Fetal head and neck tumors.

Imaging plays a leading role in detection and diagnosis of fetal head and neck lesions. These lesions comprise a heterogeneous group of congenital tumors and malformations. Complementary imaging modalities that can be used in prenatal medicine are ultrasound and MRI. The authors discuss imaging characteristics of fetal lesions, assessment of potential complications and pregnancy management options for the most common pathology of the fetal head and neck.

Imaging of Pediatric Hearing Loss.

Temporal bone high-resolution computed tomography (HRCT) and magnetic resonance (MR) imaging are valuable tools in the evaluation of pediatric hearing loss. Computed tomography is important in the evaluation of pediatric conductive hearing loss and is the imaging modality of choice for evaluation of osseous abnormalities. MR imaging is the modality of choice for evaluation of sensorineural hearing loss. A broad spectrum of imaging findings can be seen with hearing loss in children. HRCT and MR imaging provide complementary information and are often used in conjunction in the preoperative evaluation of pediatric candidates for cochlear implantation.

Neurologic challenges in 22q11.2 deletion syndrome.

Children with 22q11.2 deletion syndrome often come to medical attention due to signs and symptoms of neurologic dysfunction. It is imperative to understand the expected neurologic development of patients with this diagnosis in order to be alert for the potential neurologic complications, including cortical malformations, tethered cord, epilepsy, and movement disorders. We present an update of brain imaging findings from the CHOP 22q and You Center, a review of the current literature, and our current management practices for neurological issues.

N-acetylaspartate supports the energetic demands of developmental myelination via oligodendroglial aspartoacylase.

Breakdown of neuro-glial N-acetyl-aspartate (NAA) metabolism results in the failure of developmental myelination, manifest in the congenital pediatric leukodystrophy Canavan disease caused by mutations to the sole NAA catabolizing enzyme aspartoacylase. Canavan disease is a major point of focus for efforts to define NAA function, with available evidence suggesting NAA serves as an acetyl donor for fatty acid synthesis during myelination. Elevated NAA is a diagnostic hallmark of Canavan disease, which contrasts with a broad spectrum of alternative neurodegenerative contexts in which levels of NAA are inversely proportional to pathological progression. Recently generated data in the nur7 mouse model of Canavan disease suggests loss of aspartoacylase function results in compromised energetic integrity prior to oligodendrocyte death, abnormalities in myelin content, spongiform degeneration, and motor deficit. The present study utilized a next-generation "oligotropic" adeno-associated virus vector (AAV-Olig001) to quantitatively assess the impact of aspartoacylase reconstitution on developmental myelination. AAV-Olig001-aspartoacylase promoted normalization of NAA, increased bioavailable acetyl-CoA, and restored energetic balance within a window of postnatal development preceding gross histopathology and deteriorating motor function. Long-term effects included increased oligodendrocyte numbers, a global increase in myelination, reversal of vacuolation, and rescue of motor function. Effects on brain energy observed following AAV-Olig001-aspartoacylase gene therapy are shown to be consistent with a metabolic profile observed in mild cases of Canavan disease, implicating NAA in the maintenance of energetic integrity during myelination via oligodendroglial aspartoacylase.

Risk of optic pathway glioma in children with neurofibromatosis type 1 and optic nerve tortuosity or nerve sheath thickening.

