Biomedical subjects
Publications and source records attributed to B S Brooks.
CT scans of 70 patients with seizures and 48 patients with headaches were studied. Using accepted CT criteria for the diagnosis of cerebellar atrophy, the films were analyzed in a blind, unbiased fashion to evaluate possible relationship between cerebellar atrophy and phenytoin use or epilepsy itself. We found no evidence that either phenytoin or epilepsy caused cerebellar atrophy.
Cranial computed tomography (CT) is an extremely useful diagnostic modality in the evaluation and follow-up of children undergoing treatment for metastatic neuroblastoma. Information regarding the location, extent of the cranial metastatic lesions, and their response to treatment was provided by sequential CT examinations in three patients. Computed tomography showed nonneoplastic lesions in four patients treated by parenteral chemotherapy alone using vincristine and Cytoxan. We postulate that these lesions were neurotoxic sequelae of the prolonged chemotherapy.
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Increasing experience with computed tomographic evaluation of head trauma reveals this radiologic modality to be superior to conventional polytomography in the assessment of certain areas of maxillofacial injury. A comparison of hypocycloidal polytomography and computed tomography in nine patients with fractures of the medial wall of the orbit reveals CT to be superior in localization of the fracture site, delineation of displaced bone fragments, and recognition of herniation of intraorbital contents into the ethmoid labyrinth. Information regarding damage to the nasolacrimal duct and associated intraorbital abnormalities such as the presence and location of hemorrhage and foreign bodies is also available from the CT scan.
Metastasis of pineal germinoma to the peritoneal cavity via the patient's ventriculoperitoneal shunt represents an unusual complication of this rare tumor. We report such a case with autopsy correlation of the abdominal CT findings. CT accurately delineated the extent of the metastatic mass and revealed associated complications including biliary tract obstruction, thrombosis of the inferior vena cava and a small amount of ascitic fluid. Since this tumor is very sensitive to radiotherapy and chemotherapy, the need for early detection of such metastasis is apparent. Possible implications with respect to the management of these patients are considered.
Primitive neuroectodermal tumors (PNETs) are highly cellular primitive CNS neoplasms that resemble microscopically the undifferentiated cells of the germinal matrix of the primitive neural tube. These tumors exhibit a highly malignant behavior with a tendency to disseminate along the CSF pathways. Previous descriptions of the neuroradiological findings in patients with PNET were published prior to the clinical application of magnetic resonance (MR) imaging. We describe our experience with the MR evaluation of four patients with pathologically proven PNET.
Detailed neurologic studies, high-field-strength MR imaging, and CT scanning were performed preoperatively in 53 patients with intractable complex partial seizures who underwent surgical treatment for epilepsy. Macroscopic structural (tumoral or vascular) lesions were found in 28% of patients. The remainder had pathologic findings consistent with mesial temporal gliosis. Tumors were found in 22% of the patients and were benign or of low-grade malignancy in every case. MR was accurate in the preoperative diagnosis of structural lesions, including very small occult tumors and cryptic vascular malformations. In patients with mesial temporal gliosis, there was correlation between the MR observation of a unilaterally dilated anterior temporal horn and the EEG-identified seizure focus and side of temporal lobectomy. However, MR demonstrated T2-weighted signal abnormalities correlating with the epileptogenic focus in only 8% of cases of mesial temporal gliosis. MR provided useful information in 28% of patients who underwent surgery for refractory complex partial epilepsy. MR obviated invasive EEG monitoring in 93% of the patients with structural lesions. MR was useful in only 8% of the patients with pathologic changes of mesial temporal gliosis.
High-field-strength MR studies of 13 patients with sellar and/or parasellar tumors revealed an aberrant location of the posterior pituitary bright signal in the hypothalamus in seven cases and in relation to the pituitary infundibulum in six cases. Five of the MR studies were obtained in patients who had not had surgery and had pituitary adenomas producing compression and/or destruction of the posterior lobe. In the other eight cases, the aberrant bright signal occurred after hypophysectomy in seven patients and after removal of a craniopharyngioma in the eighth. Accumulation of neurosecretory material and regeneration of pituitary tissue in these ectopic locations have been documented previously in animal experiments and in a few reports in humans after hypophysectomy. MR imaging now provides further corroborative evidence in vivo of this process in which a "miniature posterior lobe" is formed.
