Background and current status of postmortem imaging in Japan: short history of "Autopsy imaging (Ai)"

Postmortem CT and MRI for detecting bowel obstruction in cases of pediatric sepsis deaths

This article describes the utility of postmortem CT and MRI in diagnosing pediatric bowel obstruction (BO) as the cause of septic shock-induced death. Six pediatric cases with confirmed septic shock were retrospectively analyzed. Postmortem CT scans revealed clear signs of BO in all cases, with volvulus, intussusception, diaphragmatic hernia, or Meckel's diverticulum identified. MRI scans, performed in three cases, did not provide additional diagnostic information. The presented case series highlights the potential of postmortem CT for diagnosing BO in children, potentially aiding in understanding the cause and manner of death. While MRI offered limited additional benefits, its role in conjunction with CT and autopsy warrants further exploration. Combining these modalities could enhance diagnostic accuracy and provide a more complete picture of the cause of death in children.

The effects of bystander interventions for foreign body airway obstruction on survival and neurological outcomes: Findings of the MOCHI registry

INTRODUCTION

Foreign body airway obstruction (FBAO) is a life-threatening condition. We aimed to quantify the impact of bystander FBAO interventions on survival and neurological outcomes.

METHODS

We conducted a Japan-wide prospective, multi-center, observational study including all FBAO patients who presented to the Emergency Department from April 2020 to March 2023. Information on bystander FBAO interventions was collected through interviews with emergency medical services personnel. Primary outcomes included 1-month survival and favorable neurologic outcome defined as Cerebral Performance Category 1 or 2. We performed a multivariable logistic regression and a Cox proportional hazards modeling to adjust for confounders.

RESULTS

We analyzed a total of 407 patients in the registry who had the median age of 82 years old (IQR 73-88). The FBAO incidents were often witnessed (86.5%, n = 352/407) and the witnesses intervened in just over half of the cases (54.5%, n = 192/352). The incidents frequently occurred at home (54.3%, n = 221/407) and nursing home (21.6%, n = 88/407). Common first interventions included suction (24.8%, n = 101/407) and back blow (20.9%, n = 85/407). The overall success rate of bystander interventions was 48.4% (n = 93/192). About half (48.2%, n = 196/407) survived to 1-month and 23.8% patients (n = 97/407) had a favorable neurological outcome. Adjusting for pre-specified confounders, bystander interventions were independently associated with survival (hazard ratio, 0.55; 95% CI, 0.39-0.77) and a favorable neurological outcome (adjusted OR, 2.18; 95% CI, 1.23-3.95).

CONCLUSION

Bystander interventions were independently associated with survival and favorable neurological outcome, however, they were performed only in the half of patients.

Distinguishing true from pseudo hematoma in the cervical spinal canal using postmortem computed tomography

Spinal cord injury is difficult to detect directly on postmortem computed tomography (PMCT) and it is usually diagnosed by indirect findings such as a hematoma in the spinal canal. However, we have encountered cases where the hematoma-like high-attenuation area in the cervical spinal canal was visible on PMCT, while no hematoma was observed at autopsy; we called it a "pseudo hematoma in the cervical spinal canal (pseudo-HCSC)." In this retrospective study, we performed statistical analysis to distinguish true from pseudo-HCSC. The cervical spinal canal was dissected in 35 autopsy cases with a hematoma-like high-attenuation area (CT values 60-100 Hounsfield Unit (HU)) in the spinal canal from the first to the fourth cervical vertebrae in axial slices of PMCT images. Of these 22 had a hematoma and 13 did not (pseudo-HCSC). The location and length of the hematoma-like high-attenuation and spinal cord areas were assessed on reconstructed PMCT images, true HCSC cases had longer the posterior hematoma-like area and shorter the spinal cord area in the midline of the spinal canal (P < 0.05). Furthermore, we found that true HCSC cases were more likely to have fractures and gases on PMCT while pseudo-HCSC cases were more likely to have significant facial congestion (P < 0.05). We suggest that pseudo-HCSC on PMCT is related to congestion of the internal vertebral venous plexus. This study raises awareness about the importance of distinguishing true HCSC from pseudo-HCSC in PMCT diagnosis, and it also presents methods for differentiation between these two groups.

A Virtual, 3D Multimodal Approach to Victim and Crime Scene Reconstruction

In the last two decades, forensic pathology and crime scene investigations have seen a rapid increase in examination tools due to the implementation of several imaging techniques, e.g., CT and MR scanning, surface scanning and photogrammetry. These tools encompass relatively simple visualization tools to powerful instruments for performing virtual 3D crime scene reconstructions. A multi-modality and multiscale approach to a crime scene, where 3D models of victims and the crime scene are combined, offers several advantages. A permanent documentation of all evidence in a single 3D environment can be used during the investigation phases (e.g., for testing hypotheses) or during the court procedures (e.g., to visualize the scene and the victim in a more intuitive manner). Advanced computational approaches to understand what might have happened during a crime can also be applied by, e.g., performing a virtual animation of the victim in the actual context, which can provide important information about possible dynamics during the event. Here, we present an overview of the different techniques and modalities used in forensic pathology in conjunction with crime scene investigations. Based on our experiences, the advantages and challenges of an image-based multi-modality approach will be discussed, including how their use may introduce new visualization modalities in court, e.g., virtual reality (VR) and 3D printing. Finally, considerations about future directions in research will be mentioned.

