Prognostic Significance of Central Skull Base Remodeling in Chiari II Malformation.

BACKGROUND AND PURPOSE: Outward convexity of the basiocciput and posterior atlanto-occipital membrane are common in patients with Chiari II malformation associated with an open neural tube defect. We aimed to determine if the severity of these findings correlated with the need for future hydrocephalus treatment. MATERIALS AND METHODS: A retrospective chart and imaging review identified patients who underwent open neural tube defect repair at a quaternary care pediatric hospital from July 2014 through September 2022. Patients were classified by the need for hydrocephalus treatment and whether they received prenatal or postnatal neural tube defect repair. Measurements of imaging parameters related to posterior fossa maldevelopment and skull base remodeling were performed. RESULTS: Compared with 65 patients who did not require hydrocephalus treatment, 74 patients who required treatment demonstrated statistically significantly greater mean basiocciput convexity (P < .001). While the mean basiocciput length in the hydrocephalus treatment group was smaller (P < .001), the ratio of basiocciput convexity to length was larger (P < .001). Notably, 100% of patients with a basiocciput convexity of ≥4 mm required hydrocephalus treatment. The mean posterior atlanto-occipital membrane convexity was significantly greater for patients who required hydrocephalus treatment in the postnatal group (P = .02), but not the prenatal group (P = .09). CONCLUSIONS: Pediatric patients with Chiari II malformation who ultimately required surgical hydrocephalus treatment had greater outward convexity of the basiocciput but had greater posterior atlanto-occipital membrane outward convexity only if the repair was performed postnatally. Together these measurements may be useful in predicting the need for hydrocephalus treatment.

Pediatric and adult meningeal, parenchymal, and spinal tuberculosis: A neuroimaging review.

Neurotuberculosis is defined as a tuberculous infection of the meninges, brain parenchyma, vessels, cranial and spinal nerves, spinal cord, skull, and spine that can occur either in a localized or in a diffuse form. It is a heterogeneous disease characterized by many imaging appearances and it has been defined as "the great mimicker" due to similarities with many other conditions. The diagnosis of central nervous system (CNS) tuberculosis (TB) is based on clinical presentation, neuroimaging findings, laboratory and microbiological findings, and comprehensive evaluation of the response to anti-TB drug treatment. However, the absence of specific symptoms, the wide spectrum of neurological manifestations, the myriad of imaging findings, possible inconclusive laboratory results, and the paradoxical reaction to treatment make the diagnosis often challenging and difficult, potentially delaying adequate treatment with possible devastating short-term and long-term neurologic sequelae. Familiarity with the imaging characteristics helps in accurate diagnosis and may prevent or limit significantly morbidity and mortality. The goal of this review is to provide a comprehensive up-to-date overview of the conventional and advanced imaging features of CNS TB for radiologists, neuroradiologists, and pediatric radiologists. We discuss the most typical neurotuberculosis imaging findings and their differential diagnosis in children and adults with the goal to provide a global overview of this entity.

Advances in Imaging Modalities for Pediatric Brain and Spinal Cord Tumors.

BACKGROUND: Neuroimaging has evolved from anatomical imaging toward a multi-modality comprehensive anatomical and functional imaging in the past decades, important functional data like perfusion-weighted imaging, permeability imaging, diffusion-weighted imaging (DWI), and diffusion tensor imaging (DTI), tractography, metabolic imaging, connectomics, event-related functional imaging, resting state functional imaging, and much more is now being offered. SUMMARY: Precision diagnostics has proven to be essential for precision treatment. Many minimal invasive techniques have been developed, taking advantage of digital subtraction angiography and interventional neuroradiology. Furthermore, intraoperative CT and/or MRI and more recently MR-guided focused ultrasound have complemented the diagnostic and therapeutic armamentarium. KEY MESSAGES: In the current manuscript, we discuss standard imaging sequences including advanced techniques like DWI, DTI, susceptibility-weighted imaging, and 1H magnetic resonance spectroscopy, various perfusion weighted imaging approaches including arterial spin labeling, dynamic contrast enhanced imaging, and dynamic susceptibility contrast imaging. Pre-, intra, and postoperative surgical imaging including visualize imaging will be discussed. The value of connectomics will be presented for its value in neuro-oncology. Minimal invasive therapeutic possibilities of interventional neuroradiology and image-guided laser ablation and MR-guided high-intensity-focused ultrasound will be presented for treatment of pediatric brain and spinal cord tumors. Finally, a comprehensive review of spinal cord tumors and matching neuropathology has been included.

