Maura E. Ryan

Pediatric cochlear implantation of children with eighth nerve deficiency

OBJECTIVE To evaluate the auditory outcomes of children implanted in an ear with eighth nerve hypoplasia or aplasia and to determine whether preoperative characteristics are predictive of auditory performance achieved. METHODS STUDY DESIGN retrospective case review. SETTING tertiary care medical center. PATIENTS ten children implanted in an ear with eighth nerve hypoplasia or aplasia, as determined by high resolution magnetic resonance imaging. MAIN OUTCOME MEASURES Neural response test measurements, detection and speech awareness thresholds, Meaningful Auditory Integration Scale scores, as well as speech perception level achieved. RESULTS Post-implantation, three children demonstrated little to no detection of sound, three had improved detection and awareness of environmental sounds, one developed closed-set speech perception and spoken language, and three developed open-set speech perception and spoken language. No imaging findings appeared related to outcomes. Significantly better implant detection thresholds and Meaningful Auditory Integration Scale scores were found in children who had preoperative aided auditory detection (ps ≤ 0.02-0.05). CONCLUSION Some children with eighth nerve hypoplasia or aplasia may derive significant benefit from a cochlear implant. In our study high resolution magnetic resonance imaging was more sensitive than high resolution computer tomography in detecting neural deficiency. However, no imaging findings were predictive of auditory performance level achieved post-implantation.

A multinational, multidisciplinary consensus for the diagnosis and management of spinal cord compression among patients with mucopolysaccharidosis VI

Cervical cord compression is a sequela of mucopolysaccharidosis VI, a rare lysosomal storage disorder, and has devastating consequences. An international panel of orthopedic surgeons, neurosurgeons, anesthesiologists, neuroradiologists, metabolic pediatricians, and geneticists pooled their clinical expertise to codify recommendations for diagnosing, monitoring, and managing cervical cord compression; for surgical intervention criteria; and for best airway management practices during imaging or anesthesia. The recommendations offer ideal best practices but also attempt to recognize the worldwide spectrum of resource availability. Functional assessments and clinical neurological examinations remain the cornerstone for identification of early signs of myelopathy, but magnetic resonance imaging is the gold standard for identification of cervical cord compression. Difficult airways of MPS VI patients complicate the anesthetic and, thus, the surgical management of cervical cord compression. All patients with MPS VI require expert airway management during any surgical procedure. Neurophysiological monitoring of the MPS VI patient during complex spine or head and neck surgery is considered standard practice but should also be considered for other procedures performed with the patient under general anesthesia, depending on the length and type of the procedure. Surgical interventions may include cervical decompression, stabilization, or both. Specific techniques vary widely among surgeons. The onset, presentation, and rate of progression of cervical cord compression vary among patients with MPS VI. The availability of medical resources, the expertise and experience of members of the treatment team, and the standard treatment practices vary among centers of expertise. Referral to specialized, experienced MPS treatment centers should be considered for high-risk patients and those requiring complex procedures. Therefore, the key to optimal patient care is to implement best practices through meaningful communication among treatment team members at each center and among MPS VI specialists worldwide.

ACR Appropriateness Criteria Head Trauma—Child

Head trauma is a frequent indication for cranial imaging in children. CT is considered the first line of study for suspected intracranial injury because of its wide availability and rapid detection of acute hemorrhage. However, the majority of childhood head injuries occur without neurologic complications, and particular consideration should be given to the greater risks of ionizing radiation in young patients in the decision to use CT for those with mild head trauma. MRI can detect traumatic complications without radiation, but often requires sedation in children, owing to the examination length and motion sensitivity, which limits rapid assessment and exposes the patient to potential anesthesia risks. MRI may be helpful in patients with suspected nonaccidental trauma, with which axonal shear injury and ischemia are more common and documentation is critical, as well as in those whose clinical status is discordant with CT findings. Advanced techniques, such as diffusion tensor imaging, may identify changes occult by standard imaging, but data are currently insufficient to support routine clinical use. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every 3 years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Preoperative Imaging of Sensorineural Hearing Loss in Pediatric Candidates for Cochlear Implantation

Cochlear implantation is the only U.S. Food and Drug Administration-approved treatment for children with marked bilateral sensorineural hearing loss. It provides auditory benefits that range from simple sound detection to substantial word understanding. Improved hearing through cochlear implantation has been demonstrated to enhance the rate of language acquisition, enable development of spoken language, and advance literacy in deaf children. Magnetic resonance imaging and computed tomography both have roles in the preoperative assessment of inner-ear abnormalities, cochlear nerve deficiency, and variant anatomy that may affect the decision to implant and the prognosis for auditory improvement and increase the risk for complications. Most cochlear abnormalities may be successfully treated with cochlear implantation, but the presence of a cochlear malformation may increase the risk for intraoperative cerebrospinal fluid leakage and postoperative bacterial meningitis. Eighth-nerve deficiency correlates with poor auditory outcomes and may affect eligibility for cochlear implantation. Another important consideration for implantation is the presence of labyrinthitis ossificans in some children with deafness resulting from bacterial meningitis, which may cause obstruction that limits electrode insertion. Anatomic variations of the facial nerve or middle-ear cavity, which are more common in syndromic patients, may also affect the surgical approach and make implantation difficult.