Methamphetamine-related forensic autopsy cases in a Japanese prefecture over a 7-year period: Characteristics of deaths and blood concentrations

Understanding the actual conditions of methamphetamine (MA)-related death is important from the perspectives of criminal justice and public health. In this report, we review 104 cases of MA-related death handled by our departments between January 2014 and December 2020. Based on information from police and autopsy examinations, we classified the cases into the following categories: "accidental intoxication" ("MA only" and "multiple drugs or alcohol"), "fatal disease" ("definitively MA-related," "possibly MA-related," and "unlikely MA-related"), "accident," "suicide," "homicide," and "undetermined." The total number and annual trends for each category and their respective femoral blood concentrations were investigated. "Fatal disease" was the most common category (48 cases), followed by "suicide" (25 cases), "accidental intoxication" (14 cases), and "accident" (11 cases). "Definitively MA-related" in which MA may have played a role in their onset or exacerbation accounted for the majority of "fatal disease": 12 cases of heart disease, 4 cases of aortic dissection, 12 cases of cerebral hemorrhage, and 4 cases of subarachnoid hemorrhage. Cases classified as "definitively MA-related" died with lower femoral blood concentrations of MA compared with "MA only." Cases with "fatal disease" might have been misdiagnosed as "death by natural causes" if a proper autopsy and toxicology examinations were not performed. In death investigations, it is necessary to keep in mind that there are some MA-related deaths, and efforts should be made to increase awareness about the risk of death in using this drug.

Optimization of the fluid-attenuated inversion recovery (FLAIR) imaging for use in autopsy imaging of the brain region using synthetic MRI

BACKGROUND

The failure of cerebrospinal fluid (CSF) signal suppression in postmortem fluid-attenuated inversion recovery (FLAIR) of the brain is a problem.

OBJECTIVE

The present study was to clarify the relationship between the temperature of deceased persons and CSF T1, and to optimize the postmortem brain FLAIR imaging method using synthetic MRI.

METHODS

Forehead temperature was measured in 15 deceased persons. Next, synthetic MRI of the brain was performed, the CSF T1 was measured, and the optimal TI was calculated. Two types of FLAIR images were obtained with the clinical and optimal TI. The relationship between forehead temperature and the CSF T1 and optimal TI was evaluated. The optimized FLAIR images were physically and visually evaluated.

RESULTS

The CSF T1 and optimal TI were strongly correlated with forehead temperature. Comparing the average SNR and CNR ratios and visual evaluation scores of the two FLAIR images, those captured with the optimal TI showed statistically lower SNR, higher CNR, and higher visual evaluation scores (p< 0.01).

CONCLUSIONS

Synthetic MRI enables the quantification of the CSF T1 resulting from postmortem temperature decreases and calculation of the optimal TI, which could aid in improving the failure of CSF signal suppression and in optimizing postmortem brain FLAIR imaging.

Usefulness of virtual autopsy in diagnosing pathologies in the paediatric population: A systematic review

Objective

Virtual autopsy is a non-invasive/minimally invasive method for conducting an autopsy, with the assistance of imaging techniques. We aim to review the benefits of virtual autopsy in detecting pathologies in the paediatric population.

Method

The procedure adhered to Institute of Medicine and Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines. Seven databases including MEDLINE and SCOPUS were searched for articles published 2010-2020 worldwide in English. A narrative synthesis of the findings of included studies was carried out to discuss and summarize the results of the review.

Results

From 686 studies on paediatric deaths, 23 met selection/quality criteria. Virtual autopsy was better than conventional autopsy in detecting skeletal lesions and bullet trajectory, thus a crucial tool in the investigation of traumatic and firearm deaths. Virtual autopsy was superior to conventional autopsy in identifying the point of bleeding in postoperative deaths and objectively quantifying air/fluid in body cavities. Virtual autopsy was a useful adjunct for detecting pulmonary thrombo-embolism, foreign body aspiration, drowning and metastatic malignancies. The use of non-contrast imaging in investigating natural paediatric deaths did not offer more information than conventional autopsy. Misinterpretation of normal post-mortem changes as pathological findings was another disadvantage of virtual autopsy leading to erroneous conclusions. But accuracy may be improved with contrast enhancement and post-mortem magnetic resonance imaging.

