehead, as well as the rectal temperature, can be used to model the brain temperature measured in the longitudinal fissure. Comparable fit results were observed for the longitudinal fissure-forehead temperature relation and for the longitudinal fissure-rectal temperature relation. Combined with the fact that the forehead temperature overcomes the problem of measurement invasiveness, the results suggest using the forehead temperature for modelling the brain temperature in the longitudinal fissure.

Beyond Δ9-tetrahydrocannabinol and cannabidiol: chemical differentiation of cannabis varieties applying targeted and untargeted analysis.

Cannabis sativa (C. sativa) is commonly chemically classified based on its Δ9-tetrahydrocannabinol (THC) and cannabidiol (CBD) content ratios. However, the plant contains nearly 150 additional cannabinoids, referred to as minor cannabinoids. Minor cannabinoids are gaining interest for improved plant and product characterization, e.g., for medical use, and bioanalytical questions in the medico-legal field. This study describes the development and validation of an analytical method for the elucidation of minor cannabinoid fingerprints, employing liquid chromatography coupled to high-resolution mass spectrometry. The method was used to characterize inflorescences from 18 different varieties of C. sativa, which were cultivated under the same standardized conditions. Complementing the targeted detection of 15 cannabinoids, untargeted metabolomics employing in silico assisted data analysis was used to detect additional plant ingredients with focus on cannabinoids. Principal component analysis (PCA) was used to evaluate differences between varieties. The overall purpose of this study was to examine the ability of targeted and non-targeted metabolomics using the mentioned techniques to distinguish cannabis varieties from each other by their minor cannabinoid fingerprint. Quantitative determination of targeted cannabinoids already gave valuable information on cannabinoid fingerprints as well as inter- and intra-variety variability of cannabinoid contents. The untargeted workflow led to the detection of 19 additional compounds. PCA of the targeted and untargeted datasets revealed further subgroups extending commonly applied phenotype classification systems of cannabis. This study presents an analytical method for the comprehensive characterization of C. sativa varieties.

Post mortem brain temperature and its influence on quantitative MRI of the brain.

OBJECTIVE: MRI temperature sensitivity presents a major issue in in situ post mortem MRI (PMMRI), as the tissue temperatures differ from living persons due to passive cooling of the deceased. This study aims at computing brain temperature effects on the MRI parameters to correct for temperature in PMMRI, laying the foundation for future projects on post mortem validation of in vivo MRI techniques. MATERIALS AND METHODS: Brain MRI parameters were assessed in vivo and in situ post mortem using a 3 T MRI scanner. Post mortem brain temperature was measured in situ transethmoidally. The temperature effect was computed by fitting a linear model to the MRI parameters and the corresponding brain temperature. RESULTS: Linear positive temperature correlations were observed for T1, T2* and mean diffusivity in all tissue types. A significant negative correlation was observed for T2 in white matter. Fractional anisotropy revealed significant correlations in all gray matter regions except for the thalamus. DISCUSSION: The linear models will allow to correct for temperature in post mortem MRI. Comparing in vivo to post mortem conditions, the mean diffusivity, in contrast to T1 and T2, revealed additional effects besides temperature, such as cessation of perfusion and active diffusion.

Sensitivity of fiber orientation dependent R2∗ to temperature and post mortem interval.

PURPOSE: R2∗ imaging of brain white matter is well known for being sensitive to the orientation of nerve fibers with respect to the B0 field of the MRI scanner. The goal of this study was to evaluate whether and to which extent fiber orientation dependent R2∗ differs between in vivo and post mortem in situ examinations, and to investigate the influence of varying temperatures and post mortem intervals (PMI). METHODS: Post mortem in situ and in vivo MRI scans were conducted at 3T. R2∗ was acquired with a multi-echo gradient-echo sequence, and the orientation of white matter fibers was computed using diffusion tensor imaging (DTI). Fitting of the measured fiber orientation dependent R2∗ was performed using three different formulations of a previously proposed model. RESULTS: R2∗ increased with increasing fiber angle for in vivo and post mortem in situ examinations, whereby the orientation dependency was lower post mortem. The different formulations of the fiber orientation model resulted in an identical fit, but showed large variations of the estimated parameters. The higher order orientation dependent R2∗ components significantly decreased with decreasing temperature, while the orientation independent R2∗ components showed no significant correlation with either temperature or PMI. CONCLUSION: Although the mean diffusivity is strongly reduced post mortem, we could successfully estimate the fiber angle using DTI. Due to the strong correlation of the higher order orientation dependent R2∗ components with temperature, the decreased R2∗ fiber orientation dependency post mortem in situ might primarily be attributed to the lower brain temperature.