BACKGROUND/AIMS: Optic nerve tortuosity and nerve and sheath thickening are observed on MRI in some patients with neurofibromatosis type 1 (NF-1). This study aimed to determine if tortuosity and thickening are associated with the development of optic pathway glioma (OPG) and subsequent vision loss. METHODS: Children with NF-1 who underwent brain MRI between 1992 and 2005, and had at least 1 year of subsequent visual acuity (VA) follow-up, were identified retrospectively. The baseline MRI was independently reviewed by three neuroradiologists for consensus assessment. Tortuosity was identified using validated operational criteria. Optic nerve and sheath thicknesses and VA at last follow-up were directly measured. RESULTS: Of 132 evaluable children, seven (5%) had tortuosity on baseline MRI. 20 subjects (15%) ultimately developed OPG at a median of 1.9 years (range 7 months-8.0 years) following the baseline MRI. Subjects with tortuosity were significantly more likely to develop OPG than those without tortuosity (57% vs 13%, p=0.01). In subjects who developed OPG, the prevalence of tumour-related vision loss was not significantly different between those with and without baseline tortuosity (14% vs 4%, p=0.28). No difference existed between mean baseline optic nerve (2.3 vs 2.2 mm) or sheath (5.2 vs 5.4 mm) thicknesses comparing subjects who did and did not develop OPG. CONCLUSIONS: Optic nerve tortuosity at baseline is associated with OPG development among patients with NF-1, but does not predispose to aggressive OPG with associated vision loss. Neither nerve nor sheath thickening at baseline is associated with OPG development.

Morphology of the foramen magnum in syndromic and non-syndromic brachycephaly.

PURPOSE: The shape and size of the foramen magnum (FM) can be altered in craniosynostoses. However, few studies have investigated these changes. In this paper, we investigate the morphology of the foramen magnum in syndromic and non-syndromic brachycephaly. METHODS: Surface area, anteroposterior (AP) diameter, and transverse diameters of the FM were measured on high-resolution CT scans in children with Crouzon (25), Pfeiffer (21), Apert (26), Saethre-Chotzen (7) syndromes, and isolated bicoronal synostosis (9) and compared to an age-matched control group (30). RESULTS: A significantly smaller FM surface area was observed in Crouzon (6.3 ± 1.7 cm(2)) and Pfeiffer (6.4 ± 2.3 cm(2)) syndromes as compared to the control group (7.4 ± 1.3 cm(2), p = 0.006 and p = .017, respectively). In comparison to the control group, no statistically significant alteration in FM surface area was noted in patients with Apert, Saethre-Chotzen, or isolated bicoronal synostosis (p = 0.37, p = 0.71, p = 0.40 respectively). The transverse diameter of FM was significantly smaller in Crouzon, Pfeiffer, and Apert syndromes compared to the control group (p = 0.005, p = 0.002, p = 0.03 respectively). In Saethre-Chotzen and isolated bicoronal synostosis, no difference in transverse diameter was demonstrated. Among all groups, only Crouzon syndrome showed reduced anteroposterior diameter as compared to controls (p = 0.005). In Pfeiffer and Apert syndromes, there was elongation of the shape of the FM with a relatively narrowed width as demonstrated in a significantly increased AP to transverse diameter ratio (p = 0.002 and p = 0.019, respectively). DISCUSSION AND CONCLUSIONS: The FM shape and area is significantly altered in fibroblast growth factor receptor (FGFR)-related brachycephaly syndromes (Crouzon, Pfeiffer, and Apert), whereas in patients with Saethre-Chotzen syndrome (TWIST-1 mutation) and isolated non-syndromic bicoronal synostosis, the shape and mean FM area was not statistically different from that of normals. This study brings to light the important role of FGFRs on FM growth and shape. TWIST-1 mutation (Saethre-Chotzen syndrome) does not appear to have an important effect in shaping the FM.

Childhood encephalitis: relationship between diffusion abnormalities and clinical outcome.

