Pediatrics

Characteristic MR Imaging Findings of the Neonatal Brain in RASopathies

Editor’s Choice

An observational case-control study of neonates with a confirmed RASopathy was conducted. The authors reviewed 48 brain MR studies performed at 3 academic centers in 3 countries between 2009 and 2017. Sixteen of these infants had a genetically confirmed RASopathy (group 1), and 32 healthy infants were enrolled as the control group (group 2). An increased rate of white matter lesions, extracerebral space enlargement, simplification of the cortical gyrification, and white matter abnormalities were seen in group 1. The vermis height of patients was significantly lower, and tentorial and infratentorial angles were significantly higher in group 1. Neonates with a RASopathy had characteristic structural and acquired abnormalities in the cortical gray matter, white matter, corpus callosum, cerebellum, and posterior fossa.

Multiparametric Analysis of Permeability and ADC Histogram Metrics for Classification of Pediatric Brain Tumors by Tumor Grade

Fellows’ Journal Club

DTI and dynamic contrast-enhanced MR imaging using T1-mapping with flip angles of 2°, 5°, 10°, and 15°, followed by a 0.1-mmol/kg body weight gadolinium-based bolus was performed on 41 patients in addition to standard MR imaging. Permeability data were processed and transfer constant from the blood plasma into the extracellular extravascular space, rate constant from the extracellular extravascular space back into blood plasma, extracellular extravascular volume fraction, and fractional blood plasma volume were calculated from 3D tumor volumes. Apparent diffusion coefficient histogram metrics were calculated. Wilcoxon tests showed a higher transfer constant from blood plasma into extracellular extravascular space and rate constant from extracellular extravascular space back into blood plasma, and lower extracellular extravascular volume fraction in high-grade tumors. The mean ADCs of FLAIR and enhancing tumor volumes were significantly lower in high-grade tumors. The authors conclude that ADC histogram metrics combined with permeability metrics differentiate low- and high-grade pediatric brain tumors with high accuracy.

Deep Brain Nuclei T1 Shortening after Gadobenate Dimeglumine in Children: Influence of Radiation and Chemotherapy

Fellows’ Journal Club

The authors reviewed clinical charts and images of patients 18 years of age or younger with ≥4 gadobenatedimeglumine–enhanced MRIs for 6 years. Seventy-six children (60 unconfounded by treatment, 16 with radiochemotherapy) met the selection criteria. T1 signal intensity ratios for the dentate to pons and globus pallidus to thalamus were calculated and correlated with number of injections, time interval, and therapy. Among the 60 children without radiochemotherapy, only 2 had elevated T1 signal intensity ratios. Twelve of the 16 children with radiochemotherapy showed elevated signal intensity ratios. Statistical analysis demonstrated a significant signal intensity ratio change for the number of injections. Compared with published adult series, children show a similar pattern of T1 hyperintense signal changes of the dentate and globus pallidus after multiple gadobenatedimeglumine injections. The T1 signal changes in children are accelerated by radiochemotherapy.

Hindbrain Herniation in Chiari II Malformation on Fetal and Postnatal MRI

Editor’s Choice

The authors examined the neuroimaging findings with a focus on hindbrain herniation and ventricular size in fetuses with open spinal dysraphism and compared them with postnatal imaging features in groups undergoing prenatal-versus-postnatal repair. Thirty-two of 102 (31.3%) fetuses underwent in utero repair of open spinal dysraphism; 68.6% (70/102) underwent postnatal repair. Of those who underwent prenatal repair 81.3% (26/32) had resolved cerebellar ectopia postnatally. Of those who had severe cerebellar ectopia (grade 3) that underwent postnatal repair, 65.5% (36/55) remained grade 3, while 34.5% (19/55) improved to grade 2. They conclude that most fetuses who undergo in utero repair have resolved cerebellar ectopia postnatally.

