MR and CT characteristics of gangliocytoma: a rare cause of epilepsy in children.

Three children were examined who had surgery to remove gangliocytomas in order to control seizures that were refractory to medical therapy. The CT characteristics of gangliocytomas are those of a hyperdense lesion that does not demonstrate contrast enhancement. The MR findings show a region of mixed signal intensity on T1-weighted and proton-density images, and decreased signal intensity on T2-weighted images. Little mass effect, if any, is seen with these lesions.

MR imaging of spinal dysraphism.

Spinal dysraphism includes anomalies of midline fusion involving bony, mesenchymal, and neural elements. MR imaging of the spine was performed as the initial imaging technique to determine its role in the evaluation of 31 children when spinal dysraphism was clinically suspected or when radiographs revealed errors of ossification of the posterior elements (spina bifida). Correlation of surgical findings in 17 of 18 abnormal examinations and metrizamide myelography with CT in six of these cases indicated that accurate diagnosis was provided by MR in all instances. Examples of spina bifida aperta (spina bifida cystica)--including myelomeningocele, myelocystocele, and lipomyelomeningocele--and those of occult spinal dysraphism--such as dorsal dermal sinus, spinal lipoma, and tight filum terminale (thickened filum)--are presented. These cases show MR to be a reliable technique in the initial evaluation of these disorders.

Holoprosencephaly classified by computed tomography.

Five cases are presented to demonstrate the computed tomographic (CT) spectrum of holoprosencephaly. The classifications of alobar, semilobar, and lobar types A and B holoprosencephaly are each represented, with an additional case of semilobar holoprosencephaly complicated by a subdural effusion.

Placement of intracerebral depth electrodes during excisional surgery for epilepsy: value of intraoperative ultrasound.

The authors describe the use of intraoperative US for directing placement of depth electrodes for the localization of seizure foci prior to temporal lobectomy. They used this technique in seven patients (six undergoing temporal and one frontal resection), and encountered no complications.

Intracranial infection in children.

This article discusses the neuroradiologic characteristics of central nervous system infections in children. These disorders are divided into two groups: those of congenital infections and those of infections in the infant and child. Congenital infections are referred to by the acronym TORCH. Inflammatory diseases in the infant and child encompass meningitis, cerebritis, and encephalitis. The heterogeneous etiologies often can be suggested by the neuroradiologic findings, as demonstrated with computed tomography and magnetic resonance imaging. This article also addresses the sequelae of destructive brain injuries.

Phase contrast cine magnetic resonance imaging: normal cerebrospinal fluid oscillation and applications to hydrocephalus.

Two-dimensional cine phase contrast (2D-cine PC) magnetic resonance (MR) imaging is an imaging technique that sensitizes MR images to velocity changes in a specific direction while cancelling signals from stationary protons and from motion in other directions. This article reviews the technique, conventions, and applications of this imaging technique to hydrocephalus. 2D-Cine PC and additional more rapid MR imaging methods now in development will allow clinicians to measure CSF velocity, pulsation, and bulk flow noninvasively in normal individuals and in patients with a variety of pathologic conditions. It is hoped that these measurements may be correlated with intracranial pressures to develop clinical tests of brain compliance and improved management of patients with hydrocephalus.

Brain activation in sedated children: auditory and visual functional MR imaging.

PURPOSE: To map developing areas of activation with functional magnetic resonance (MR) imaging in sedated children by using passive auditory and visual tasks. MATERIALS AND METHODS: Forty children between 2 months and 9 years old were examined and grouped according to age. Children were selected from patients referred to undergo brain MR imaging. Patients received pentobarbital (3.0-7.0 mg per kilogram of body weight) or chloral hydrate (50-75 mg/kg). The functional MR imaging study was performed at the end of the examination. Paradigms consisted of flashing lights at 8 Hz displayed on special goggles and a prerecorded mother's voice presented through headphones. Activation maps were obtained from a paired t test with a P value of.0005 (uncorrected). RESULTS: The visual stimulus produced statistically significant negative values in the rostral aspect of the primary visual area (28 [90%] of 31 patients). The auditory paradigm activated either temporal or frontal areas in 26 (68%) of 31 patients. There was more frontal activation in the older children. CONCLUSION: Visual and auditory cortices can be activated in children who have been sedated. Visual responses show negative values in the rostral visual cortex, independent of age. Auditory activation is seen in temporal and frontal lobes.

Tuberous sclerosis: characteristics at CT and MR imaging.

