Postmortem Magnetic Resonance Research Articles

THE USING OF VIRTOPSIA IN FORENSIC MEDICAL EXAMINATION OF HANGING (literature review)

Background. For the third decade in a row, forensic medical expertise in the world has been introducing and developing the use of virtopsia as a virtual alternative to traditional examination of corpse. It is believed that the combination of postmortem computed tomography (PMCT), postmortem magnetic resonance imaging (PMRI) 3D surface scanning and postmortem angiography is sufficient to replace the traditional autopsy with a virtual one. Yjwever, the practical experience of using virtopsia has revealed both its positive aspects and disadvantages that should be taken into account when using in practice. Aim: To study the peculiarities of the use of virtopsia in forensic medical examinations of corpses in general and in cases where the cause of death was mechanical asphyxia due to hanging. Material and methods: systematic review of electronic databases of medical and biological publications, bibliographic, analytical. Results. Virtopsia can be useful in cases of identification by dental status, in case of damage of the bones of the skull and in the diagnosis of craniocerebral injuries. Analysis of the role of PMCT in trauma and diagnostic features showed that the presumed cause of death as a result of trauma was proven in approximately 30% of cases. The properties of PMCT make it possible to use it in cases of drawing, in the examination of gunshot injuries to detect skeletal injuries in high-energy trauma and it can be used as a tool for selecting individual parts of the body for further detailed autopsy and reconstruction of the cause of events and finding the cause of death. In addition, it is advisable to use postmortem PMRI for the radiological assessment of gunshot wounds. Postmortem CT angiography is particularly useful for identifying vascular involvement and coronary death. During virtopsia signs of mechanical asphyxia, fractures of the hyoid bone, larynx or thyroid cartilage and intramuscular hemorrhages were revealed which can be used as an adjunct to the autopsy. A combined approach with radiological methods demonstrates the utility of a multidisciplinary approach to significantly reduce the number of unidentified injuries. Conclusion. Analysis of the literature suggests that both postmortem PMCT and PMRI have become widely used, but forensic medical examination of corpse is the gold standard for diagnosing injuries and determining of the cause of death yet. In cases of mechanical asphyxia due to hanging, it is advisable to use PMCT to detect injuries to the hyoid bone and cartilage of the larynx, and using PMRI to detect hemorrhages in the soft tissues of the neck. Detection of specific signs of perpetuity of neck tissue injury during mechanical asphyxia with the help of PMCT allows to improve the diagnosis of hanging by applying innovative technologies and using a multidisciplinary approach.

Deep Learning based Automated Segmentation of Hippocampus and Hippocampal Subfields from Postmortem MRI

AbstractBackgroundThe hippocampus and its subfields in the human brain play a pivotal role in forming new memories and spatial navigation. The automated assessment of the hippocampus and its subfields are useful tools for the early diagnosis of Alzheimer's disease and other neurodegenerative diseases such as primary age‐related tauopathy, Lewy body dementia, limbic‐predominant age‐related TDP‐43 encephalopathy (LATE), and frontotemporal lobar Dementia. Postmortem brain magnetic resonance imaging plays a crucial role in neuroscience and clinical research, providing valuable insights into the structural and pathological features of the brain after death. Postmortem MRI can be used to validate findings from in vivo imaging studies, link these findings to histopathological data. Deep learning methods such as convolutional neural networks are widely used in image segmentation. However, deep learning methods have not previously been applied to segmenting the hippocampus and its subfields (Head, Body, Tail, and Dentate Gyrus) from postmortem MRI.MethodDouble U‐Net is a convolutional neural network architecture that combines two U‐Net architectures. The U‐Net architecture is widely used for semantic segmentation tasks, particularly in medical image analysis, where it has shown success in functions such as tumor segmentation. We have trained a double U‐Net model on 15 annotated postmortem MRI scans include scans from nine females and six males, with an average age of 78 and a standard deviation of 7, which have been collected at our university brain bank (Figure 1). Before feeding the data to the model, all the data were registered, intensity normalized, and cropped to a size of 64 x 96 x 48. The model is trained with a learning rate of 0.0001s and dice loss as the objective function.ResultThe model's performance is evaluated quantitatively (Table 1) and qualitatively (Figure 2). The qualitative analysis is performed with metrics such as Dice, Precision, and Recall. In whole hippocampus segmentation, the model achieved an overall Dice score of 93.01%, and for subfield segmentation, it reached a Dice score of 87.30%.ConclusionDeep learning‐based segmentation of the hippocampus and its subfields can be performed on postmortem brain images and may be helpful in diagnosing Alzheimer's and other neurodegenerative diseases.

