How to Perform Fetal MR Imaging.

This article provides the readers with practical guidance on how to perform fetal MR imaging, including technical considerations such as scanner field strength and use of appropriate radiofrequency receive coils, and summarizes the role, strengths, and limitations of the various MR imaging sequences. The authors review the various factors to consider in scan preparation, including study indication, timing, maternal preparation, and the creation of an institutional fetal imaging protocol. Additional factors that go into scan optimization during acquisition including prioritizing maternal comfort and ways to troubleshoot various artifacts that maybe encountered in fetal imaging are discussed.

Diverse childhood neurologic disorders and outcomes following fetal neurologic consultation.

Fetal neurology encompasses the full spectrum of neonatal and child neurology presentations, with complex additional layers of diagnostic and prognostic challenges unique to the specific prenatal consultation. Diverse genetic and acquired etiologies with a range of potential outcomes may be encountered. Three clinical case presentations are discussed that highlight how postnatal phenotyping and longitudinal follow-up are essential to address the uncertainties that arise in utero, after birth, and in childhood, as well as to provide continuity of care.

Cell-Type Specificity of Mosaic Chromosome 1q Gain Resolved by snRNA-seq in a Case of Epilepsy With Hyaline Protoplasmic Astrocytopathy.

Objectives: Mosaic gain of chromosome 1q (chr1q) has been associated with malformation of cortical development (MCD) and epilepsy. Hyaline protoplasmic astrocytopathy (HPA) is a rare neuropathologic finding seen in cases of epilepsy with MCD. The cell-type specificity of mosaic chr1q gain in the brain and the molecular signatures of HPA are unknown. Methods: We present the case of a child with pharmacoresistant epilepsy who underwent epileptic focus resections at age 3 and 5 years and was found to have mosaic chr1q gain and HPA. We performed single-nuclei RNA sequencing (snRNA-seq) of brain tissue from the second resection. Results: snRNA-seq showed increased expression of chr1q genes specifically in subsets of neurons and astrocytes. Differentially expressed genes associated with inferred chr1q gain included AKT3 and genes associated with cell adhesion or migration. A subpopulation of astrocytes demonstrated marked enrichment for synapse-associated transcripts, possibly linked to the astrocytic inclusions observed in HPA. Discussion: snRNA-seq may be used to infer the cell-type specificity of mosaic chromosomal copy number changes and identify associated gene expression alterations, which in the case of chr1q gain may involve aberrations in cell migration. Future studies using spatial profiling could yield further insights on the molecular signatures of HPA.

Clinical and Imaging Findings in Children with Myelin Oligodendrocyte Glycoprotein Antibody Associated Disease (MOGAD): From Presentation to Relapse.

BACKGROUND AND PURPOSE: Myelin oligodendrocyte glycoprotein-antibody associated disease (MOGAD) is an increasingly recognized cause of demyelinating disease in children. The purpose of this study is to characterize the CNS imaging manifestations of pediatric MOGAD and identify clinical and imaging variables associated with relapse. MATERIALS AND METHODS: We retrospectively identified children with serum antibody-positive MOGAD evaluated at our institution between 1997 and 2020. Clinical and demographic data were collected. MRIs of the brain, orbit, and spine at presentation and relapse were reviewed for location and pattern of abnormality. RESULTS: Among 61 cases (34 girls), mean age at presentation was 7 years (IQR 4-11). At presentation, there was imaging involvement of the brain in 78.6% (44/56), optic pathway in 55.4% (31/56), and spine in 19.6% (11/56). Brain involvement was commonly in the frontal (70.5%, 31/44) and subcortical (75%, 33/44) white matter, with involvement of the thalamus and pons in 47.7% each (21/44). Optic neuritis (ON) was commonly bilateral (80.6%, 25/31) involving intraorbital segments (77.4%, 24/31). Spinal cord lesions were typically cervical (72.7%, 8/11) and multifocal (72.7%, 8/11).The imaging patterns were age-dependent; children ≤9 years more commonly demonstrated ADEM-like imaging pattern at presentation (39.4%, 13/33) and first relapse (8/23, 34.8%), while children >9 years more commonly had ON at presentation (34.8%, 8/23, P = .001) and FLAIR-hyperintense lesions in anti-MOG-associated encephalitis with seizures at first relapse (5/18, 27.8%, P = .008). CONCLUSIONS: We describe the CNS imaging findings in pediatric MOGAD. The imaging pattern is age-dependent at presentation and first relapse. Younger age at presentation is associated with longer time to relapse.

