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We reviewed the records of 70 consecutive adult patients with meningitis after a neurosurgical procedure, to determine the characteristics that might help to distinguish a sterile postoperative chemical meningitis from bacterial infection. The spinal fluid profiles in bacterial and chemical meningitis are similar. The exceptions are that a spinal fluid white blood cell count > 7500/microL (7500 x 10(6)/L) and a glucose level of < 10 mg/dL were not found in any case of chemical meningitis. The clinical setting and clinical manifestations were distinct enough that no antibiotic was administered after lumbar puncture to 30 (43%) of the 70 patients with postoperative meningitis. Chemical meningitis was infrequent after surgery involving the spine and sinuses. Patients with chemical meningitis did not have purulent wound drainage or significant wound erythema or tenderness, coma, new focal neurological findings, or onset of a new seizure disorder. They rarely had temperatures > 39.4 degrees C or cerebrospinal fluid rhinorrhea or otorrhea.

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We performed percutaneous CT-guided needle biopsies with a transfacial approach in the diagnosis of lesions of the parapharyngeal region. Via the buccal space, core needle biopsy specimens were obtained in eight patients with known parapharyngeal abnormalities identified by CT and/or MR imaging. In all cases, sufficient tissue was obtained to provide a definitive histologic diagnosis. There were no significant complications. This approach provides a reliable method for evaluation of parapharyngeal lesions.

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A patient received an overdose of intravascular contrast medium and experienced protracted seizures associated with radiographic evidence of prolonged retention of the contrast agent in the cerebral cortex, basal ganglia, and thalami. This is only the second report and the first survivor of a similar neurologic syndrome occurring in a patient after contrast agent overdose. After the seizures resolved, there was a transient period of parkinsonism probably due to the toxic effect of contrast on the basal ganglia.

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PURPOSE: To study the role of Gd-DTPA in cranial MR of patients with Sturge-Weber syndrome. METHODS AND MATERIALS: Seven patients with Sturge-Weber syndrome, ages 3 months to 36 years, were evaluated with unenhanced and contrast-enhanced (Gd-DTPA) MR imaging. Correlation was made to cranial CT in five patients. RESULTS: MR findings included (in decreasing frequency): pial angiomatosis, cerebral atrophy, decrease in cortical veins, enlargement of deep veins, enlargement of choroid plexus, and parenchymal calcification. Contrast MR imaging was essential in diagnosis in four cases in which cranial CT, unenhanced MR, or angiography was normal or demonstrated nonspecific abnormalities. Pial angiomatosis with adjacent cerebral atrophy were the only consistent radiographic abnormalities. CONCLUSION: In all patients, contrast MR demonstrated the radiographic spectrum of central nervous system abnormalities in Sturge-Weber syndrome to a greater degree than unenhanced MR or CT and may represent the method of diagnosis in these patients. Demonstration of the pial angioma on contrast MR should be considered the most important criterion for the radiographic diagnosis of Sturge-Weber syndrome.

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Computed tomography (CT) and magnetic resonance (MR) imaging have dramatically improved the ability to visualize the deep gray structures of the basal ganglia (primarily, the caudate nucleus, putamen, and globus pallidus). Any process that alters cerebral metabolism can lead to basal ganglia damage. This article presents the spectrum of disease that may be seen with bilateral basal ganglia abnormalities in the pediatric population. A simplified approach to the differential diagnosis of these entities is based on acute versus chronic conditions and radiologic manifestations. Acute processes include hypoxia, hypoglycemia, carbon monoxide poisoning, hemolytic-uremic syndrome, osmotic myelinolysis, and encephalitis. Chronic conditions include inherited ("inborn errors of metabolism," Huntington disease, and dysmyelinating diseases) or acquired (sequelae of acute disorders) conditions that represent abnormal biochemical or structural processes within the basal ganglia. Elimination of acute causes gives little hope for improvement. Recognition of chronic disorders is important for counseling purposes, since most of these conditions have specific patterns of inheritance.

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Osmotic myelinolysis is a distinctive clinical syndrome with characteristic MR features in the central pons (central pontine myelinolysis) and in other locations (extrapontine myelinolysis). We describe the resolving MR features in an adolescent who has experienced complete neurologic recovery. Regions of involvement manifested increased T2 signal intensity. The extrapontine involvement was noted to resolve earlier with interim-increased T1-weighted signal. The mechanism for the variable appearance of increased T1 signal intensity is discussed.

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The cause of adolescent idiopathic scoliosis remains an enigma. Several studies have demonstrated abnormalities of posture, proprioception, and equilibrium control in patients with adolescent idiopathic scoliosis. These functions are integrated by structures in and around the brain stem. Twenty-seven patients with adolescent idiopathic scoliosis were studied with magnetic resonance imaging to delineate the anatomy of the brain stem in such patients. Imaging was conducted from the hypothalamus to the spinal cord at C3 in 26 patients; the remaining patient underwent an incomplete study because of a claustrophobic reaction. The study group consisted of 25 females and 2 males with an average age of 16 + 5 years. There were 19 right thoracic curves, 5 thoracolumbar curves, and 3 left lumbar curves. The mean primary curve size was 27 degrees at the most recent clinical evaluation. Seven patients were treated with observation, 14 with bracing, and 6 with surgery. The magnetic resonance imaging studies were read independently by three attending radiologists in a randomized, blinded fashion along with the magnetic resonance imaging studies of 11 controls. Asymmetry in the ventral pons or medulla in the area of the corticospinal tracts was noted in seven study patients and one control; one study patient had an enlarged cisterna magna and one an inconclusive (incomplete) study. These findings may support previous studies that have suggested a central nervous system abnormality as a cause of adolescent idiopathic scoliosis.