Mapping local and distal effects of different neuropathologies on amygdala volume

AbstractBackgroundThe amygdala is a hotspot for neuropathologies; however, it is unclear 1) which neuropathologies lead to amygdala neurodegeneration, 2) what specific amygdala subnuclei are affected, and 3) if the neuropathologies related to amygdala volume are local (inside the amygdala), or distal (in other regions). We investigate the relationships between different neuropathologies (tau, amyloid‐β [Aβ], α‐synuclein [α‐syn], and transactive response DNA‐binding protein 43 [TDP‐43]) and amygdala volumes.MethodWe analyzed postmortem data from 73 individuals with and without neurodegenerative diseases (age: 77±11 [45–101] years; 26 [36%] females; 51 [70%] cognitively impaired). Volumes of the whole amygdala and three amygdala subregions (lateral, B/Ab [basal/accessory basal], Co/Me/Ce [cortical/medial/central] nuclei: for n=24 individuals) were manually segmented on 0.2x0.2x0.2 mm3 postmortem magnetic resonance images (Figure 1). We used semiquantitative scores (0–3) of Aβ, tau, α‐syn, and TDP‐43 in the amygdala, the dentate gyrus (DG), the Cornu Ammonis 1 and subiculum (CA1/SUB), the entorhinal cortex (ERC), and averaged between the medial temporal lobe (MTL) regions (excluding the amygdala). Partial Spearman correlations were performed to investigate the relationships between neuropathologies and amygdala volumes, adjusting for age, sex, and other pathologies.ResultsHigher ratings of amygdala TDP‐43, MTL TDP‐43, and MTL tau were associated with smaller whole amygdala volume (Figure 2A–B, Figure 3A). However, MTL TDP‐43 was no longer significant when adjusting for amygdala TDP‐43 (Figure 3B). As MTL tau was associated with amygdala volume, we looked into which MTL subregions could be responsible for this association. Here, tau in DG, CA1/SUB, and ERC were all negatively associated with whole amygdala volume (Figure 2B). For exploratory subregional analyses, amygdala α‐syn was initially associated with B/Ab volume (Figure 2C, Figure 3C), but this correlation did not survive FDR‐correction.ConclusionsThese preliminary results indicate that TDP‐43 has a local effect on whole amygdala volume, whereas tau seems to affect amygdala volume distantly through other MTL regions, with the largest effect seen in DG tau, followed by CA1/SUB and ERC. Subregional analyses will be updated once a larger sample is available, as well as further analyses on non‐MTL regions.

White matter hyperintensities and microplastics.

White matter hyperintensities are abnormalities that appear in MRI scans of living patients but are not apparent in MRI post-mortem. Our goal is to understand the cellular/biological basis of white matter hyperintensities (WMH). We aligned post-mortem MR scans with those collected ante-mortem and performed histopathology and pyrGC/MS for plastics on regions with WMH. PyrGC/MS detected large amounts of plastics and we determined their cellular locations with a novel optical imaging approach in regions with small vessel disease and Abeta plaques. Microplastics in the brains of people with cognitive impairment may be due to pre-existing vascular injury or contribute to it. Many questions remain: Where do they come from, do they impair function? Can they be diagnosed by MRI ante-mortem?

Whole-body non-forensic fetal virtopsy using postmortem magnetic resonance imaging at 7 Tesla vs classical autopsy.

