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With improved availability and a practical understanding of the principles of utilization, MRI will continue to replace CT and US in pediatric neuroimaging, just as it has impacted upon the more invasive modalities. In general, US remains the procedure of choice for screening of fetal and infant CNS abnormalities, and CT continues as the principal screening modality beyond infancy and especially for acute, emergent presentations. MRI has now emerged as a primary option for screening as well as for more definitive assessment of many intracranial and most intraspinal conditions.

We reviewed 24 children who had symptomatic gliomas that involved the optic chiasm and were treated with definitive radiation therapy from 1971 to 1986. In eight patients (33%), histologic confirmation of low-grade astrocytoma was obtained. Patients had radiation therapy only if there was evidence of visual deterioration or other clinical or radiographic evidence of disease progression. Radiation doses ranged from 4500 to 5660 cGy (median, 5400 cGy) with up to a 17-year follow-up period (median, 6 years). The 6-year actuarial freedom from disease progression and overall 6-year survival are 88% and 100%, respectively. Visual improvement or stabilization was seen in 21 (91%) patients after radiation. A high incidence of endocrine abnormalities is reported, with 15 of the 18 patients evaluated after treatment showing growth hormone deficiency. We conclude that definitive radiation therapy is associated with tumor control in most of the patients with progressive optic chiasm gliomas. However, neuropsychiatric and endocrine abnormalities are significant problems that need additional evaluation in these children.

A case is reported of a 5-month-old girl with Hallermann-Streiff syndrome who was evaluated for possible premature closure of the cranial sutures. Skull radiographs revealed numerous Wormian bones along sutures in the parietal skull bilaterally. Hallermann-Streiff syndrome is added to the list of diseases in which extensive Wormian bones can appear.

Dural venous sinus thrombosis is an important complication of L-asparaginase chemotherapy. The diagnosis and followup of this condition, using spin echo and fast imaging techniques, is described in three patients. Magnetic Resonance (MR) imaging is a rapid, noninvasive technique for diagnosis and follow-up of this condition. Fast imaging techniques can improve the assessment of these patients.

The association of imperforate anus with bony sacral abnormalities and neurologic deficits is well recognized. These neurologic deficits have been considered static rather than progressive. However, recent experience indicates that some patients may develop progressive neurologic problems due to spinal cord lesions that are amenable to neurosurgical correction. To investigate the frequency of such lesions, routine myelography of imperforate anus patients with sacral anomalies was undertaken. The extraordinarily high incidence of unsuspected lesions known to cause progressive bowel, bladder, and musculoskeletal dysfunction is the basis of this interim report. Thirty percent of patients with anorectal abnormalities had sacral dysplasia. Of the nine patients undergoing myelography to date, eight have been abnormal. Six children had a tethered spinal cord, one had narrowing of the bony spinal canal and dural sac stenosis, and one an anterior meningocele. Spinal cord conditions that may cause deterioration of bowel, bladder, and extremity function should be defined and corrected before irreversible damage occurs. Because of the high incidence of spinal cord lesions detected in these patients with coexisting anorectal and sacral anomalies, routine screening for spinal cord lesions is recommended.

Magnetic resonance imaging (MRI) of the spine was used in 37 infants and children to assess the potential of this new technology to evaluate suspected lumbosacral dysraphic myelodysplasia. Eighteen of these patients had correlative metrizamide myelotomography and metrizamide computed tomography (CT). MRI using a spin-echo pulse sequence with short repetition times (TR) and echo delay times (TE) affords optimal delineation of normal and abnormal spinal cord morphology in the lumbosacral region. Coronal projections usually provide an adequate demonstration of the normal conus medullaris for screening purposes; however, multiplanar acquisitions are necessary for more complete delineation of the dysraphic myelopathy. The sensitivity of MRI compares favorably with metrizamide tomography and CT, although these procedures provide somewhat better specificity. These results suggest that MRI is a reliable, noninvasive procedure to screen patients for lumbosacral dysraphism.