Systematic review on the characterization of chronic traumatic encephalopathy by MRI and MRS.

BACKGROUND: Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease that is found in people who have suffered from chronic traumatic brain injury (TBI). Up to now, diagnosis of CTE could only be made based on postmortem histopathological examinations. The application of MR techniques might offer a promising possibility for in vivo diagnoses. PURPOSE/HYPOTHESIS: To provide a critical systematic review of the characterization of chronic TBI and CTE by considering the range of MR techniques. STUDY TYPE: This was a systematic review for which the electronic databases PubMed and Embase were searched using the terms ("chronic traumatic encephalopathy" OR "punch drunk syndrome" OR "chronic traumatic brain injury" OR "dementia pugilistica" OR "chronic head trauma") AND ("magnetic resonance imaging" OR mri OR imaging OR mrs OR "magnetic resonance spectroscopy" OR spectroscopy). POPULATION/SUBJECTS/PHANTOM/SPECIMEN/ANIMAL MODEL: Of the 432 studies identified by the database search, 25 were included in this review. FIELD STRENGTH/SEQUENCE: Diffusion, structural, and functional MRI sequences and MR spectroscopy were evaluated at 1.5T or 3T and at 11.74T for the ex vivo studies. ASSESSMENT: Data were extracted by two reviewers independently. Specific inclusion and exclusion criteria like the study design, publication type, and applied MR techniques were used to select studies for review. STATISTICAL TESTS: Results of the original research articles were stated in this review as significant if P ≤ 0.05. RESULTS: Of the included articles, two were ex vivo studies focusing on the coregistration of histology and MRI. All other studies were based on in vivo data. DATA CONCLUSION: The included studies varied considerably regarding study setup, MR techniques, and results. Nevertheless, this work aims to establish links between the studies and discusses the results and limitations associated with the characterization of chronic TBI and CTE based on MR. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:212-228.

Reproducibility of relaxometry of human lumbar vertebrae at 3 Tesla using 1 H MR spectroscopy.

BACKGROUND: MR spectroscopy is widely used for fat fraction quantification of human lumbar vertebrae. However, the measurements need to be corrected for relaxation effects. PURPOSE: The aim of this study was to determine the reproducibility of relaxometry in human lumbar vertebrae required for the correction of fat fraction measurements using magnetic resonance spectroscopy at 3 Tesla. Such information provides error estimates and guidance regarding reliability for future studies. STUDY TYPE: Prospective. SUBJECTS: Forty-six healthy volunteers (22 female [f], 24 male [m]) participated in this study. FIELD STRENGTH: All subjects underwent three consecutive multi-TE /multi-TR MR spectroscopy measurements at 3 Tesla. ASSESSMENT: A total of 2580 spectra of lumbar vertebrae L2 and L3 of 43 subjects (21f, 22m) were quantified using jMRUI software. Data were exported and mono-exponential fits were applied to the signals of water and fat compartments to derive relaxation times and calculate the fat fraction corrected for relaxation effects. Finally, relaxation times and fat fraction results of repeated measurements were analyzed for reproducibility. STATISTICAL TESTS: Reproducibility was evaluated by calculating the coefficient of variation (CV). Influences of volunteer age and sex were tested by analysis of covariance. RESULTS: The CV for all calculated parameters ranged between 1.22% (T2 of the fat compartment) and 3.02% (T1 of the fat compartment). Relaxation times and fat fraction were statistically different for female and male volunteers (P < 0.01) and relaxation times of the water compartment showed significant (P < 0.01) correlation with the fat fraction. DATA CONCLUSION: Based on repeated acquisitions using the measurement parameters applied in this study, magnetic resonance spectroscopy allowed a reproducible calculation of the fat fraction corrected for relaxation effects. T1 of the water compartment showed high reproducibility and correlation with the fat fraction. It, therefore, might be considered as a parameter linked to the composition of the water compartment and patient health. LEVEL OF EVIDENCE: 1 Technical Efficacy Stage 1 J. Magn. Reson. Imaging 2017.