To determine the diagnostic accuracy of virtual autopsy using whole-body postmortem ultra-high field magnetic resonance imaging (MRI) at 7 Tesla (T), using a short T2-weighted imaging (T2-WI) protocol, compared with classical autopsy, for detecting structural abnormalities in small second-trimester fetuses. Thirty consecutive fetuses at 13-19 weeks' gestation (weight, 17-364 g) were included following spontaneous pregnancy loss or termination of pregnancy. After fixation in 10% formaldehyde solution (48 h to 1 week), all fetuses were scanned using a two-dimensional turbo high-resolution T2-WI protocol with multislice relaxation time, followed by an invasive autopsy. The diagnostic accuracy of virtual autopsy vs classical autopsy was calculated for 990 anatomical structures (30 fetuses × 33 items). Sensitivity, specificity, positive and negative predictive values and Cohen's κ coefficient of agreement, with their 95% CIs, as well as the McNemar test, were used to evaluate the accuracy and agreement of the two diagnostic methods. Analysis was stratified by anatomical segment (nervous, pulmonary, cardiovascular, digestive, renal, facial and skeletal) and across three gestational-age intervals (13-14, 15-16 and 17-19 weeks). Considering classical autopsy as the gold standard, virtual autopsy had a sensitivity of 92.04% (95% CI, 85.42-96.29%) and a specificity of 97.87% (95% CI, 94.64-99.42%), with a positive predictive value of 96.30% (95% CI, 90.78-98.56%) and a negative predictive value of 95.34% (95% CI, 91.61-97.45%), achieving a diagnostic accuracy of 95.68% (95% CI, 92.73-97.68%) for detecting structural abnormalities in second-trimester fetuses. Cohen's κ for virtual vs classical autopsy was 0.907. The diagnostic ability of virtual autopsy at 7 T for malformed fetuses was superior to that of classical autopsy for analyzing the nervous system in small fetuses with pronounced autolysis, equivalent to that of classical autopsy when analyzing pulmonary, cardiovascular and renal systems and inferior when evaluating the fetal intestines. The sensitivity of virtual autopsy at 7 T for describing structural abnormalities increased with gestational age. Virtual fetal autopsy using 7-T MRI and a turbo high-resolution T2-WI protocol with multislice relaxation time is a feasible postmortem diagnostic tool for the identification of fetal structural anomalies. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

THE USING OF VIRTOPSIA IN FORENSIC MEDICAL EXAMINATION OF HANGING (literature review)

Background. For the third decade in a row, forensic medical expertise in the world has been introducing and developing the use of virtopsia as a virtual alternative to traditional examination of corpse. It is believed that the combination of postmortem computed tomography (PMCT), postmortem magnetic resonance imaging (PMRI) 3D surface scanning and postmortem angiography is sufficient to replace the traditional autopsy with a virtual one. Yjwever, the practical experience of using virtopsia has revealed both its positive aspects and disadvantages that should be taken into account when using in practice. Aim: to study the peculiarities of the use of virtopsia in forensic medical examinations of corpses in general and in cases where the cause of death was mechanical asphyxia due to hanging. Material and methods: systematic review of electronic databases of medical and biological publications, bibliographic, analytical. Results. Virtopsia can be useful in cases of identification by dental status, in case of damage of the bones of the skull and in the diagnosis of craniocerebral injuries. Analysis of the role of PMCT in trauma and diagnostic features showed that the presumed cause of death as a result of trauma was proven in approximately 30% of cases. The properties of PMCT make it possible to use it in cases of drawing, in the examination of gunshot injuries to detect skeletal injuries in high-energy trauma and it can be used as a tool for selecting individual parts of the body for further detailed autopsy and reconstruction of the cause of events and finding the cause of death. In addition, it is advisable to use postmortem PMRI for the radiological assessment of gunshot wounds. Postmortem CT angiography is particularly useful for identifying vascular involvement and coronary death. During virtopsia signs of mechanical asphyxia, fractures of the hyoid bone, larynx or thyroid cartilage and intramuscular hemorrhages were revealed which can be used as an adjunct to the autopsy. A combined approach with radiological methods demonstrates the utility of a multidisciplinary approach to significantly reduce the number of unidentified injuries. Conclusion. Analysis of the literature suggests that both postmortem PMCT and PMRI have become widely used, but forensic medical examination of corpse is the gold standard for diagnosing injuries and determining of the cause of death yet. In cases of mechanical asphyxia due to hanging, it is advisable to use PMCT to detect injuries to the hyoid bone and cartilage of the larynx, and using PMRI to detect hemorrhages in the soft tissues of the neck. Detection of specific signs of perpetuity of neck tissue injury during mechanical asphyxia with the help of PMCT allows to improve the diagnosis of hanging by applying innovative technologies and using a multidisciplinary approach.

Blunt force trauma in forensic radiology

Description of the main forensic radiological examination modalities and findings in blunt force trauma in living and deceased adults. Elaboration of the essential points based on the authors' own experiences and relevant literature. Injury-related consequences of blunt force are frequently observed in forensic radiological diagnostics, especially in the context of accidents and suicides, and less frequently in homicides. The method of choice for radiological imaging of blunt force in deceased persons is native postmortem computed tomography (PMCT). In principle, the radiological effects of blunt force in PMCT do not differ significantly from those in living persons. Postmortem magnetic resonance imaging (PMMRI) is very suitable for imaging blunt soft tissue injuries in the shorter postmortem interval. In the case of living individuals with the consequences of blunt force trauma, imaging is primarily indicated for clinical diagnostic reasons. Common indications are domestic violence, violence against the elderly, and disputes in public spaces. The choice of radiological examination method depends on the clinical history and symptoms, and the radiological examinations can be subjected to aforensic assessment.

