Pediatric forensic postmortem computed tomography: basics to advanced.

The approach to postmortem computed tomography (CT) differs significantly from that of diagnostic CT in living patients. Elimination of artifacts such as noise and beam hardening as well as optimization of tissue contrast requires alteration of exposure parameters from protocols designed to limit radiation dose in children. Multiple scans may be performed, and detailed post-processing can be used to enhance subtle findings such as small intracranial extra axial collections and non-displaced fractures. Basics of postmortem CT technique are discussed here as well as advanced techniques in scanning and post-processing.

Unlocking the genetic diversity and population structure of the newly introduced two-row spring European HerItage Barley collecTion (ExHIBiT).

In the last century, breeding programs have traditionally favoured yield-related traits, grown under high-input conditions, resulting in a loss of genetic diversity and an increased susceptibility to stresses in crops. Thus, exploiting understudied genetic resources, that potentially harbour tolerance genes, is vital for sustainable agriculture. Northern European barley germplasm has been relatively understudied despite its key role within the malting industry. The European Heritage Barley collection (ExHIBiT) was assembled to explore the genetic diversity in European barley focusing on Northern European accessions and further address environmental pressures. ExHIBiT consists of 363 spring-barley accessions, focusing on two-row type. The collection consists of landraces (~14%), old cultivars (~18%), elite cultivars (~67%) and accessions with unknown breeding history (~1%), with 70% of the collection from Northern Europe. The population structure of the ExHIBiT collection was subdivided into three main clusters primarily based on the accession's year of release using 26,585 informative SNPs based on 50k iSelect single nucleotide polymorphism (SNP) array data. Power analysis established a representative core collection of 230 genotypically and phenotypically diverse accessions. The effectiveness of this core collection for conducting statistical and association analysis was explored by undertaking genome-wide association studies (GWAS) using 24,876 SNPs for nine phenotypic traits, four of which were associated with SNPs. Genomic regions overlapping with previously characterised flowering genes (HvZTLb) were identified, demonstrating the utility of the ExHIBiT core collection for locating genetic regions that determine important traits. Overall, the ExHIBiT core collection represents the high level of untapped diversity within Northern European barley, providing a powerful resource for researchers and breeders to address future climate scenarios.

The establishment of winter wheat root system architecture in field soils: The effect of soil type on root development in a temperate climate.

Winter wheat (Triticum aestivum L.) is an important cereal crop in the temperate climates of western Europe. Root system architecture is a significant contributor to resource capture and plant resilience. However, the impact of soil type on root system architecture (RSA) in field structured soils is yet to be fully assessed. This work studied the development of root growth using deep cultivation (250 mm) during the tillering phase stage (Zadock stage 25) of winter wheat across three soil types. The three sites of contrasting soil types covered a geographical area in the UK and Ireland in October 2018. Root samples were analysed using two methods: X-ray computed tomography (CT) which provides 3D images of the undisturbed roots in the soil, and a WinRHIZO™ scanner used to generate 2D images of washed roots and to measure further root parameters. Important negative relationships existed between soil bulk density and root properties (root length density, root volume, surface area and length) across the three sites. The results revealed that despite reduced root growth, the clay (Southoe) site had a significantly higher crop yield irrespective of root depth. The loamy sand (Harper Adams) site had significantly higher root volume, surface area and root length density compared with the other sites. However, a reduction in grain yield of 2.42 Mt ha-1 was incurred compared with the clay site and 1.6 Mt ha-1 compared with the clay loam site. The significantly higher rooting characteristics found in the loamy sand site were a result of the significantly lower soil bulk density compared with the other two sites. The loamy sand site had a lower soil bulk density, but no significant difference in macroporosity between sites (p > 0.05). This suggests that soil type and structure directly influence crop yield to greater extent than root parameters, but the interactions between both need simultaneous assessment in field sites.

Current utilization of pediatric postmortem imaging in North America: a questionnaire-based survey.

BACKGROUND: Postmortem imaging is used more widely as the number of conventional autopsies has decreased over the last several decades. It is widely accepted in Europe, Asia and Oceania, but there has been a delay in acceptance in North America. Education, scanning protocols, resourcing and clinical incentives are needed to support this emerging field. OBJECTIVE: To determine the use of postmortem imaging and define perceived barriers to its implementation with the goal of expanding postmortem imaging in the United States and Canada. MATERIALS AND METHODS: We sent an online survey to active members of the Society for Pediatric Radiology (SPR) addressing the use of postmortem imaging, indications, readers, practical aspects, anticipated barriers and potential solutions to more widespread use. RESULTS: More than 50% of the 50 institutions that returned surveys used postmortem computed tomography; 24% used postmortem magnetic resonance imaging. Most postmortem imaging cases were read by radiologists. Fewer than 50% had formal correlation with autopsy results or an established relationship with the local medical examiner. Seven institutions reported reimbursement for postmortem imaging. Major barriers to postmortem imaging included lack of funding and lack of interest among clinicians. Funding and education were seen as important issues requiring attention. CONCLUSION: While most responding institutions provide pediatric postmortem imaging, the modalities, protocols, reporting procedures and clinical correlation vary widely. A lack of funding and few opportunities for education are limiting factors. Attention to these issues along with active support from the SPR are seen as potential solutions to recognize the value and promote widespread acceptance of postmortem imaging.

Large aortic pseudoaneurysm after Bentall procedure in a patient with Marfan's syndrome.