Computed tomography (CT) and magnetic resonance (MR) imaging findings were reviewed in 26 patients with tuberous sclerosis. All patients underwent CT; 16 patients underwent both. The CT features included subependymal nodules in 25 of 26 patients (96%) and calcifications in 23 of 26 (88%). Parenchymal hamartomas (cortical tubers) were seen in 23 of 26 patients (88%). These lesions had less attenuation than surrounding brain in 16 of 26 patients (62%) and were calcified in 14 of 26 patients (54%). Contrast enhancement of a lesion, indicating a subependymal giant cell astrocytoma, occurred in three of 26 patients (12%). The MR imaging characteristics included subependymal nodules (periventricular nodules) of intermediate signal intensity in ten of the 16 patients (63%). Parenchymal hamartomas, demonstrated in 15 of the 16 patients (94%), usually exhibited long T1 and T2 relaxation characteristics. The pattern was noted to be reversed in the two newborn patients (13%). One parent demonstrated a forme fruste at CT but had a normal MR image.

CT and MRI of pleomorphic xanthoastrocytoma: unusual biologic behavior.

OBJECTIVE: Our goal was to present three cases of pleomorphic xanthoastrocytoma (PXA) with unusual radiographic, clinical, and pathologic aspects. MATERIALS AND METHODS: The imaging findings in three patients with proven PXA were reviewed and correlated with clinical information and review of pathologic material. Two females and one male were studied, ranging in age from 8 to 42 years old. All patients underwent MRI with gadolinium (0.1 mmol/kg). Two of the patients had serial MR studies. CT scans with and without contrast agent were also available for two patients. The medical records for all three patients were reviewed. Radiographic findings were correlated with pathologic material obtained at surgery. RESULTS: Seizure disorder was the initial presentation in two patients. The third patient presented with a lytic lesion of the calvarium. Radiographic features showed rapid progression of disease over 3 months in one patient. Rapid tumor recurrence (within 7 months) without malignant transformation was proven in another patient. While typical pathological features of PXA were evident in two cases, a mixed tumor consisting of PXA and other tissue components was identified in the third case. CONCLUSION: Although generally regarded as a benign lesion in the literature, PXA has potential for aggressive behavior. Rapid tumor recurrence can occur without malignant transformation. Radiographic features may evolve over a short period of time. Dura and bony calvarium are not necessarily respected. PXA can occur as a separate entity or as a tumor of mixed components.

Three-dimensional CT reformation in children.

Three-dimensional computed tomographic (CT) reformation has proven useful in the evaluation of congenital malformations of the brain as well as in the surgical approach and postoperative assessment of craniofacial anomalies in children. This technique was performed on 41 patients, of whom eight are presented. The congenital anomalies of semilobar holoprosencephaly and colpocephaly are described. Six representative cases of craniofacial anomalies with pre- and postoperative examinations include Crouzon syndrome, orbital fibrous dysplasia, frontonasal encephalocele, cranial involvement from neurofibromatosis, Treacher-Collins syndrome, and a Tessier III facial cleft. Addition of the dimension of depth provides a view heretofore not obtainable by standard imaging techniques and allows more accurate diagnosis as well as a more specific approach to surgical planning and follow-up.

MR imaging of tuberous sclerosis: pathogenesis of this phakomatosis, use of gadopentetate dimeglumine, and literature review.

Findings on cranial magnetic resonance (MR) images were correlated with known histopathologic findings in 42 patients with tuberous sclerosis (TS), 17 of whom received gadopentetate dimeglumine, to extend the range of signs on MR images. Four neuroradiologists recorded the number, sites, configurations, and relative signal intensities of intracranial abnormalities. White matter lesions, found in 39 patients (93%), showed four distinct patterns: (a) straight or curvilinear bands extending radially from the ventricle through the cerebral mantle toward the cortex, (b) wedge-shaped lesions, (c) nonspecific conglomerate foci, and (d) cerebellar radial bands. It is concluded that cortical tubers, white matter lesions, subependymal nodules, and sub-ependymal giant cell astrocytomas (SGCAs) may be enhanced after administration of gadopenetetate dimeglumine. Enhancement of a TS lesion does not indicate neoplastic transformation into SGCA. Imaging surveillance every 12 months appears indicated during the peak ages (8-18 years) of occurrence of SGCA. The appearance of white matter lesions supports the theory that the cerebral lesions of TS may be caused by disordered migration of dysgenetic cells.

Phase III multicenter clinical investigation to determine the safety and efficacy of gadoteridol in children suspected of having neurologic disease.

A phase III open-label clinical trial was conducted at 11 institutions to determine the safety and efficacy of gadoteridol in children suspected of having neurologic disease. One hundred three children were included in the safety analysis; 92 were evaluated for efficacy (76 intracranial and 16 spinal examinations). Three adverse events were reported in two children. All adverse events were considered minor and resolved spontaneously without treatment or sequelae. In a comparison of enhanced T1-weighted magnetic resonance images with unenhanced T1- and T2-weighted images, enhancement of disease was noted in 70% of the intracranial and 38% of the spinal examinations. Additional diagnostic information was reported in 82% of the postcontrast intracranial examinations and 62% of the spinal examinations. Use of this additional information contributed to a potential modification of patient diagnosis in 48% of intracranial and 20% of spinal cases with additional information. These results indicate excellent safety and efficacy for use of gadoteridol in children with suspected intracranial or spinal disease.