Synthetic MRI and MR Fingerprinting-Derived Relaxometry of Antenatal Human Brainstem Myelination: A Postmortem-Based Quantitative Imaging Study.

The radiologic evaluation of ongoing myelination is currently limited prenatally. Novel quantitative MR imaging modalities provide relaxometric properties that are linked to myelinogenesis. In this retrospective postmortem imaging study, the capability of Synthetic MR imaging and MR fingerprinting-derived relaxometry for tracking fetal myelin development was investigated. Moreover, the consistency of results for both MR approaches was analyzed. In 26 cases, quantitative postmortem fetal brain MR data were available (gestational age range, 15 + 1 to 32 + 1; female/male ratio, 14/12). Relaxometric measurements (T1-/T2-relexation times) were determined in the medulla oblongata and the midbrain using Synthetic MR imaging/MR fingerprinting-specific postprocessing procedures (Synthetic MR imaging and MR Robust Quantitative Tool for MR fingerprinting). The Pearson correlations were applied to detect relationships between T1-relaxation times/T2-relaxation times metrics and gestational age at MR imaging. Intraclass correlation coefficients were calculated to assess the consistency of the results provided by both modalities. Both modalities provided quantitative data that revealed negative correlations with gestational age at MR imaging: Synthetic MR imaging-derived relaxation times (medulla oblongata [r = -0.459; P = .021]; midbrain [r = -0.413; P = .040]), T2-relaxation times (medulla oblongata [r = -0.625; P < .001]; midbrain [r = -0.571; P = .003]), and MR fingerprinting-derived T1-relaxation times (medulla oblongata [r = -0.433; P = .035]; midbrain [r = -0.386; P = .062]), and T2-relaxation times (medulla oblongata [r =-0.883; P < .001]; midbrain [r = -0.890; P < .001]).The intraclass correlation coefficient analysis for result consistency between both MR approaches ranged between 0.661 (95% CI, 0.351-0.841) (T2-relaxation times: medulla oblongata) and 0.920 (95% CI, 0.82-0.965) (T1-relaxation times: midbrain). There is a good-to-excellent consistency between postmortem Synthetic MR imaging and MR fingerprinting myelin quantifications in fetal brains older than 15 + 1 gestational age. The strong correlations between quantitative myelin metrics and gestational age indicate the potential of quantitative MR imaging to identify delayed or abnormal states of myelination at prenatal stages of cerebral development.

In situ temperature determination using magnetic resonance spectroscopy thermometry for noninvasive postmortem examinations.

Magnetic resonance spectroscopy (MRS) thermometry offers a noninvasive, localized method for estimating temperature by leveraging the temperature-dependent chemical shift of water relative to a temperature-stable reference metabolite under suitable calibration. Consequentially, this technique has significant potential as a tool for postmortem MR examinations in forensic medicine and pathology. In these examinations, the deceased are examined at a wide range of body temperatures, and MRS thermometry may be used for the temperature adjustment of magnetic resonance imaging (MRI) protocols or for corrections in the analysis of MRI or MRS data. However, it is not yet clear to what extent postmortem changes may influence temperature estimation with MRS thermometry. In addition, N-acetylaspartate, which is commonly used as an in vivo reference metabolite, is known to decrease with increasing postmortem interval (PMI). This study shows that lactate, which is not only present in significant amounts postmortem but also has a temperature-stable chemical shift, can serve as a suitable reference metabolite for postmortem MRS thermometry. Using lactate, temperature estimation in postmortem brain tissue of severed sheep heads was accurate up to 60 h after death, with a mean absolute error of less than 0.5°C. For this purpose, published calibrations intended for in vivo measurements were used. Although postmortem decomposition resulted in severe metabolic changes, no consistent deviations were observed between measurements with an MR-compatible temperature probe and MRS thermometry with lactate as a reference metabolite. In addition, MRS thermometry was applied to 84 deceased who underwent a MR examination as part of the legal examination. MRS thermometry provided plausible results of brain temperature in comparison with rectal temperature. Even for deceased with a PMI well above 60 h, MRS thermometry still provided reliable readings. The results show a good suitability of MRS thermometry for postmortem examinations in forensic medicine.

