Rocky Mountain spotted fever: 'starry sky' appearance with diffusion-weighted imaging in a child.

We present a case of Rocky Mountain spotted fever encephalitis in a child imaged utilizing diffusion-weighted MRI. Although the imaging and clinical manifestations of this entity have been previously described, a review of the literature did not reveal any such cases reported in children utilizing diffusion-weighted imaging. The imaging findings and clinical history are presented as well as a brief review of this disease.

Findings on preoperative brain MRI predict histopathology in children with cerebellar neoplasms.

BACKGROUND/AIMS: The majority of pediatric patients with cerebellar neoplasms harbor pilocytic astrocytomas (PAs), medulloblastomas, or ependymomas. Knowledge of a preoperative likelihood of histopathology in this group of patients has the potential to influence many aspects of care. Previous studies have demonstrated hyperintensity on diffusion-weighted imaging to correlate with medulloblastomas. Recently, measurement of T(2)-weighted signal intensity (T2SI) was shown to be useful in identification of low-grade cerebellar neoplasms. The goal of this study was to assess whether objective findings on these MRI sequences reliably correlated with the underlying histopathology. METHODS: We reviewed the radiologic findings of 50 pediatric patients who underwent resection of a cerebellar neoplasm since 2003 at our institution. Region of interest placement was used to calculate the relative diffusion-weighted signal intensity (rDWSI) and relative T2SI (rT2SI) of each neoplasm. RESULTS: Tukey's multiple comparison test demonstrated medulloblastomas to have significantly higher rDWSIs than PAs/ependymomas, and PAs to have significantly higher rT2SIs than medulloblastomas/ependymomas. A simple method consisting of sequential measurement of rDWSI and rT2SI to predict histopathology was then constructed. Using this method, 39 of 50 (78%) tumors were accurately predicted. CONCLUSION: Measurement of rDWSI and rT2SI using standard MRI of the brain can be used to predict histopathology with favorable accuracy in pediatric patients with cerebellar tumors.

Periventricular Leukomalacia in Patients With Pseudo-glaucomatous Cupping.

PURPOSE: Periventricular leukomalacia (PVL) is a structural loss of white matter pathways that carry visual information from the lateral geniculate bodies to the visual cortex. It is observed radiologically in patients with a history of prematurity and is associated with visual field (VF) defects and optic disc cupping. Advances in perinatal care have improved survival for premature babies, so many now present as adolescents and adults to comprehensive eye doctors who are unaware of the relationship of cupping, field defects, and prematurity and who may diagnose manifest or suspected normal tension glaucoma. We describe 2 such patients to raise awareness of this entity. DESIGN: Case series. METHODS: Review of clinical information of 2 patients identified during clinical practice. Charts were reviewed for gestational age, optic nerve appearance, intraocular pressure (IOP), and sequelae of prematurity. Magnetic resonance imaging (MRI), optical coherence tomography (OCT), VF, and optic disc photographs were reviewed. RESULTS: Two young patients with a history of prematurity presented with enlarged cup-to-disc ratio and normal IOP. OCT thinning was most prominent superiorly, with VF defects more notable inferior and homonymous. No progression on VF or OCT was noted in the index case over almost 4 years. CONCLUSIONS: Periventricular leukomalacia should be added to the differential diagnosis of normal tension glaucoma (NTG) when there is a history of prematurity. Careful examination of the optic nerve will assist in differentiating from NTG. Specifically, horizontal cupping with minimal or no nasal displacement of vessels, and superior optic nerve thinning with inferior VF defects, suggest PVL.

Second brachial cleft cyst mimic: case report.

We report the CT findings in a patient with a lateral neck mass histologically shown to be a schwannoma but having certain radiographic features commonly considered pathognomonic for a type III second branchial cleft cyst. Our case, therefore, represents an exception to this long-established rule.

Evaluation of the skin to epidural and subarachnoid space distance in young children using magnetic resonance imaging.

BACKGROUND AND OBJECTIVES: Epidural catheters placed for perioperative analgesia in young children confer clinical benefits but are technically challenging to insert. Approximations of the skin to epidural space depth in this population are limited to direct needle measurement and ultrasonography. Magnetic resonance imaging (MRI) is the most comprehensive imaging modality of the spine. This study aims to produce a more clinically useful formula from MRI data to estimate pediatric epidural depth. METHODS: Seventy children with normal lumbar spine MR images were enrolled. After determination of epidural depth, linear regression was used to estimate a weight-based formula. Analysis of variance and bootstrap methods were used to evaluate this formula against 4 commonly cited formulae. The quality of predictions was evaluated using the mean absolute prediction error. RESULTS: The estimated weight-based formula as derived by MRI data is given by: skin to epidural depth (mm) = 9.00 + 0.62 * weight in kilograms. The mean absolute prediction error was 2.56 mm (95% confidence interval [95% CI], 2.12-3.04) for the new formula. Additional derived formulae are skin to dorsal dura depth (mm) = 13.52 + 0.71 * weight in kilograms (mean absolute prediction error, 2.48 mm; 95% CI, 2.00-3.03) and skin to ventral dural depth (mm) = 23.08 + 0.86 * weight in kilograms (mean absolute prediction error, 2.50 mm; 95% CI, 2.04-3.06). CONCLUSIONS: We provide the first predictive formulae, based on MRI data, for pediatric epidural depth estimation.