Conclusion

Virtual autopsy is a crucial tool in the investigation of traumatic and firearm deaths in the paediatric population. Virtual autopsy will be useful as an adjunct to conventional autopsy in asphyxial deaths, stillbirths and decomposed bodies. Virtual autopsy has limited value in differentiating antemortem and post-mortem changes with the added risk of misinterpretations, therefore should be used with caution in natural deaths.

Forensic imaging: a powerful tool in modern forensic investigation

Forensic imaging is a non-invasive examination process during the forensic investigation. It is mainly used in forensic pathology as an adjunct to the traditional autopsy. In the past two decades, forensic imaging has been vigorously developed by forensic experts from computed tomography (CT) to multiple augmented techniques through CT and magnetic resonance imaging (MRI). The application field of forensic imaging has also been broadened as its advantages are recognised by more forensic practitioners. In addition to the forensic pathology, this technique has been used in other forensic disciplines, including forensic anthropology, forensic odontology, forensic ballistics and wildlife forensics, etc. This article reviews the development of forensic imaging as the practice and research development in different forensic disciplines based on the relevant literature analysis.

Role of autopsy imaging-computed tomography in the post-mortem study of farm animals

BACKGROUND

Autopsy imaging (Ai) is used to determine the cause of death, providing pre-dissection information. Ai is often used in the field of human forensic medicine but has never been applied on farm animals.

METHODS

Ai-computed tomography (CT) was performed before necropsy for farm animals (one goat, one ox, one cow and three calves) that died or were euthanised.

RESULTS

Ai-CT findings of rib fractures (case 1), urethral calculi (case 2), multiple osteolytic bone lesions (case 3 and 4) and hair balls (case 4) were confirmed by dissection. However, a tentative diagnosis of actinomycosis was made in an ox (case 5) using antemortem radiography and Ai-CT, and the mass was identified as ameloblastic fibro-odontoma on histological examination. A tentative diagnosis of maxillary abscess was made from antemortem radiography in a cow (case 6); however, the lesion was shown to be maxillary neoplasia on Ai-CT. The mass was identified as hemangiosarcoma on histopathological examination.

CONCLUSION

Ai is helpful in pathological examination because the specific findings are known before the dissection, the lesions can be pinpointed in the pathological dissection, facilitating workflow; furthermore, the oversight of lesions can be reduced. In addition, Ai-CT images, including three-dimensional images and a three-dimensional printed model, allowed an easy understanding of pathology among students and farmers. Ai-CT for farm animals represents a novel option for veterinary education.

Technical and interpretive pitfalls of postmortem CT: Five examples of errors revealed by autopsy

Image acquisition of dead bodies, particularly using postmortem computed tomography (PMCT), has become common in forensic investigations worldwide. Meanwhile, in countries such as Japan which have an extremely low rate of autopsy, PMCT is being increasingly used in the clinical field to certify the cause of death (COD) without performing an autopsy or toxicological tests, even in cases of unnatural death. Additionally, these PMCT images are predominantly interpreted by clinical personnel such as emergency physicians or clinicians who are not trained in PMCT interpretation and who work for the police, that is, the so-called police doctors. Many potential pitfalls associated with the use of PMCT have been previously described in textbooks and published papers, including the pitfalls of not performing a complete forensic pathology investigation, and the use of physicians without appropriate PMCT training to interpret PMCT and direct death investigation and certification. We describe five examples in which apparent misdiagnosis of COD based on PMCT misinterpretation was revealed by autopsy. Here are the five examples of errors: (1) Postmortem changes were misinterpreted as COD, (2) resuscitation effects were misinterpreted as COD, (3) COD was determined after an incomplete examination, (4) fatal findings caused by external origin were wrongly interpreted as 'of internal origin' based on PMCT, and (5) non-fatal findings on PMCT were wrongly interpreted as fatal. Interpretation of PMCT by appropriately trained physicians and an accompanying complete forensic investigation, including autopsy when indicated, is necessary to prevent significant errors in COD determination and related potential adverse medicolegal consequences.

Height and Mortality from Aortic Aneurysm and Dissection

AIMS

Reports on the association between height and aortic disease have been modest, and there are only a few studies investigating the association between height and mortality from specific aortic disease types or by sex.

METHODS

We conducted the Japan Collaborative Cohort Study, a prospective study of 99,067 Japanese (41,730 men and 57,337 women) aged 40-79 years old. Height was self-reported, and the participants were followed up from 1988-1989 to the end of 2009. Sex-specific hazard ratios (95% confidence intervals) of mortality from aortic disease type according to sex-specific quartiles of height were analyzed using the Cox proportional hazards model.