Spectrum of Fetal Intraparenchymal Hemorrhage in COL4A1/A2-Related Disorders.

BACKGROUND: COL4A1/A2 variants affecting the alpha 1 and 2 chains of type IV collagen are increasingly recognized as a cause of fetal and neonatal intracranial hemorrhage, porencephaly, and schizencephaly. Fetal magnetic resonance imaging (MRI) findings in COL4A1/A2-related disorders are not well characterized. METHODS: This is a retrospective case series of fetal MRI findings in eight patients with intraparenchymal hemorrhage (IPH) and COL4A1/A2 variants, five of whom have postnatal imaging and clinical follow-up. RESULTS: IPH was multifocal and bilateral in four of eight patients. IPH involved the frontal lobes in all cases and basal ganglia in six of eight. The median maximum diameter of IPH was 16 mm (range 6 to 65 mm). All patients had ventriculomegaly, and four of eight had intraventricular hemorrhage. Prenatal IPH size correlated clinically with motor outcomes, and none had clinically symptomatic recurrent hemorrhage. CONCLUSION: COL4A1/A2 variants can present with a spectrum of IPH prenatally, including small and/or unifocal IPH, as well as multifocal and bilateral IPH, involving the frontal lobes and basal ganglia. Given the wide spectrum of IPH severity seen on fetal brain MRI, genetic testing for COL4A1/A2 variants should be considered in all cases of fetal IPH.

Factors and Labor Cost Savings Associated with Successful Pediatric Imaging without Anesthesia: a Single-Institution Study.

RATIONALE AND OBJECTIVES: In pediatric imaging, sedation is often necessary to obtain diagnostic quality imaging. We aim to quantify patient and imaging-specific factors associated with successful pediatric scans without anesthesia and to evaluate labor cost savings associated with our institutional Scan Without Anesthesia Program (SWAP). MATERIALS AND METHODS: Patients who participated in SWAP between 2019-2022 were identified. Chart review was conducted to obtain sociodemographic and clinical information. Radiology database was used to obtain scan duration, modality/body part of examination, and administration of contrast. Mann-Whitney U and Chi-Square tests were used for univariate analysis of factors associated with success. Multivariate logistic regression was used to evaluate independent contributions to success. Associated hospital labor cost savings were estimated using salary information obtained through publicly available resources. RESULTS: Of 731 patients, 698 had successful and 33 had unsuccessful scans (95% success rate). In univariate analysis, older age, female sex, absence of developmental delay, and administration of contrast were significantly associated with successful scans. Multivariate analyses revealed that older age, female sex, and absence of developmental delay were significant independent factors lending toward success. Imaging-related factors were not associated with outcome in multivariate analysis. Estimated labor cost savings were $139,367.80 per year for the medical center. CONCLUSION: SWAP had an overall success rate of 95%. Older age, absence of developmental delay, and female sex were independently significantly associated with successful outcome. Cost analysis reveals substantial labor cost savings to the institution compared with imaging under anesthesia.

ACR Appropriateness Criteria® Ataxia-Child.

Childhood ataxia may be due to multifactorial causes of impairment in the coordination of movement and balance. Acutely presenting ataxia in children may be due to infectious, inflammatory, toxic, ischemic, or traumatic etiology. Intermittent or episodic ataxia in children may be manifestations of migraine, benign positional vertigo, or intermittent metabolic disorders. Nonprogressive childhood ataxia suggests a congenital brain malformation or early prenatal or perinatal brain injury, and progressive childhood ataxia indicates inherited causes or acquired posterior fossa lesions that result in gradual cerebellar dysfunction. CT and MRI of the central nervous system are the usual modalities used in imaging children presenting with ataxia, based on the clinical presentation. This document provides initial imaging guidelines for a child presenting with acute ataxia with or without a history of recent trauma, recurrent ataxia with interval normal neurological examination, chronic progressive ataxia, and chronic nonprogressive ataxia. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Deep Learning to Predict Neonatal and Infant Brain Age from Myelination on Brain MRI Scans.