Sagittal T1-weighted series with 3-mm sections have routinely been used for all cranial MR studies at our institution. It was apparent from examining these studies that the rate of occurrence of a normal posterior pituitary bright signal was lower than has been previously reported, particularly in older patients. This prompted both a retrospective and a prospective review and analysis of the posterior lobe bright signal in three patient categories. The overall frequency of posterior pituitary bright signal and the influence of sex and age were evaluated in one category. An age-related statistically significant decline in the frequency of posterior pituitary bright signal was found, with a decline rate of approximately 1% per year. An evaluation of the occurrence of anatomic variation in the location of posterior lobe bright signal was made in a second group of 1500 patients. Aberrant location of the posterior lobe was found to be uncommon and was seen most frequently in patients with a sellar fossula. Temporal variation in the presence or absence and size of the posterior lobe bright signal was evaluated in a third group of 36 patients who had at least two MR examinations available for review. Follow-up MR study showed an obvious posterior lobe bright signal in 8% of these patients for whom no bright signal was apparent at the time of initial examination. Loss of the posterior lobe bright signal was apparent in another 25% of patients. A significant change in size of the bright signal was apparent in 19% of patients within this category. Our results indicate that variation in the bright signal of the posterior pituitary lobe should be expected as a normal physiological occurrence.
Stroke is a common complication of sickle cell disease. Using MR and CT, we studied 10 patients with sickle cell disease and a history of stroke and compared these findings with those of 10 sickle cell patients without stroke. The purpose was to determine if MR could visualize the large vessel vasculopathy previously seen on angiography and to estimate the incidence of asymptomatic abnormalities in the nonstroke group. MR consistently demonstrated the major intracranial arteries and showed three cases with occlusion and three with stenosis of either the internal carotid or middle cerebral arteries. Infarctions were better delineated on MR but were also seen on CT. Seven cases with and two without stroke had high-signal white matter lesions on MR. Further research using cranial MR to develop noninvasive means of identifying sickle cell patients at risk for stroke is warranted.
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Comparison of metrizamide and iohexol contrast media for myelography performed via lateral C1-C2 puncture in a total of 64 patients demonstrated superiority of iohexol with respect to the incidence of postprocedure adverse reactions. There was no significant difference between the two media in quality of radiographic demonstration in the cervical region. Patients in whom posterior fossa positive-contrast radiographic examinations were performed at the same time as myelography, using either water-soluble agent, did not demonstrate any increased incidence of side effects over those having myelography alone.
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A modified technique for performing Amipaque myelocisternography is described and results obtained in the first 100 patients are analyzed. Diagnostic quality examinations were obtained in 90% of patients in whom the technique was employed. The complication rate was comparable to studies using C1-C2 puncture and to other reports using Amipaque contrast medium. This examination is valuable for high cervical and craniocervical junction lesions, cervical cord atrophy or enlargement, cerebellar ectopia, lower cranial nerve neuropathies, and cerebellopontine angle problems, especially the early detection of small acoustic neurinomas.
In the past, neurologic deficits found in association with sacral agenesis were thought to be unamenable to surgical therapy. Recent experience and a careful review of autopsy and case reports form the literature have demonstrated that this assumption is unwarranted. Four cases of sacral agenesis are reported with description of the myelographic findings of each case. Surgical confirmation was obtained in three of these patients. Dural sac stenosis treated with duraplasty resulted in striking improvement in the neurologic status of two patients, while in the third, a 2-month-old infant, adhesive arachnoidal bands in the distal thecal sac were found at surgery and a taut and thickened filum terminale was transected. The fourth patient has a low-lying spinal cord and a posterior meningocele. The myelographic findings appear to be divisible into two categories. One group of patients may have high termination of the subarachnoid space with a dural sac stenosis and will benefit from duraplasty, while in the other, findings may include a widened or normal subarachnoid space and low-lying tethered spinal cord. It is emphasized that treatment of dural sac stenosis, tethered cord, and intrathecal or extrathecal masses that occur in some of these patients may afford significant improvement in their neurologic condition. These children deserve careful baseline neurologic evaluation and follow-up and a more aggressive approach toward adequate myelographic assessment.