Postmortem Imaging Research Articles

Post-mortem perinatal imaging: what is the evidence?

Post-mortem imaging for the investigation of perinatal deaths is an acceptable tool amongst parents and religious groups, enabling a less invasive autopsy examination. Nevertheless, availability is scarce nationwide, and there is some debate amongst radiologists regarding the best practice and optimal protocols for performing such studies. Much of the published literature to date focusses on single centre experiences or interesting case reports. Diagnostic accuracy studies are available for a variety of individual imaging modalities (e.g. post-mortem CT, MRI, ultrasound and micro-CT), however, assimilating this information is important when attempting to start a local service.In this article, we present a comprehensive review summarising the latest research, recently published international guidelines, and describe which imaging modalities are best suited for specific indications. When the antenatal clinical findings are not supported by the post-mortem imaging, we also suggest how and when an invasive autopsy may be considered. In general, a collaborative working relationship within a multidisciplinary team (consisting of radiologists, radiographers, the local pathology department, mortuary staff, foetal medicine specialists, obstetricians and bereavement midwives) is vital for a successful service.

Accuracy and clinical utility of standard postmortem radiological imaging after early second trimester termination of pregnancy

ObjectiveThis study aims to assess accuracy and clinical utility of postmortem radiological exams [Magnetic Resonance Imaging (MRI), Computed Tomography (CT) and Radiography (XR)] after termination of pregnancy at <23 weeks’ gestation for congenital fetal malformations in comparison to autopsy. Study designThis a prospective single-center study on fetuses underwent termination of pregnancy for fetal defects. Overall concordance between any radiological exam and autopsy was evaluated. For postmortem MRI only, the following subgroups were analyzed: 1) total agreement; 2) agreement for main findings; 3) agreement for main findings but major relevant additional findings at autopsy; 4) total disagreement. Results174 cases were collected. The overall concordance with autopsy for main findings was 71% (115/163) for postmortem MRI and 99% (173/174) for prenatal ultrasound (US). Postmortem MRI detection rate was high for central nervous system (CNS) defects (98%), gastrointestinal, genitourinary and respiratory defects (100%), while it was poor for cardiovascular and musculoskeletal defects (25% and 42%, respectively). For musculoskeletal abnormalities, the performance of postmortem XR and postmortem CT exams improved the detection rate from 42% for postmortem MRI alone to 92%. ConclusionsPostmortem MRI has a good overall concordance for fetal defects after termination of pregnancy performed at <23 weeks. Along with autopsy, postmortem MRI may be offered for all cases of CNS defects in order to prevent inconclusive exams due to autolysis of the brain tissue, while postmortem CT and postmortem XR are indicated for musculoskeletal defects. In the presence of multiple abnormalities or cardiac defects the couple should be counseled on the poor performance of radiological investigations.

Postmortem Fetal Temperature Estimation with Magnetic Resonance Imaging: Apparent Diffusion Coefficient Measurements in the Vitreous Body and Cerebrospinal Fluid.

Magnetic resonance imaging (MRI) is increasingly used in postmortem fetal imaging. Several factors influence the quality of MRI in this setting, such as small size, autolytic and maceration changes, and temperature. Knowing the fetal temperature at the time of scanning can improve the MRI interpretation. Temperature can be calculated using diffusion-weighted imaging with measurements of the apparent diffusion coefficient (ADC) in the cerebrospinal fluid (CSF). However, this is complicated by small ventricle size and hemorrhage and, therefore, may be unreliable in postmortem imaging. The current study evaluated the feasibility and reliability of using the ADC for temperature measurements of the vitreous body compared to that of CSF. Two lambs were scanned postmortem at five different time points over 28 hours. Furthermore, 10 stillborn fetuses were scanned once, at 4 to 62 hours after birth. The temperature was measured with a digital thermometer and calculated using the ADCs of the vitreous body (lambs and fetuses) and CSF (fetuses). There was an excellent correlation between measured and calculated temperatures in vitreous bodies of lambs (r = 0.997, P < 0.001) and fetuses (r = 0.970, P < 0.001). The correlation between measured and calculated temperatures in the CSF was poor (r = 0.522, P = 0.122). The calculation of the temperature based on the ADC of the vitreous body is feasible and reliable for postmortem fetal imaging.