Assessment of pharmacokinetics for microvessel proliferation by DCE-MRI for early detection of physeal bone bridge formation in an animal model.

OBJECTIVES: Bone bridge formation occurs after physeal lesions and can lead to growth arrest if not reversed. Previous investigations on the underlying mechanisms of this formation used histological methods. Therefore, this study aimed to apply a minimally invasive method using dynamic contrast-enhanced MRI (DCE-MRI). MATERIALS AND METHODS: Changes in functional parameters related to the microvessel system were assessed in a longitudinal study of a cohort of an animal model applying a reference region model. The development of morphology of the injured physis was investigated with 3D high-resolution MRI. To acquire complementary information for MRI-related findings qRT-PCR and immunohistochemical data were acquired for a second cohort of the animal model. RESULTS: The evaluation of the pharmacokinetic parameters showed a first rise of the transfer coefficient 7 days post-lesion and a maximum 42 days after operation. The analysis of the complementary data showed a connection of the first rise to microvessel proliferation while the maximum value was linked to bone remodeling. CONCLUSION: The pharmacokinetic analysis of DCE-MRI provides information on a proliferation of microvessels during the healing process as a sign for bone bridge formation. Thereby, DCE-MRI could identify details, which up to now required analyses of highly invasive methods.

Detection and volume estimation of artificial hematomas in the subcutaneous fatty tissue: comparison of different MR sequences at 3.0 T.

In legal medicine, reliable localization and analysis of hematomas in subcutaneous fatty tissue is required for forensic reconstruction. Due to the absence of ionizing radiation, magnetic resonance imaging (MRI) is particularly suited to examining living persons with forensically relevant injuries. However, there is limited experience regarding MRI signal properties of hemorrhage in soft tissue. The aim of this study was to evaluate MR sequences with respect to their ability to show high contrast between hematomas and subcutaneous fatty tissue as well as to reliably determine the volume of artificial hematomas. Porcine tissue models were prepared by injecting blood into the subcutaneous fatty tissue to create artificial hematomas. MR images were acquired at 3T and four blinded observers conducted manual segmentation of the hematomas. To assess segmentability, the agreement of measured volume with the known volume of injected blood was statistically analyzed. A physically motivated normalization taking into account partial volume effect was applied to the data to ensure comparable results among differently sized hematomas. The inversion recovery sequence exhibited the best segmentability rate, whereas the T1T2w turbo spin echo sequence showed the most accurate results regarding volume estimation. Both sequences led to reproducible volume estimations. This study demonstrates that MRI is a promising forensic tool to assess and visualize even very small amounts of blood in soft tissue. The presented results enable the improvement of protocols for detection and volume determination of hemorrhage in forensically relevant cases and also provide fundamental knowledge for future in-vivo examinations.

Closed-form solution for T2 mapping with nonideal refocusing of slice selective CPMG sequences.

PURPOSE: T2 quantification with multiecho sequences is typically impaired by the contribution of stimulated echoes to the echo decay due to B1 + inhomogeneity and slice profile effects. In this work, a compact signal model based on the generating functions approach, which accounts for both sources of error, is presented. METHODS: The generating functions (GF) approach is used to obtain a closed solution to the evolution of the transverse magnetization in an echo train, however, not in the time domain, but in the transformed z-domain. The approach is generalized by the incorporation of flip angle distribution across the refocusing slice profiles. The approach is tested by fitting the model to simulated data as well as to phantom and in vivo measurements, followed by a comparison with the common monoexponential fitting approach. RESULTS: The fitting simulations indicate that T2 errors of up to 30% can be commonplace in a clinical setting using the monoexponential method. Conversely, the GF approach produced accurate results. Phantom and in vivo experiments showed a good agreement of the GF values with spectroscopic measurements and single-echo spin-echo sequences. CONCLUSION: A correction for stimulated echoes is necessary to compute comparable T2 values. The presented approach provides a solution to this issue.

