Precise placement of sphenoidal electrodes via fluoroscopic guidance.

Fluoroscopically guided placement of sphenoidal electrodes for the assessment of epileptiform activity in the mesial-basal-temporal lobes offers distinct advantages over standard techniques, such as more precision in placement, reduced likelihood of facial pain, and fewer complications (vessel perforation or nerve injury). We describe our instrumentation, technique, and results in over 40 patients.

Complications of sublaminar wiring.

Complications of sublaminar wiring are reported, including four cases that involved the cervical spine and one case that included the thoracolumbar spine. The complication rate at our institution involving the cervical spine was about 7% and less than 1% for the thoracic spine. A direct correlation exists between the degree of anterior bowing, number of consecutive laminae the wire passes beneath, and the complication rate. The clinical presentations, radiologic findings, and indications for surgical removal of the wires are discussed. To our knowledge, nothing has been reported in the literature regarding the complications caused by sublaminar wiring of consecutive vertebrae.

CNS complications of AIDS: CT and MR findings.

AIDS is now a common disease, seen daily in large metropolitan medical centers. Neuroimaging techniques such as CT and MR are critical to the detection and diagnosis of CNS complications. Intracerebral infections are common. These infections frequently are caused by opportunistic organisms; less commonly, they are bacterial infections. The cranial imaging features on CT and MR are not pathognomonic, but their distribution or appearance (e.g., asymmetric target lesions of toxoplasmosis) may have predictive value in a known AIDS patient. The superior contrast resolution of MR makes it a more sensitive cross-sectional imaging tool for evaluating intracerebral abnormalities associated with a variety of infectious processes. Differential diagnoses still include metastatic disease, lymphoma, and infarcts. When MR is used as the initial cross-sectional imaging study, contrast-enhanced CT may still be necessary to further characterize a lesion. Currently, more experience exists with CT for follow-up of the AIDS patient with CNS manifestations. MR, particularly with gadolinium-DTPA as a contrast medium, will probably become the imaging method of choice.

Computed tomography of gliomatosis cerebri.

Gliomatosis cerebri, a rare diffusely infiltrating astrocytoma, was discovered on the postmortem examination of a 22-year-old woman with a 13 year history of seizures. Computed tomography of the brain revealed bifrontal white matter low density changes that were most consistent with a demyelinating or dysmyelinating disorder.

CT demonstration of cervical diastematomyelia.

Cervical diastematomyelia, a rare anomaly, was found in a 14-year-old girl with congenital scoliosis. Metrizamide myelography and metrizamide CT demonstrated anomalies of the cervical spine and a split cervical cord within a single dural tube, without the presence of a fibrous, cartilaginous, or bony spur.

Magnetic resonance imaging compared with computed tomography in adrenoleukodystrophy.

Adrenoleukodystrophy was diagnosed in two siblings and confirmed by analysis of very-long-chain fatty acids in skin fibroblasts. Both boys had computed tomograms (CTs) and magnetic resonance imaging (MRI) of the brain. In the most severely affected child, the CT and MRI examinations were both abnormal, but in the other child, the CT was mildly abnormal but the MRI was unequivocally abnormal. This suggests that MRI is more sensitive than CT in detecting the acute demyelinating changes of adrenoleukodystrophy and, in conjunction with very-long-chain fatty acid analysis, should be useful in screening unaffected or mildly affected siblings of patients with this disease.

Use of cerebral oximetry to monitor brain oxygenation reserves for skull base surgery.

We used cerebral oximetry based on near-infrared re-emittance spectroscopy for noninvasive evaluation of the cerebral regional oxygen saturation (rSO(2)) to preoperatively assess patients with skull base tumors and giant arterial aneurysms, for whom possible occlusion or partial resection of the internal carotid artery was considered. Monitoring cerebral oxygen saturation was performed during both endovascular (balloon) and open surgical test occlusions of the internal carotid artery. The presence (or absence) of changes in the cerebral oxygen saturation served as a criterion of the patient's tolerance to permanent occlusion of the internal carotid artery. In all cases the curves of saturation accurately corresponded to the clinical condition of the patients, primarily to the developing of neurological signs. Cerebral oximetry was an extremely informative and reliable technique for fast, easy, and noninvasive detection of changes in brain blood circulation. Generally, cerebral oximetry serves as a valuable adjunct in detection of brain tolerance to the occlusion of major arterial vessels and in monitoring the condition of the brain in regard to its oxygenation and perfusion.

Multiple cerebral metastases: detectability with Gd-DTPA-enhanced MR imaging.

Sixteen patients with suspected cerebral metastases were studied with magnetic resonance (MR) imaging before and after the intravenous administration of 0.1 mmol/kg of gadolinium diethylenetriaminepenta-acetic acid. The images were interpreted blindly by two neuroradiologists; all clinical, radiologic (computed tomographic and MR imaging), and pathologic data were reviewed to arrive at a final "best diagnosis," which was then compared with the prior blinded interpretations. Of seven patients found to have multiple metastases, six (86%) had at least one tumor nodule depicted by postinfusion MR imaging that was missed by one or both observers on review of preinfusion images alone. Lesions missed on preinfusion studies were usually small nodules hidden by or not detected next to regions of high-signal edema thought to be related to the adjacent tumor nodule. The authors believe that contrast enhancement improves detection of metastatic foci with MR imaging and that the findings indicate broader implications for the detection of multiple lesions from other causes.

The magnetic resonance hypointense spine of AIDS.

The T1-weighted magnetic resonance examinations in 11 acquired immunodeficiency syndrome patients showed substantial reduction in signal intensity of vertebral bodies. Review of bone marrow aspirates and biopsies that were available in eight patients suggested that the abnormality resulted from markedly increased amounts of storage iron within the bone marrow, probably secondary to the anemia of chronic disease.