A novel male Japanese quail structural connectivity atlas using ultra-high field diffusion MRI at 11.7 T

The structural connectivity of animal brains can be revealed using post-mortem diffusion-weighted magnetic resonance imaging (MRI). Despite the existence of several structural atlases of avian brains, few of them address the bird’s structural connectivity. In this study, a novel atlas of the structural connectivity is proposed for the male Japanese quail (Coturnix japonica), aiming at investigating two lines divergent on their emotionality trait: the short tonic immobility (STI) and the long tonic immobility (LTI) lines. The STI line presents a low emotionality trait, while the LTI line expresses a high emotionality trait. 21 male Japanese quail brains from both lines were scanned post-mortem for this study, using a preclinical Bruker 11.7 T MRI scanner. Diffusion-weighted MRI was performed using a 3D segmented echo planar imaging (EPI) pulsed gradient spin-echo (PGSE) sequence with a 200 upmum isotropic resolution, 75 diffusion-encoding directions and a b-value fixed at 4500 s/mm2. Anatomical MRI was likewise performed using a 2D anatomical T2-weighted spin-echo (SE) sequence with a 150 upmum isotropic resolution. This very first anatomical connectivity atlas of the male Japanese quail reveals 34 labeled fiber tracts and the existence of structural differences between the connectivity patterns characterizing the two lines. Thus, the link between the male Japanese quail’s connectivity and its underlying anatomical structures has reached a better understanding.

The Digital Brain Bank, an open access platform for post-mortem imaging datasets.

Post-mortem magnetic resonance imaging (MRI) provides the opportunity to acquire high-resolution datasets to investigate neuroanatomy and validate the origins of image contrast through microscopy comparisons. We introduce the Digital Brain Bank (open.win.ox.ac.uk/DigitalBrainBank), a data release platform providing open access to curated, multimodal post-mortem neuroimaging datasets. Datasets span three themes-Digital Neuroanatomist: datasets for detailed neuroanatomical investigations; Digital Brain Zoo: datasets for comparative neuroanatomy; and Digital Pathologist: datasets for neuropathology investigations. The first Digital Brain Bank data release includes 21 distinctive whole-brain diffusion MRI datasets for structural connectivity investigations, alongside microscopy and complementary MRI modalities. This includes one of the highest-resolution whole-brain human diffusion MRI datasets ever acquired, whole-brain diffusion MRI in fourteen nonhuman primate species, and one of the largest post-mortem whole-brain cohort imaging studies in neurodegeneration. The Digital Brain Bank is the culmination of our lab's investment into post-mortem MRI methodology and MRI-microscopy analysis techniques. This manuscript provides a detailed overview of our work with post-mortem imaging to date, including the development of diffusion MRI methods to image large post-mortem samples, including whole, human brains. Taken together, the Digital Brain Bank provides cross-scale, cross-species datasets facilitating the incorporation of post-mortem data into neuroimaging studies.

PET in vivo generators 134Ce and 140Nd on an internalizing monoclonal antibody probe

The in vivo-generator radionuclides 140Nd (t1/2 = 3.4 d) and 134Ce (t1/2 = 3.2 d) were used to trace a urokinase-type plasminogen activator (uPA)-targeting mouse monoclonal antibody, ATN-291, in U87 MG xenograft tumor-bearing mice. ATN-291 is known to internalize on the uPA/uPA-receptor pair, making it an appropriate targeting vector for investigating the fate of in vivo generator daughters on internalizing probes. Ante-mortem and post-mortem PET imaging at 120 h post-injection gave no indication of redistribution of the positron emitting daughter nuclides 134La and 140Pr from tumor tissue (p > 0.5). The lack of redistribution indicates that the parent radionuclides 134Ce and 140Nd could be considered as long-lived PET-diagnostic matches to therapeutic radionuclides like 177Lu, 161Tb and 225Ac when internalizing bioconjugates are employed.

