Imaging approach to pediatric calvarial bulges.

Palpable calvarial lesions in children may require multi-modality imaging for adequate characterization due to non-specific clinical features. Causative lesions range from benign incidental lesions to highly aggressive pathologies. While tissue sampling may be required for some lesions, others have a typical imaging appearance, and an informed imaging approach facilitates diagnosis. This review illustrates imaging findings of common and clinically important focal pediatric calvarial bulges to aid the radiologist in narrowing the differential diagnosis and directing appropriate referral. We focus on birth-related lesions, congenital abnormalities, and modeling disturbances (i.e., those that produce a change in calvarial contour early in development), normal variants, and neoplastic lesions with their mimics.

Pediatric orbital lesions: neoplastic extraocular soft-tissue lesions.

Pediatric neoplastic extraocular soft-tissue lesions in the orbit are uncommon. Early multimodality imaging work-up and recognition of the key imaging features of these lesions allow narrowing of the differential diagnoses in order to direct timely management. In this paper, the authors present a multimodality approach to the imaging work-up of these lesions and highlight the use of ocular ultrasound as a first imaging modality where appropriate. We will discuss vascular neoplasms (congenital hemangioma, infantile hemangioma), optic nerve lesions (meningioma, optic nerve glioma), and other neoplastic lesions (plexiform neurofibroma, teratoma, chloroma, rhabdomyosarcoma, infantile fibrosarcoma, schwannoma).

Pediatric orbital lesions: ocular pathologies.

Orbital pathologies can be broadly classified as ocular, extra-ocular soft-tissue (non-neoplastic and neoplastic), osseous, and traumatic. In part 1 of this orbital series, the authors will discuss the differential diagnosis and key imaging features of pediatric ocular pathologies. These include congenital and developmental lesions (microphthalmos, anophthalmos, persistent fetal vasculature, coloboma, morning glory disc anomaly, retinopathy of prematurity, Coats disease), optic disc drusen, infective and inflammatory lesions (uveitis, toxocariasis, toxoplasmosis), and ocular neoplasms (retinoblastoma, retinal hamartoma, choroidal melanoma, choroidal nevus). This pictorial review provides a practical approach to the imaging work-up of these anomalies with a focus on ocular US as the first imaging modality and additional use of CT and/or MRI for the evaluation of intracranial abnormalities. The characteristic imaging features of the non-neoplastic mimics of retinoblastoma, such as persistent fetal vasculature and Coats disease, are also highlighted.

Pediatric orbital lesions: bony and traumatic lesions.

Orbital pathologies can be broadly classified as ocular lesions, extraocular soft-tissue pathologies (non-neoplastic and neoplastic), and bony and traumatic lesions. In this paper, we discuss the key imaging features and differential diagnoses of bony and traumatic lesions of the pediatric orbit and globe, emphasizing the role of CT and MRI as the primary imaging modalities. In addition, we highlight the adjunctive role of ocular sonography in the diagnosis of intraocular foreign bodies and discuss the primary role of sonography in the diagnosis of traumatic retinal detachment.

Pediatric orbital lesions: non-neoplastic extraocular soft-tissue lesions.

Orbital pathologies can be broadly classified as ocular, extraocular soft-tissue (non-neoplastic and neoplastic), osseous, and traumatic. In this paper, we discuss the key imaging features and differential diagnoses of congenital and developmental lesions (dermoid cyst, dermolipoma), infective and inflammatory pathologies (pre-septal cellulitis, orbital cellulitis, optic neuritis, chalazion, thyroid ophthalmopathy, orbital pseudotumor), and non-neoplastic vascular anomalies (venous malformation, lymphatic malformation, carotid-cavernous fistula), emphasizing the key role of CT and MRI in the imaging work-up. In addition, we highlight the adjunctive role of ocular ultrasound in the diagnosis of dermoid cyst and chalazion, and discuss the primary role of ultrasound in the diagnosis of vascular malformations.

Nasal monobloc osteotomy for correction of late nasal and orbital asymmetry of unicoronal synostosis: A morphometric and outcomes study.