Imaging Characteristics of Pediatric Diffuse Midline Gliomas with Histone H3 K27M Mutation

Fellows’ Journal Club

The 2016 WHO Classification of Tumors of the Central Nervous System includes “diffuse midline glioma with histone H3 K27M mutation” as a new diagnostic entity. This study of 33 patients with diffuse midline gliomas found histone H3 K27M mutation was present in 24 patients (72.7%) and absent in 9 (27.3%). The location was the thalamus in 27.3%; the pons in 42.4%; within the vermis/fourth ventricle in 15%; and the spinal cord in 6%. The radiographic features of diffuse midline gliomas with histone H3 K27M mutation were highly variable, ranging from expansile masses without enhancement or necrosis with large areas of surrounding infiltrative growth to peripherally enhancing masses with central necrosis with significant mass effect.

Microstructure of the Default Mode Network in Preterm Infants

Editor’s Choice

A cohort of 44 preterm infants underwent T1WI, resting-state fMRI, and DTI at 3T, including 21 infants with brain injuries and 23 infants with normal-appearing structural imaging as controls. Neurodevelopment was evaluated with the Bayley Scales of Infant Development at 12 months’ adjusted age. Results showed decreased fractional anisotropy and elevated radial diffusivity values of the cingula in the preterm infants with brain injuries compared with controls. The Bayley Scales of Infant Development cognitive scores were significantly associated with cingulate fractional anisotropy. The authors suggest that the microstructural properties of interconnecting axonal pathways within the default mode network are of critical importance in the early neurocognitive development of infants.

White Matter Injury and General Movements in High-Risk Preterm Infants

Fellows’ Journal Club

Cerebral palsy has been predicted by analysis of spontaneous movements in the infant termed “General Movement Assessment.” The authors evaluated the utility of General Movement Assessment in predicting adverse cognitive, language, and motor outcomes in very preterm infants and attempted to identify brain imaging markers associated with both adverse outcomes and aberrant general movements in 47 preterm infants using MRI volumetric analysis and DTI. Nine infants had aberrant general movements and were more likely to have adverse neurodevelopmental outcomes, compared with infants with normal movements. In infants with aberrant movements, Tract-Based Spatial Statistics analysis identified significantly lower fractional anisotropy in widespread WM tracts. They conclude that aberrant general movements at 10–15 weeks’ postterm are associated with adverse neurodevelopmental outcomes and specific white matter microstructure abnormalities for cognitive, language, and motor delays.

Abstract

BACKGROUND AND PURPOSE

Very preterm infants (birth weight, <1500 g) are at increased risk of cognitive and motor impairment, including cerebral palsy. These adverse neurodevelopmental outcomes are associated with white matter abnormalities on MR imaging at term-equivalent age. Cerebral palsy has been predicted by analysis of spontaneous movements in the infant termed “General Movement Assessment.” The goal of this study was to determine the utility of General Movement Assessment in predicting adverse cognitive, language, and motor outcomes in very preterm infants and to identify brain imaging markers associated with both adverse outcomes and aberrant general movements.

MATERIALS AND METHODS

In this prospective study of 47 preterm infants of 24–30 weeks’ gestation, brain MR imaging was performed at term-equivalent age. Infants underwent T1- and T2-weighted imaging for volumetric analysis and DTI. General movements were assessed at 10–15 weeks’ postterm age, and neurodevelopmental outcomes were evaluated at 2 years by using the Bayley Scales of Infant and Toddler Development III.

RESULTS

Nine infants had aberrant general

Limited Dorsal Myeloschisis and Congenital Dermal Sinus: Comparison of Clinical and MR Imaging Features

Editor’s Choice

These investigators retrospectively reviewed the clinical and MR imaging findings of 12 patients with limited dorsal myeloschisis and 10 patients with congenital dermal sinus. A crater covered with pale epithelium was the most common skin lesion in limited dorsal myeloschisis (83%). Infectious complications were common in congenital dermal sinus (60%), but not found in limited dorsal myeloschisis. They show that limited dorsal myeloschisis has distinct MR imaging features including a visible intrathecal tract with dorsal tenting of the cord at the tract-cord union.