In order to determine the frequency and natural history of benign extracerebral fluid collections, computed tomography reports from a period of 26 months at Oklahoma Children's Memorial Hospital were reviewed (total scans: 3,411). Bilateral frontal extracerebral fluid collections were found in 94 infants under 1 year of age. Eighty-two infants had computed tomography scans as part of the evaluation for macrocrania. Thirteen patients had the typical findings of benign extracerebral fluid collections but otherwise were completely asymptomatic. Longitudinal observation for up to 30 months failed to reveal any changes in neurologic status of these patients. Benign extracerebral fluid collections are a relatively common cause of macrocrania in infants. The presence of these fluid collections is not of immediate concern, providing that clinical evaluations fail to identify either neurologic or developmental abnormalities.

Magnetic Resonance Imaging (MRI) was compared with computerized tomography (CT) in 40 pediatric and adolescent patients with intracranial mass lesions as part of an ongoing project to determine the potential of MRI as a primary and definitive imaging modality. Multiplanar, multisequence MRI surpassed CT in providing mass localization, extent of involvement, and delineating the relationship to adjacent vital structures. Further development of MRI is encouraged to overcome current inconsistencies in pathologic characterization in order for this new technology to be employed not only as a primary screening modality but also as a definitive diagnostic test.

Neurologic impairment and sacral spinal anomalies are a finding in children with imperforate anus. The neurologic deficits previously had been considered static rather than progressive. Recent experience at this institution has documented the frequent association of imperforate anus patients having bony sacral and other spinal deformities with progressive neurologic dysfunction. These deficits are related to underlying spinal cord anomalies, which may be amenable to neurosurgical correction. To investigate the nature and frequency of such lesions, spinal cord imaging was done in these patients. From July 1976 to June 1985, 106 patients with imperforate anus were screened with plain radiographs of the sacral spine; 37 (35%) patients had abnormalities. Of these, 26 have been evaluated with a variety of spinal cord imaging techniques, including magnetic resonance imaging (18), digital metrizamide myelotomography (14), computed tomography (10), metrizamide myelography (5), or ultrasound (4). Four patients were lost to follow-up, and seven have not yet been studied. Fifteen of the 26 patients (53%) had one or more abnormal studies. Thirteen were considered to have progressive dysfunction with operable lesions and have undergone neurosurgical correction. At follow-up, there was improved leg function in five patients and improved bladder function in two patients. No patient had additional neurologic deficits after surgery. Because of the high incidence of progressive but potentially correctable myelodysplasias in patients with coexisting anorectal and sacral anomalies, routine radiographic screening of the spine is recommended, followed by spinal cord imaging and neurosurgical evaluation if warranted.

Eight infants with radiographic and bone biopsy evidence of autosomal recessive osteopetrosis were evaluated by cranial CT. The clinical presentations and CT characteristics support the theory that this disorder exhibits severe and mild variants. At an early stage the severe variant demonstrates small optic canals, small orbits with proptosis, and a small nasoethmoid complex without significant bone thickening. The paranasal sinuses show bud formation but no pneumatization. The temporal bone retains a fetal appearance with trumpet-shaped internal auditory canals, prominent subarcuate fossae, and no mastoid pneumatization. The ventricles and subarachnoid spaces are enlarged. Bone thickness increases with age, leading to further orbital encroachment. Similar but less severe features are present in the mild variant. Underdevelopment of the orbits, nasoethmoid complex, and temporal bone suggests that delayed maturation is the primary morphologic abnormality of the skull base in osteopetrosis, and that bone thickening is a secondary manifestation caused by reduced bone turnover.

A standard nuclear medicine computer system was modified to accept video input and utilized to perform digital intravenous and intra-arterial angiography, substration of CT images and enhance ultrasound images as well as to read video and magnetic tape. This system provides greater versatility and adaptability than presently conceptualized and produced digital systems and deserves further evaluation as a multipurpose imaging device.

Colpocephaly is an abnormal enlargement of the occipital horn of the lateral ventricle, also described as persistence of the fetal configuration of the lateral ventricles. Since it was first described, colpocephaly has been found in association with a number of abnormalities of the brain. In order to determine the frequency of this ventricular configuration at our hospital, we reviewed 3,411 computed tomographic (CT) scans done over a 26-month period. Fourteen cases were identified in which the CT scan had the appearance of colpocephaly. These CT scans were performed during the evaluation of a number of different clinical problems. Agenesis of the corpus callosum was the most frequently associated malformation. The types of malformations commonly associated with colpocephaly suggest that colpocephaly is merely a marker of disordered brain formation and that insults occurring anytime between one and four months of gestation may result in this anomaly.