INTRODUCTION: The impact of restricted diffusion on clinical outcome has not been well studied in childhood encephalitis. We hypothesized that the patients with lesions with restricted diffusion (LRD) would have worse clinical outcome. METHODS: We reviewed the MR studies of 83 children with encephalitis for LRD. An MRI scoring system (0-12) based on fluid-attenuated inversion recovery (FLAIR) imaging was created to evaluate the extent of imaging abnormality. Clinical outcome was graded by using Glasgow outcome scale (GOS) (1-5) in 1st and 12th month: 1 for death and five for full recovery. With respect to diffusion, the correlation between imaging score and GOS was assessed. Logistic regression analysis was used to explore the impact of diffusion and imaging score on clinical outcome. The patients were divided into three subgroups regarding imaging score: I, 0-4; II, 5-8; and III, 9-12. RESULTS: LRD was found in 28 patients. Negative significant correlation was found between imaging score and GOS in the group with LRD in both 1st month (R = -0.67, P < 0.001) and 12th month (R = -0.56, P = 0.001). Multivariate logistic regression showed that LRD (P < 0.001) and age (P = 0.026) were significant independent risk factors for unfavorable outcome in 1st month, and both LRD (P = 0.001) and imaging score (P = 0.043) were significant risk factors for unfavorable outcome in 12th month. CONCLUSIONS: Patients with LRD have a worse clinical outcome than those without LRD. In patients with LRD, those with a greater extent of abnormality have a poorer outcome.

Imaging findings of patients with metastatic neuroblastoma to the brain.

RATIONALE AND OBJECTIVES: Metastatic involvement of brain is rare in neuroblastoma (NB). We retrospectively evaluated conventional and advanced imaging and clinical findings of seven patients with secondary intra-axial brain NB metastases. MATERIALS AND METHODS: Magnetic resonance imaging and computed tomography examinations of patients with metastatic brain NB were reviewed. Recent iodine-123 metaiodobenzylguanidine ((123)I-MIBG) scans were also reviewed. A medical record review was performed for relevant clinical, laboratory, histopathologic, and genetic data. RESULTS: Mean age at the time of primary tumor diagnosis was 35 months, and all were considered high-risk NB at diagnosis. Mean time interval between diagnosis and brain involvement was 23.2 months. Extensive prior extra-central nervous system (CNS) disease was present in all patients, but concomitant extra-CNS disease at the time of brain involvement was absent in three (43%) patients. Various forms of disease, including intraparenchymal, intraventricular, and leptomeningeal lesions were detected. Most intraparenchymal lesions were supratentorial and hemorrhagic; however, hemorrhage was absent in multiple leptomeningeal nodules in one patient. Contrast enhancement of lesions was present on all contrast-enhanced studies. Restricted diffusion of lesions was present in two patients. Arterial spin labeling (ASL) perfusion in two patients also revealed increased cerebral blood flow. Recent (123)I-MIBG scans were available in four patients and showed lesions in two patients with larger metastases but failed to demonstrate lesions in another two patients with smaller lesions. CONCLUSIONS: Brain metastases of NB are often supratentorial and hemorrhagic and demonstrate contrast enhancement. Diffusion-weighted imaging can show restricted diffusion. ASL images may reveal increased perfusion. MIBG scans may not show smaller brain metastases.

Functional outcome measures for NF1-associated optic pathway glioma clinical trials.

OBJECTIVE: The goal of the Response Evaluation in Neurofibromatosis and Schwannomatosis Visual Outcomes Committee is to define the best functional outcome measures for future neurofibromatosis type 1 (NF1)-associated optic pathway glioma (OPG) clinical trials. METHODS: The committee considered the components of vision, other ophthalmologic parameters affected by OPG, potential biomarkers of visual function, and quality of life measures to arrive at consensus-based, evidence-driven recommendations for objective and measurable functional endpoints for OPG trials. RESULTS: Visual acuity (VA) assessments using consistent quantitative testing methods are recommended as the main functional outcome measure for NF1-OPG clinical trials. Teller acuity cards are recommended for use as the primary VA endpoint, and HOTV as a secondary endpoint once subjects are old enough to complete it. The optic disc should be assessed for pallor, as this appears to be a contributory variable that may affect the interpretation of VA change over time. Given the importance of capturing patient-reported outcomes in clinical trials, evaluating visual quality of life using the Children's Visual Function Questionnaire as a secondary endpoint is also proposed. CONCLUSIONS: The use of these key functional endpoints will be essential for evaluating the efficacy of future OPG clinical trials.