Advanced medical imaging for forensic triage: A study of the added value of combining PMCT and PMMR of the head

BackgroundApproximately 170,000 individuals die annually in the Netherlands. Dutch law mandates examinations to distinguish between natural death and unnatural death. Traditionally, this involves external examinations and an inspection of medical records; however, medical imaging has emerged as a tool for investigating deaths. ObjectiveThe objective of the study was to investigate whether the addition of post-mortem magnetic resonance (PMMR) to post-mortem computed tomography (PMCT) could assist in the categorisation of deaths as natural or unnatural and augment confidence in those classifications. MethodsIn this retrospective study, the PMCT and PMMR head images of 50 individuals were evaluated by a forensic radiologist. The impact of PMMR on lesion detection, the cause of death (COD), the differentiation between natural death and unnatural death, and confidence levels were assessed. All available case information was used as the reference standard. ResultsThe addition of the PMMR led to a statistically significant increase in lesion detection (48%), changes in the classification of COD in four cases, and an increased level of confidence in the classification. Differentiation between natural death and unnatural death reversed in 10 cases, altering the overall manner of death (MOD) classification in 20% of cases. ConclusionWhen PMCT indicates a natural or unnatural death, PMMR is unnecessary. PMMR of the head is recommended in situations in which the MOD is uncertain based on PMCT findings. The ultimate determination of a natural death and unnatural death should always take into account the results of external examinations, police investigations, and other available information.

Gray–white matter contrast reversal on T1-weighted spin-echo in postmortem brain

PurposeThe image contrast of postmortem magnetic resonance imaging (MRI) may differ from that of antemortem MRI because of circulator arrest, changes in postmortem tissue, and low-body-temperature scanning conditions. In fact, we have found that the signal intensity of white matter (WM) on T1-weighted spin-echo (T1WSE) images of the postmortem brain was lower than that of gray matter (GM), which resulted in image contrast reversal between GM and WM relative to the living brain. However, the reason for this phenomenon is unclear. Therefore, the aim of this study is to clarify the reason why image contrast reversal occurs between GM and WM of the postmortem brain. Materials and methodsTwenty-three corpses were included in the study (mean age, 60.6 years; range: 19–60 years; mean rectal temperature at scan, 6.9℃; range: 4–11℃). On a 1.5 T MRI system, postmortem T1W-SE MRI of the brain was conducted in the 23 corpses prior to medico-legal autopsy. Next, T1 and T2 of the GM and WM at the level of the basal ganglia were determined in the same participants using inversion recovery and multiple SE sequences, respectively. The proton density (PD) was also calculated from the T1 and T2 images (in the same slice). ResultsT1W-SE image contrast between the GM and WM of all postmortem brains was inverted relative to the living brain. T1 (579 ms in GM and 307 ms in WM) and PD (64 in GM and 44 in WM) of the postmortem brain decreased compared with the living brain. While T1 of WM/GM remained below 1 even postmortem, the PD of WM/GM decreased. T2 (110 ms in GM and 98 ms in WM) of the postmortem brain did not differ from the living brain. ConclusionThe decrease in PD of WM/GM in the postmortem brain may be the major driver of contrast reversal between the GM and WM relative to the living brain.

Ultrasonography and Postmortem Magnetic Resonance Imaging of Bilateral Ocular Disease in a Heifer

Bovine ocular diseases are typically characterized by the concurrent appearances of both macroscopic and intraocular abnormalities. This study examines the diagnostic efficacy of a combination of ultrasonography and magnetic resonance imaging (MRI) for the bilateral ocular disease observed in a 9-month-old Japanese Black heifer. This case presented with bilateral strabismus and a white-colored lens structure in the right eye. A combination of ultrasonography and MRI revealed formations of corn-like and V-shaped membranous structures within the vitreous cavities of the left and right eyeballs, respectively. In the right eye, a cataract was suspected on both ultrasonogram and MRI. This case involved bilateral retinal detachments and strabismus similar to the signs of an autosomal recessive hereditary ocular disease; however, the cataract in the right eye differed from that hereditary disease. Finally, in genetic analysis, a known mutation of the WFDC1 gene was not detected. Ultrasonography is superior to MRI in demonstrating intraocular pathological changes. On the other hand, MRI is helpful for evaluating invasiveness of the ocular lesions to the peripheral structures. Thus, the combined use of these imaging modalities is recommended for diagnosing various bovine ocular diseases.

