Neural preservation underlies speech improvement from auditory deprivation in young cochlear implant recipients.

Although cochlear implantation enables some children to attain age-appropriate speech and language development, communicative delays persist in others, and outcomes are quite variable and difficult to predict, even for children implanted early in life. To understand the neurobiological basis of this variability, we used presurgical neural morphological data obtained from MRI of individual pediatric cochlear implant (CI) candidates implanted younger than 3.5 years to predict variability of their speech-perception improvement after surgery. We first compared neuroanatomical density and spatial pattern similarity of CI candidates to that of age-matched children with normal hearing, which allowed us to detail neuroanatomical networks that were either affected or unaffected by auditory deprivation. This information enables us to build machine-learning models to predict the individual children's speech development following CI. We found that regions of the brain that were unaffected by auditory deprivation, in particular the auditory association and cognitive brain regions, produced the highest accuracy, specificity, and sensitivity in patient classification and the most precise prediction results. These findings suggest that brain areas unaffected by auditory deprivation are critical to developing closer to typical speech outcomes. Moreover, the findings suggest that determination of the type of neural reorganization caused by auditory deprivation before implantation is valuable for predicting post-CI language outcomes for young children.

Extended diffusion weighted magnetic resonance imaging with two-compartment and anomalous diffusion models for differentiation of low-grade and high-grade brain tumors in pediatric patients.

PURPOSE: The purpose of this study was to examine advanced diffusion-weighted magnetic resonance imaging (DW-MRI) models for differentiation of low- and high-grade tumors in the diagnosis of pediatric brain neoplasms. METHODS: Sixty-two pediatric patients with various types and grades of brain tumors were evaluated in a retrospective study. Tumor type and grade were classified using the World Health Organization classification (WHO I-IV) and confirmed by pathological analysis. Patients underwent DW-MRI before treatment. Diffusion-weighted images with 16 b-values (0-3500 s/mm2) were acquired. Averaged signal intensity decay within solid tumor regions was fitted using two-compartment and anomalous diffusion models. Intracellular and extracellular diffusion coefficients (Dslow and Dfast), fractional volumes (Vslow and Vfast), generalized diffusion coefficient (D), spatial constant (µ), heterogeneity index (ß), and a diffusion index (index_diff = µ × Vslow/ß) were calculated. Multivariate logistic regression models with stepwise model selection algorithm and receiver operating characteristic (ROC) analyses were performed to evaluate the ability of each diffusion parameter to distinguish tumor grade. RESULTS: Among all parameter combinations, D and index_diff jointly provided the best predictor for tumor grades, where lower D (p = 0.03) and higher index_diff (p = 0.009) were significantly associated with higher tumor grades. In ROC analyses of differentiating low-grade (I-II) and high-grade (III-IV) tumors, index_diff provided the highest specificity of 0.97 and D provided the highest sensitivity of 0.96. CONCLUSIONS: Multi-parametric diffusion measurements using two-compartment and anomalous diffusion models were found to be significant discriminants of tumor grading in pediatric brain neoplasms.

Transcranial Doppler Identification of Neurologic Injury during Pediatric Extracorporeal Membrane Oxygenation Therapy.

BACKGROUND: We used transcranial Doppler to examine changes in cerebral blood flow velocity in children treated with extracorporeal membrane oxygenation. We examined the association between those changes and radiologic, electroencephalographic, and clinical evidence of neurologic injury. METHODS: This was a retrospective review and prospective observational study of patients 18 years old and younger at a single university children's hospital. Transcranial Doppler studies were obtained every other day during the first 7 days of extracorporeal membrane oxygenation, and 1 additional study following decannulation, in conjunction with serial neurologic examinations, brain imaging, and 6- to 12-month follow-up. RESULTS: The study included 27 patients, the majority (26) receiving veno-arterial extracorporeal membrane oxygenation. Transcranial Doppler velocities during extracorporeal membrane oxygenation were significantly lower than published values for age-matched healthy and critically ill children across different cerebral arteries. Neonates younger than 10 days had higher velocities than expected. Blood flow velocity increased after extracorporeal membrane oxygenation decannulation and was comparable with age-matched critically ill children. There was no significant association between velocity measurements of individual arteries and acute neurologic injury as defined by either abnormal neurologic examination, seizures during admission, or poor pediatric cerebral performance category. However, case analysis identified several patients with regional and global increases in velocities that corresponded to neurologic injury including stroke and seizures. CONCLUSIONS: Cerebral blood flow velocities during extracorporeal membrane oxygenation deviate from age-specific normal values in all major cerebral vessels and across different age groups. Global or regional elevations and asymmetries in flow velocity may suggest impending neurologic injury.