BACKGROUND: Craniofacial asymmetry associated with unicoronal synostosis (UCS) may persist into the teenage years despite surgery in infancy. This study evaluated outcomes following a nasal monobloc procedure by mobilizing a united nasomaxillary and bilateral medial orbital segment of bone (nasal monobloc) to perform corrective translational and rotational movement for secondary correction of residual nasal-orbital asymmetry associated with UCS. METHODS: A retrospective review of all UCS patients treated with nasal monobloc at our institution was performed. Demographic information was recorded, and pre- and postoperative 2D imaging was used for morphometric outcome analysis. Outcomes and complications were tabulated. RESULTS: The study included 14 patients (5 males, 9 females; mean age 14.6 years; range 9.6 to 22.5 years; mean follow-up 70.6 months range 12 to 132 months). Ancillary procedures (scar revision, forehead/orbital contouring, MEDPOR® augmentation) were performed in all patients at the time of the nasal monobloc. One patient underwent a repeat procedure 6 years later following technique modification. Additionally, another patient experienced late overgrowth of the frontal sinus with forehead asymmetry. The morphometric analysis demonstrated significant (p < 0.05) pre-op to post-op improvements in naso-orbital asymmetry, as demonstrated by horizontal orbital aperture ratio (0.88 vs 0.99), midline to exocanthion ratio (0.91 vs 0.98), orbital index ratio (1.15 vs 1.01), and midline discrepancy (7.1 degrees vs 2.7 degrees). CONCLUSION: Nasal monobloc osteotomy provides a reasonable surgical treatment to improve both the nasal and orbital asymmetries associated with unicoronal synostosis, including frontal nasal deviation, basal nasal deviation, and orbital aperture asymmetry. It is important to note that confounding anatomic variables such as globe dystopia, strabismus, and scleral show may affect the perception of orbital symmetry.

Major Surgery, Brain Injury, and Neurodevelopmental Outcomes in Very Preterm Infants.

OBJECTIVES: We determined whether (1) major surgery is associated with an increased risk for brain injury and adverse neurodevelopment and (2) brain injury modifies associations between major surgery and neurodevelopment in very preterm infants. METHODS: Prospectively enrolled infants across 3 tertiary neonatal intensive care units underwent early-life and/or term-equivalent age MRI to detect moderate-severe brain injury. Eighteen-month neurodevelopmental outcomes were assessed with Bayley Scales of Infant and Toddler Development, third edition. Multivariable logistic and linear regressions were used to determine associations of major surgery with brain injury and neurodevelopment, adjusting for clinical confounders. RESULTS: There were 294 infants in this study. Major surgery was associated with brain injury (odds ratio 2.54, 95% CI 1.12-5.75, p = 0.03) and poorer motor outcomes (ß = -7.92, 95% CI -12.21 to -3.64, p < 0.001), adjusting for clinical confounders. Brain injury x major surgery interaction significantly predicted motor scores (p = 0.04): Lowest motor scores were in infants who required major surgery and had brain injury. DISCUSSION: There is an increased risk for brain injury and adverse motor outcomes in very preterm infants who require major surgery, which may be a marker of clinical illness severity. Routine brain MRI to detect brain injury and close neurodevelopmental surveillance should be considered in this subgroup of infants.

Child Neurology: Progressive Cerebellar Atrophy and Retinal Dystrophy: Clues to an Ultrarare ACO2-Related Neurometabolic Diagnosis.

Pathogenic biallelic variants in ACO2, which encodes the enzyme mitochondrial aconitase, are associated with the very rare diagnosis of ACO2-related infantile cerebellar retinal degeneration (OMIM 614559). We describe the diagnostic odyssey of a 4-year-old female patient with profound global developmental delays, microcephaly, severe hypotonia, retinal dystrophy, seizures, and progressive cerebellar atrophy. Whole-exome sequencing revealed 2 variants in ACO2; c.2105_2106delAG (p.Gln702ArgfsX9), a likely pathogenic variant, and c.988C>T (p.Pro330Ser) which was classified as a variant of uncertain significance (VUS). While the VUS was confirmed to be maternally inherited, the phase of the other variant could not be confirmed due to lack of a paternal sample. Functional biochemical studies were performed on a research basis to clarify the interpretation of the VUS, which enabled clinical confirmation of the diagnosis of ACO2-related infantile cerebellar retinal degeneration for our patient.