Operation Deans post-mortem imaging: A radiologist’s perspective

Mass casualty incidents are typically unexpected, disruptive and stressful events. Priority of resources are directed towards managing the live victims. Yet optimal death investigation of the remaining victims should also begin as early as is practicable. This presentation looks into the response of one hospital’s radiology department to help with post-mortem imaging of the deceased victims in the immediate aftermath of that country’s largest mass shooting incident.

Imaging in craniocervical trauma

Injuries to the craniocervical region are usually caused by high-velocity deceleration events, and are frequently fatal. Post-mortem imaging of this region has traditionally been difficult, due to the complex anatomy of the craniocervical region. The introduction of cross-sectional imaging has revolutionised the diagnosis of injuries to this area.

Organic solution-phase transmission electron microscopy of copolymer nanoassembly morphology and dynamics

Direct imaging of the dynamics of polymeric assemblies in organic solvents is an outstanding challenge. Herein, we apply liquid cell transmission electron microscopy (LCTEM) to study polymeric nanomaterials in organic solvents. LCTEM is distinct from other TEM methods as it can be applied to characterize the morphology of nanomaterials in organic solvents. To enable this demonstration, we examined electron-solvent interactions for two common organic solvents, N,N-dimethylformamide and methanol, and compared these solvents to water. For each solvent, we developed Monte Carlo simulations and kinetic radiolysis models, providing scattering and chemical insight, respectively. Guided by theoretical results, we applied LCTEM and postmortem mass spectral imaging of poly(styrene)-b-poly(4-vinylpyridine) assemblies in each solvent. Then, a worm-to-micelle transformation in poly(styrene)-b-poly(4-vinylpyridine) was triggered via organic solvent mixing during LCTEM, enabling an experiment not possible through a cryogenic TEM time series. Our work provides a pathway for an expanded examination of nanomaterials in organic solvents via LCTEM, a neglected research area despite the obvious prevalence of such materials across chemistry and materials science.

Microglia and Astrocyte Function and Communication: What Do We Know in Humans?

Microglia and astrocytes play essential roles in the central nervous system contributing to many functions including homeostasis, immune response, blood–brain barrier maintenance and synaptic support. Evidence has emerged from experimental models of glial communication that microglia and astrocytes influence and coordinate each other and their effects on the brain environment. However, due to the difference in glial cells between humans and rodents, it is essential to confirm the relevance of these findings in human brains. Here, we aim to review the current knowledge on microglia-astrocyte crosstalk in humans, exploring novel methodological techniques used in health and disease conditions. This will include an in-depth look at cell culture and iPSCs, post-mortem studies, imaging and fluid biomarkers, genetics and transcriptomic data. In this review, we will discuss the advantages and limitations of these methods, highlighting the understanding these methods have brought the field on these cells communicative abilities, and the knowledge gaps that remain.

Sudden Cardiac Death and Ex-Situ Post-Mortem Cardiac Magnetic Resonance Imaging: A Morphological Study Based on Diagnostic Correlation Methodology.