Concurrent Chiari decompression and spinal cord untethering in children: feasibility in a small case series.

BACKGROUND AND PURPOSE: We describe the rationale and safety of concurrent decompression of Chiari type 1 malformation (CM1) and untethering of the spinal cord. Spinal cord traction is considered one of the pathogenic mechanisms involved in the development of CM, and 14% of patients with CM1 have tethered cord syndrome (Milhorat et al., Surg Neurol 7:20-35, 2009; Roth, Neuroradiology 21:133-138, 1981; Royo-Salvador, Rev Neurol 24:937-959, 1996; Royo-Salvador et al., Acta Neurochir 147:515-523, 2005). Therefore, intraspinal anomalies that require intervention are commonly treated before surgical decompression of Chiari malformation (Cheng et al., Neurologist 8:357-362, 2002; Menezes, Pediatr Neurosurg 23:260-269, 1995; Milhorat et al., Surg Neurol 7:20-35, 2009; Royo-Salvador et al., Acta Neurochir 147:515-523, 2005; Schijman and Steinbok, Childs Nerv Syst 20:341-348, 2004; Yamada et al., Neurol Res 26:719-721, 2004). However, in the interval between the spinal cord untethering and the decompression surgery, patients may continue to suffer from the untreated symptoms of CM. In a series of four patients with concurrent severe and progressive symptoms referable to both conditions, we performed both surgeries simultaneously. METHODS: Charts of four patients who underwent concurrent Chiari decompression and spinal cord untethering were reviewed. RESULTS: All patients tolerated the procedures well without complication. They reported significant or complete early postsurgical resolution of headaches and ambulating difficulties. On average, patients started to walk on postoperative day 3 (3 ± 1 days) and were discharged on hospital day 6 (6 ± 1 days). No patient experienced a persistent subcutaneous or transcutaneous cerebrospinal fluid leak. Subsequent postoperative courses were uneventful. CONCLUSION: Concurrent Chiari decompression and untethering of the spinal cord is a feasible option and in some patients may be preferred in lieu of staged procedures.

Ocular anatomy and cross-sectional imaging of the eye.

Ocular cross-sectional imaging is usually obtained as an adjunct to clinical ophthalmologic examination and ocular ultrasound. Computed tomography/magnetic resonance imaging (CT/MRI) are complimentary for ocular imaging and are performed for evaluation of the vitreous cavity, choroid, retina, sclera, and potential spaces and for the assessment of extension of disease beyond the globe into the orbit or brain. CT has superior spatial resolution aided by the natural contrast between bone, soft tissues, air, and fat. The short scanning time is advantageous to reduce motion effects and the need for sedation. CT is also the modality of choice for evaluation of traumatic injury and for visualization of foreign bodies. Potential clinical indications for MRI include staging of retinoblastoma and other causes of leukocoria, assessment of retinal or choroidal detachments for underlying retinal mass or hemorrhage, uveal melanoma, ocular metastases, choroidal hemangioma, and buphthalmus, staphyloma, and coloboma. Last, but not least, MRI has the advantage of no ionizing radiation.

Neuroimaging findings in children with rare or novel de novo chromosomal anomalies.

BACKGROUND: De novo constitutional chromosomal anomalies provide important insights into the genetic loci responsible for congenital neurological disorders. However, most phenotypic descriptions of patients with rare chromosomal abnormalities are published as individual case reports or small group studies, making genotype-phenotype correlations unclear. Moreover, many clinical genetic reports do not include neuroimaging. METHODS: We conducted a retrospective case series study of all children who had genetic testing done at Children's Memorial Hospital in Chicago, Illinois between 1985 and 2006. The case series was selected from a database containing all chromosomal testing results, clinical data, and neuroimaging. Clinical examination results were assigned by board certified geneticists and/or neurologists and neuroimages were reviewed by both a neurologist or neuroradiologist and a blinded neurologist. RESULTS: Of the 28,108 children in the series, we identified 34 children with novel or apparently novel de novo chromosomal abnormalities. Several of the cases represent potentially new genetic loci for neurological malformations and novel syndromic conditions. CONCLUSIONS: This study demonstrates the utility of large clinical databases in assessing genotype-phenotype correlations and mapping loci for congenital neurological disorders. We describe a case-series strategy to analyze existing databases to reveal new genotype-phenotype correlations.

Magnetic Resonance Imaging of Cochlear Implant Recipients.