Arterial Spin Labeling Changes Parallel Asymmetric Perisylvian and Perirolandic Symptoms in 3 Pediatric Cases of Anti-NMDAR Encephalitis.

BACKGROUND AND OBJECTIVES: Anti-NMDA receptor autoimmune encephalitis (NMDAR AE) is an autoantibody-mediated disorder characterized by seizures, neuropsychiatric symptoms, movement disorder, and focal neurologic deficits. Conventionally defined broadly as an inflammatory brain disease, the heterotopic localization is rarely discussed in children. Imaging findings are often nonspecific, and there are no early biomarkers of disease other than the presence of anti-NMDAR antibodies. METHODS: We conducted a retrospective analysis of our pediatric NMDAR AE cases (as determined by either positive serum or CSF antibodies or both) at Texas Children's Hospital between 2020-2021 and extracted medical record data of those patients who had arterial spin labeling (ASL) as part of their imaging workup for encephalitis. The ASL findings were described in the context of their symptoms and disease courses. RESULTS: We identified 3 children on our inpatient floor, intensive care unit (ICU), and emergency department (ED) settings who were diagnosed with NMDAR AE and had ASL performed as part of their focal neurologic symptom workup. All 3 patients presented with focal neurologic deficits, expressive aphasia, and focal seizures before the onset of other well-characterized NMDAR AE symptoms. Their initial MRI revealed no diffusion abnormalities but uncovered asymmetric and predominantly unilateral multifocal hyperperfusion of perisylvian/perirolandic regions on ASL that correlated with focal EEG abnormalities and their focal examination findings. All 3 patients were treated with first-line and second-line therapies, and their symptoms improved. DISCUSSION: We found that ASL may be a suitable early imaging biomarker to highlight perfusion changes corresponding to the functional localization of NMDAR AE in pediatric patients. We briefly highlight the neuroanatomic parallels between working models of schizophrenia, chronic NMDAR antagonist administration (ketamine abuse), and NMDAR AE affecting primarily language centers. The regional specificity seen in NMDAR hypofunction may make ASL a reasonable early and specific biomarker of NMDAR AE disease activity. Future studies are necessary to evaluate regional changes in those patients who present with primarily psychiatric phenotypes rather than classical focal neurologic deficits.

Cognitive Sparing in Proton versus Photon Radiotherapy for Pediatric Brain Tumor Is Associated with White Matter Integrity: An Exploratory Study.

Radiotherapy for pediatric brain tumors is associated with reduced white matter structural integrity and neurocognitive decline. Superior cognitive outcomes have been reported following proton radiotherapy (PRT) compared to photon radiotherapy (XRT), presumably due to improved sparing of normal brain tissue. This exploratory study examined the relationship between white matter change and late cognitive effects in pediatric brain tumor survivors treated with XRT versus PRT. Pediatric brain tumor survivors treated with XRT (n = 10) or PRT (n = 12) underwent neuropsychological testing and diffusion weighted imaging >7 years post-radiotherapy. A healthy comparison group (n = 23) was also recruited. Participants completed age-appropriate measures of intellectual functioning, visual-motor integration, and motor coordination. Tractography was conducted using automated fiber quantification (AFQ). Fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD) were extracted from 12 tracts of interest. Overall, both white matter integrity (FA) and neuropsychological performance were lower in XRT patients while PRT patients were similar to healthy control participants with respect to both FA and cognitive functioning. These findings support improved long-term outcomes in PRT versus XRT. This exploratory study is the first to directly support for white matter integrity as a mechanism of cognitive sparing in PRT.

Superior verbal learning and memory in pediatric brain tumor survivors treated with proton versus photon radiotherapy.