Intake of mother's milk by very-low-birth-weight infants and variation in DNA methylation of genes involved in neurodevelopment at 5.5 years of age.

BACKGROUND: Mechanisms responsible for associations between intake of mother's milk in very-low-birth-weight (VLBW, <1500 g) infants and later neurodevelopment are poorly understood. It is proposed that early nutrition may affect neurodevelopmental pathways by altering gene expression through epigenetic modification. Variation in DNA methylation (DNAm) at cytosine-guanine dinucleotides (CpGs) is a commonly studied epigenetic modification. OBJECTIVES: We aimed to assess whether early mother's milk intake by VLBW infants is associated with variations in DNAm at 5.5 y, and whether these variations correlate with neurodevelopmental phenotypes. METHODS: This cohort study was a 5.5-y follow-up (2016-2018) of VLBW infants born in Ontario, Canada who participated in the Donor Milk for Improved Neurodevelopmental Outcomes trial. We performed an epigenome-wide association study (EWAS) to test whether percentage mother's milk (not including supplemental donor milk) during hospitalization was associated with DNAm in buccal cells during early childhood (n = 143; mean ± SD age: 5.7 ± 0.2 y; birth weight: 1008 ± 517 g). DNAm was assessed with the Illumina Infinium MethylationEPIC array at 814,583 CpGs. In secondary analyses, we tested associations between top-ranked CpGs and measures of early childhood neurodevelopment, e.g., total surface area of the cerebral cortex (n = 41, MRI) and Full-Scale IQ (n = 133, Wechsler Preschool and Primary Scale of Intelligence-IV). RESULTS: EWAS analysis demonstrated percentage mother's milk intake by VLBW infants during hospitalization was associated with DNAm at 2 CpGs, cg03744440 [myosin XVB (MYO15B)] and cg00851389 [metallothionein 1A (MT1A)], at 5.5 y (P < 9E-08). Gene set enrichment analysis indicated that top-ranked CpGs (P < 0.001) were annotated to genes enriched in neurodevelopmental biological processes. Corroborating these findings, DNAm at several top identified CpGs from the EWAS was associated with cortical surface area and IQ at 5.5 y (P < 0.05). CONCLUSIONS: In-hospital percentage mother's milk intake by VLBW infants was associated with variations in DNAm of neurodevelopmental genes at 5.5 y; some of these DNAm variations are associated with brain structure and IQ.This trial was registered at isrctn.com as ISRCTN35317141 and at clinicaltrials.gov as NCT02759809.

Neurovascular Manifestations in Pediatric Patients With Hereditary Haemorrhagic Telangiectasia.

BACKGROUND: Hereditary hemorrhagic telangiectasia (HHT) is a multiorgan vascular dysplasia with limited data regarding its neurovascular manifestations and genotype-phenotype correlation in children. The objective of this study was to describe the neurovascular findings in a large cohort of children with HHT and correlate between phenotype and genotype. METHODS: This retrospective study was conducted on 221 children (<18 years) with a definite or possible diagnosis of HHT based on Curacao criteria, or with positive genetics for the mutated genes of ENG, ACVRL-1, and SMAD-4, who also underwent brain MRI and/or conventional angiography. Demographic and clinical information, imaging findings, and follow up information were gathered. RESULTS: Two hundred twenty-one children with HHT (70.6% genetically confirmed, and 99.5% positive family history) were included, with a median age of 7 years (interquartile range: 3 to 11 years) and 58.8% male predominance. Neurovascular lesions were found in 64 of 221 (28.9%), with 3.1% prevalence of intracranial hemorrhage. The most commonly observed vascular malformations were developmental venous anomalies (48.5%) and brain arteriovenous malformations (AVMs) (31.2%), followed by capillary malformations (14.1%). Multiple AVMs were seen in 10.0% of the cohort. We found no instances of de novo AVM (1281.8 patient-years).A significantly higher proportion of patients with ENG mutations (19.7%) had brain AVM than those with ACVRL-1 (4.9%) and SMAD-4 (0%) mutations (P < 0.01). There was no significant difference in the hemorrhagic risk of shunting lesions associated with ENG (35.3%) or ACVRL-1 (33.3%) positivity (P = 0.9). CONCLUSIONS: We describe the neurovascular imaging and genetic findings from a large pediatric cohort of HHT, to enhance clinical awareness and guide management of patients with HHT.