Background Assessment of appropriate brain myelination on T1- and T2-weighted MRI scans is based on gestationally corrected age (GCA) and requires subjective visual inspection of the brain with knowledge of normal myelination milestones. Purpose To develop a convolutional neural network (CNN) capable of estimating neonatal and infant GCA based on brain myelination on MRI scans. Materials and methods In this retrospective study from one academic medical center, brain MRI scans of patients aged 0-25 months with reported normal myelination were consecutively collected between January 1995 and June 2019. The GCA at MRI was manually calculated. After exclusion criteria were applied, T1- and T2-weighted MRI scans were preprocessed with skull stripping, linear registration, z scoring for normalization, and downsampling. A three-dimensional regression CNN was trained to predict GCA using mean absolute error (MAE) as its loss function. Attention maps were calculated using layer-wise relevance propagation. Models were validated on an external test set from the National Institutes of Health (NIH). Model MAEs were compared using Kruskal-Wallis and Mann-Whitney tests. Results A total of 518 neonates and infants (mean GCA, 67 weeks ± 33 [SD], 56% male) was included, comprising 469 T1-, 438 T2-, and 389 T1- and T2-weighted studies. Across 10 runs, MAEs of T1-, T2-, and T1- and T2-weighted networks were 9.8 ± 2.3, 9.1 ± 1.9, and 7.7 ± 1.7 weeks, respectively. Attention map analysis demonstrated increased network attention to the cerebellum, posterior white matter, and basal ganglia signal in neonates with GCA of less than 40 weeks and the anterior white matter signal in infants with GCA of more than 120 weeks, corresponding to the known progression of myelination. The T1- and T2-weighted network tested on the external NIH test set had an MAE of 9.1 weeks, which was reduced to 5.9 weeks with further training using half the external test set (P < .001). Conclusion A three-dimensional convolutional neural network can predict the gestationally corrected age of neonates and infants aged 0-25 months based on brain myelination patterns on T1- and T2-weighted MRI scans. © RSNA, 2022 Online supplemental material is available for this article.

Disorders of Neuronal Migration/Organization Convey the Highest Risk of Neonatal Onset Epilepsy Compared With Other Congenital Brain Malformations.

BACKGROUND: Although seizures in neonates are common and often due to acute brain injury, 10-15% are unprovoked from congenital brain malformations. A better understanding of the risk of neonatal-onset epilepsy by the type of brain malformation is essential for counseling and monitoring. METHODS: In this retrospective cohort study, we evaluated 132 neonates with congenital brain malformations and their risk of neonatal-onset epilepsy. Malformations were classified into one of five categories based on imaging patterns on prenatal or postnatal imaging. Infants were monitored with continuous video EEG (cEEG) for encephalopathy and paroxysmal events in addition to abnormal neuroimaging. RESULTS: Seventy-four of 132 (56%) neonates underwent EEG monitoring, and 18 of 132 (14%) were diagnosed with neonatal-onset epilepsy. The highest prevalence of epilepsy was in neonates with disorders of neuronal migration/organization (9/34, 26%; 95% confidence interval [CI] = 13-44%), followed by disorders of early prosencephalic development (6/38, 16%; 95% CI = 6-31%), complex total brain malformations (2/16, 13%; 95% CI = 2-38%), and disorders of midbrain/hindbrain malformations (1/30, 3%; 95% CI = 0-17%). Of neonates with epilepsy, 5 of 18 (28%) had only electrographic seizures, 13 of 18 (72%) required treatment with two or more antiseizure medicines (ASMs), and 7 of 18 (39%) died within the neonatal period. CONCLUSION: Our results demonstrate that disorders of neuronal migration/organization represent the highest-risk group for early-onset epilepsy. Seizures are frequently electrographic only, require treatment with multiple ASMs, and portend a high mortality rate. These results support American Clinical Neurophysiology Society recommendations for EEG monitoring during the neonatal period for infants with congenital brain malformations.

ACR Appropriateness Criteria® Seizures-Child.