RESULTS

During the median follow-up period of 19.1 years, the numbers of deaths due to aortic aneurysm, thoracic aortic aneurysm, abdominal aortic aneurysm, and aortic dissection were 87, 29, 48, and 56 among men and 35, 17, 15, and 65 among women, respectively. The sex-specific multivariate hazard ratios (95% confidence intervals) and p for trend for the highest versus lowest quartiles of height were 1.10 (0.66-1.83), p=0.58 among men and 1.54 (0.85-2.79), p=0.06 among women for total aortic disease; 1.85 (0.80-4.28), p=0.16 among men and 5.67 (0.90-35.77), p=0.08 among women for abdominal aortic aneurysm; and 1.13 (0.48-2.64), p=0.65 among men and 1.70 (0.82-3.50), p=0.04 among women for aortic dissection. The positive association was observed for both sexes, albeit more prominent among women. No association was found between height and mortality from thoracic aortic aneurysms.

CONCLUSIONS

As per our findings, we were able to determine that height was positively associated with mortality from abdominal aortic aneurysm in the Japanese population.

Longitudinal comparison of ascites attenuation between antemortem and postmortem computed tomography

OBJECTIVE

To investigate the changes in ascites attenuation between antemortem (AMCT) and postmortem computed tomography (PMCT) analyses of the same subjects.

METHODS

Thirty-five subjects who underwent unenhanced or enhanced AMCT within 7 days before death, unenhanced PMCT, and autopsy were evaluated. In each subject, ascites attenuation was measured at similar sites on AMCT and PMCT. Attenuation changes were evaluated in 42 unenhanced AMCT/PMCT site pairs (23 subjects) and 20 enhanced AMCT/PMCT site pairs (12 subjects). Factors contributing to CT attenuation changes were also assessed, including the time interval between AMCT and PMCT, serum albumin level, estimated glomerular filtration rate, and ascites volume.

RESULTS

Significantly elevated CT attenuation was observed between enhanced AMCT and PMCT (12.2 ± 6.3 vs. 18.7 ± 10.4 Hounsfield units; paired t-test, p = 0.006), but not between unenhanced AMCT and PMCT (13.5 ± 8.9 vs. 13.4 ± 9.3; p = 0.554). A significant inverse association was observed between the degree of CT attenuation change and the time interval between enhanced AMCT and PMCT (Spearman's rank correlation coefficient, r = -0.56, p = 0.01).

CONCLUSIONS

We confirmed an elevated level of ascites attenuation on PMCT relative to AMCT in subjects who underwent enhanced AMCT shortly before death.

Oleic Acid (OA), A Potential Dual Contrast Agent for Postmortem MR Angiography (PMMRA): A Pilot Study

Choosing proper perfusates as contrast agents is an important aspect for postmortem magnetic resonance angiography (PMMRA). However, in this emerging field, the number of suitable kinds of liquid is still very limited. The objective of this research is to compare MR images of oleic acid (OA) with paraffin oil (PO) in vitro and in ex situ animal hearts, in order to evaluate the feasibility to use OA as a novel contrast agent for PMMRA. In vitro, OA, PO and water (control) were introduced into three tubes separately and T₁weighted-spin echo (T₁w-SE) and T₂w-SE images were acquired on a 1.5T MR scanner. In the second experiment, OA and PO were injected into left coronary artery (LCA) and left ventricle (LV) of ex situ bovine hearts and their T₁w-SE, T₂w-SE, T₁w-multipoint Dixon (T₁w-mDixon) and 3DT₂w-mDixon images were acquired. The overall results indicate that OA may have a potential to be used as a dual (T₁ and T₂ based) contrast agent for PMMRA when proper sequence parameters are utilized. However, as the pilot study was based on limited number of animal hearts, more researches using OA in cadavers are needed to validate our findings.

Protocol for a nationwide prospective, observational cohort study of foreign-body airway obstruction in Japan: the MOCHI registry

INTRODUCTION

Foreign body airway obstruction (FBAO) is a major public health issue worldwide. In 2017, there were more than 5000 fatal choking cases in the USA alone, and it was the fourth leading cause of preventable injury-related death in the home and community. In Japan, FBAO is the leading cause of accidental death and with almost 9000 fatalities annually. However, research on FBAO is limited, particularly on the impact of a foreign body (FB) removal manoeuvres by bystanders. The primary objective of this study is to determine the impact of bystander FB removal manoeuvres on 1 month neurological outcome. Our secondary objectives include (1) evaluating the efficacy of a variety of FB removal manoeuvres; (2) identifying risk factors for unsuccessful removal and (3) evaluating the impact of time intervals from incidents of FBAO to FB removal on neurological outcome.