Contrast of artificial subcutaneous hematomas in MRI over time.

In clinical forensic medicine, hematomas and other externally visible injuries build the basis for the reconstruction of events. However, dating of subcutaneous hematomas based on their external aspect is difficult. Magnetic resonance imaging (MRI) has proven its use in dating intracranial hemorrhage. Thus, the aim was to investigate if MRI can also be used for dating subcutaneous hematomas and to analyze an eventual influence of the hematoma shape. In 20 healthy volunteers (11 females, 9 males, aged 26.9 ± 3.8 years), 4 ml of autologous blood were injected subcutaneously in the thigh. The hematoma was scanned immediately after the injection, after 3 and 24 h and 3, 7, and 14 days using three sequences with different contrast. Data was analyzed by measuring signal intensities of the hematoma, the muscle, and the subcutaneous tissue over time, and the Michelson contrast coefficients between the tissues were calculated. In the analysis, hematoma shape was considered. Signal intensity of blood in the proton density-weighted sequence reached its maximum 3 h after the injection with a subsequent decrease, whereas the signal intensities of muscle and fatty tissue remained constant. The time course of the Michelson coefficient of blood versus muscle decreased exponentially with a change from hyperintensity to hypointensity at 116.9 h, depending on hematoma shape. In the other sequences, either variability was large or contrast coefficients stayed constant over time. The observed change of contrast of blood versus muscle permits a quick estimate of a hematoma's age. The consideration of the hematoma shape is expected to further enhance dating using MRI.

Age determination of soft tissue hematomas.

In clinical forensic medicine, the estimation of the age of injuries such as externally visible subcutaneous hematomas is important for the reconstruction of violent events, particularly to include or exclude potential suspects. Since the estimation of the time of origin based on external inspection is unreliable, the aim of this study was to use contrast in MRI to develop an easy-to-use model for hematoma age estimation. In a longitudinal study, artificially created subcutaneous hematomas were repetitively imaged using MRI over a period of two weeks. The hemorrhages were created by injecting autologous blood into the subcutaneous tissue of the thigh in 20 healthy volunteers. For MRI, standard commercially available sequences, namely proton-density-weighted, T2 -weighted and inversion recovery sequences, were used. The hematomas' MRI data were analyzed regarding their contrast behavior using the most suitable sequences to derive a model allowing an objective estimation of the age of soft tissue hematomas. The Michelson contrast between hematoma and muscle in the proton-density-weighted sequence showed an exponentially decreasing behavior with a dynamic range of 0.6 and a maximum standard deviation of 0.1. The contrast of the inversion recovery sequences showed increasing characteristics and was hypointense for TI = 200ms and hyperintense for TI =1000ms. These sequences were used to create a contrast model. The cross-validation of the model finally yielded limits of agreement for hematoma age determination (corresponding to ±1.96 SD) of ±38.7h during the first three days and ±54 h for the entire investigation period. The developed model provides lookup tables which allow for the estimation of a hematoma's age given a single contrast measurement applicable by a radiologist or a forensic physician. This is a first step towards an accurate and objective dating method for subcutaneous hematomas, which will be particularly useful in child abuse.

Consent to forensic radiologic examinations by living crime victims.

The purpose of this prospective study was to evaluate whether people approve radiological examinations specifically for the documentation of findings for the use in criminal proceedings. Forty two crime victims and 42 controls without a history of sustained violence were asked via telephone interview whether they would agree to forensic radiological examinations and if radiation exposure and the duration of the examination were factors influencing their consent. The consent to specifically forensic radiological examinations was high in both groups, however, higher in victims than in controls (85-96% compared to 64-77%, respectively, depending on the imaging modality). All of the victims and 93% of the controls consented to at least one of the proposed imaging modalities, i.e. X-ray, computed tomography and magnetic resonance imaging. Most of the interviewees did not consider the duration of the examination to be relevant to their consent (79% of the crime victims and 93% of the controls); however, the radiation exposure associated with the examination was relevant for 55% of the controls but only for 19% of the victims. These results show that there is a great consent to the application of radiological methods for forensic purposes. This is important for the growing field of forensic radiology as the approval of the examination by the victim is a legal prerequisite.