Unilateral cochlear nerve deficiency in children.

OBJECTIVE: Cochlear nerve deficiency (CND) is increasingly diagnosed in children with sensorineural hearing loss (SNHL). We sought to determine the prevalence of CND, its imaging characteristics, and correlations with audiologic phenotype in children with unilateral SNHL. DESIGN: Case series with chart review. SETTING: Tertiary pediatric hospital. SUBJECTS/METHODS: In 128 consecutive children with unilateral SNHL who underwent high-resolution magnetic resonance imaging, the diameters, area, and signal intensity of the cochlear nerve (CN) were measured and normalized to the ipsilateral facial nerve. Presence of CND was determined by comparison to normative data. Relationships among hearing loss severity, progression, and nerve size were investigated. RESULTS: Cochlear nerve deficiency was present in 26% of children with unilateral SNHL. Its prevalence was higher (48%) in severe to profound SNHL, especially when in infants (100%). Width of the bony cochlear nerve canal (BCNC) correlated strongly with relative CN diameter, density, and area (R = 0.5); furthermore, a narrow BCNC (<1.7 mm) strongly predicted CND. Severity of hearing loss modestly correlated with nerve size, although significant variability was observed. Progression never occurred unless there were other inner ear malformations, whereas in the non-CND group, it occurred in 22%. Ophthalmologic abnormalities were very common (67%) in CND children, particularly oculomotor disturbances. CONCLUSION: Cochlear nerve deficiency is a common cause of unilateral SNHL, particularly in congenital unilateral deafness. Width of the BCNC effectively predicts CND, a finding useful when only computed tomography imaging is available. In an ear with CND, hearing can be expected to remain stable over time. Diagnosis should prompt evaluation by an ophthalmologist.

Hemizygous mutations in SNAP29 unmask autosomal recessive conditions and contribute to atypical findings in patients with 22q11.2DS.

BACKGROUND: 22q11.2 deletion syndrome (22q11.2DS) is the most common microdeletion disorder, affecting an estimated 1 : 2000-4000 live births. Patients with 22q11.2DS have a broad spectrum of phenotypic abnormalities which generally includes congenital cardiac abnormalities, palatal anomalies, and immunodeficiency. Additional findings, such as skeletal anomalies and autoimmune disorders, can confer significant morbidity in a subset of patients. 22q11.2DS is a contiguous gene DS and over 40 genes are deleted in patients; thus deletion of several genes within this region contributes to the clinical features. Mutations outside or on the remaining 22q11.2 allele are also known to modify the phenotype. METHODS: We utilised whole exome, targeted exome and/or Sanger sequencing to examine the genome of 17 patients with 22q11.2 deletions and phenotypic features found in <10% of affected individuals. RESULTS AND CONCLUSIONS: In four unrelated patients, we identified three novel mutations in SNAP29, the gene implicated in the autosomal recessive condition cerebral dysgenesis, neuropathy, ichthyosis and keratoderma (CEDNIK). SNAP29 maps to 22q11.2 and encodes a soluble SNARE protein that is predicted to mediate vesicle fusion at the endoplasmic reticulum or Golgi membranes. This work confirms that the phenotypic variability observed in a subset of patients with 22q11.2DS is due to mutations on the non-deleted chromosome, which leads to unmasking of autosomal recessive conditions such as CEDNIK, Kousseff, and a potentially autosomal recessive form of Opitz G/BBB syndrome. Furthermore, our work implicates SNAP29 as a major modifier of variable expressivity in 22q11.2 DS patients.

Long-term follow-up after gene therapy for canavan disease.