OBJECTIVE: Radiotherapy for pediatric brain tumor has been associated with late cognitive effects. Compared to conventional photon radiotherapy (XRT), proton radiotherapy (PRT) delivers lower doses of radiation to healthy brain tissue. PRT has been associated with improved long-term cognitive outcomes compared to XRT. However, there is limited research comparing the effects of XRT and PRT on verbal memory. METHOD: Survivors of pediatric brain tumor treated with either XRT (n = 29) or PRT (n = 51) completed neuropsychological testing > 1 year following radiotherapy. Performance on neuropsychological measures was compared between treatment groups using analysis of covariance. Chi-squared tests of independence were used to compare the frequency of encoding, retrieval, and intact memory profiles between treatment groups. Associations between memory performance and other neurobehavioral measures were examined using Pearson correlation. RESULTS: Overall, patients receiving PRT demonstrated superior verbal learning and recall compared to those treated with XRT. Encoding and retrieval deficits were more common in the XRT group than the PRT group, with encoding problems being most prevalent. The PRT group was more likely to engage in semantic clustering strategies, which predicted better encoding and retrieval. Encoding ability was associated with higher intellectual and adaptive functioning, and fewer parent-reported concerns about day-to-day attention and cognitive regulation. CONCLUSION: Results suggest that PRT is associated with verbal memory sparing, driven by effective encoding and use of learning strategies. Future work may help to clarify underlying neural mechanisms associated with verbal memory decline, which will better inform treatment approaches. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Imaging of pediatric calvarial and skull base tumors: A COG Diagnostic Imaging Committee/SPR Oncology Committee/ASPNR White Paper.

A standardized imaging protocol for pediatric oncology patients is essential for accurate and efficient imaging, while simultaneously promoting collaborative understanding of pathologies and radiologic assessment of treatment response. The objective of this article is to provide standardized pediatric imaging guidelines and parameters for evaluation of tumors of the pediatric orbit, calvarium, skull base, and temporal bone. This article was drafted based on current scientific literature as well as consensus opinions of imaging experts in collaboration with the Children's Oncology Group Diagnostic Imaging Committee, Society of Pediatric Radiology Oncology Committee, and American Society of Pediatric Neuroradiology.

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.

Invasive Streptococcus Gallolyticus Infections in Infants At Texas Children's Hospital: A 9-Year Retrospective Review.

Streptococcus gallolyticus subsp. pasteurianus is an unusual pathogen in infants, which causes sepsis and meningitis. We describe the clinical course and treatment of 15 infants with bacteremia and/or meningitis due to S. gallolyticus. Outcomes were favorable with limited neuroimaging findings. One-third of isolates displayed reduced susceptibility to penicillin highlighting the importance of performing antimicrobial susceptibility testing in infants with meningitis.

Predicting neurocognitive function in pediatric brain tumor early survivorship: The neurological predictor scale and the incremental validity of tumor size.

BACKGROUND: The Neurological Predictor Scale (NPS) quantifies cumulative exposure to conventional treatment-related neurological risks but does not capture potential risks posed by tumors themselves. This study evaluated the predictive validity of the NPS, and the incremental value of tumor location and size, for neurocognitive outcomes in early survivorship following contemporary therapies for pediatric brain tumors. PROCEDURE: Survivors (N = 69) diagnosed from 2010 to 2016 were administered age-appropriate versions of the Wechsler Intelligence Scales. Hierarchical multiple regressions examined the predictive and incremental validity of NPS score, tumor location, and tumor size. RESULTS: Participants (51% female) aged 6-20 years (M = 13.22, SD = 4.09) completed neurocognitive evaluations 5.16 years (SD = 1.29) postdiagnosis. The NPS significantly predicted Full-Scale Intelligence Quotient (FSIQ; ΔR2  = .079), Verbal Comprehension Index (VCI; ΔR2  = 0.051), Perceptual Reasoning Index (PRI; ΔR2  = 0.065), and Processing Speed Index (PSI; ΔR2  = 0.049) performance after controlling for sex, age at diagnosis, and maternal education. Tumor size alone accounted for a significant amount of unique variance in FSIQ (ΔR2  = 0.065), PRI (ΔR2  = 0.076), and PSI (ΔR2  = 0.080), beyond that captured by the NPS and relevant covariates. Within the full model, the NPS remained a significant independent predictor of FSIQ (ß = -0.249, P = 0.016), VCI (ß = -0.223, P = 0.048), and PRI (ß = -0.229, P = 0.037). CONCLUSIONS: Tumor size emerged as an independent predictor of neurocognitive functioning and added incrementally to the predictive utility of the NPS. Pretreatment disease burden may provide one of the earliest markers of neurocognitive risk following contemporary treatments. With perpetual treatment advances, measures quantifying treatment-related risk may need to be updated and revalidated to maintain their clinical utility.

Neuroimaging in cerebellar ataxia in childhood: A review.