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Small cell lung cancer is an aggressive neoplasm; metastases are detected in two-thirds of patients at diagnosis with use of conventional staging, which includes bilateral bone marrow biopsy, bone scintigraphy, and computed tomography (CT) of the head and abdomen. In 25 patients, small cell lung cancer was staged prospectively with both conventional staging and a magnetic resonance (MR) imaging protocol that included 1.5-T MR imaging of the pelvis, abdomen, spine, and brain. According to conventional staging, 14 patients had extensive disease and 11 patients had limited disease; according to staging with MR, 19 patients had extensive disease and six had limited disease. All metastatic disease sites seen with conventional staging were identified on MR images. MR images showed additional metastatic involvement in bone (four patients) and liver (three patients) not detected at conventional staging. A low-attenuation hepatic lesion on a CT scan was identified as a hemangioma on MR images. These preliminary data suggest that small cell lung cancer may be accurately staged with use of a single MR imaging study.

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The cavernous hemangioma (cavernoma) is increasingly recognized as a vascular malformation of the brain that may present with seizures, hemorrhage, or progressive neurological deficit. Since 1985 we have identified 13 cases of presumed cavernoma of the brain based on the findings on CT, selective angiography, and magnetic resonance (MR) imaging. In each case CT showed a high density lesion that was "occult" or "cryptic" on angiography. However, within all lesions MR revealed a complex internal structure consisting of reticulated patches of high and low intensity signal surrounded by a hypointense rim on T1- and T2-weighted pulse sequences. Of the nine operated cases, five resected specimens were compatible with pure arteriovenous malformations (AVMs), and the other four were mixtures of cavernoma with either AVM or venous angioma. Our experience strongly suggests that the above complex of radiographic findings is not at all specific for the cavernoma. We propose that the major common factor shared by such "cavernomatoid" malformations is low blood flow. We believe low flow lesions follow a relatively benign clinical course, and they readily lend themselves to surgical resection.

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Seven patients with suspected cerebral venous angioma studied by either CT or angiography were imaged with magnetic resonance. Six of seven cases demonstrated a stellate appearance on contrast enhanced CT. In two patients this finding was verified by angiography. Flow void was identified on both T1- and T2-weighted pulse sequences. In one patient a field echo sequence demonstrated high intensity signal within the venous angioma. Magnetic resonance proved superior to CT in the identification of these lesions. A stellate configuration with an emanating transcortical vein and centrifugal drainage (transcortical venous flow) from the angioma into a sinus was present in all cases. Centripetal drainage via thalamostriate and internal cerebral veins was not seen. There was no evidence of mass effect, scar, or hemorrhage. Four of the angiomas were located in a frontal lobe and three in a cerebellar hemisphere. This distribution of the lesions is similar to that reported in the literature in which the frontal lobe is the most common location followed by the cerebellar hemisphere. An embryological explanation is cited and supported by a review of the literature.

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Magnetic resonance (MR) imaging and CT were used in supporting the diagnosis of Leigh disease (subacute necrotizing encephalomyelopathy) in five patients. Two cases were confirmed at postmortem examination, and three patients have laboratory and/or clinical histories suggestive of Leigh disease. Four cases demonstrated findings in the basal ganglia, especially the putamina, with symmetrical areas of low attenuation on CT. Correspondingly, on proton saturation and T2-weighted pulse sequences, these areas showed high intensity signal characteristics by MR. Similar findings were noted in the caudate nucleus (two cases). Magnetic resonance proved to be superior to CT in establishing other areas of involvement: tectum and tegmentum (one case) and medullary olive (one case). Pathology identified these lesions as representing necrosis. Magnetic resonance may be diagnostic in the appropriate clinical setting.

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Both CT and MR can aid in the differentiation between benign and less favorable pediatric movement disorders. However, MR is the more sensitive imaging modality and thus preferable. This was demonstrated in 18 patients with conditions ranging from idiopathic dystonias to aminoacidopathies, Leigh's disease, and Hallervorden-Spatz disease. In the latter three entities characteristic lesions were shown in the basal ganglia, although not consistently. A specific diagnosis seems possible in Leigh's disease, provided the clinical setting is appropriate.

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Magnetic resonance imaging was used to define quantitatively the position of the cerebellar tonsils in the normal population and in patients with Chiari malformations. The average distance of the tonsillar tips from the foramen magnum was 2.9 +/- 3.4 mm above the foramen in 82 subjects without posterior fossa abnormality or increased intracranial pressure, and 10.3 +/- 4.6 mm below the foramen in 13 patients with Chiari malformations (p less than 0.005). Consequently, extension of the tonsils below the foramen magnum is considered normal up to 3 mm, borderline between 3 and 5 mm, and clearly pathologic when it exceeds 5 mm.

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