During the last years, post-mortem imaging has gradually been assumed within research in the field of forensic pathology. This role appears to be clearly and simply applied in the trauma field with the use of conventional radiography or Post Mortem Computed Tomography (PMCT). Recently, particular attention was paid to cardiovascular imaging using Post Mortem Magnetic Resonance Imaging (PMMRI). The present experimental study aims to: (i) confirm the efficacy of a Post Mortem Cardiac Resonance Imaging (PMCRI) study protocol for the study of human hearts collected during the autopsy; (ii) apply the defined protocol on subjects who died of “SCD (sudden cardiac death)”, to identify alterations that could guide subsequent sampling. Two hearts of healthy subjects (A: male 22 years; B: female 26 years), who died from causes other than SCD were collected and compared to hearts that belonged to SCD individuals (C: male, 47 years old; D: female, 44 years old; E: male; 72 years old). The exams were performed on a 1.5 T scanner (Philips Intera Achieva, Best, the Netherlands) on hearts collected during autopsy and after a 30-day formalin fixation. Two readers analyzed the obtained images blindly and after randomization. From the comparison between the data from imaging and the macroscopic and histological investigations carried out, the present study proved the effectiveness of a PMMRI protocol to study ex-situ hearts. Moreover, it suggested the following semeiology in post-mortem SCD cases: the hyperintense area with indistinct margins in the Short Tau Inversion Recovery (STIR) sequence was linked to edema or area of pathological fibers, whereas the hypointense area in the T2-FFE sequences was linked to fibrosis. PMMRI can provide a valuable benefit to post-mortem investigations, helping to distinctly improve the success rate of histological sampling and investigations, which remains the gold standard in the diagnosis of sudden death.

The Evaluation of the Four-Chamber Cardiac Dissection Method of the Fetal Heart as an Alternative to Conventional Inflow-Outflow Dissection in Small Gestational-Age Fetuses.

The examination of very small fetal hearts requires special equipment and a specialist that are not available in many general pathology laboratories. Compared to conventional examination, the four-chamber cardiac dissection (4CCD) method can be performed by any pathologist using instruments generally available in pathology services. The aim of this study is to evaluate the efficiency of the 4CCD method in the examination of small fetal hearts using post-mortem magnetic resonance imaging (pm-MRI) at 7T as the standard. Twelve fetuses with gestational ages between 13 and 19 weeks have been included in this study. All fetuses underwent pm-MRI examination prior to pathologic examination. The 4CCD method was used for the cardiac examination in all cases following the same guidelines for cardiac sectioning. The 4CCD was able to identify all cardiac anatomic structures as compared to pm-MRI at 7T, demonstrating a sensibility of 95.8% (95% CI, 94.5–95.8) and specificity of 100% (95% CI, 32.3–100). The overall accuracy in identifying cardiac anatomic structures was 95.8% (95% CI, 93.4–95.8). Additionally, the 4CCD method was able to detect cardiac anomalies with an overall diagnostic accuracy of 91% (95% CI, 85.8–94.2), sensibility of 67.6% (95% CI, 54.5–75.3), and specificity of 97% (95% CI, 93.7–99) as compared to pm-MRI at 7T. The four-chamber view dissection method can be considered as an alternative to the conventional inflow–outflow dissection method in selected cases.

Forensic radiography services: The experiences of radiographers and forensic pathologists in Nigeria

IntroductionRadiographers can play an essential role within forensic teams and contribute by producing high quality images. There are several aspects of forensic imaging, these commonly include but are not limited to imaging as part of post-mortem investigations, evaluation of non-accidental injuries and the identification of the presence of illicit drugs.In some countries radiographers perform post-mortem imaging before conventional autopsy, a practice that needs to be advanced in less developed countries. In this study, we explored experiences, attitudes and knowledge of radiographers' and forensic pathologists’ in delivering forensic radiography services in Nigeria. MethodA qualitative exploratory descriptive study was undertaken. Three focus group interviews were conducted with 14 radiographers and five forensic pathologists. Participants were recruited through purposive sampling from two government owned tertiary hospitals in Lagos-State, Nigeria. Focus groups were audio recorded and lasted approximately 1 h. Data were thematically analysed and managed using the Atlas Ti computer software. ResultsForensic pathologists and radiographers perceived forensic radiography differently. Radiographers reported a reluctance to take images of deceased people and were generally not aware of medicolegal issues involved in performing forensic examinations. Three themes emerged in the study, namely participants' experiences in forensic radiography, participants' knowledge of forensic radiography principles and guidelines, and participants’ attitude towards forensic radiography services. ConclusionImproving forensic radiography services is likely to require development of postgraduate curricula in forensic radiography and a fellowship curriculum in radiography for forensic pathologists. Implication for practiceThis paper argues that, for radiographers to produce high quality diagnostic images that can assist the forensic team in medico-legal investigations subspecialisation in the field of forensic radiography would be advantageous.

