Multidelay Arterial Spin Labeling MRI in the Assessment of Cerebral Blood Flow: Preliminary Clinical Experience in Pediatrics.

OBJECTIVES: We attempted to demonstrate the clinical applicability and utility of a three-dimensional multidelay arterial spin labeling magnetic resonance imaging technique in pediatric neuroimaging through a series of case studies. METHODS: Whole-brain three-dimensional multidelay arterial spin labeling data were acquired in five pediatric patients with different neurological conditions using 3 mm to 4 mm slices and a scan time of six to seven minutes. RESULTS: Three-dimensional multidelay arterial spin labeling provided complementary diagnostic information via quantitative cerebral blood flow and arterial transit time maps. CONCLUSIONS: Three-dimensional multidelay arterial spin labeling sequence provides simultaneous quantification of cerebral blood flow and arterial transit time and is feasible for pediatric patients.

Post-contrast T1-weighted spine 3T MRI in children using a golden-angle radial acquisition.

PURPOSE: MRI methods that have reduced sensitivity to motion are attractive in pediatric applications. In spine imaging, physiologic motion such as respiration and cerebrospinal fluid pulsation can hamper diagnostic image quality. We compare a 3D T1-weighted non-Cartesian radial acquisition with a conventional Cartesian 2D turbo-spin-echo (TSE) acquisition in axial post-contrast spine imaging at 3T. METHODS: Thirty-two patients (mean age 12.2 ± 5.3 years) scheduled for routine clinical spine exams with contrast were enrolled. Three pediatric neuroradiologists compared the two sequences and assessed the presence of motion, the conspicuity of nerve roots, and whether one of the sequences was preferred in visualizing pathology using Likert scales. RESULTS: The Fleiss' kappa statistic for inter-rater agreement was 0.29 (95% confidence interval, 0.15-0.43) for the presence of motion, 0.30 (0.21-0.38) for conspicuity, and 0.37 (0.19-0.55) for sequence preference. Radial images were less sensitive to motion than TSE (p < 0.01). Motion and consequent artifacts were present in all TSE cases, while it was absent in 51% of the radial cases. In depicting nerve roots, radial images were superior in the cervical (p < 0.05), thoracic (p < 0.01), and lumbar spines (p < 0.01). Lastly, in 28 of the 32 patients who demonstrated contrast-enhancing pathology, radial images were preferred in 51% of the cases, while both sequences were equally preferred in 41% of the cases. CONCLUSION: We demonstrate the potential utility of radial MRI in post-contrast spine imaging. The free-breathing method is robust in generating diagnostic image quality and is superior in visualizing nerve roots and extramedullary metastases than traditional Cartesian TSE acquisitions.

Germinoma Involving the Retina: An Unusual Presentation of Recurrent Intracranial Mixed Germ Cell Tumor.

BACKGROUND: We report a patient with primary central nervous system mixed malignant germ cell tumor (GCT) who presented with recurrent malignant germinomatous infiltration of the retina. CASE DESCRIPTION: A 10-year-old girl initially presented with a large suprasellar mixed malignant GCT with a near-complete response after initial induction of chemotherapy and irradiation. Three and a half years after initial therapy, she presented with progressively worsening vision in her left eye. Magnetic resonance imaging showed infiltrative changes within the left optic nerve but no discrete mass. Serum and cerebrospinal fluid tumor markers were not elevated and cerebrospinal fluid cytology was negative. Left optic nerve biopsy confirmed the presence of mature teratoma and pure germinoma components. She was treated with gross-total resection of the left eye and optic nerve and chemotherapy. Histopathologic evaluation of the optic nerve showed only mature teratoma elements, but with pure germinoma cells infiltrating the inner layers of the retina. CONCLUSIONS: Loco-regional extension of suprasellar GCT to the optic nerve is not uncommon; however, to the best of our knowledge, infiltration of the tumor into the retina is not reported in the literature. Early detection of optic pathway involvement and proper delineation of the irradiation field may prevent GCT infiltration of the retina with subsequent vision loss.

Sporadic pediatric meningiomas: a neuroradiological and neuropathological study of 15 cases.