Forensic age estimation of the knee by post-mortem DR, CT, and MR imaging: a comparative study

It is believed by many that reference data for age estimation purposes must be imaging-modality specific. A study from our department has however proven otherwise. We therefore found it interesting to investigate this further by looking at the level of agreement between different imaging modalities. The aim of this study was to investigate the level of agreement between the three radiological modalities, computed tomography (CT), magnetic resonance imaging (MRI), and digital radiography (DR), in assessing the ossification of the epiphyses of the knee. A total of 34 deceased individuals of 10–25 years of age, brought in for a medicolegal autopsy at our department, were scanned by CT, MRI, and DR. The ossification stages of the three bones of the right knee, distal femoral, proximal tibial, and proximal fibular epiphysis were assessed using the established combined staging method by Schmeling et al. and Kellinghaus et al. Analysis of the results by Cohen’s weighted kappa showed a good agreement between CT and DR (K = 0.61–0.70), and MRI and DR (K = 0.68–0.79) but only moderate agreement between CT and MRI (K = 0.55–0.57). This leads us to conclude that different radiological images cannot be used interchangeably for age estimation purposes, so reference material needs to be imaging-modality specific. However, to make a more general conclusion research on a larger population is needed.

A novel reconstruction model for thoracic spinal cord injury in swine.

Spinal cord (SC) reconstruction (process to reestablish the severed neural continuity at the injury site) may provide better recovery from blunt SC injury (SCI). A miniature swine model of blunt SC compression was used to test the hypothesis that reconstruction of the SC with sural nerve in combination with surgical decompression and stabilization improves functional, macro- and microstructural recovery compared to decompression and stabilization alone. Following blunt T9-T11 SC compression injury, five adult Yucatan gilts randomly received laminectomy and polyethylene glycol (as fusogen) with (n = 3) or without (n = 2) sural nerve graft SC reconstruction. Fusogens are a heterogeneous collection of chemicals that fuse the axon membrane and are currently used to augment epineural coaptation during peripheral nerve graft reconstruction. Outcome measures of recovery included weekly sensory and motor assessments, various measurements obtained from computed tomography (CT) myelograms up to 12 weeks after injury Measurements from postmortem magnetic resonance imaging (MRI) and results from spinal cord histology performed 12 weeks after injury were also reported. Vertebral canal (VC), SC and dural sac (DS) dimensions and areas were quantified on 2-D CT images adjacent to the injury. Effort to stand and response to physical manipulation improved 7 and 9 weeks and 9 and 10 weeks, respectively, after injury in the reconstruction group. Myelogram measures indicated greater T13-T14 VC, smaller SC, and smaller DS dimensions in the reconstruction cohort, and increased DS area increased DS/VC area ratio, and higher contrast migration over time. Spinal cord continuity was evident in 2 gilts in the reconstruction cohort with CT and MRI imaging. At the SCI, microstructural alterations included axonal loss and glial scarring. Better functional outcomes were observed in subjects treated with sural nerve SC reconstruction. Study results support the use of this adult swine model of blunt SCI. Long-term studies with different nerve grafts or fusogens are required to expand upon these findings.

Noninvasive estimation of heart organ mass by postmortem magnetic resonance imaging and computed tomography compared to conventional autopsy in fetuses: a pilot study

ObjectivesThe purpose of this pilot study is to investigate the accuracy of mass estimation of the heart using postmortem MRI and CT in this population. MethodsThe mass of the heart was estimated using three different methods: sequential segmentation of the right and left ventricles by MRI in 30 patients; sequential segmentation of the left ventricle chamber using CT and an ellipsoid method of the left ventricle (LV) using CT in 6 patients. The estimated mass by each method was compared to conventional autopsy mass using linear regression. ResultsThe correlation between estimated and measured cardiac mass using postmortem MRI measurements of the right and left ventricles, CT derived volumes of the left ventricle, or by the LV ellipsoid CT method are as follows: y = 0.87744x - 0.74813 (R2 = 0.958); y = 0.6004x - 2.16 (R2 = 0.8681); y = 0.6019 - 2.1615 (R2 = 0.8599), respectively. When separating the fetuses evaluated by pmMRI into a ≤20 weeks subset or >20 weeks subset, the correlation are as follows: y = 0.5176x + 0.2428 (R2 = 0.645) and y = 0.91237x - 1.53647 (R2 = 0.9475), respectively. ConclusionMass of the heart at autopsy modestly correlates with MRI derived volumes measuring the right and left ventricles. The small sample in the CT derived volume of the left ventricle alone or by the simplified estimated method using the ellipsoid measurements of the left ventricle by CT compared to autopsy weights make it difficult to conclude CT's utility using these methods.