OBJECTIVE: Determine the diagnostic usefulness of postimplantation 1.5 T magnetic resonance imaging (MRI) and review magnet-related MRI complications. STUDY DESIGN: Retrospective chart review with additional review of MRIs. SETTING: Tertiary care children's hospital. PATIENTS: Twelve patients who underwent MRI after receiving a cochlear implant (CI). INTERVENTION: One or more episodes of 1.5 T MRI with CI in place. MAIN OUTCOME MEASURES: Occurrence of magnet-related complications; whether imaging was clinically useful. RESULTS: The 12 patients underwent 23 episodes of MRI, including 13 episodes in 11 patients (18 ears) during which a magnet was present and 17 studies were obtained. Complications related to the magnet occurred during 4 of the 13 imaging episodes (30.8%), all during body or spine studies. Magnet torsion with reversal of polarity occurred in three devices; reduced magnet strength in one; and displacement of the magnet from its housing in one. One patient required surgical magnet replacement, whereas other headpiece retention problems were resolved without surgery. All studies but one brain with bilateral magnets were clinically useful. CONCLUSIONS: CI patients who undergo MRI with a magnet in situ may experience complications, especially when imaged below the head. Most complications may be resolved without surgery. Diagnostic usefulness of non-cranial MRI is not likely to be limited by presence of the magnet, while a magnet may prevent clinically useful brain imaging. Obtaining MRI with the magnet in situ avoids the cost and risks associated with multiple surgeries to remove and replace the magnet or the entire implant.

Pharmacokinetics and Safety of Macrocyclic Gadobutrol in Children Aged Younger Than 2 Years Including Term Newborns in Comparison to Older Populations.

OBJECTIVES: This clinical study evaluated the pharmacokinetics (PK) and safety data of macrocyclic extracellular contrast agent gadobutrol in pediatric subjects aged younger than 2 years. MATERIALS AND METHODS: Pediatric subjects (term newborns to those aged younger than 2 years) with normal renal function undergoing magnetic resonance imaging with gadobutrol (0.1 mmol/kg body weight [BW]) were prospectively enrolled in this open-label, multicenter clinical trial to evaluate PK as a primary end point. Plasma PK was analyzed using a population-based PK approach. Safety and qualitative efficacy (evaluation of images) were secondary end points. Safety and tolerability were assessed throughout study participation (approximately 7 days). Imaging efficacy variables were assessed by investigators. RESULTS: Forty-four subjects were evaluated for safety and efficacy; 43 subjects were eligible for PK evaluation including 9 term newborns and infants aged younger than 2 months. Gadobutrol PK in pediatric subjects aged younger than 2 years were adequately described by a linear 2-compartmental model with elimination from the central compartment. Total median systemic exposure (area under the curve) of gadobutrol was estimated at 776 µmol · h/L (range, 544-1470 µmol · h/L). Simulated median concentration at 20 minutes after injection of gadobutrol (C20) was 339 µmol/L (range, 230-456 µmol/L). Safety and tolerability profile were similar to older populations. In 1 subject (2.3%), vomiting was reported as a mild adverse event related to gadobutrol, and there were no reported serious adverse events. The evaluation of gadobutrol-enhanced images provided improved diagnosis, increased confidence in diagnosis, and contributed to subject clinical management. CONCLUSIONS: The PK profile of gadobutrol in children aged younger than 2 years including newborns is similar to that in older children and adults. At the dose of 0.1 mmol/kg BW, gadobutrol had a favorable safety profile and was well tolerated with similar profile across the age range 0 to younger than 2 years and compared with older children and adults. Extrapolation of efficacy data from adults to the younger pediatric population, including term newborns, is justified. The recommended standard dose of gadobutrol (0.1 mmol/kg BW), as used in the population aged 2 years and older, is also appropriate in children aged younger than 2 years.

Unsuspected Ganglioneuroma of the Choroid Diagnosed after Enucleation.

We report a case of an unsuspected ganglioneuroma of the choroid in a patient with neurofibromatosis type 1. A 5-year-old girl presented from an outside institution with right proptosis and glaucoma since birth. Magnetic resonance imaging was obtained and showed a cavernous sinus mass extending into the right orbit and multiple orbital lesions. Additionally, increased signal in the posterior globe of the right eye was noted, but its etiology was unclear at the time. She was lost to follow-up for 3 years and later returned with a blind painful eye. Enucleation was performed, and histopathology was significant for diffuse choroidal ganglioneuroma and advanced glaucoma. We report the atypical history, examination findings, and histopathology to support the diagnosis.

Systemic lymphoma mimicking acute disseminated encephalomyelitis.

We describe a 10-year-old immunocompetent male whose initial presentation was consistent with the diagnosis of acute disseminated encephalomyelitis. He relapsed 3 months later, with new neurologic signs and lymphadenopathy. T-cell lymphoma was diagnosed by lymph node and stereotaxic brain biopsy. This patient represents a rare report of T-cell lymphoma in an immunocompetent child presenting with central nervous system symptoms.

