The future of pediatric and perinatal postmortem imaging

Unexplained and Unexpected Pediatric Deaths: Forensic Review and New Perspectives

Unexplained and unexpected pediatric deaths are a major challenge in global healthcare. The role of the forensic pathologist is crucial in determining the cause and manner of death in these cases, although to date, there are many limitations in post-mortem diagnosis. The role of the autopsy and related forensic investigations become a fundamental tool to investigate and give an explanation for an unacceptable event, considering the young age of the victims. From this point of view, even today, it is necessary that this phenomenon is correctly recorded through standardized systems and universally accepted methods. Furthermore, it is essential that scientific research on this topic is increased through the implementation of universally accepted operating protocols recognizing real risk factors in order to prevent such events. The purpose of the study is to offer a review of the state of the art about unexplained pediatric death and, above all, to propose an international reporting platform, extending proper investigations not only to judicial cases but also to all the other cases of unexpected pediatric death.

The Practicality of Post-mortem Imaging in Prenatal, Perinatal, and Pediatric Cases

The essential role of the autopsy is seen in its contributions to medical care, scientific research, and family counseling. Major contributions are also noted in forensic pathology as a means to determine cause-of-death for legal and medical experts. However, autopsy acceptance rates are quite low due to an array of reasons including delayed burials, faith, and moral burdening. Thus, non-invasive post-mortem imaging strategies are becoming increasingly popular. The objective of this literature review is to evaluate the strengths and weaknesses of numerous post-mortem imaging modalities and consider their benefits over the traditional autopsy. The need for expertise in image interpretation for pediatric and perinatal cases is also discussed. A variety of publications, totaling 32 pieces, were selected from available literature on the basis of relevance. These articles studied various perinatal and pediatric post-mortem imaging strategies and their applications in clinical practice. Key strategies include post-mortem MRI, post-mortem CT, fetal post-mortem sonography, post-mortem computed tomographic angiography, and three-dimensional surface scanning. There is a general consensus that no standard model for post-mortem imaging currently exists in the United States and European countries. Amongst the imaging modems studied, post-mortem MRI has been acknowledged to show the greatest promise in diagnostic accuracy for fetal age groups. Most studies demonstrated that post-mortem CT had limited use for autopsy. Post-mortem imaging strategies for autopsy have high potential given their minimal invasiveness and increasing popularity. Furthermore, it is vital to crafting a global standard procedure for post-mortem imaging for prenatal, perinatal, and pediatric cases to better understand the cause of death, decomposition factors, and effects in-utero, and to provide an alternative to traditional autopsy.

Does Postmortem Imaging Provide Additional Findings After Unexpected Deaths in Infants and Children?

METHODS

We performed a retrospective study of unexpected deaths in children 2 years or younger between 2008 and 2018. Children with known traumatic deaths and those transferred after a cardiopulmonary arrest at an outside institution were excluded. We collected patient demographics, physical examination findings, and type of PMI performed along with their results.

RESULTS

We analyzed 150 deaths with majority (128; 85.3%) being infants. No PMI was performed in 20 children (13.3%). An autopsy was not performed in 22 children (14.6%). A skeletal survey and an autopsy were performed only in 72.6% (93/128) infants. PMI provided additional findings in 51 infants (34%) and 13 children (59.1%) aged 13 to 24 months. PMI identified abuse in 11 children with a negative physical examination result, 3 of whom had a negative autopsy.

CONCLUSIONS

The American Academy of Pediatrics recommendations of performance of a skeletal survey and an autopsy were not adhered to after all infant deaths. PMI is useful in identification of additional findings in children 2 years or younger, especially those concerning for physical abuse in infants with a negative physical examination.

The Ogival Palate: A New Risk Marker of Sudden Unexpected Death in Infancy?

OBJECTIVE

Ogival palate (i.e., a narrow and high-arched palate) is usually described in obstructive breath disorder but has been found in infants unexpectedly deceased. We studied the association between ogival palate and sudden unexpected death in infancy (SUDI) on the basis of a computed tomography (CT) evaluation.