Central nervous system relapse in a child with anaplastic large cell lymphoma: potential for new therapeutic strategies.

BACKGROUND: Central nervous system (CNS) relapse is rare in childhood anaplastic large cell lymphoma (ALCL) and is associated with a poor prognosis. CASE: We describe an 8-year-old boy with ALCL who developed an early CNS relapse without initial CNS disease. Despite aggressive medical management, the patient's neurological status deteriorated rapidly and he died shortly after. CONCLUSION: Optimal treatment for children with relapsed ALCL involving the CNS remains unclear. Novel agents, including ALK inhibitors, that have CNS-penetration might be helpful and pediatric studies are warranted.

Locations, associations and temporal evolution of intracranial arterial infundibular dilatations in children.

BACKGROUND: There are few data in the literature on the characteristics and natural history of intracranial arterial infundibular dilatations in children. METHODS: An institutional review board-approved retrospective review was performed of infundibula reported on MR angiography in patients <18 years of age at our tertiary pediatric institute from 1998 to 2016. Clinical data (age, sex, diagnosis, other vascular variants/pathologies) were recorded and images assessed for vessel of origin, infundibulum size and exact location. Ratios of infundibulum:parent artery were assessed at diagnosis and last follow-up. Temporal evolution to aneurysm was evaluated. RESULTS: We found 60 intracranial infundibula in 60 children (male:female=27:33; mean age 9.7±5.2 years, range 2-18 years,). Family history of aneurysms was present in 2/60 (3.3%). Syndromic association was found in 14/60 (23.3%), most frequently sickle cell disease (4/14=28.6%). Mean infundibulum size was 2.2±0.5 mm, with mean ratio to parent artery of 0.54±0.17. The most common location was on the P1-posterior cerebral artery (34/63=56.7%), whereas posterior communicating infundibula were seen in only 4/60 (6.7%) cases. Other cerebrovascular variants were seen in 12/60 (20%) patients. On follow-up imaging (in 32/60 patients over 86 patient-years, mean 32.3±35.7 months), no significant change in infundibulum:parent artery ratio was noted. None of the infundibular dilatations showed interval evolution to aneurysm. CONCLUSION: We present the largest reported cohort of pediatric intracranial arterial infundibula, which we found to be distinct from their adult counterparts with regard to location, etiology and temporal evolution. Growth over time and/or aneurysmal formation are rare, not necessitating frequent short-term imaging surveillance during childhood.

Predicting developmental outcomes in preterm infants: A simple white matter injury imaging rule.

OBJECTIVE: To develop a simple imaging rule to predict neurodevelopmental outcomes at 4.5 years in a cohort of preterm neonates with white matter injury (WMI) based on lesion location and examine whether clinical variables enhance prediction. METHODS: Sixty-eight preterm neonates born 24-32 weeks' gestation (median 27.7 weeks) were diagnosed with WMI on early brain MRI scans (median 32.3 weeks). 3D T1-weighted images of 60 neonates with 4.5-year outcomes were reformatted and aligned to the posterior commissure-eye plane and WMI was classified by location: anterior or posterior-only to the midventricle line on the reformatted axial plane. Adverse outcomes at 4.5 years were defined as Wechsler Preschool and Primary Scale of Intelligence full-scale IQ <85, cerebral palsy, or Movement Assessment Battery for Children, second edition percentile <5. The prediction of adverse outcome by WMI location, intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD), and retinopathy of prematurity (ROP) was assessed using multivariable logistic regression. RESULTS: Six children had adverse cognitive outcomes and 17 had adverse motor outcomes. WMI location predicted cognitive outcomes in 90% (area under receiver operating characteristic curve [AUC] 0.80) and motor outcomes in 85% (AUC 0.75). Adding IVH, BPD, and ROP to the model enhances the predictive strength for cognitive and motor outcomes (AUC 0.83 and 0.88, respectively). Rule performance was confirmed in an independent cohort of children with WMI. CONCLUSIONS: WMI on early MRI can be classified by location to predict preschool age outcomes in children born preterm. The predictive value of this WMI classification is enhanced by considering clinical factors apparent by term-equivalent age.