Spinal Cord Lesions in Congenital Toxoplasmosis Demonstrated with Neuroimaging, Including Their Successful Treatment in an Adult.

Neuroimaging studies for persons in the National Collaborative Chicago-Based Congenital Toxoplasmosis Study (NCCCTS) with symptoms and signs referable to the spinal cord were reviewed. Three infants had symptomatic spinal cord lesions, another infant a Chiari malformation, and another infant a symptomatic peri-spinal cord lipoma. One patient had an unusual history of prolonged spinal cord symptoms presenting in middle age. Neuroimaging was used to establish her diagnosis and response to treatment. This 43 year-old woman with congenital toxoplasmosis developed progressive leg spasticity, weakness, numbness, difficulty walking, and decreased visual acuity and color vision without documented re-activation of her chorioretinal disease. At 52 years of age, spinal cord lesions in locations correlating with her symptoms and optic atrophy were diagnosed with 3 Tesla MRI scan. Treatment with pyrimethamine and sulfadiazine decreased her neurologic symptoms, improved her neurologic examination, and resolved her enhancing spinal cord lesions seen on MRI.

Rolandic mitochondrial encephalomyelopathy and MT-ND3 mutations.

Mitochondrial encephalopathies may be caused by mutations in the respiratory chain complex I subunit genes. Described here are the cases of two pediatric patients who presented with MELAS-like calcarine lesions in addition to novel, bilateral rolandic lesions and epilepsia partialis continua, secondary to MT-ND3 mutations. Data were collected included neurologic symptoms, serial brain imaging, metabolic evaluations, skeletal muscle biopsies, mitochondrial biochemical and molecular testing. Permission for publication was given by the families. Muscle histology revealed nonspecific changes, with no ragged red or blue or COX-negative fibers. Sequencing of the mitochondrial DNA indicated patient 2 to be homoplasmic in muscle for the mt.10158T>C mutation in the ND3 subunit and Patient 1 to be 75% heteroplasmic for the mt.10191T>C mutation, also in ND3. Bilateral rolandic lesions and epilepsia partialis continua accompanied by suspicion of mitochondrial disease are indications to search for an underlying mutation in the MT-ND3 gene.

Intracranial vertebral artery dissection with subarachnoid hemorrhage following child abuse.

Child abuse is often suspected based on particular patterns of injury. We report a case of intracranial vertebral artery dissection with subarachnoid hemorrhage (SAH) in a 3-month-old boy following child abuse. The mechanisms of injury and the clinical and imaging findings are discussed. This particular pattern of injury has rarely been reported in association with child abuse. We hope to raise physician awareness of child abuse when faced with these imaging findings.

Intracranial vascular abnormalities in patients with Alagille syndrome.

OBJECTIVES: To define the spectrum of intracranial events and cerebrovascular lesions in patients with Alagille syndrome using magnetic resonance imaging with angiography of the head and medical histories and to correlate the presence of lesions with the clinical outcome of bleeding or ischemic intracranial events. METHODS: 26 patients with Alagille syndrome underwent magnetic resonance imaging with angiography of the head; 22 had no symptoms and underwent study for screening purposes and 4 were symptomatic with neurologic changes. The results of studies and the history of ischemic intracranial events were reviewed. RESULTS: Cerebrovascular abnormalities were detected in 10 of 26 (38%) patients (9 by head magnetic resonance imaging with angiography and 1 by necropsy). The findings included stenoses of the internal carotid arteries unilaterally (n = 5) or bilaterally (n = 3), basilar artery aneurysm (n = 1) and middle cerebral artery aneurysm (n = 1). Among the 9 patients with cerebrovascular abnormalities detected by magnetic resonance imaging with angiography, 5 had no symptoms (23%, 5 of 22) and 4 were symptomatic. Thus, 100% of symptomatic patients had detected abnormalities and 23% of screened, asymptomatic patients had detected anomalies. Screening magnetic resonance imaging with angiography failed to detect vascular anomalies in 2 asymptomatic patients who had fatal ischemic intracranial events years later. There was evidence of progression of vascular abnormalities in 4 patients. Ischemic intracranial events occurred in 10 of 26 (38%) patients and were associated with cerebrovascular abnormalities in 6 of 10 patients. CONCLUSION: The cerebral vasculopathy of Alagille syndrome predominantly involves the internal carotid arteries. It is more prevalent than would be suggested by the number of symptomatic individuals, appears to be progressive and shares many similarities with moyamoya. Magnetic resonance imaging with angiography is useful to detect these lesions and may have a valuable role in screening for treatable lesions such as aneurysms.