METHODS

We conducted a monocentric case-control study of children under 2 years of age who died of SUDI, for which a head CT scan and an autopsy were performed between 2011 and 2018. Each case was matched by sex and age (± 30 days) to two controls selected among living children in the same center who benefited from a cranio-encephalic CT scan. Four parameters of the hard palate were measured by CT: height, width, length, and sagittal angle; the height/width ratio was calculated. The presence of an ogival palate was also subjectively evaluated by the radiologists, independently from the measurements. Standardized odds ratios (OR) were calculated using conditional logistic regression models, all expressed for +1 standard deviation (SD).

RESULTS

Thirty-two deceased children were matched to 64 living control children. Mean ages were 5.0 and 5.3 months, respectively. Twenty-eight cases were considered to have died as a result of SIDS. The mean heights of the hard palate were significantly higher in the deceased children [4.1 (± 0.7) millimeters (mm)] than in the living children [3.2 (± 0.6) mm], with OR (+1SD) = 4.30 (95% confidence interval [CI], 2.04-9.06, P = 0.0001). The mean widths of the hard palate were 21.0 (± 1.9) mm and 23.2 (± 2.1) mm, respectively, with OR = 0.15 (95% CI, 0.06-0.40, P = 0.0001). The mean sagittal angles were significantly more acute in deceased children [134.5° (± 9.3)] than in living children [142.9° (± 8.1)], with OR = 0.28 (95% CI, 0.14-0.56, P = 0.0003). The mean height/width ratios were 19.8 (± 3.7) and 14.1 (± 3.3), respectively, with OR = 6.10 (95% CI, 2.50-14.9, P = 0.0001). The hard palate was subjectively considered as ogival in 59.4% (19/32) of the cases versus 12.5% (8/64) of the controls.

CONCLUSION

Radiological features of the ogival palate were strongly associated with SUDI. This observation still needs to be confirmed and the corresponding clinical features must be identified.

Pictorial review of the postmortem computed tomography in neonaticide cases

Neonaticide is defined by the deliberate killing or homicide of a child within 24 h of its birth. In this context, three fundamental questions are generally asked of the forensic pathologist: what is the cause of death of the neonate? Was the child viable (i.e., what is the gestational age of the neonate)? Finally, was the neonate stillborn or liveborn?Postmortem imaging can help answer these questions by conducting (1) a complete lesional analysis of the body and the placenta, (2) an estimation of the gestational age by measuring the lengths of the diaphyseal long bones, and (3) an analysis of the aeration of the lungs and intestines. Using the details of 18 cases, we illustrate aspects of neonaticide cases in postmortem computed tomography (PMCT), offering detailed examples of notable postmortem changes and abnormalities, especially in the analysis of the pulmonary parenchyma. This article presents a useful iconography for the radiologist confronted with this rare yet complex forensic situation.

Navigating the perils and pitfalls of pediatric forensic postmortem imaging in the United States

Postmortem CT is widely used in the general adult and military populations. It is used extensively in pediatric death investigations in Europe and Asia, but distinctive challenges are encountered when launching a postmortem imaging program in the United States. We describe the issues we have encountered specific to establishing a pediatric postmortem imaging service in this country and propose potential solutions.

Pediatric postmortem computed tomography: initial experience at a children's hospital in the United States

Postmortem CT might provide valuable information in determining the cause of death and understanding disease processes, particularly when combined with traditional autopsy. Pediatric applications of postmortem imaging represent a new and rapidly growing field. We describe our experience in establishing a pediatric postmortem CT program and present a discussion of the distinct challenges in developing this type of program in the United States of America, where forensic practice varies from other countries. We give a brief overview of recent literature along with the common imaging findings on postmortem CT that can simulate antemortem pathology.