METHODS AND ANALYSIS

We will conduct a nationwide multi-centre prospective cohort study of patients with FBAO who present to approximately 100 emergency departments in both urban and rural areas in Japan. Research personnel at each participating site will collect variables including patient demographics, type of FB and prehospital variables, such as bystander FB removal manoeuvres, medical interventions by prehospital personnel, advanced airway management and diagnostic findings. Our primary outcome is 1 month favourable neurological outcome defined as cerebral performance category 1 or 2. Our secondary outcomes include success of FB removal manoeuvres and complications from the manoeuvres. We hypothesise that bystander FB removal manoeuvres improve patient survival with a favourable neurological outcome.

ETHICS AND DISSEMINATION

This study received research ethics approval from Nippon Medical School Hospital (B-2019-019). Research ethics approval will be obtained from all participating sites before entering patients into the registry. The study was registered at the University Hospital Medical Information Network (UMIN) Clinical Trials Registry.

TRIAL REGISTRATION NUMBER

UMIN 000039907.

Utility of unenhanced postmortem computed tomography for investigation of in-hospital nontraumatic death in children up to 3 years of age at a single Japanese tertiary care hospital

To evaluate the utility of unenhanced postmortem computed tomography (PMCT) for the investigation of in-hospital nontraumatic death in children up to 3 years of age.This study included the cadavers of children who died from intrinsic diseases before 3 years of age. The major underlying disease and the main organ-disease systems associated with the immediate causes of death were determined by clinical evaluation, PMCT, and autopsy, which were used as a reference standard. The rates of concordance between the former two methods and autopsy were calculated for all cases.In total, 22 cadavers (12 male and 10 female; mean age, 6.1 ± 8.2 months) were included. The rates of concordance between clinical evaluation/PMCT and autopsy for diagnosis of the major underlying disease and main organ-disease systems associated with the immediate causes of death were 100%/36% (P = .0015) and 59%/41% (P = .37), respectively. In cases where the respiratory system was associated with the immediate cause of death, PMCT showed greater diagnostic sensitivity (90%) than did clinical evaluation (20%). In contrast, the diagnostic sensitivity of PMCT was lower than that of clinical evaluation in cases involving disorders of the cardiac system and multiple organ systems (0% vs 100% for both).The findings of this study suggest that the use of unenhanced PMCT with clinical evaluation can result in improved detection of the immediate cause of death in select cases of in-hospital nontraumatic death before 3 years of age.

Should we resuscitate elderly patients with blunt traumatic cardiac arrest? Analysis of National Trauma Registry Data in Japan

OBJECTIVES

Recent studies suggest that survival after traumatic cardiac arrest (TCA) has been improving. Many elderly adults enjoy active lifestyles, which occasionally result in TCA. The epidemiology and efficacy of resuscitative procedures on blunt TCA in elderly patients are largely unknown. Our primary aim was to compare the survival to discharge following blunt TCA between non-elderly adult (ages 18-59 years) and elderly patients (age ≥60 years).

METHODS

We analysed 2004-2015 observational cohort data from a nationwide trauma registry in Japan. We included all adult patients (18 years and older) who experienced blunt TCA. We excluded patients missing data for age, survival, mechanism of injury or initial vital signs. Resuscitative procedures included thoracotomy and resuscitative endovascular balloon occlusion of the aorta. We compared survival for elderly patients (age ≥60 years old) to younger adults.

RESULTS

Of 8347 patients with blunt TCA, 3547 (42.5%) were elderly. Survival differed significantly by age: 164/4800 (3.4%) of younger adults survived whereas 188/3547 (5.3%) of elderly patients survived (p<0.001). Survival increased but Injury Severity Scores (ISSs) declined with increasing patient age. The efficacy of resuscitative procedures did not vary by age. In logistic regression models, increasing age was independently associated with better survival.

CONCLUSION

In a cohort of patients with blunt TCA, survival increased with increasing patient age. A number of patients with low ISS in the elderly group raises the possibility that this improved survival is due to preceding or concomitant medical cardiac arrest in the older cohort. Clinicians should be cautious about applying TCA algorithms to elderly patients and should not be discouraged from resuscitating TCA because of patient age.

Secular evolution of femoral morphology from a clinical perspective

INTRODUCTION

Intramedullary nailing is the surgical method of choice for the treatment of proximal femur or femoral shaft fractures. Implant manufacturers aim to design implants fitting for the broadest possible population segment. As complete morphological data sets of long bones are not widely available, anatomical collections of historical dry bone specimens may represent abundant additional sources of morphological three-dimensional (3D) data for implant design, provided they are consistent with present populations. This study aims to investigate secular trends and age-related changes of femoral morphology of the Caucasian population over the past 800 years.

MATERIALS AND METHODS

Computer graphical measurements of 3D-datasets of right and left femora derived from computed tomography (CT) scans, representative of the present Caucasian population, were compared to computer graphical measurements of 3D-datasets of right and left femora derived from CT scans of specimens from a historical medieval European bone collection.