Correlation of MRI Brain Injury Findings with Neonatal Clinical Factors in Infants with Congenital Diaphragmatic Hernia

Fellows’ Journal Club

The authors evaluated MRIs performed before hospital discharge in 53 infants with congenital diaphragmatic hernia that were scored forbrain injury by 2 pediatric neuroradiologists. Potential associations with perinatal and clinical variables from the neonatal intensive care unit stay were probed. The most common findings were enlarged extra-axial spaces (36%), intraventricular hemorrhage (23%), ventriculomegaly (19%), white matter injury (17%), and cerebellar hemorrhage (17%). Brain injury score was associated with extracorporeal membrane oxygenation, lack of oral feeding at discharge, use of inotropes, and gastrostomy tube placement before hospital discharge.

Abstract

BACKGROUND AND PURPOSE

Infants with congenital diaphragmatic hernia are reported to have evidence of brain MR imaging abnormalities. Our study aimed to identify perinatal clinical factors in infants with congenital diaphragmatic hernia that are associated with evidence of brain injury on MR imaging performed before hospital discharge.

MATERIALS AND METHODS

MRIs performed before hospital discharge in infants with congenital diaphragmatic hernia were scored for brain injury by 2 pediatric neuroradiologists. Perinatal variables and clinical variables from the neonatal intensive care unit stay were analyzed for potential associations with brain MR imaging findings.

RESULTS

Fifty-three infants with congenital diaphragmatic hernia (31 boys) were included. At least 1 abnormality was seen on MR imaging in 32 infants (60%). The most common MR imaging findings were enlarged extra-axial spaces (36%), intraventricular hemorrhage (23%), ventriculomegaly (19%), white matter injury (17%), and cerebellar hemorrhage (17%). The MR imaging brain injury score was associated with extracorporeal membrane oxygenation (P = .0001), lack of oral feeding at discharge (P = .012), use of inotropes (P = .027), and gastrostomy tube placement before hospital discharge (P = .024). The MR imaging brain injury score was also associated with a large diaphragmatic defect size (P = .011).

CONCLUSIONS

Most infants with congenital diaphragmatic hernia have at least 1

Full Dose-Reduction Potential of Statistical Iterative Reconstruction for Head CT Protocols in a Predominantly Pediatric Population

Fellows’ Journal Club

The authors set out to determine the maximum level of statistical iterative reconstruction that can be used to establish dose-reduced head CT protocols in a primarily pediatric population while maintaining similar appearance and level of image noise in the reconstructed image. Dose-reduced head protocols using an adaptive statistical iterative reconstruction were compared for image quality with the original filtered back-projection reconstructed protocols in a phantom and CT dose index and image noise magnitude were assessed in 737 pre- and post-dose-reduced examinations. Implementation of 40% and 60% adaptive statistical iterative reconstruction led to an average reduction in the volume CT dose index of 43% for brain, 41% for orbit, 30% for maxilla, 43% for sinus, and 42% for temporal bone protocols for patients between 1 month and 26 years of age, while improving the contrast-to-noise ratio of low-contrast soft-tissue targets.

Abstract

BACKGROUND AND PURPOSE

A statistical iterative reconstruction algorithm provides an effective approach to reduce patient dose by compensating for increased image noise in CT due to reduced radiation output. However, after a point, the degree to which a statistical iterative algorithm is used for image reconstruction changes the image appearance. Our aim was to determine the maximum level of statistical iterative reconstruction that can be used to establish dose-reduced head CT protocols in a primarily pediatric population while maintaining similar appearance and level of image noise in the reconstructed image.

MATERIALS AND METHODS

Select head examinations (brain, orbits, sinus, maxilla, and temporal bones) were investigated. Dose-reduced head protocols using an adaptive statistical iterative reconstruction were compared for image quality with the original filtered back-projection reconstructed protocols in a phantom by using the following metrics: image noise frequency (change in perceived appearance of noise texture), image noise magnitude, contrast-to-noise ratio, and spatial resolution. Dose-reduction estimates were based on