A multispecialty pediatric neurovascular conference: a model for interdisciplinary management of complex disease.

INTRODUCTION: In 2013, our institution established a multidisciplinary pediatric neurovascular conference for coordination of care. Here, we review our initial experience. METHODS: Clinical and demographic data were obtained from medical records for patients presented to the pediatric neurovascular conference from April 2013 to July 2014. Patient descriptive characteristics were described by mean and standard deviation for continuous measures and by number and percent for categorical measures. Patients were secondarily stratified by lesion/disease type, and descriptive statistics were used to measure demographic and clinical variables. RESULTS: The pediatric neurovascular conference met 26 times in the study period. Overall, 75 children were presented to the conference over a 15-month period. The mean age was 9.8 (standard deviation, 6.3) years. There were 42 (56%) male patients. These 75 children were presented a total of 112 times. There were 28 (37%) patients with history of stroke. Complex vascular lesions were the most frequently discussed entity; of 62 children (83%) with a diagnosed vascular lesion, brain arteriovenous malformation (29%), cavernous malformation (15%), and moyamoya (11%) were most common. Most discussions were for review of imaging (35%), treatment plan formulation (27%), the need for additional imaging (25%), or diagnosis (13%). Standardized care protocols for arteriovenous malformation and moyamoya were developed. CONCLUSION: A multidisciplinary conference among a diverse group of providers guides complex care decisions, helps standardize care protocols, promotes provider collaboration, and supports continuity of care in pediatric neurovascular disease.

Chronic primary central nervous system histoplasmosis in a healthy child with intermittent neurological manifestations.

Meningitis is an unusual clinical manifestation of Histoplasma capsulatum infection in nonimmunosuppressed children. We report a previously healthy 6-year-old boy with primary, chronic histoplasma meningitis and magnetic resonance imaging findings consistent with demyelinating disease presenting with brief, intermittent neurological manifestations for 7 months before diagnosis.

Orbital pleomorphic liposarcoma in an eight-year-old boy.

Adult-type sarcomas are, as the name indicates, rare tumors in the pediatric population. Although soft tissue sarcomas as a group are not uncommon diagnoses, nonrhabdomyosarcoma soft tissue sarcomas are much rarer and encompass a wide range of diagnoses. A few of these tumors are commonly found in the adult population and are thus referred to as adult-type sarcomas. We present a case of a pleomorphic liposarcoma, an adult-type sarcoma, arising as a primary tumor in the orbit of an 8-year-old boy. The histologic analysis revealed bizarre tumor giant cells and definitive lipoblastic differentiation. The atypical cells were positive for S100, and negative for CD34, desmin, MyoD1, and myogenin. This is a high-grade sarcoma, very rarely encountered in the pediatric population. We present the histologic findings of this unusual pediatric sarcoma and review the literature.

Use of T2 signal intensity of cerebellar neoplasms in pediatric patients to guide preoperative staging of the neuraxis.

OBJECT: The question of whether to obtain routine or selective preoperative imaging of the neuraxis in pediatric patients with cerebellar neoplasms remains a controversial topic. Staging of the neuraxis is generally considered beneficial in patients with neoplasms associated with an elevated risk of leptomeningeal dissemination (LD). When these studies are obtained preoperatively, there is a decrease in the number of false-positive images related to debris in the immediate postoperative period. Additionally, knowledge of the extent of spread has the potential to affect the risk/benefit analysis of aggressive resection. Although the majority of pediatric neurosurgeons surveyed choose to obtain selective preoperative imaging of the neuraxis in cases of cerebellar neoplasms "with findings suggestive of high-grade pathology," an evidence-based protocol in the literature is lacking. The goal of this study was to assess radiological characteristics of tumors with an elevated risk of LD and identify a method to help guide preoperative imaging of the neuraxis. METHODS: The authors first reviewed the literature to gain an appreciation of the risk of LD of pediatric cerebellar neoplasms based on underlying histopathology and/or grade. Available evidence indicates preoperative imaging of the neuraxis in patients with Grade I tumors to be of questionable utility. In contrast, evidence suggested that preoperative imaging of the neuraxis in patients with Grades II-IV neoplasms was clinically warranted. The authors then evaluated an extensive base of neuroradiological literature to identify possible MR imaging and/or CT findings with the potential to differentiate Grade I from higher-grade neoplasms in pediatric patients. They analyzed the preoperative radiological findings in 50 pediatric patients who had undergone craniotomy for resection of cerebellar neoplasms at Vanderbilt Children's Hospital since 2003 with reference to 7 chosen radiological criteria. Logistic regression models were fit using radiological features to determine the best predictors of Grades II-IV tumors. Receiver operating characteristic methods were used to identify diagnostic properties of the best predictors. RESULTS: The relative T2 signal intensity (RT2SI), an indirect measure of the water content of the solid component of the tumor, was best able to identify neoplasms with an elevated risk of LD. An RT2SI value of 0.71 was selected by the authors as the best operating point on the curve. Of the 31 neoplasms retrospectively designated as hypointense T2-weighted lesions (RT2SI ≤ 0.71), 30 (97%) were Grade II or higher. All medulloblastomas, ependymomas, and high-grade (Grades III and IV) neoplasms were hypointense T2-weighted lesions. Of the 19 T2-weighted hyperintense neoplasms (RT2SI > 0.71), 16 (84%) were Grade I and 3 were Grade II. CONCLUSIONS: Measurement of the RT2SI can help predict Grade II-IV tumors at an elevated risk of leptomeningeal spread and guide staging of the neuraxis. Pediatric patients with cerebellar neoplasms found to have an RT2SI of less than or equal to 0.71 are recommended for neuraxis imaging prior to surgery.