An 11-year-old male with Marfan's syndrome and aortic root dilatation underwent an uneventful Bentall procedure to replace his aortic root and valve. Five months later, surveillance echocardiogram revealed a slowly enlarging pseudoaneurysm arising from the ascending aorta. This finding was subsequently confirmed by computed tomographic angiogram. The patient had successful open surgical repair and paraaortic hematoma evacuation.

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.

Computerized Tomography Analysis of Young Children for Prevention of Aspiration Injuries.

OBJECTIVE: The Small Parts Test Fixture (SPTF) (16 CFR 1501) was developed from cadavers of young children and foreign body (FB) data. Recent FB studies reveal that the SPTF misses outliers. Computerized tomography (CT) provides detailed dimensional data for young children. Our null hypothesis is that the SPTF (31.75 mm) is smaller than relevant portions of the aerodigestive tract. METHODS: A 3-year retrospective review (2011-2014) of head/neck CT data for infants and children (N = 106) aged 6 months to 6 years was completed. Six measurements (mm) were recorded: 1) maxillary incisors to posterior edge of hard palate (MI/HP); 2) posterior edge of hard palate to first cervical (C1) vertebra (HP/C1); 3) soft palate to posterior pharyngeal wall; and 4) interpalatine tonsillar distance; 5, 6) larynx diameter, and width. Two ratios were calculated: 1) ratio of lengths (hard palate to soft palate), and 2) laryngeal dimensional ratio. RESULTS: A linear trend of increasing dimensions with increased age was noted. The length measured MI/HP best correlates with known data of potential FBs causing injury or death. This MI/HP length can range from 33.8 to 45.8 mm for all children younger than 3 years of age and exceeds the SPTF diameter (31.75 mm). There were no statistical anatomical differences by gender in any of the age groups. CONCLUSION: Computed tomography measurements appear larger than SPTF values developed from cadavers. These CT data support enlargement of the SPTF to enhance safety for choking hazards in children. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:1468-1476, 2019.

Maturation of pelvic ossification centers on computed tomography in normal children.

BACKGROUND: The pelvis is composed of three paired primary ossification centers: the pubis, the ischium and the ilium. During maturation, multiple secondary ossification centers can be seen in the synchondroses between these bones and in the pelvic apophyses. The fragmented appearance of these centers can be confused with pathology. OBJECTIVE: To examine development of pelvic ossification centers by CT and determine normal appearance throughout childhood. MATERIALS AND METHODS: Three pediatric radiologists reviewed 325 pelvic CT scans in children and young adults 5-18 years old and graded 6 pelvic ossification centers to evaluate maturational changes in critical structures. RESULTS: Rate and progression of ossification and age at complete fusion vary with gender at the different ossification centers in the growing pelvis. CONCLUSION: Knowledge of the normal CT appearance of ossification centers throughout childhood is important to differentiate the normal appearance from pathology.

Pulmonary embolus as cause of death in an adolescent: demonstration on postmortem CT.

Computed tomography (CT) is widely accepted in adult forensic death investigations (determination of cause and manner of death) but is only beginning to play a larger role in the cause of death determination in infants and children. We present a case of an adolescent with nephrotic syndrome who sustained cardiac arrest and died in the emergency department. A postmortem CT was requested by the state Office of the Medical Examiner as part of the medicolegal death investigation. Postmortem CT showed a saddle pulmonary embolus that was confirmed on conventional autopsy, demonstrating a natural manner of death.

Aneurysmal bone cysts and pathologic fracture associated with supernumerary ring chromosome 6 in two unrelated patients.

Small supernumerary ring chromosome 6 (sSRC[6]) is a rare chromosomal abnormality characterized by a broad clinical phenotype. The spectrum of this disorder can range from phenotypically normal to severe developmental delay and congenital anomalies. We describe two unrelated patients with small SRCs derived from chromosome 6 with a novel bone phenotype. Both patients presented with a complex bone disorder characterized by severe osteopenia, pathologic fractures, and cyst-like lesions within the bone. Imaging revealed decreased bone mineral density, mutiple multiloculated cysts and cortical thinning. Lesion pathology in both patients demonstrated a bland cyst wall with woven dysplastic appearing bone entrapped within it. In patient 1, array comparative genomic hybridization (CGH) detected a tandem duplication of region 6p12.3 to 6q12 per marker chromosome. Cytogenetic analysis further revealed a complex patient of mosaicism with some cell lines displaying either one or two copies of the marker indicative of both tetrasomy and hexasomy of this region. Patient 2 was mosaic for a sSRC that encompassed a 26.8 Mb gain from 6p21.2 to 6q12. We performed an in-depth clinical analysis of a phenotype not previously observed in sSRC(6) patients and discuss the potential influence of genes located within this region on the skeletal presentation observed.

Imaging of neuroblastoma and Wilms' tumor.

Neuroblastoma and Wilms' tumor are the most common noncentral nervous system solid tumors in children. Imaging plays a crucial role in the evaluation of the primary tumor and regional and metastatic disease. There is a growing body of literature supporting the use of MRI as the technique of choice for the evaluation of local and regional disease in children with suspected neuroblastoma; however, in children with suspected Wilms' tumor, MRI will likely continue to play a role as a problem-solver when the results of CT are equivocal or indeterminant.

Intraosseous vascular access defect: fracture mimic in the skeletal survey for child abuse.

Two infants were transferred to the emergency department for injuries suggestive of child abuse. Skeletal surveys showed cortical bone defects in the proximal tibiae that were initially interpreted as healing fractures. Further investigation, however, revealed that intraosseous (IO) vascular access needles had been placed at these sites in both infants. In the appropriate clinical setting, a cortical lesion in the proximal tibia corresponding to the site of IO needle insertion should not be mistaken for a radiographic sign of child abuse.