Diagnosis of SLC25A46-related pontocerebellar hypoplasia in two siblings with fulminant neonatal course: role of postmortem CT and whole genomic analysis: a case report

BackgroundPontocerebellar hypoplasia (PCH) is increasingly known as a degenerative disease rather than simple “hypoplasia”. At least 21 disease-causing genes have been identified for PCH so far. Because PCH is very heterogenous, prognostic prediction based solely on clinical or radiologic findings is not feasible.Case presentationHere, we report two siblings who had a fulminant neonatal course. The documentation of pontocerebellar hypoplasia by postmortem brain CT imaging in one of the siblings and a subsequent complex and comprehensive whole genome analysis established that both siblings had bi-allelic compound heterozygous variants (a splicing variant and a deletion) in the SLC25A46 gene which encodes a solute carrier protein essential for mitochondrial function. Long-read whole genome sequencing was required to confirm the presence of the deletion. The fulminant courses suggest that SLC25A46-related PCH is an acutely progressive degenerative condition starting in utero, rather than a simple static hypoplasia.ConclusionThe genomic analysis was instrumental and essential to solving the enigma of the unexplained neonatal deaths of these two siblings and to provide accurate genetic counseling.

Reactive astrogliosis: A friend or foe in the pathogenesis of Alzheimer's disease.

Astrocytes are highly efficient homeostatic glial cells playing a crucial role in optimal brain functioning and homeostasis. Astrocytes respond to changes in brain homoeostasis following central nervous system (CNS) injury/diseased state by a specific defence mechanism called reactive astrogliosis. Recent studies have implicated and placed reactive astrogliosis in the centre of pathophysiology of Alzheimer's disease (AD) and other neurodegenerative disorders. The AD biomarker field is evolving rapidly with new findings providing strong evidence which supports the notion that a reactive astrogliosis is an early event in the time course of AD progression which may precede other pathological hallmarks of AD. Clinical/translational in vivo PET and in vitro postmortem brain imaging studies demonstrated 'a first and second wave' of reactive astrogliosis in AD with distinct close-loop relationships with other pathological biomarkers at different stages of the disease. At the end stages, reactive astrocytes are found to be associated, or in proximity, with amyloid plaque and tau pathological deposits in postmortem AD brains. Several new PET-tracers, which are being in pipeline and validated at a very fast pace for mapping and visualising reactive astrogliosis in the brain, will provide furtherinvaluable mechanistic insights into AD and other non-AD dementia pathologies. The complementary roles of microglia and astrocyte activation in AD progression, along with the clinicalvalue ofnew fluid astrocytes biomarkers in the context of existing biomarkers, arethe latest avenue that needs further exploration.

Coupling of 3D Porous Hosts for Li Metal Battery Anodes with Viscous Polymer Electrolytes

As the energy storage markets demand increased capacity of rechargeable batteries, Li metal anodes have regained major attention due to their high theoretical specific capacity. However, Li anodes tend to have dendritic growth and constant electrolyte consumption upon cycling, which lead to safety concerns, low Coulombic efficiency, and short battery lifetime. In this work, both conductive and non-conductive 3D porous hosts were coupled with a viscous (melt) polymer electrolyte. The cross-section of the hosts showed good contact between porous hosts and the melt polymer electrolyte before and after extensive cycling, indicating that the viscous electrolyte successfully refilled the space upon Li stripping. Upon deep Li deposition/stripping cycling (5 mAh cm−2), the non-conductive host with the viscous electrolyte successfully cycled, while the conductive host allowed rapid short circuiting. Post-mortem cross-sectional imaging showed that the Li deposition was confined to the top layers of the host. COMSOL simulations indicated that current density was higher and more restricted to the top of the conductive host with the polymer electrolyte than the liquid electrolyte. This resulted in quicker short circuiting of the polymer electrolyte cell during deep cycling. Thus, the non-conductive 3D host is preferred for coupling with the melt polymer electrolyte.