Lung density measurement in postmortem computed tomography: a new tool to assess immediate neonatal breath in suspected neonaticides

INTRO

Evidence of breath after birth is one of the main forensic issues in suspected neonaticide. Hydrostatic test (HT) and pathological examination are currently used to assess it, but they are not entirely reliable or immediately available.

OBJECTIVE

To determine the performance of postmortem computed tomography (PMCT) to assess neonatal breath in suspected neonaticide, by comparing lung CT attenuation values between live birth and stillbirth cases, in correlation with HT and pathology.

METHOD

Cases of suspected neonaticides who underwent a PMCT and complete forensic autopsy with an HT were retrospectively selected from the databases of four French Forensic Medicine Departments. The diagnosis of vitality (i.e., stillbirth or live birth) was based on the pathological examination and/or a combination of arguments, including HT result. Lung density on CT was measured in Hounsfield units (HU) by ROIs drawn in both pulmonary parenchymas.

RESULTS

Eleven patients were included, six live birth and five stillbirth cases. The result of HT was concordant with pathological examination when available (seven cases). Mean lung densities in live birth cases (- 173 HU [- 255; - 91 CI 95%]) were significantly lower than in stillbirth cases (40 HU [28; 52 CI 95%]) (p < 0.05), with a very high degree of interobserver reproducibility (ICC = 0.998 (CI 95% 0.991-0.999; p < 0.001).

CONCLUSION

PMCT and especially lung CT attenuation measurement is a reliable and easy-to-use method for assessing neonatal breath in suspected neonaticides.

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.

Evaluation of septal insertion of atrioventricular valves in fetuses by postmortem 4.7 Tesla cardiac MRI: A feasibility study

PURPOSE

The purpose of this study was to compare non-invasive high-spatial-resolution postmortem cardiac magnetic resonance imaging (MRI) and autopsy findings for evaluating the septal insertion of atrioventricular valves in fetuses.

MATERIALS AND METHODS

Five fetal heart specimens including two normal hearts, one heart with complete atrioventricular septal defect (AVSD) and two hearts with linear insertion of atrioventricular valves (LIAVV; gestational age 17 to 34 weeks) were studied with cardiac MRI using a 4.7 T MRI scanner without sample preparation. Three (3D) and two-dimensional (2D) turbo-RARE (rapid imaging with refocused echoes) sequences in four-chamber and left-ventricular long-axis planes were obtained with a minimal isotropic/in-plane resolution of 156μm. Nonparametric tests were performed to compare the distance between insertions of medial leaflets of the atrioventricular valves and the inlet/outlet distance ratio between MRI and autopsy findings in normal, complete AVSD and with linear insertion of atrioventricular valves (LIAVV) fetal hearts.

RESULTS

Despite apparent differences between LIAVV/normal hearts, no significant differences were found between differential insertion of medial leaflets and inlet/outlet distance ratios with both techniques. Very good to excellent reliability between both techniques was found for differential insertion (ICC: 87.2%; 95% CI: -21.7%, 99.1%) (P=0.963) and inlet/outlet distance ratio (ICC 98.3%; 95%CI: 85.2%, 99.8%) (P=0.537) measurements.

CONCLUSION

Postmortem cardiac MRI could replace autopsy for assessing normal or abnormal septal insertion of atrioventricular valves in fetuses without requiring specific preparation of the heart.

Post-mortem magnetic resonance foetal imaging: a study of morphological correlation with conventional autopsy and histopathological findings