Associations Between Age at Arterial Switch Operation, Brain Growth, and Development in Infants With Transposition of the Great Arteries.

BACKGROUND: Brain injury, impaired brain growth, and long-term neurodevelopmental problems are common in children with transposition of the great arteries. We sought to identify clinical risk factors for brain injury and poor brain growth in infants with transposition of the great arteries undergoing the arterial switch operation, and to examine their relationship with neurodevelopmental outcome. METHODS: The brains of 45 infants with transposition of the great arteries undergoing surgical repair were imaged pre- and postoperatively using magnetic resonance imaging. Brain weight z scores were calculated based on brain volume and autopsy reference data. Brain injury scores were determined as previously described. Neurodevelopment was assessed at 18 months using the Bayley-III scores of infant development. The relationships between clinical variables, brain injury, perioperative brain growth, and 18-month Bayley-III scores were analyzed. RESULTS: On preoperative imaging, moderate or severe white matter injury was present in 10 of 45 patients, whereas stroke was seen in 4 of 45. A similar prevalence of injury was seen on postoperative imaging, and we were unable to identify any clinical risk factors for brain injury. Brain weight z scores decreased perioperatively in 35 of 45 patients. The presence of a ventricular septal defect ( P=0.009) and older age at surgery ( P=0.007) were associated with impaired perioperative brain growth. When patients were divided into those undergoing surgery during the first 2 weeks of life (32/45) versus those being repaired later (13/45), infants repaired later had significantly worse perioperative brain growth (late repair postoperative brain weight z = -1.0±0.90 versus early repair z = -0.33±0.64; P=0.008). Bayley-III testing scores fell within the normal range for all patients, although age at repair ( P=0.03) and days of open chest ( P=0.03) were associated with a lower composite language score, and length of stay was associated with a lower composite cognitive score ( P=0.02). CONCLUSIONS: Surgery beyond 2 weeks of age is associated with impaired brain growth and slower language development in infants with transposition of the great arteries cared for at our center. Although the mechanisms underlying this association are still unclear, extended periods of cyanosis and pulmonary overcirculation may adversely impact brain growth and subsequent neurodevelopment.

Pediatric Brain Tumor Genetics: What Radiologists Need to Know.

Brain tumors are the most common solid tumors in the pediatric population. Pediatric neuro-oncology has changed tremendously during the past decade owing to ongoing genomic advances. The diagnosis, prognosis, and treatment of pediatric brain tumors are now highly reliant on the genetic profile and histopathologic features of the tumor rather than the histopathologic features alone, which previously were the reference standard. The clinical information expected to be gleaned from radiologic interpretations also has evolved. Imaging is now expected to not only lead to a relevant short differential diagnosis but in certain instances also aid in predicting the specific tumor and subtype and possibly the prognosis. These processes fall under the umbrella of radiogenomics. Therefore, to continue to actively participate in patient care and/or radiogenomic research, it is important that radiologists have a basic understanding of the molecular mechanisms of common pediatric central nervous system tumors. The genetic features of pediatric low-grade gliomas, high-grade gliomas, medulloblastomas, and ependymomas are reviewed; differences between pediatric and adult gliomas are highlighted; and the critical oncogenic pathways of each tumor group are described. The role of the mitogen-activated protein kinase pathway in pediatric low-grade gliomas and of histone mutations as epigenetic regulators in pediatric high-grade gliomas is emphasized. In addition, the oncogenic drivers responsible for medulloblastoma, the classification of ependymomas, and the associated imaging correlations and clinical implications are discussed. ©RSNA, 2018.

Tumor volumetric measurements in surgically inaccessible pediatric low-grade glioma.