RESULTS

Clinically relevant parameters of historical medieval European femora were found mostly consistent with correlative data of the present Caucasian population. Additionally, for some of the evaluated parameters, particularly anteversion, morphological differences significantly correlated to individual age and sex could be identified, whereas other parameters such as caput-collum-diaphyseal angle or radius of anterior femoral bowing were not correlated to individual age or sex.

CONCLUSION

The findings suggest that more recent historical specimen collections may be a convenient and easily accessible source of new 3D morphological data, as well as to complement existing data, to be used by researchers and manufacturers for the development of intramedullary femoral nails.

Autopsy imaging for aspergillosis in King Penguin, an economically valuable zoo animal

Autopsy imaging (Ai) was performed for a King Penguin. Ai-computed tomography (CT) revealed air sac membrane thickening, multiple nodules in the cranial air sac, suspected abscess, lung infiltration, and air sac contraction. Based on these findings, respiratory disorder was concerned. Aspergillosis, which is the highly observed in penguins, was considered as the primary differential diagnosis. The cultured sample showed characteristic conidial head of Aspergillus spp., the DNA of which was 100% identical to that of A. fumigatus. The cause of death was determined to respiratory failure due to aspergillosis. Ai-CT findings facilitated the dissection workflow and alerted the pathologist to potential hazards during the autopsy. Ai is useful to determine the cause of death and for readiness and safe pathological dissection.

Forensic Radiology: A Primer

RATIONALE AND OBJECTIVE

Forensic radiology is a relatively unknown subspecialty which is becoming increasingly more important. The field incorporates antemortem and postmortem imaging for the detection and documentation of various pathologies for medicolegal purposes. Postmortem imaging is increasingly used in conjunction with the traditional autopsy in a process called a "virtual" autopsy. Radiography has been a staple of forensic investigations for over a century, first used in 1896. Advanced imaging techniques such as postmortem computed tomography and postmortem magnetic resonance imaging have only recently gained acceptance in the forensic science community. Postmortem computed tomography and postmortem magnetic resonance imaging methods are now widely used in some parts of the world, while other countries including the United States have been slower to adopt these methods into their daily practice. Advanced forensic imaging is increasingly used in the courts where juries have responded positively to such presentation of forensic data. For these reasons, advanced postmortem imaging is becoming a regular part of forensic investigations. The increase in the use of forensic imaging presents a unique opportunity for radiologists to collaborate with pathologists and law enforcement officials. This paper provides an overview of forensic radiology and identifies potential challenges and opportunities.

Postmortem volume change of the spleen and kidney on early postmortem computed tomography: comparison with antemortem computed tomography

PURPOSE

To clarify an early postmortem change, we investigated the volume changes of the spleen and kidney on postmortem CT compared with antemortem CT in the same patients.

MATERIALS AND METHODS

We retrospectively evaluated the volumes of 56 spleens (56 cases) and 50 kidneys (25 cases) using antemortem and postmortem CT, which were performed within 168 min after death. We divided the cases of spleen analysis into a hemorrhagic group (n = 12) and a non-hemorrhagic group (n = 44).

RESULTS

The volumes of the organs before and after death were 101.0 ± 70.9 (cm³, mean ± standard deviation) and 81.1 ± 57.8 in spleens, 120.3 ± 49.2 and 109.2 ± 39.2 in kidneys, respectively. Both spleens and kidneys shrank after death (p < 0.05). The volumes of spleens before and after death were 111 ± 66.5 and 67.5 ± 27.7 in the hemorrhagic group, and 98.2 ± 72.5 and 84.9 ± 63.3 in the non-hemorrhagic group, respectively. The median value of the ratio of postmortem splenic volume to antemortem volume in the hemorrhagic group (65.0%) was smaller than the one in the non-hemorrhagic group (90.5%) (p < 0.05).

CONCLUSION

We demonstrated that spleens and kidneys significantly reduced in size after death. The rate of shrinkage of spleens in the hemorrhagic group significantly became larger than the one in the non-hemorrhagic group.

State of the art in post-mortem computed tomography: a review of current literature

Computed tomography (CT) and other advanced diagnostic imaging techniques are gaining popularity in forensic pathology. This paper aims to define and offer complete and easily accessible "state of the art" for post-mortem computed tomography (PMCT), by reviewing the latest international literature. The proposed format answers the "five Ws" that follows: (1) What: We report the different kinds of CT scan and settings generally used in post-mortem imaging. The machine most employed is a 8/16-slice spiral CT, usually without contrast enhancement. The introduction of some variables, such as CT-guided biopsies, post-mortem ventilation, and PMCT angiography is becoming increasingly useful. (2) Why: Literature highlights the many advantages of PMCT. Limitations can be partly overcome by modern imaging techniques and combined evaluation with traditional autopsy. (3) Who: Most authors agree that collaboration between different specialists, i.e., radiologists and pathologists, is the best scenario, since radiologic, anatomic, and forensic skills are needed simultaneously. The most important human factor is "teamwork". (4) When: Literature provides no absolute limits for performing PMCT. Some authors have tested PMCT as a replacement for conventional autopsy but found some limitations. Others evaluated PMCT as a guide or screening tool for traditional autopsy. (5) Where: Many research groups around the world have performed studies on the use of PMCT. Although few countries adopt PMCT in routine practice, its use is rapidly spreading.

