Terminal myelocystoceles constitute approximately 5% of skin-covered lumbosacral masses and are especially common in patients with cloacal exstrophy. Pathologically, terminal myelocystocele consists of (a) a skin-covered lumbosacral spina bifida (b) an arachnoid-lined meninogocele that is directly continuous with the spinal subarachnoid space; and (c) a low-lying, hydromyelic spinal cord that traverses the meningocele and then expands into a large terminal cyst. The terminal cyst bulges into the extraarachnoid compartment caudal to the meningocele and forms a distal sac that does not communicate with the subarachnoid space. The terminal cyst is lined by ependyma and dysplastic glia, is directly continuous with the dilated central canal of the cord, and probably represents a ballooned terminal ventricle. Patients with terminal myelocystocele have normal intellectual potential and are usually born without neurological deficit, so these defects must be identified and repaired early, before the onset or progression of lower extremity pareses. (Neurosurgery 16:36-43, 1985)
We too have become concerned with the sensitivity of CT for the diagnosis of subarachnoid hemorrhage. The initial draft of our communication was written 16 months before publication and expressed great enthusiasm for CT diagnosis of subarachnoid hemorrhage. At revision of the proofs six months ago, this enthusiasm was tempered conspicuously to a bare statement citing the results of Scotti et al. Since that time, we, in addition to Christopher Moran, MD, and Mokhtar Gado, MD, have reviewed a small series of 31 patients in whom CT and lumbar puncture were performed within a short time of each other and both within the first two days of initial clinical signs and symptoms of subarachnoid hemorrhage. Computerized tomography successfully detected subarachnoid hemorrhage in 27 (87%) of 31 cases; however, it failed to demonstrate the subarachnoid hemorrhage in four (13%) of the patients, including some with grossly bloody CSF at
*Department of Radiology, Montefiore Hospital and Medical Center, Bronx, New York **Department of Radiology, New York University Medical Center, New York, New York.
Direct sagittal computed tomography (CT) was performed on 47 children with pathology in the posterior fossa, orbit, parasellar region, face and ear. The direct sagittal projection provided additional information about the extent of disease and relationship of the pathologic process to the adjacent tissues in 43% of patients studied. Direct sagittal CT has improved spatial resolution over reformatted images. It is readily available, less costly than magnetic resonance and can provide similar useful anatomic information.
Many lesions that are found within the sella may be cystic in nature. The differential diagnosis for such lesions includes craniopharyngioma, Rathke's cleft cyst, cystic pituitary adenoma, and arachnoid cyst. This chapter describes the evaluation and management of patients who present with these sometimes troublesome lesions.
Improvements in ultrasound (US) equipment now permit display of anatomic structures not previously shown. Correlation of US images of the posterior fossa with gross and myelin-stained sections of the human brain illuminates the nature of the structures displayed sonographically.