Tumor measurement is important in unresectable pediatric low-grade gliomas (pLGGs) to determine either the need for treatment or assess response. Standard methods measure the product of the largest 2 lengths from transverse, anterior-posterior, and cranio-caudal dimensions (SM, cm). This single-institution study evaluated tumor volume measurements (VM, cm) in such pLGGs. Of 50 patients treated with chemotherapy for surgically inaccessible pLGG, 8 met the inclusion criteria of having 2 or more sequential MRI studies of T1-weighted Fast-Spoiled Gradient Recalled acquisition. SM and VM were performed by 2 independent neuroradiologists. Associations of measurement methods with defined therapeutic response criteria and patient clinical status were assessed. The mean tumor size at the first MRI scan was 20 cm and 398 cm according to SM and VM, respectively. VM results did not differ significantly from SM-derived spherical volume calculations (Pearson correlation, P<0.0001) with a high interrater reliability. Both methods were concordant in defining the tumor response according to the current criteria, although radiologic progressive disease was not associated with clinical status (SM: P=0.491, VM: P=0.208). In this limited experience, volumetric analysis of unresectable pLGGs did not seem superior to the standard linear measurements for defining tumor response.

Temporal and occipital lobe features in children with hypochondroplasia/FGFR3 gene mutation.

BACKGROUND: Thanatophoric dysplasia (TD) and hypochondroplasia are both caused by FGFR3 (fibroblast growth factor receptor 3) gene mutations. Temporal lobe dysplasia has been well described in thanatophoric dysplasia; however, only a couple of anecdotal cases of temporal lobe dysplasia in hypochondroplasia have been described. OBJECTIVE: To define temporal lobe abnormalities in patients with hypochondroplasia, given that they share the same genetic mutation. MATERIALS AND METHODS: We identified brain imaging studies of nine children with hypochondroplasia. The temporal lobes were assessed on CT and MRI for size and configuration of the temporal horn and aberrant sulcation of the inferior surface of the temporal lobe. RESULTS: All children had a triangular-shape temporal horn and deep transverse fissures of the inferior temporal lobe surface. Neuroimaging in our cohort revealed enlarged temporal lobes and oversulcation of the mesial temporal and occipital lobes, with abnormal inferomedial orientation of these redundant gyri. Hippocampal dysplasia was also universal. CONCLUSION: We confirmed frequent inferomesial temporal and occipital lobe abnormalities in our cohort of children with hypochondroplasia. Murine models with mutant fgfr3 display increased neuroprogenitor proliferation, cortical thickness and surface area in the temporo-occipital cortex. This is thought to result in excessive convolution and likely explains the imaging findings in this patient cohort. (Note that fgfr3 is the same genetic mutation in mice as FGFR3 is in humans.).

Childhood transverse myelitis and its mimics.

Childhood transverse myelitis is an acute inflammatory disorder of the spinal cord with a risk of permanent disability. A timely and accurate diagnosis is imperative, and the radiologist needs to discern between a variety of extra-axial and spinal cord abnormalities that produce similar symptoms but require vastly differing treatments. This article presents the range of imaging characteristics seen in childhood transverse myelitis and the differentiation from its mimics.

Trends in treatment and outcomes of pediatric craniopharyngioma, 1975-2011.

BACKGROUND: Craniopharyngioma tumors and their treatment can lead to significant long-term morbidity due to their proximity to vital structures. The optimal treatment has been debated for many years. We aimed to review the long-term outcomes of children treated for craniopharyngioma in our institution over the past decade and describe trends in treatment and outcomes over the past 3 decades. METHODS: Charts of children with craniopharyngioma treated and followed at The Hospital for Sick Children between 2001 and 2011 were reviewed. Data regarding findings at diagnosis, treatment, and long-term outcomes were analyzed. Comparison was made with previously published data from our institution. RESULTS: Data from 33 patients are included; mean age at treatment, 10.7 ± 4.8 years. In 18 children (55%), the initial surgical approach was tumor cyst decompression with or without adjuvant therapy, compared with only 0-2% in the preceding decades (P < .01). Diabetes insipidus occurred in 55% of children and panhypopituitarism in 58% compared with 88% (P < .01) and 86% (P < .01), respectively, in the previous 10 years. Overall, there was a 36% reduction in the number of children who developed severe obesity compared with the preceding decade. Body mass index at follow-up was associated with body mass index at diagnosis (P = .004) and tumor resection as an initial treatment approach (P = .028). CONCLUSIONS: A shift in surgical treatment approach away from gross total resection has led to improved endocrine outcomes. This may have beneficial implications for quality of life in survivors.