Detection of pulmonary thrombembolism and postmortem clotting on postmortem magnetic resonance imaging

The purpose of this study was to develop a feasible imaging protocol superior to postmortem computed tomography (PMCT) and to establish diagnostic parameters for diagnosing pulmonary thromboembolism (PE) on postmortem magnetic resonance imaging (PMMR).The study collective of 113 subjects was prospectively investigated by PMMR for the presence of PE and / or postmortem clotting (cruor). PE was detected in 20 cases; the remaining 93 cases were investigated for the morphology of cruor. Age grading was performed by PMMR, autopsy and histology. The postmortem sedimentation effect was used for the applied imaging protocol on PMMR (supine and prone position). Visual distension of the pulmonary arteries in PE was seen in all cases, but not in the controls. Re-positioning of the corpse from supine in prone position proved to be beneficial in 90 %. Postmortem motion artifacts are firstly described in 20.4 %. Hyperacute PE (grade 1) presented with a homogenous and hypointense signal on T2w images, acute PE (grade 2) with slightly heterogeneous, but still homogenous hypointense signal, subacute PE (grade 3) was with heterogeneous and slightly hyperintense signal and chronic PE (grade 4) with predominately homogenous with scarce portions of heterogeneous but hyperintense signal. PMMR allowed for the detection of PE and for in situ depiction of combined age grading.

Multimodal analytical tools for the molecular and elemental characterisation of lesions in brain tissue of multiple sclerosis patients

Multiple sclerosis (MS) is a prevalent immune-mediated inflammatory disease of the central nervous system inducing a widespread degradation of myelin and resulting in neurological deficits. Recent advances in molecular and atomic imaging provide the means to probe the microenvironment in affected brain tissues at an unprecedented level of detail and may provide new insights. This study showcases state-of-the-art spectroscopic and mass spectrometric techniques to compare distributions of molecular and atomic entities in MS lesions and surrounding brain tissues.MS brains underwent post-mortem magnetic resonance imaging (MRI) to locate and subsequently dissect MS lesions and surrounding white matter. Digests of lesions and unaffected white matter were analysed via ICP-MS/MS revealing significant differences in concentrations of Li, Mg, P, K, Mn, V, Rb, Ag, Gd and Bi. Micro x-ray fluorescence spectroscopy (μXRF) and laser ablation – inductively coupled plasma – time of flight – mass spectrometry (LA-ICP-ToF-MS) were used as micro-analytical imaging techniques to study distributions of both endogenous and xenobiotic elements. The essential trace elements Fe, Cu and Zn were subsequently calibrated using in-house manufactured gelatine standards. Lipid distributions were studied using IR-micro spectroscopy and matrix assisted laser desorption/ionisation mass spectrometry imaging (MALDI-MSI). MALDI-MSI was complemented with high-resolution tandem mass spectrometry and trapped ion mobility spectroscopy for the annotation of specified phospho- and sphingolipids, revealing specific lipid species decreased in MS lesions compared to surrounding white matter.This explorative study demonstrated that modern molecular and atomic mapping techniques provide high-resolution imaging for relevant bio-indicative entities which may complement our current understanding of the underlying pathophysiological processes.

Caudal regression syndrome type 1 with minimally invasive computed tomography and magnetic resonance imaging autopsy: a case report