Canavan disease is a hereditary leukodystrophy caused by mutations in the aspartoacylase gene (ASPA), leading to loss of enzyme activity and increased concentrations of the substrate N-acetyl-aspartate (NAA) in the brain. Accumulation of NAA results in spongiform degeneration of white matter and severe impairment of psychomotor development. The goal of this prospective cohort study was to assess long-term safety and preliminary efficacy measures after gene therapy with an adeno-associated viral vector carrying the ASPA gene (AAV2-ASPA). Using noninvasive magnetic resonance imaging and standardized clinical rating scales, we observed Canavan disease in 28 patients, with a subset of 13 patients being treated with AAV2-ASPA. Each patient received 9 × 10(11) vector genomes via intraparenchymal delivery at six brain infusion sites. Safety data collected over a minimum 5-year follow-up period showed a lack of long-term adverse events related to the AAV2 vector. Posttreatment effects were analyzed using a generalized linear mixed model, which showed changes in predefined surrogate markers of disease progression and clinical assessment subscores. AAV2-ASPA gene therapy resulted in a decrease in elevated NAA in the brain and slowed progression of brain atrophy, with some improvement in seizure frequency and with stabilization of overall clinical status.

Magnetic resonance imaging of the pediatric neck: an overview.

Evaluation of neck lesions in the pediatric population can be a diagnostic challenge, for which magnetic resonance (MR) imaging is extremely valuable. This article provides an overview of the value and utility of MR imaging in the evaluation of pediatric neck lesions, addressing what the referring clinician requires from the radiologist. Concise descriptions and illustrations of MR imaging findings of commonly encountered pathologic entities in the pediatric neck, including abnormalities of the branchial apparatus, thyroglossal duct anomalies, and neoplastic processes, are given. An approach to establishing a differential diagnosis is provided, and critical points of information are summarized.

Fetal MRI: head and neck.

Abnormalities of the fetal head and neck may be seen in isolation or in association with central nervous system abnormalities, chromosomal abnormalities, and syndromes. Magnetic resonance imaging (MRI) plays an important role in detecting associated abnormalities of the brain as well as in evaluating for airway obstruction that may impact prenatal management and delivery planning. This article provides an overview of the common indications for MRI of the fetal head and neck, including abnormalities of the fetal skull and face, masses of the face and neck, and fetal goiter.

Visual outcomes in children with neurofibromatosis type 1-associated optic pathway glioma following chemotherapy: a multicenter retrospective analysis.

Optic pathway gliomas (OPGs) occur in 15%-20% of children with neurofibromatosis type 1 (NF1); up to half become symptomatic. There is little information regarding ophthalmologic outcomes after chemotherapy. A retrospective multicenter study was undertaken to evaluate visual outcomes following chemotherapy for NF1-associated OPG, to identify risks for visual loss, and to ascertain indications for treatment. Subjects included children undergoing initial treatment for OPGs with chemotherapy between January 1997 and December 2007. Of 115 subjects, visual acuity (VA) decline and tumor progression were the primary reasons to initiate treatment, although there were significant differences in the pattern of indications cited among the institutions. Eighty-eight subjects and 168 eyes were evaluable for VA outcome. At completion of chemotherapy, VA improved (32% of subjects), remained stable (40%), or declined (28%). Tumor location was the most consistent prognostic factor for poor VA outcome. There was poor correlation between radiographic and VA outcomes. Although visual outcomes for NF1-associated OPG are not optimal, approximately one-third of children regain some vision with treatment. Since radiographic outcomes do not predict visual outcomes, their use as the primary measure of treatment success is in question. The lack of consensus regarding the indications for treatment underlines the need for better standardization of care. Future clinical trials for OPG require standardized visual assessment methods and clear definitions of visual outcomes.

Prenatal MR imaging of Dandy-Walker complex: midline sagittal area analysis.