In children, seizures represent an extremely heterogeneous group of medical conditions ranging from benign cases, such as a simple febrile seizure, to life-threatening situations, such as status epilepticus. Underlying causes of seizures also represent a wide range of pathologies from idiopathic cases, usually genetic, to a variety of acute and chronic intracranial or systemic abnormalities. This document discusses appropriate utilization of neuroimaging tests in a child with seizures. The clinical scenarios in this document take into consideration different circumstances at the time of a child's presentation including the patient's age, precipitating event (if any), and clinical and electroencephalogram findings and include neonatal seizures, simple and complex febrile seizures, post-traumatic seizures, focal seizures, primary generalized seizures in a neurologically normal child, and generalized seizures in neurologically abnormal child. This practical approach aims to guide clinicians in clinical decision-making and to help identify efficient and appropriate imaging workup. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Bilateral Choroid Plexus Papillomas Diagnosed by Prenatal Ultrasound and MRI.

We present a rare prenatal diagnosis of bilateral choroid plexus papillomas by obstetrical ultrasound and fetal MRI at 20 weeks 6 days gestation. The fetus demonstrated bilateral enlarged, echogenic choroid plexus with increased Doppler flow suggestive of vascularized choroid tissue. Same-day fetal MRI demonstrated that the choroid plexus appeared enlarged bilaterally without definite hemorrhage. The combined features on ultrasound and MRI suggested bilateral choroid plexus papillomas with increased cerebrospinal fluid production, leading to ventriculomegaly and enlarged extra-axial spaces. The diagnosis was confirmed by postnatal pathology, which demonstrated WHO grade II atypical choroid plexus papillomas.

Acute Fulminant Cerebral Edema: A Newly Recognized Phenotype in Children With Suspected Encephalitis.

BACKGROUND: Encephalitis is a severe neurological syndrome associated with significant morbidity and mortality. The California Encephalitis Project (CEP) enrolled patients for more than a decade. A subset of patients with acute and fulminant cerebral edema was noted. METHODS: All pediatric encephalitis patients with cerebral edema referred to the CEP between 1998 and 2012 were reviewed. A case definition was developed for acute fulminant cerebral edema (AFCE) that included the CEP case definition for encephalitis and progression to diffuse cerebral edema on neuroimaging and/or autopsy, and no other recognized etiology for cerebral edema (eg, organic, metabolic, toxin). Prodromic features, demographic and laboratory data, neuroimaging, and outcomes were compared with non-AFCE encephalitis cases. RESULTS: Of 1955 pediatric cases referred to the CEP, 30 (1.5%) patients met the AFCE case definition. The median age for AFCE and non-AFCE cases was similar: 8.2 years (1-18 years) and 8.0 years (0.5-18 years), respectively. Asian-Pacific Islanders comprised a larger proportion of AFCE cases (44%) compared with non-AFCE cases (14%, P < .01). AFCE cases often had a prodrome of high fever, vomiting, and profound headache. Mortality among AFCE patients was significantly higher than among non-AFCE patients (80% vs 13%, P < .01). A confirmed etiology was identified in only 2 cases (enterovirus, human herpes virus type 6), while 10 others had evidence of a respiratory pathogen.Thirty pediatric patients referred to the California Encephalitis Project with a unique, and often fatal, form of encephalitis are reported. Demographic and clinical characteristics, possible etiologies and a proposed case definition for acute fulminant cerebral edema (AFCE) are described. CONCLUSIONS: AFCE is a recently recognized phenotype of encephalitis with a high mortality. AFCE may be triggered by common pediatric infections. Here, we propose a case definition.

ACR Appropriateness Criteria® Head Trauma-Child.

Head trauma is a frequent indication for cranial imaging in children. The majority of accidental pediatric head trauma is minor and sustained without intracranial injury. Well-validated pediatric-specific clinical decision guidelines should be used to identify very low-risk children who can safely forgo imaging. In those who require acute imaging, CT is considered the first-line imaging modality for suspected intracranial injury because of the short duration of the examination and its high sensitivity for acute hemorrhage. MRI can accurately detect traumatic complications, but often necessitates sedation in children, owing to the examination length and motion sensitivity, which limits rapid assessment. There is a paucity of literature regarding vascular injuries in pediatric blunt head trauma and imaging is typically guided by clinical suspicion. Advanced imaging techniques have the potential to identify changes that are not seen by standard imaging, but data are currently insufficient to support routine clinical use. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Prenatal Repair of Myelomeningocele and School-age Functional Outcomes.