OBJECTIVE Sporadic meningiomas have been classified in many different ways. Radiographically, these lesions can be described as occurring in either typical or atypical locations. The purpose of this study was to determine if there are any histopathological differences between sporadic meningiomas that arise in these varying locations in children. METHODS The neuroimaging, histopathological findings, and clinical records in patients with sporadic pediatric meningiomas not associated with neurofibromatosis Type 2 or prior radiation therapy were retrospectively reviewed. Tumors were classified by radiological findings as either typical or atypical, and they were categorized histopathologically by using the latest WHO nomenclature and grading criteria. RESULTS Fifteen sporadic meningiomas in pediatric patients were biopsied or resected at the authors' institution between 1989 and 2013. Five (33%) were typical in radiographic appearance and/or location and 10 (67%) were atypical. Four (80%) typical meningiomas were WHO Grade I tumors. Most (60%) of the atypical meningiomas were WHO Grade II or III. CONCLUSIONS This study is the largest series of sporadic pediatric meningiomas in atypical locations to date. Although sporadic meningiomas are relatively infrequent in children, those with atypical imaging, specifically those with apparently intraparenchymal and intraosseous locations, may be more common than previously recognized. In this study, pediatric sporadic meningiomas arising in atypical locations, in particular intraparenchymal meningiomas, may be of higher histopathological grade. The authors' findings should alert clinicians to the potential for more aggressive clinical behavior in these tumors.

Neuropathology Associated With Diffuse Excessive High Signal Intensity Abnormalities on Magnetic Resonance Imaging in Very Preterm Infants.

BACKGROUND: Diffuse excessive high signal intensity abnormality is the most common finding on term-equivalent age magnetic resonance imaging in extremely preterm infants. Yet its clinical significance remains a matter of debate, in part because of a lack of prior imaging-pathology correlational studies. PATIENT PRESENTATIONS: We present two 24-week-gestation infants with complicated clinical courses who died at 33 and 46 weeks postmenstrual age with magnetic resonance imaging evidence of diffuse excessive high signal intensity. Two patients with periventricular leukomalacia and two without injury were examined for comparison. Immunohistochemistry characterized the presence of reactive astrocytes, microglia, myelin, and axons. Infants with periventricular leukomalacia demonstrated the typical microscopic necrosis with spheroids, gliosis/microgliosis with reduction in stainable myelin and axons. Infants with diffuse excessive high signal intensity showed vacuolated regions with increased reactive astrocytes and microglia and fewer oligodendroglial cell bodies/processes and dramatic reduction in axon number. CONCLUSION: These two individuals with diffuse excessive high signal intensity exhibited pathologic characteristics that were overlapping but distinct from those of periventricular leukomalacia.

Cranial nerve and cervical root enhancement in an infant with polymerase gamma mutation mitochondrial disease.

BACKGROUND: Nuclear polymerase gamma (POLG) mutations are the most common cause of inherited mitochondrial disease. POLG mutation diseases have a broad spectrum of clinical manifestations; the lethal infantile form is myocerebrohepatopathy spectrum. PATIENT: A 4-month-old boy was referred for poor feeding, emesis, failure to thrive, and hypotonia. RESULTS: Brain computed tomography was normal. Brain magnetic resonance imaging with and without contrast demonstrated bilateral enhancement of cranial nerves III, V-X, and the upper and midcervical nerve roots. Liver biopsy revealed early cirrhosis, steatosis, and focal necrosis. Muscle biopsy did not demonstrate specific abnormalities of mitochondrial morphology or number. Electron transport chain analysis of both fibroblasts and muscle demonstrated deficiencies. Because of suspected mitochondrial depletion disorder, testing was performed for mitochondrial abnormalities including analysis of the POLG gene, which revealed two pathogenic mutations, c.1399G>A (p.A467T) and c.3285C>G (p.S1095R). CONCLUSIONS: We report abnormal gadolinium enhancement of multiple cranial nerves and cervical nerve roots in an infant with myocerebrohepatopathy spectrum disease whose brain MRI otherwise revealed only mild atrophy. Mitochondrial disease should be included in the differential diagnosis of cranial nerve enhancement. Contrast-enhanced MRI aids in the diagnostic evaluation of infants with developmental delay and suspected neurological disease.

Isolated neurosarcoidosis presenting as headache and multiple brain and spinal cord lesions mimicking central nervous system metastases.

Sarcoidosis is uncommon in children. Although isolated neurosarcoidosis has been seen in 15% adults with sarcoidosis, pediatric neurosarcoidosis is rarely reported. Neurosarcoidosis may present with cranial neuropathy, including facial palsy, optic nerve or other cranial nerve involvement, peripheral neuropathy, or manifestations of the central nervous system affecting the hypothalamus, pituitary gland, cerebral cortex, cerebellum, meninges, and spinal cord. The useful diagnostic investigations include magnetic resonance imaging of the brain and spinal cord, cerebrospinal fluid studies, brain and meningeal biopsy if feasible, chest radiography to reveal sarcoidosis, angiotensin-converting enzyme level in the serum or cerebrospinal fluid, and Kveim test when available. We herein report a case of isolated brain biopsy-confirmed neurosarcoidosis in a 17-year-old boy presenting with severe unilateral headache and multiple brain and spinal cord MRI lesions mimicking central nervous system metastases.