Imaging of pediatric head and neck masses

Medical imaging is an important tool in the evaluation and classification of pediatric head and neck masses. Such lesions may include congenital, inflammatory, infectious, vascular, or neoplastic processes. Ultrasound is often the first line modality in the workup of a neck mass in a child, followed by MRI or CT depending on the scenario. This information must be interpreted in the context of the patients clinical history, physical examination, and demographics. The medical imaging workup of a neck mass in a child must be focused to yield the maximum information possible while minimizing the risks of radiation and sedation.

ACR Appropriateness Criteria® Suspected Physical Abuse—Child

The youngest children, particularly in the first year of life, are the most vulnerable to physical abuse. Skeletal survey is the universal screening examination in children 24 months of age and younger. Fractures occur in over half of abused children. Rib fractures may be the only abnormality in about 30%. A repeat limited skeletal survey after 2 weeks can detect additional fractures and can provide fracture dating information. The type and extent of additional imaging for pediatric patients being evaluated for suspected physical abuse depends on the age of the child, the presence of neurologic signs and symptoms, evidence of thoracic or abdominopelvic injuries, and social considerations. Unenhanced CT of the head is the initial study for suspected intracranial injury. Clinically occult abusive head trauma can occur, especially in young infants. Therefore, head CT should be performed in selected neurologically asymptomatic physical abuse patients. Contrast-enhanced CT of the abdomen/pelvis is utilized for suspected intra-abdominal or pelvic injury. Particular attention should be paid to discrepancies between the patterns of injury and the reported clinical history. Making the diagnosis of child abuse also requires differentiation from anatomical and developmental variants and possible underlying metabolic and genetic conditions. 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.

Nasal chondromesenchymal hamartoma: correlation of typical MR, CT and pathological findings.

Sir, We read with great interest the case report on nasal chrondromesenchymal hamartoma (NCMH) by Johnson et al. [1]. They presented the spectrum of CT findings of this rare, benign pathological entity that can be locally aggressive and mimic malignancy. We would like to highlight the MR appearance of NCMH, which correlates with known CT and pathological features, as well as findings seen with intraorbital and intracranial extension. The described CT findings include internal calcifications, bony remodeling, variable enhancement, cystic components, local extension into the orbit, paranasal sinuses and, rarely, intracranial compartment [1–5] (Fig. 1). The imaging spectrum reflects the histology of NCMH, which is composed of different mesenchymal elements, the most prominent being sheets/fascicles of spindled cells in a fibrous or myxoid background. Other components include well-demarcated islands of cartilage and prominent vessels often with perivascular fibrosis or prominent collagen deposition. Reactive bone may be seen in some of them, which is mainly reactive bone remodeling. Areas of mineralization, within the matrix of the cartilaginous components of the lesion, are better visualized on CT but correlate with areas of T2 hypointensity and low gradient signal seen on MRI. Additionally, areas of fibrosis would have expected hypointensity on T2-weighted images. Cystic and myxoid components are poorly discernible as areas of low density on CT but are more clearly defined on MRI by characteristic, discrete areas of marked T2 hyperintensity (Fig. 2). A companion case of NCMH confined to the nasal cavity demonstrates similar MR findings (Figs. 3 and 4). As

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 childrens 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.

MRI Predicts Outcome After HIE Treated with Hypothermia

Investigators from Childrens National Medical Center and George Washington University School of Medicine, Washington, DC, studied the correlation between white matter tract changes and developmental outcomes in a series of infants with hypoxic ischemic encephalopathy (HIE) treated with whole body cooling.

Teaching NeuroImages: Meningioangiomatosis.

A 23-month-old full-term boy presented with tonic-clonic seizures. Lumbar puncture and routine laboratory tests were unremarkable. CT (figure 1A) showed bifrontal parasagittal calcification. Brain MRI revealed corresponding signal abnormalities with gradient susceptibility (figure 1D) and enhancement (figure 1F). Differential diagnoses included prior infection, vascular malformation, and tumor. Biopsy (figure 2) was consistent with meningioangiomatosis.