The aim of the present study is to offer our experience concerning post-mortem magnetic resonance (PMMR) in foetal death cases and an evaluation of the differences between the findings acquired by PMMR and by forensic autopsy. Fifteen foetuses were recruited from July 2014 to December 2015. These had suffered intrauterine death in women in the 21st to 38th week of gestation who were treated in the emergency department for non-perception of foetal movements. We performed a PMMR on foetuses, 3 ± 1 days on average from the time of death, and then a complete forensic autopsy was performed. All 15 foetuses were examined with a whole-body study protocol, starting from the skull, down to and including the lower limbs. The total time of examination ranged from 20 to 30 min in each case. The external evaluation and description of post-mortem phenomena (maceration), record of the weight and detection and the various measurements of foetal diameters were evaluated before performing autopsy. A complete histopathological study was performed in each case. Out of 15 cases examined, eight were negative for structural anatomical abnormalities and/or diseases, both in the preliminary radiological examination and the traditional autopsy. In the remaining seven cases, pathological findings were detected by PMMR with corresponding results at autopsy. PMMR can provide useful information on foetal medical conditions and result in improved diagnostic classification. It may enable the planning of a more suitable technique before proceeding to autopsy, including focusing on certain aspects of organ pathology otherwise not detectable. The association between PMMR, post-mortem examination and related histological study of the foetus-placenta unit could help reduce the percentage of cases in which the cause of foetal death remains unexplained. Lastly, it may allow a selective sampling of the organ in order to target histological investigations.

Comparison of diagnostic performance for perinatal and paediatric post-mortem imaging: CT versus MRI

OBJECTIVES

To compare the diagnostic yield of whole-body post-mortem computed tomography (PMCT) imaging to post-mortem magnetic resonance (PMMR) imaging in a prospective study of fetuses and children.

METHODS

We compared PMCT and PMMR to conventional autopsy as the gold standard for the detection of (a) major pathological abnormalities related to the cause of death and (b) all diagnostic findings in five different body organ systems.

RESULTS

Eighty two cases (53 fetuses and 29 children) underwent PMCT and PMMR prior to autopsy, at which 55 major abnormalities were identified. Significantly more PMCT than PMMR examinations were non-diagnostic (18/82 vs. 4/82; 21.9 % vs. 4.9 %, diff 17.1 % (95 % CI 6.7, 27.6; p < 0.05)). PMMR gave an accurate diagnosis in 24/55 (43.64 %; 95 % CI 31.37, 56.73 %) compared to 18/55 PMCT (32.73 %; 95 % CI 21.81, 45.90). PMCT was particularly poor in fetuses <24 weeks, with 28.6 % (8.1, 46.4 %) more non-diagnostic scans. Where both PMCT and PMMR were diagnostic, PMMR gave slightly higher diagnostic accuracy than PMCT (62.8 % vs. 59.4 %).

CONCLUSION

Unenhanced PMCT has limited value in detection of major pathology primarily because of poor-quality, non-diagnostic fetal images. On this basis, PMMR should be the modality of choice for non-invasive PM imaging in fetuses and children.

KEY POINTS

• Overall 17.1 % more PMCT examinations than PMMR were non-diagnostic • 28.6 % more PMCT were non-diagnostic than PMMR in fetuses <24 weeks • PMMR detected almost a third more pathological abnormalities than PMCT • PMMR gave slightly higher diagnostic accuracy when both were diagnostic.

Whole-body post-mortem computed tomography angiography of a newborn revealing transposition of great arteries

The number of medico-legal post-mortem examinations referring to newborns is considerably low: In the case of the Chair and Department of Forensic Medicine of the author's origin, the autopsy rate of such cases is less than 1%. Even experienced forensic pathologists can find the technical autopsy procedure of a newborn quite difficult. Post-mortem imaging using unenhanced post-mortem computed tomography (PMCT) gives only a limited opportunity to help in conventional autopsy examination. By adding contrast medium (CA) administration, we can significantly expand diagnostic capabilities. However, the post-mortem computed tomography angiography (PMCTA) technique has already been developed mostly in adult death cases (as considerably much more frequent), and no standardised protocol for examination of children exists. The authors present the dual-phase PMCTA examination of a newborn by manual CA administration using the access to umbilical vessels (vein and artery) unveiling transposition of the great arteries (TGA). The results are presented as multiplanar reformatted (MPR) images and three-dimensional (3D) images by volume/surface-rendered reconstructions, giving a contribution towards proving the value of forensic imaging in post-mortem examinations of heart and vascular malformations in newborns.