Active spontaneous decompression of a suprasellar-prepontine arachnoid cyst detected with routine magnetic resonance imaging. Case report.

Arachnoid cysts are congenital CSF collections that arise adjacent to arachnoid cisterns. These lesions can be incidental neuroimaging findings but may also cause symptoms and necessitate treatment, particularly in children. The authors present their experience with a male infant harboring a large suprasellar-prepontine arachnoid cyst who underwent spontaneous decompression into the ventricular system, as evidenced by a visualized CSF flow jet observed on routine MR imaging.

Quantifying cerebral changes in adolescence with MRI and deformation based morphometry.

PURPOSE: To identify and quantify structural changes in the maturing brain between childhood and adolescence. MATERIALS AND METHODS: Two three-dimensional T1-weighted MR volumes of the brain were acquired from eight subjects, 6 to 7 years apart. The subjects were 9 to 12 years old on the first scan and 15 to 19 years old on the second scan. The MR scans were converted to one millimeter isotropic volumes, globally aligned with a rigid transform, inhomogeneity corrected, and nonrigid deformation fields between the aligned volumes were calculated. Masks for brain regions were automatically warped with the deformation fields and volumes of brain regions calculated. Color overlays based on the nonrigid deformation fields were generated to identify local volume changes. RESULTS: Gray matter decreased as much as 60% and white matter increased as much as 250%. The biggest gray matter changes were in the head of the caudates, areas of the putamens, and areas of the thalamus. Some of the biggest white matter changes were in the forceps minor, forceps major, and internal capsule. CONCLUSION: Deformation based morphometry with serial scans provides a method to study regional structural changes with brain growth and maturation.

Musicogenic seizures can arise from multiple temporal lobe foci: intracranial EEG analyses of three patients.

PURPOSE: To determine the ictal-onset zone of musicogenic seizures by using intracranial EEG monitoring. METHODS: Musicogenic seizures in three patients with medically intractable musicogenic epilepsy were first localized by using noninvasive methods including, in one patient, ictal magnetoencephalography (MEG) and magnetic resonance spectroscopy (MRS). The ictal-onset zones in these patients were then further localized using by intracranial EEG monitoring, and the outcomes of the two patients who underwent epilepsy surgery were determined. RESULTS: Patient 1's musicogenic seizures localized to the right lateral temporal lobe, patient 2's originated in the right mesial temporal lobe, and patient 3's arose independently from both mesial temporal lobes. Patients 1 and 2 underwent resective epilepsy surgery and are seizure free (Engel class I). CONCLUSIONS: Musicogenic epilepsy is a heterogeneous syndrome with seizures that can arise from multiple temporal lobe foci. Patients with medically intractable musicogenic epilepsy and with unilateral ictal onset zones may be considered candidates for resective epilepsy surgery.

Melanotic neuroectodermal tumor of infancy discovered after head trauma.

Melanotic neuroectodermal tumor of infancy (MNTI) is a rare neoplasm that generally arises in the maxilla during the first year of life. Involvement of bones of the cranial vault or brain is extremely rare. We describe a 7-month-old black female who presented after falling out of bed onto a concrete floor. Subsequently, she developed an anterior frontal mass that enlarged over several days. Radiographs of the skull at her local hospital showed a depressed right frontal skull fracture. However, computerized tomography of the head (reviewed at our institution) revealed a slightly hyperdense extra-axial mass which crossed the anterior frontal midline, widening the metopic suture and extending into the anterior subgaleal scalp. Hyperostosis of the adjacent frontal calvarium was also present. A craniotomy revealed a dark, 1.5-cm calcified epidural lesion with some features of an unusual hematoma. Microscopic evaluation revealed a chronic hematoma and MNTI. The tumor recurred within a year. MNTI should be included in the differential diagnosis of epidural and skull lesions in infants.