BACKGROUND AND OBJECTIVES: The Management of Myelomeningocele Study (MOMS), a randomized trial of prenatal versus postnatal repair for myelomeningocele, found that prenatal surgery resulted in reduced hindbrain herniation and need for shunt diversion at 12 months of age and better motor function at 30 months. In this study, we compared adaptive behavior and other outcomes at school age (5.9-10.3 years) between prenatal versus postnatal surgery groups. METHODS: Follow-up cohort study of 161 children enrolled in MOMS. Assessments included neuropsychological and physical evaluations. Children were evaluated at a MOMS center or at a home visit by trained blinded examiners. RESULTS: The Vineland composite score was not different between surgery groups (89.0 ± 9.6 in the prenatal group versus 87.5 ± 12.0 in the postnatal group; P = .35). Children in the prenatal group walked without orthotics or assistive devices more often (29% vs 11%; P = .06), had higher mean percentage scores on the Functional Rehabilitation Evaluation of Sensori-Neurologic Outcomes (92 ± 9 vs 85 ± 18; P < .001), lower rates of hindbrain herniation (60% vs 87%; P < .001), had fewer shunts placed for hydrocephalus (49% vs 85%; P < .001) and, among those with shunts, fewer shunt revisions (47% vs 70%; P = .02) than those in the postnatal group. Parents of children repaired prenatally reported higher mean quality of life z scores (0.15 ± 0.67 vs 0.11 ± 0.73; P = .008) and lower mean family impact scores (32.5 ± 7.8 vs 37.0 ± 8.9; P = .002). CONCLUSIONS: There was no significant difference between surgery groups in overall adaptive behavior. Long-term benefits of prenatal surgery included improved mobility and independent functioning and fewer surgeries for shunt placement and revision, with no strong evidence of improved cognitive functioning.

Congenital Oral Masses: An Anatomic Approach to Diagnosis.

Although congenital oral masses are rare, they are readily detectable during fetal US screening. Most congenital oral masses are benign, but some may cause mechanical airway obstruction, resulting in poor outcomes at delivery. The radiologist's ability to describe these abnormalities and their physiologic sequelae accurately can have a substantial effect on perinatal treatment. Furthermore, despite being rare, congenital oral lesions encountered at screening and at follow up fetal MRI provide the opportunity to make a specific diagnosis by following a simple anatomic approach. This article describes an anatomic algorithm as the framework for accurate diagnosis of congenital oral lesions. The imaging appearance of the most common congenital oral cavity neoplasms is outlined, including vascular anomalies, epulides, choristomas, congenital lingual thyroid anomalies, lingual hamartomas, and epignathi, and other conditions that mimic these at US. Also reviewed are perinatal management of masses that affect the fetal airway and the imaging features key to optimizing delivery outcomes. Online supplemental material is available for this article. ©RSNA, 2019.

Cobalamin D Deficiency Identified Through Newborn Screening.

Cobalamin D deficiency (cblD) is one of the least common cobalamin metabolism disorders. It may result in isolated homocystinuria, isolated methylmalonic aciduria, or combined methylmalonic aciduria and homocystinuria (cblD-combined). Only seven cases of the combined cblD form have been reported to date. Due to the rarity of this disorder, the presentation and symptoms are not well described. We present an eighth case of the cblD-combined subtype, who had a positive newborn screen (NBS) on day of life 3. She was symptomatic and developed lethargy and poor oral intake at 8 days of life. She was treated with 10% dextrose, folinic acid, intramuscular hydroxocobalamin, and betaine. Despite the early initiation of treatment, she developed complications of the disease and was found to have abnormal brain imaging findings at 17 days of age and macular atrophy at 3 months of age and has global developmental delay. We provide detailed description of her presentation, her treatment, and her complications to aid in the understanding of this rare disorder, which is very similar to the more common cobalamin C disorder (cblC).

Abnormal Morphology of Select Cortical and Subcortical Regions in Neurofibromatosis Type 1.