DEPArray™ single-cell technology: A validation study for forensic applications.

In forensics investigations, it is common to encounter biological mixtures consisting of homogeneous or heterogeneous components from multiple individuals and with different genetic contributions. One promising mixture deconvolution strategy is the DEPArray™ technology, which enables the separation of cell populations before genetic analysis. While technological advances are fundamental, their reliable validation is crucial for successful implementation and use for casework. Thus, this study aimed to 1) systematically validate the DEPArray™ system concerning specificity, sensitivity, repeatability, and contamination occurrences for blood, epithelial, and sperm cells, and 2) evaluate its potential for single-cell analysis in the field of forensic science. Our findings confirmed the effective identification of different cell types and the correct assignment of successfully genotyped single cells to their respective donor(s). Using the NGM Detect™ Amplification Kit, the average profile completeness for diploid cells was approximately 80%, with ∼ 290 RFUs. In contrast, haploid sperm analysis yielded an average completeness of 51% referring to the haploid reference profile, accompanied by mean peak heights of ∼ 176 RFUs. Although certain alleles of heterozygous loci in diploid cells showed strong imbalances, the overall peak balances yielded acceptable values above ≥ 60% with a mean value of 72% ± 0.21, a median of 77%, but with a maximum imbalance of 9% between heterozygous peaks. Locus dropouts were considered stochastic events, exhibiting variations among donors and cell types, with a notable failure incidence observed for TH01. Within the wet-lab experimentation with >500 single cells for the validation, profiling was performed using the consensus approach, where profiles were selected randomly from all data to better mirror real casework results. Nevertheless, complete profiles could be achieved with as few as three diploid cells, while the average success rate increased to 100% when using profiles of 6-10 cells. For sperms, however, a consensus profile with completeness >90% of the autosomal diploid genotype could be attained using ≥15 cells. In addition, the robustness of the consensus approach was evaluated in the absence of the respective reference profile without severe deterioration. Here, increased stutter peaks (≥ 15%) were found as the main artifact in single-cell profiles, while contamination and drop-ins were ascertained as rare events. Lastly, the technique's potential and limitations are discussed, and practical guidance is provided, particularly valuable for cold cases, multiple perpetrator rapes, and analyses of homogeneous mixed evidence.

Detection and characterization of traumatic scalp injuries for forensic evaluation using computed tomography.

The purpose of this prospective study was to evaluate the rate of detection and correct classification of traumatic soft tissue injuries of the head using clinical multislice computed tomography (MSCT) compared with an external forensic examination. Thirty-one patients with soft tissue injuries after head trauma and clinically indicated cerebral MSCT scan underwent an external forensic examination with documentation of the morphological appearance and the exact localization of scalp and facial injuries. MSCT data were evaluated by a radiologist blinded to the results of the external examination using axial images as well as multiplanar reconstruction tools. The results of the radiological and forensic report were compared and analyzed. The main finding was that clinical MSCT data of the head detected 55 % of all external lesions and diagnosed the correct morphological type of lesion in 30 %. All lacerations and 44 % of the hematomas were correctly identified in the radiological report, whereas the diagnosis of swellings and abrasions was difficult. MSCT showed a high specificity for all types of soft tissue lesions. Additionally, a substantial number of internal lesions such as fractures or intracerebral bleedings were revealed which were not detected in the external examination. The results demonstrate that the forensic-radiologic evaluation of clinical MSCT data has a good diagnostic performance and is a valuable method to retrospectively supplement external forensic examination in living crime victims. It also might-to a certain extent-be used as the only source in cases where no forensic external examination has taken place within due time.

A systematic approach to improve downstream single-cell analysis for the DEPArray™ technology.