BackgroundCaudal regression syndrome is a rare complex congenital anomaly with reduced penetrance and phenotypic variability characterized by osseous defects of the caudal spine, lower limb anomalies, and accompanying genitourinary, gastrointestinal/anorectal, and cardiac system soft tissue defects. We report a rare presentation of type 1 caudal regression syndrome in a pregnant woman with preexisting diabetes, in which early recognition of severe fetal anomalies on routine antenatal ultrasound facilitated confirmation with fetal magnetic resonance imaging to characterize extent of disease and prognosticate fetal outcome.Case presentationThis case of type 1 caudal regression syndrome in the setting of maternal pregestational diabetes mellitus resulted in stillbirth. The mother was a 29-year-old Caucasian primigravida female with past medical history of poorly controlled type 2 diabetes managed with metformin prior to pregnancy, prompting admission for glucose management and initiation of insulin at 13 weeks. Baseline hemoglobin A1c was high at 8.0%. Fetal ultrasound at 22 weeks was notable for severe sacral agenesis, bilateral renal pelvis dilatation, single umbilical artery, and pulmonary hypoplasia. Fetal magnetic resonance imaging at 29 weeks showed absent lower two-thirds of the spine with corresponding spinal cord abnormality compatible with type 1 caudal regression syndrome. The mother delivered a male stillborn at 39 and 3/7 weeks. Minimally invasive postmortem magnetic resonance imaging and computed tomography autopsy were performed to confirm clinical findings when family declined conventional autopsy. Etiology of sacral agenesis was attributed to poorly controlled maternal diabetes early in gestation.ConclusionMaternal preexisting diabetes is a known risk factor for development of congenital malformations. This rare case of type 1 caudal regression syndrome in a mother with preexisting diabetes with elevated hemoglobin A1c highlights the importance of preconception glycemic control in diabetic women and the utility of fetal magnetic resonance imaging for confirmation of ultrasound findings to permit accurate prognostication. Additionally, minimally invasive postmortem magnetic resonance imaging and computed tomography autopsy can facilitate diagnostic confirmation of clinical findings in perinatal death due to complex congenital anomalies while limiting the emotional burden on bereaved family members who decline conventional autopsy.

Diagnostic accuracy of coronary artery stenosis and thrombosis assessment using unenhanced multiplanar 3D post-mortem cardiac magnetic resonance imaging

BackgroundA 3D sequence was introduced to unenhanced post-mortem cardiac magnetic resonance imaging (PMCMR) to enable multiplanar coronary artery image analysis and to investigate its diagnostic accuracy for the diagnosis of coronary artery stenosis and thrombosis. Materials and MethodsN = 200 forensic cases with suspected coronary artery pathology underwent 3 Tesla PMCMR (sequence used: T2 weighted transversal 3D turbo spin echo) before autopsy. Main coronary artery stenosis and thrombosis were assessed in PMCMR by multiplanar image analysis by two observers. Coronary artery histology was determined as the gold standard and compared to PMCMR. Sensitivity, specificity, negative (NPV) and positive predictive values (PPV) with 95% confidence intervals were calculated. ResultsFor all coronary arteries combined, sensitivity was 75% (PPV 73%) for the diagnosis of stenosis and 72% (PPV 71%) for the diagnosis of thrombosis. Specificity was 92% (NPV 90%) for correct diagnosis of non-existing stenosis and 97% (NPV 97%) for non-existing thrombosis. Sensitivity for correct diagnosis of different degrees of stenosis ranged between 67% and 80% (PPVs 67–82%); specificity ranged between 96% and 99% (NPVs 96–99%). ConclusionMultiplanar PMCMR coronary artery stenosis and thrombosis assessment based on an unenhanced T2 weighted 3D sequence provide moderate sensitivity and high specificity for the diagnosis of coronary artery stenosis and/or thrombosis. Hence, 3D T2w PMCMR cannot reliably detect existing coronary artery stenosis and thrombosis but may be particularly useful for the exclusion of stenosis or thrombosis of the main coronary arteries.

Twenty Years of Managed Epilepsy for a Stranded Male Guadalupe Fur Seal (Arctocephalus townsendi) Secondary to Suspect Domoic Acid Toxicosis

Many wild otariids (sea lions and fur seals) strand along the California coast annually with seizures following presumed exposure to harmful algal blooms (HABs). This is a long-term case study of a stranded subadult male Guadalupe fur seal (Arctocephalus townsendi) that stranded in 2001 and within days after admission began demonstrating seizure activity. The epilepsy was stabilized with antiepileptic drug (AED) therapy and advanced imaging was performed. Magnetic resonance (MR) scans showed signs of encephalopathy consistent with domoic acid (DA) toxicosis. This fur seal was deemed “non-releasable” and over the following 19 years, he received supportive veterinary care and AED treatment at a permitted facility. In the summer of 2020, the fur seal showed progressive behavioral and functional deterioration whereupon humane euthanasia was performed. Post-mortem MR and diffusion tensor images (DTI) were acquired. A volumetric comparison with historic scans showed evidence of severe progressive unilateral right hippocampal atrophy. Histopathology confirmed severe chronic right and mild left hippocampal atrophy. The progressive degenerative brain changes demonstrate how adaptive brain function can be with neuronal atrophy secondary to DA exposure. This case highlights some considerations and decision-making processes needed for the rehabilitation and placement of wild stranded otariids with acquired epilepsy secondary to DA toxicity.