Ataxia is one of the most common pediatric movement disorders and can be caused by a large number of congenital and acquired diseases affecting the cerebellum or the vestibular or sensory system. It is mainly characterized by gait abnormalities, dysmetria, intention tremor, dysdiadochokinesia, dysarthria, and nystagmus. In young children, ataxia may manifest as the inability or refusal to walk. The diagnostic approach begins with a careful clinical history including the temporal evolution of ataxia and the inquiry of additional symptoms, is followed by a meticulous physical examination, and, depending on the results, is complemented by laboratory assays, electroencephalography, nerve conduction velocity, lumbar puncture, toxicology screening, genetic testing, and neuroimaging. Neuroimaging plays a pivotal role in either providing the final diagnosis, narrowing the differential diagnosis, or planning targeted further workup. In this review, we will focus on the most common form of ataxia in childhood, cerebellar ataxia (CA). We will discuss and summarize the neuroimaging findings of either the most common or the most important causes of CA in childhood or present causes of pediatric CA with pathognomonic findings on MRI. The various pediatric CAs will be categorized and presented according to (a) the cause of ataxia (acquired/disruptive vs. inherited/genetic) and (b) the temporal evolution of symptoms (acute/subacute, chronic, progressive, nonprogressive, and recurrent). In addition, several illustrative cases with their key imaging findings will be presented.

Pediatric tinnitus: The role of neuroimaging.

Tinnitus is defined as the perception of sound without an external source and can be categorized as either pulsatile or nonpulsatile (ie, continuous). A variety of etiologies have been reported to cause pediatric tinnitus, many with long-lasting implications due to hearing and concentration impairments. Therefore, imaging can be an essential part of the accurate and timely diagnosis of treatable etiologies. We describe neuroimaging findings in different etiologies of pediatric tinnitus. Etiologies of pulsatile tinnitus are frequently vascular in nature and include vascular loops, congenital vascular anomalies or variants, high riding jugular bulbs with or without a jugular bulb diverticulum, idiopathic intracranial hypertension, aneurysms, internal auditory canal hemangiomas, and petrous apex cephaloceles. Etiologies of continuous tinnitus frequently affect the middle/inner ear structures and include vestibular schwannomas, cholesteatomas, trauma, Chiari malformations, and labyrinthitis ossificans. CT and MR are often complementary modalities: CT is better suited to evaluate the integrity of the temporal osseous structures and MR is better suited to evaluate the vestibulocochlear nerve and to assess for the presence of any masses or malformations. Prompt diagnosis of the etiology of tinnitus in pediatric patients is important to avoid any potential long-term developmental impairments. In the approach to pediatric tinnitus, categorizing the symptoms as either pulsatile versus nonpulsatile and then being aware of the possible causes and imaging findings of either can assist both the clinician and the radiologist in making an expeditious diagnosis.

Radiologic and clinical outcome of isolated fourth ventricle following post-hemorrhagic hydrocephalus in children.

PURPOSE: Few studies report radiologic and clinical outcome of post-hemorrhagic isolated fourth ventricle (IFV) with focus on surgical versus conservative management in neonates and children. Our aim is to investigate differences in radiological and clinical findings of IFV between patients who had surgical intervention versus patients who were treated conservatively. METHODS: A retrospective analysis of patients diagnosed with IFV was performed. Data included demographics, clinical exam findings, surgical history, and imaging findings (dilated FV extent, supratentorial ventricle dilation, brainstem and cerebellar deformity, tectal plate elevation, basal cistern and cerebellar hemisphere effacement, posterior fossa upward/downward herniation). RESULTS: Sixty-four (30 females) patients were included. Prematurity was 94% with 90% being < 28 weeks of gestation. Mean age at first ventricular shunt was 3.6 (range 1-19); at diagnosis of IFV, post-lateral ventricular shunting was 26.2 (1-173) months. Conservatively treated patients were 87.5% versus 12.5% treated with FV shunt/endoscopic fenestration. Severe FV dilation (41%), severe deformity of brainstem (39%) and cerebellum (47%) were noted at initial diagnosis and stable findings (34%, 47%, and 52%, respectively) were seen at last follow-up imaging. FV dilation (p = 0.0001) and upward herniation (p = 0.01) showed significant differences between surgery versus conservative management. No other radiologic or clinical outcome parameters were different between two groups. CONCLUSION: Only radiologic outcome results showed stable or normal FV dilation and stable or decreased upward herniation in the surgically treated group.

Neuroimaging of primary mitochondrial disorders in children: A review.