Postmortem computed tomographic features in the diagnosis of drowning: a comparison of fresh water and salt water drowning cases

PURPOSE

To investigate the effectiveness of postmortem computed tomography in the diagnosis of drowning, focusing on the comparison of fresh water and salt water cases using three-dimensionally (3D) reconstructed data.

MATERIALS AND METHODS

We examined features of drowning in 25 fresh water drowning cases (FWDCs; 13 men, 12 women; mean age 73.1 years; range 43-95 years), and compared these with 12 salt water drowning cases (SWDCs; 5 men, 7 women; mean age 66.0 years; range 55-77 years). Pulmonary opacities, volume and density (CT number) of accumulated fluid in the paranasal sinuses and central airways, volume of the stomach/stomach contents, and cardiac blood density were examined.

RESULTS

In SWDCs, pulmonary ground-glass opacities with wholly thickened interstitium was frequently identified (P = 0.0274). Whereas in FWDCs, a significantly larger volume and lower density of fluid in the paranasal sinuses (P = 0.0195 and P = 0.0104, respectively), lower density of fluid in the central airways (P = 0.0077), lower stomach content density (P = 0.0216), lower density in the left atrium (P = 0.0029), and a difference of density between the atria (P = 0.0247) were observed.

CONCLUSIONS

A lower density in the left atrium was observed in FWDCs compared to SWDCs. This finding may be helpful in differentiating between FWDCs and SWDCs.

Causes and risk factors for singleton stillbirth in Japan: Analysis of a nationwide perinatal database, 2013-2014

Over 80% of perinatal mortality in Japan is due to stillbirths after 22 weeks of gestation, with one in 300 families experiencing fetal loss every year. This study aimed to assess causes and risk factors for singleton stillbirth in Japan. A retrospective cross-sectional study was conducted using the Japan Society of Obstetrics and Gynecology Perinatal Database from January 2013 to December 2014. A total of 379,211 births including 2,133 stillbirths were analyzed. Causes of death were classified into eight categories. A multi-level Poisson regression model was used to assess the relationship between stillbirth and key covariates. Causes of death were unknown in 25–40% of stillbirths across gestational age. Placental abnormality accounted for the largest proportion of known causes, followed by umbilical cord abnormality. Stillbirth risk was increased among small-for-gestational-age infants (adjusted relative risk [ARR]: 3.78, 95% confidence interval [CI]: 3.31–4.32) and nulliparous women (ARR: 1.19, 95% CI: 1.05–1.35). Maternal underweight, pregnancy-induced hypertension and oligohydramnios showed a protective effect. Our finding suggests that stillbirths occurring among women with known complications are likely already being prevented. Further reduction in stillbirths must target small-sized fetuses and nulliparous women. Improved recording of the causal pathways of stillbirths is also needed.

State of the art in post-mortem forensic imaging in China

The autopsy and histopathologic examination are traditional and classic approaches in forensic pathology. In recent years, with the tremendous progresses of computer technology and medical imaging technology, the developed post-mortem computer tomography, post-mortem magnetic resonance imaging and other new methods provide non-invasive, intuitive, high-precision examining methods and research tools for the forensic pathology. As a result, the reconstruction of the injury as well as the analysis of injury mechanism has been essentially achieved. Such methods have become popular in the research field of forensic science and related work has also been carried out in China. This paper reviews the development and application of abovementioned post-mortem forensic imaging methods in China based on the relevant literature.

CT-scan vs. 3D surface scanning of a skull: first considerations regarding reproducibility issues

Three-dimensional surface scanning (3DSS) and multi-detector computed tomography (MDCT) are two techniques that are used in legal medicine for digitalizing objects, a body or body parts such as bones. While these techniques are more and more commonly employed, surprisingly little information is known about the quality rendering of digitalized three-dimensional (3D) models provided by each of them. This paper presents findings related to the measurement precision of 3D models obtained through observation of a study case, where a fractured skull reconstructed by an anthropologist was digitalized using both post-mortem imaging methods. Computed tomography (CT) scans were performed using an 8-row MDCT unit with two different slice thicknesses. The variability of 3D CT models superimposition allowed to assess the reproducibility and robustness of this digitalization technique. Furthermore, two 3D surface scans were done using a professional high resolution 3D digitizer. The comparison of 3D CT-scans with 3D surface scans by superimposition demonstrated several regions with significant differences in topology (average difference between +1.45 and -1.22 mm). When comparing the reproducibility between these two digitalizing techniques, it appeared that MDCT 3D models led in general to greater variability for measurement precision between scanned surfaces. Also, the reproducibility was better achieved with the 3D surface digitizer, showing 3D models with fewer and less pronounced differences (from +0.32 to -0.31 mm). These experiments suggest that MDCT provides less reproducible body models than 3D surface scanning. But further studies must be undertaken in order to corroborate this first impression, and possibly explain the reason for these findings.