Application and Prospect of Postmortem Imaging Technology in Forensic Cardiac Pathology: A Systemic Review

Application and Prospect of Postmortem Imaging Technology in Forensic Cardiac Pathology: A Systemic Review

Imaging and Minimally Invasive Biopsy for Postmortem Pulmonary Fat Embolism Diagnosis

In recent years, imaging technologies and minimally invasive biopsy have been gaining importance in forensic settings. This study aimed to evaluate the role of imaging and minimally invasive biopsy in postmortem diagnosis of pulmonary fat embolism. This was a systematic literature review by using Pubmed, EBSCO-Host, and ProQuest to search for studies on postmortem diagnosis of pulmonary fat embolism with postmortem imaging and minimally invasive biopsy. Five studies were included in the systematic review. These studies employed the following diagnostic technics: postmortem computed tomography (PMCT), postmortem computed tomography angiography (PMCTA), percutaneous needle biopsy (PNB), postmortem magnetic resonance (PMMR), and traditional autopsy. Imaging and minimally invasive biopsy are potential modalities that might complement or even replace traditional autopsy in diagnosing PFE. Further studies are needed to confirm the sensitivity and specificity of each technique.

Changes in magnetic resonance imaging relaxation time on postmortem magnetic resonance imaging of formalin-fixed human normal heart tissue

BackgroundPostmortem magnetic resonance imaging (MRI) has been used to investigate the cause of death, but due to time constraints, it is not widely applied to the heart. Therefore, MRI analysis of the heart after formalin fixation was previously performed. However, the changes in MRI signal values based on the fixation time of formalin were not investigated. The objective was to investigate changes over time in the T1- and T2-values of MRI signals in normal areas of hearts removed during autopsy, hearts subsequently fixed in formalin, and heart specimens sliced for the preparation of pathological specimens.MethodsThe study subjects were 21 autopsy cases in our hospital between May 26, 2019 and February 16, 2020 whose hearts were removed and scanned by MRI. The male:female ratio was 14:7, and their ages at death ranged from 9 to 92 years (mean age 65.0 ± 19.7 years). Postmortem (PM)-MRI was conducted with a 0.3-Tesla (0.3-T) scanner containing a permanent magnet. A 4-channel QD head coil was used as the receiver coil. Scans were performed immediately after removal, post-formalin fixation, and after slicing; 7 cases were scanned at all three time points.ResultsThe T1- and T2-values were calculated from the MRI signals of each sample organ at each scanning stage. Specimens were sliced from removed organs after formalin fixation, and the changes in T1- and T2-values over time were graphed to obtain an approximate curve. The median T1-values at each measurement time point tended to decrease from immediately after removal. The T2-values showed the same tendency to decrease, but this tendency was more pronounced for the T1-values.ConclusionMRI signal changes in images of heart specimens were investigated. Formalin fixation shortened both T1- and T2-values over time, and approximation formulae were derived to show these decreases over time. The shortening of T1- and T2-values can be understood as commensurate with the reduction in the water content (water molecules) of the formalin-fixed heart.

Effects of hybridization and ply thickness on the strength and toughness of composite laminates

This work presents the results of an experimental study performed in carbon/epoxy composite materials manufactured using a ply-level hybridization technique. The aim of the study is to investigate the potential of such hybridization technique to promote pseudo-ductile failure, and to enhance fracture toughness. Two thin-ply carbon-epoxy systems and three different carbon-carbon hybrid lay-ups are considered. Both strength and fracture tests are performed on the manufactured laminates and the properties of the hybrid materials are compared to those of the baseline non-hybrid composites. Digital Image Correlation and post-mortem X-ray imaging are used to analyze the fracture process of the different materials. The comparison of the mechanical response of the different materials demonstrates that, by means of thin ply hybridization, a pseudo-ductile failure in tension can be obtained, associated with fibre fragmentation. However, the hybridization seems not to be responsible for the increased fracture toughness that is ascribable to the ply-thickness effect.