Mitochondrial disorders represent a diverse and complex group of entities typified by defective energy metabolism. The mitochondrial oxidative phosphorylation system is typically impaired, which is the predominant source of energy production. Because mitochondria are present in nearly all organs, multiple systems may be affected including the central nervous system, skeletal muscles, kidneys, and liver. In particular, those organs that are metabolically active with high energy demands are explicitly vulnerable. Initial diagnostic work up relies on a detailed evaluation of clinical symptoms including physical examination as well as a comprehensive review of the evolution of symptoms over time, relation to possible "triggering" events (eg, fever, infection), blood workup, and family history. High-end neuroimaging plays a pivotal role in establishing diagnosis, narrowing differential diagnosis, monitoring disease progression, and predicting prognosis. The pattern and characteristics of the neuroimaging findings are often highly suggestive of a mitochondrial disorder; unfortunately, in many cases the wide variability of involved metabolic processes prevents a more specific subclassification. Consequently, additional diagnostic steps including muscle biopsy, metabolic workup, and genetic tests are necessary. In the current manuscript, basic concepts of energy production, genetics, and inheritance patterns are reviewed. In addition, the imaging findings of several illustrative mitochondrial disorders are presented to familiarize the involved physicians with pediatric mitochondrial disorders. In addition, the significance of spinal cord imaging and the value of "reversed image-based discovery" for the recognition and correct (re-)classification of mitochondrial disorders is discussed.

Conventional and advanced MR imaging findings in a cohort of pathology-proven dermoid cysts of the pediatric scalp and skull.

BACKGROUND: In the pediatric population, dermoid cysts are among the most frequent lesions of the scalp and skull. Imaging plays a key role in characterizing scalp and skull lesions in order to narrow the differential diagnoses. In general, dermoids are described as heterogeneous T1-/T2-hypo- to hyperintense lesions on magnetic resonance imaging. METHODS: The goal of this retrospective study is to evaluate the diffusion weighted imaging findings while reviewing the conventional T1-/T2-/T1+C-weighted MR characteristics in a pathology-proven series of 14 dermoids of the pediatric scalp and skull. RESULTS: In our pediatric cohort (eight boys, six girls, age range 3-95 months), half of the dermoids were homogeneous T1-hypointense and homogeneous T2-hyperintense. We found a mixture of restricted (45.5%) and increased diffusion (54.5%) in dermoids. The vast majority of dermoids (91.7%) showed rim enhancement. Most dermoids (57.1%) were located at the midline and adjacent to one of its sutures. CONCLUSIONS: This study suggests that dermoids may have more variable imaging appearances than hitherto assumed and are frequently seen in close proximity or adjacent to the anterior fontanelle.

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.

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.

Neuroimaging Characteristics of Nasopharyngeal Carcinoma in Children.

BACKGROUND AND PURPOSE: Pediatric nasopharyngeal carcinoma (NPC) is a rare epithelial origin tumor associated with undifferentiated histology, Epstein-Barr virus (EBV) infection, and genetic risk factors. Childhood NPC is usually clinically silent, often presenting with advanced locoregional compromise, including skull base invasion and cervical lymphadenopathy, and has a better prognosis than adult NPC. This article describes computed tomography (CT) and magnetic resonance imaging (MRI) features in a cohort of 28 pediatric NPC patients. METHODS: A retrospective review was performed among children with histopathology proven NPC diagnoses between 1996 and 2019 for this study. The electronic medical records were reviewed to determine demographics, EBV serology, and World Health Organization (WHO) type. Nasopharyngeal CT and/or MRI at presentation for tumor spread as well as density and/or intensity, lymphadenopathy, postcontrast enhancement and diffusion characteristics before treatment were evaluated. RESULTS: Twenty-eight patients (21 males, 7 females) were included. The mean patient age at diagnosis was 13.3 (range 7 to 17) years. EBV was positive in 71.4% of patients. The majority of patients (78.6%) had a WHO type III tumor, unilateral fossa of Rosenmuller involvement (71.4%). Neuroimaging features were CT isodensity, T1-isointensity, T2-hyperintensity, and heterogeneous postcontrast enhancement for all patients (100%) and restricted diffusion (90%). CONCLUSIONS: Although uncommon in pediatric patients, NPC should be in the differential diagnosis of adolescents presenting with a nasopharyngeal mass. Recognizing key imaging characteristics is helpful in the diagnosis of NPC.