Diagnosis of coronary artery disease using targeted post-mortem computed tomography coronary angiography: a case report

Targeted post-mortem computed tomography (PMCT) combined with coronary angiography has the potential to play a significant role in the investigation of sudden cardiac death. The authors utilized a targeted PMCT coronary angiography in a case involving a 53-year-old man who died from acute myocardial ischemia and cardiac decompensation which may result from coronary artery disease (CAD). The victim collapsed suddenly at work and died soon after arrival to hospital. The body was examined using PMCT and targeted PMCT coronary angiography. The left anterior descending coronary artery exhibited 75%–100% stenosis in the middle segment; however, the distal segment could not be clearly visualized. In addition, the left circumflex and right coronary artery exhibited calcification, atherosclerosis and an area of 50% stenosis. Signs of cardiogenic pulmonary oedema were also identified. The imaging results suggested that this individual had coronary atherosclerosis and probably died from CAD. The autopsy and histological examination revealed acute myocardial ischemia and myocardial scarring, confirming the cause of death while excluding other probabilities. In summary, targeted post-mortem computed tomography angiography (PMCTA) can visualize the arteries and estimate the degree of principal pathological changes. This method is a simple, reliable and sensitive technique for identifying the presence of coronary atherosclerosis. It is a valuable post-mortem forensic imaging method and should be recommended in the investigation of suspicious cardiac deaths.

Autopsy imaging for cardiac tamponade in a Thoroughbred foal

Autopsy imaging (Ai), postmortem imaging before necropsy, is used in human forensic medicine. Ai was performed using computed tomography (CT) for a 1-month-old Thoroughbred foal cadaver found in a pasture. CT revealed pericardial effusion, collapse of the aorta, bleeding in the lung lobe, gas in the ventricles and liver parenchyma, and distension of the digestive tract. Rupture in the left auricle was confirmed by necropsy; however, it was not depicted on CT. Therefore, Ai and conventional necropsy are considered to complement each other. The cause of death was determined to be traumatic cardiac tamponade. In conclusion, Ai is an additional option for determining cause of death.

Automated liver segmentation from a postmortem CT scan based on a statistical shape model

PURPOSE

Automated liver segmentation from a postmortem computed tomography (PMCT) volume is a challenging problem owing to the large deformation and intensity changes caused by severe pathology and/or postmortem changes. This paper addresses this problem by a novel segmentation algorithm using a statistical shape model (SSM) for a postmortem liver.

METHODS

The location and shape parameters of a liver are directly estimated from a given volume by the proposed SSM-guided expectation-maximization (EM) algorithm without any spatial standardization that might fail owing to the large deformation and intensity changes. The estimated location and shape parameters are then used as a constraint of the subsequent fine segmentation process based on graph cuts. Algorithms with eight different SSMs were trained using 144 in vivo and 32 postmortem livers, and the segmentation algorithm was tested on 32 postmortem livers in a twofold cross validation manner. The segmentation performance is measured by the Jaccard index (JI) between the segmentation result and the true liver label.

RESULTS

The average JI of the segmentation result with the best SSM was 0.8501, which was better compared with the results obtained using conventional SSMs and the results of the previous postmortem liver segmentation with statistically significant difference.

CONCLUSIONS

We proposed an algorithm for automated liver segmentation from a PMCT volume, in which an SSM-guided EM algorithm estimated the location and shape parameters of a liver in a given volume accurately. We demonstrated the effectiveness of the proposed algorithm using actual postmortem CT volumes.

Multiphase Postmortem Computed Tomography Angiography in Pediatrics: A Case Report

Postmortem imaging techniques, especially postmortem computed tomography, have become integral tools in forensic investigations. Multiphase postmortem computed tomography angiography (MPMCTA) visualizes the vascular system in detail and makes it possible to evaluate the perfusion of even the smallest vessels. Although the technique has been well described for adults, no pediatric cases have been reported and no pediatric protocol has been established for this type of investigation. We present the case a 7-year-old child for which we used a previously described MPMCTA protocol and adapted values of perfusion, with the same technical equipment as for adult cases. Our main objective was to propose a perfusion protocol adapted for the investigation of infants and children. Moreover, we discuss both the difficulties that we encountered and possible ways to further improve the investigation of pediatric cases by MPMCTA.