OBJECTIVE: To measure the mid-sagittal areas of vermis (VA) and of posterior fossa (PFA) and determine their differences among fetuses with various Dandy-Walker (DW) entities and control subjects. METHODS: We reviewed data in 25 fetal patients with a MR diagnosis of DW complex including hypoplastic vermis (HV), HV with rotation (HVR), and mega cistern magna (MCM), and in 85 fetal controls with normal CNS. PFA and VA of each subject were manually traced on mid-sagittal MR images. Regarding each of VA and PFA, after age correction, we determined statistically significant differences among HVR, HV, MCM, and control groups. RESULTS: The mean VA residue of MCM was greater than that of the control, which was in turn greater than those of HVR and HV. The mean PF residue of the control was smaller than all other groups. CONCLUSION: Fetuses with HVR or HV had smaller VA than fetuses with MCM or control subjects. Fetuses with MCM, HVR, or HV had larger PFA than control subjects. These results may be an early step leading to better understanding of the confusion about the PF anomalies in future.

High prevalence of temporomandibular joint arthritis at disease onset in children with juvenile idiopathic arthritis, as detected by magnetic resonance imaging but not by ultrasound.

OBJECTIVE: To determine the prevalence of temporomandibular joint (TMJ) disease in a cohort of children with new-onset juvenile idiopathic arthritis (JIA), and to compare magnetic resonance imaging (MRI) with ultrasound (US) for the detection of acute and chronic changes of TMJ arthritis. METHODS: Between January 2005 and April 2007, children with newly diagnosed JIA were prospectively evaluated for TMJ arthritis. Prior to imaging, jaw pain and disability were assessed with questionnaires and physical examination. The TMJs of all patients were imaged with MRI and US within 8 weeks of diagnosis. RESULTS: Of the 32 patients enrolled, 78% were female, and the median age was 8.6 years (range 1.5-17.2 years). Acute TMJ arthritis was diagnosed in 75% of the children by MRI and in none by US; chronic arthritis was diagnosed in 69% by MRI and in 28% by US. Findings of both acute and chronic TMJ disease were detected by MRI in 53% of the patients. Of those with acute TMJ arthritis, 71% were asymptomatic, and 63% had normal findings on jaw examination. Fifty-six percent of patients with acute disease had an improved maximal incisal opening after corticosteroid injection. Among these responders, 56% had been asymptomatic and had normal jaw examination findings. CONCLUSION: TMJ arthritis was present in the majority of patients with new-onset JIA. Findings on MRI along with responses to treatment among asymptomatic patients with normal jaw examination findings suggest that a history review and physical examination are not sufficient to screen for TMJ disease. Our results also suggest that MRI and US findings are not well correlated, and that MRI is preferable for the detection of TMJ disease in new-onset JIA.

Imaging findings of neonatal herpes simplex virus type 2 encephalitis.

INTRODUCTION: The CT, MR, and diffusion-weighted initial and follow-up imaging findings in neonatal herpes simplex virus type 2 (HSV-2) encephalitis were assessed. METHODS: The clinical, laboratory and imaging findings in 12 patients (eight girls and four boys) with proven neonatal HSV-2 encephalitis with follow-up were retrospectively reviewed. Patterns of brain involvement and distribution of lesions were studied and the contribution of diffusion-weighted imaging to the imaging diagnosis of this disease was explored. A total of 24 CT and 22 MRI studies were performed with a mean follow-up time of 38 months. RESULTS: Neonatal HSV-2 encephalitis can be multifocal or limited to only the temporal lobes, brainstem, or cerebellum. The deep gray matter structures were involved in 57% of patients, and hemorrhage was seen in more than half of the patients. CT images were normal or showed mild abnormalities in the early stages of the disease. Conventional MR images may be normal in the early stages of the disease. Lesions were initially seen only by diffusion-weighted imaging in 20% of the patients and this modality showed a substantially more extensive disease distribution in an additional 50% of patients. In 40% of patients, watershed distribution ischemic changes were observed in addition to areas of presumed direct herpetic necrosis. CONCLUSION: Neonatal HSV-2 encephalitis has a variable imaging appearance. Diffusion-weighted MRI is an important adjunct in the imaging evaluation of this disease. Watershed distribution ischemia in areas remote from the primary herpetic lesions may be seen.