Tamara Feygin

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.

CT and MRI of pediatric skull lesions with fluid-fluid levels.

SUMMARY: Fluid-fluid levels can occur whenever different fluid densities are contained within a cystic or compartmentalized lesion, usually related to the evolution of hematoma or necrosis. Review of the literature demonstrated that throughout the skeletal system, the most common etiology for fluid-fluid levels is aneurysmal bone cyst, but there are no dedicated studies of the pediatric calvaria, to our knowledge. In this report, we present clinicopathologic characteristics and CT and MR imaging of 11 patients with pediatric skull mass lesions demonstrating fluid-fluid levels. MR imaging demonstrated more fluid-fluid levels compared with CT in all cases. The etiologies of skull lesions with fluid-fluid levels were Langerhans cell histiocytosis in 4 (36.6%), aneurysmal bone cysts in 3 (27.2%), cephalohematoma in 3 (27.2%), and metastatic neuroblastoma in 1 (9%). Radiologists should be aware of the other etiologies of calvarial lesions with fluid-fluid levels in the pediatric skull.

Central pontine myelinolysis: A case report and clinical-pathological review

Cui R, Fayek S, Rand EB, Feygin T, Khrichenko D, Shaked A. Central pontine myelinolysis: A case report and clinical–pathological review. Pediatr Transplantation 2011.

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.

Imaging of congenital central nervous system infections

Congenital central nervous system (CNS) infections are a cause of significant morbidity and mortality. The recent Zika virus outbreak raised awareness of congenital CNS infections. Imaging can be effective in diagnosing the presence and severity of infection. In this paper we review the clinical presentations and imaging characteristics of several common and less common congenital CNS infections.

Dynamic MR imaging (MR fluoroscopy): Clinical applications in pediatric radiology

D Cine Magnetic Resonance imaging (MR “fluoroscopy”) is a rapidly developing technique, which evolves from research and works in progress into routine imaging sequences. This technique is designed to demonstrate some of the physiologic and pathologic processes of the human body in almost real time. MR “fluoroscopy” offers many advantages over other dynamic imaging modalities (such as x-ray based fluoroscopy, nuclear medicine examinations or ultrasonography) due to its lack of ionized radiation and short acquisition time. These features are particularly important in pediatric and prenatal medicine. The dynamic sequences are based on fast acquisition and organization of images in a sequential-loop, resulting in an impression of observing a real-time movie. The sequences vary slightly in different manufactures but almost any sequence sensitive to flow may be employed. They are easily obtainable from a technical standpoint, and are easily tolerated by patients. These dynamic sequences prove to be valuable tools in functional assessment of intracranial/intraspinal CSF flow dynamics, evaluation of effectiveness of endoscopic procedures, esophageal or bowel motility (and almost any other type of dynamic motion in the human body); evaluation of cardiac contractility and blood flow patterns and joint mobility. Dynamic Cine MR Imaging improves our knowledge of fetal physiology, demonstrates functional impairment of fetal fluids flow dynamics; provides clinically significant prognostic information for pre and postnatal planning and contributes in very careful selection of patients eligible for fetal intervention.

Distinctive multicystic hemispheric lesions suggesting a novel variant of infantile astrocytoma.

Two unrelated female infants presented at 9 days and 2 months, respectively, with apneic episodes in the former and gaze preference in the latter. MRI revealed enlargement of almost the entire right hemisphere, apparently smooth cortex, simplification of the gyral pattern, and expanded white matter with abnormal signal intensity containing multiple intraparenchymal cysts. Histologic examination of both cases revealed white matter infiltration by a hypocellular lesion composed of uniform, fibrillary astrocytes in a microcystic background. Multilocular tumor cysts were prominent, but Rosenthal fibers and eosinophilic granular bodies were absent. Very rare mitoses were seen in the absence of necrosis or vascular change. There was no convincing cortical infiltration, but the subpial zone was diffusely expanded by a band of astrocytes set in a dense fibrillar feltwork which opened out into numerous cystic spaces. No desmoplastic changes or associated atypical ganglion cells were identified. There was no evidence for a BRAFKIAA1549 fusion or BRAF mutation in one case tested. In conclusion, both lesions are not desmoplastic infantile astrocytoma/ganglioglioma, fibrillary astrocytoma, or typical for pilocytic astrocytoma. Such extreme subpial spread with cysts is most unusual and may suggest a novel variant of infantile astrocytoma.

3T Pediatric Brain Imaging

Three Tesla imaging of the pediatric brain is feasible without significant SAR limitations and provides improved diagnostic information relative to 1.5 T for MRA, thin section T1 and T2 images, susceptibility scans, and conspicuity of contrast enhancement.