Purpose To evaluate whether patients with neurofibromatosis type 1 (NF1)-a multisystem neurodevelopmental disorder with myriad imaging manifestations, including focal transient myelin vacuolization within the deep gray nuclei, brainstem, and cerebellum-exhibit differences in cortical and subcortical structures, particularly in subcortical regions where these abnormalities manifest. Materials and Methods In this retrospective study, by using clinically obtained three-dimensional T1-weighted MR images and established image analysis methods, 10 intracranial volume-corrected subcortical and 34 cortical regions of interest (ROIs) were quantitatively assessed in 32 patients with NF1 and 245 age- and sex-matched healthy control subjects. By using linear models, ROI cortical thicknesses and volumes were compared between patients with NF1 and control subjects, as a function of age. With hierarchic cluster analysis and partial correlations, differences in the pattern of association between cortical and subcortical ROI volumes in patients with NF1 and control subjects were also evaluated. Results Patients with NF1 exhibited larger subcortical volumes and thicker cortices of select regions, particularly the hippocampi, amygdalae, cerebellar white matter, ventral diencephalon, thalami, and occipital cortices. For the thalami and pallida and 22 cortical ROIs in patients with NF1, a significant inverse association between volume and age was found, suggesting that volumes decrease with increasing age. Moreover, compared with those in control subjects, ROIs in patients with NF1 exhibited a distinct pattern of clustering and partial correlations. Discussion Neurofibromatosis type 1 is characterized by larger subcortical volumes and thicker cortices of select structures. Most apparent within the hippocampi, amygdalae, cerebellar white matter, ventral diencephalon, thalami and occipital cortices, these neurofibromatosis type 1-associated volumetric changes may, in part, be age dependent. © RSNA, 2018 Online supplemental material is available for this article.

Regionally specific TSC1 and TSC2 gene expression in tuberous sclerosis complex.

Tuberous sclerosis complex (TSC), a heritable neurodevelopmental disorder, is caused by mutations in the TSC1 or TSC2 genes. To date, there has been little work to elucidate regional TSC1 and TSC2 gene expression within the human brain, how it changes with age, and how it may influence disease. Using a publicly available microarray dataset, we found that TSC1 and TSC2 gene expression was highest within the adult neo-cerebellum and that this pattern of increased cerebellar expression was maintained throughout postnatal development. During mid-gestational fetal development, however, TSC1 and TSC2 expression was highest in the cortical plate. Using a bioinformatics approach to explore protein and genetic interactions, we confirmed extensive connections between TSC1/TSC2 and the other genes that comprise the mammalian target of rapamycin (mTOR) pathway, and show that the mTOR pathway genes with the highest connectivity are also selectively expressed within the cerebellum. Finally, compared to age-matched controls, we found increased cerebellar volumes in pediatric TSC patients without current exposure to antiepileptic drugs. Considered together, these findings suggest that the cerebellum may play a central role in TSC pathogenesis and may contribute to the cognitive impairment, including the high incidence of autism spectrum disorder, observed in the TSC population.

Perilesional edema associated with an intracranial calcifying pseudoneoplasm of the neuraxis in a child: case report and review of imaging features.

Calcifying pseudoneoplasms of the neuraxis (CAPNONs) are rare, nonneoplastic lesions of the CNS. Their radiographic features have been well described, with prominent calcifications seen on CT imaging and generally uniform hypointensity on T1- and T2-weighted MRI sequences, with variable patterns of contrast enhancement. They are not associated with significant perilesional edema. The authors present an unusual case of an 8-year-old boy who was found to have a 2.5-cm right frontal mass that demonstrated reduced signal on T2-weighted sequences, heterogeneous contrast enhancement, and extensive perilesional edema on MRI sequences. The differential diagnoses included a chronic infection or neoplasm. He underwent gross-total resection of a firm, calcified mass that had clear boundaries between it and the surrounding gliotic brain. Pathological analysis demonstrated a well-circumscribed lesion with islands of lamellar calcifications and intervening spindle cells, consistent with a CAPNON. At 8 months after surgery the patient remained seizure free, and MRI revealed no evidence of residual lesion and significant improvement in perilesional edema. This particular case highlights the potential for unusual presentation of CAPNON and the rare presence of perilesional edema.