Most commercially available STR amplification kits have never been fully validated for low template DNA analysis, highlighting the need for testing different PCR kits and conditions for improving single-cell profiling. Here, current strategies rely mainly on adjusting PCR cycle number and analytical threshold settings, with a strong preference for using 30 amplification cycles and thresholds at 30-150 RFU for allele detection. This study aimed to (1) determine appropriate conditions for obtaining informative profiles utilizing a dilution series, and (2) test the outcome on single cells using the DEPArray™ technology. Four routinely applied forensic STR kits were compared by using three different amplification volumes and DNA dilutions down to 3.0 pg, while two well-performing kits were used for single/pooled leucocyte and sperm cell genotyping. Besides reduced costs, the results demonstrate that a 50%-75% PCR volume reduction was beneficial for peak height evaluation. However, this was counteracted by an increased artifact generation in diluted DNA volumes. Regarding profile completeness, the advantage of volume reduction was only prominent in samples processed with Fusion 6C. For single and pooled cells, ESIFast and NGMDetect provided a solid basis for consensus profiling regarding locus failure, although locus dropouts were generally observed as stochastic events. Amplification volume of 12.5 µL was confirmed as appropriate in terms of peak heights and stutter frequencies, with increased stutter peaks being the main artifact in single-cell profiles. Limitations associated with these analyses are discussed, providing a solid foundation for further studies on low template DNA.

Temperature correction of post mortem quantitative magnetic resonance imaging using real-time forehead temperature acquisitions.

Performing magnetic resonance imaging (MRI) of deceased is challenging due to altered body temperatures compared to in vivo temperatures and, hence, requires a temperature correction. This study investigates the possibility to correct brain MRI parameters real-time and non invasively based on the forehead temperature. 17 post mortem cases were included and their forehead temperatures were measured continuously during the in situ brain MRI protocol consisting of a diffusion tensor imaging, multi-contrast spin echo, multi-echo gradient echo and inversion recovery spin echo sequence. Linear models were fitted to the quantitative MRI parameters in a forensically interesting temperature range for white matter, cerebral cortex and deep gray matter, separately, and the influence of the forehead temperature on the MRI parameters was determined. A statistically significant temperature sensitivity was found for T2 and mean diffusivity in white matter, for T1 in cerebral cortex, as well as for T1 and mean diffusivity in deep gray matter. Linear models were computed to temperature correct these MRI parameters in in situ post mortem scans to allow their comparison regardless of temperature. The here presented real-time and non invasive temperature correction method for the brain presents a crucial precondition for quantitative in situ post mortem MRI.

Fully automated radiologic identification focusing on the sternal bone.

A crucial task in forensic investigations is the identification of unknown deceased. In general, secure identification methods rely on a comparison of ante mortem (AM) with post mortem (PM) data. However, available morphologic approaches are often dependent on the expertise and experience of the examiner, and often lack standardisation and statistical evidence. The objective of this study was therefore to overcome the current challenges via developing a fully automated radiologic identification (autoRADid) method based on the sternal bone. An anonymised AM data set consisting of 91 chest computed tomography (CT) scans, as well as an anonymised PM data set of 42 chest CT scans were included in this work. Out of the 91 available AM CT data sets, 42 AM scans corresponded to the 42 PM CT scans. For the fully automated identification analysis, a custom-made python pipeline was developed, which automatically registers AM data to the PM data in question using a two-step registration method. To evaluate the registration procedure and subsequent identification success, the image similarity measures Jaccard Coefficient, Dice Coefficient, and Mutual Information were computed. The highest value for each metric was retrieved in order to analyse the correspondence between AM and PM data. For all three similarity measures, 38 out of the 42 cases were matched correctly. This corresponds to an accuracy of 91.2%. The four unsuccessful cases incorporated surgical interventions taking place between the AM and the PM CT acquisition or poor CT scan quality preventing robust registration results. To conclude, the presented autoRADid method seems to be a promising fully automated tool for a reliable and facile identification of unknown deceased. A final pipeline combining all three similarity measures is open source and publicly available for efficient future identifications of unknown deceased.