Vascular territories and watersheds: a zonal frequency analysis of the gyral and sulcal extent of cerebral infarcts. Part I: the anatomic template.

Our purpose was to establish a template of upper cerebral anatomy suitable for analysis of infarct distribution and for comparison among infarct types. We made a standard diagram of the key gyri and sulci of the supraventricular and occipital regions, partitioned the gray matter and white matter into specific zones useful for analyzing infarcts by CT and MRI, and numbered each zone uniquely in to establish a template suitable for tabulating the precise regions affected by each infarct and for analyzing differences among infarcts. The template provides a method for extracting a standardized set of data from CT or MRI performed at any angle, reconfiguring those data into a standard image, and characterizing the specific portions of infarcted brain in terms of unique numbers suitable for tabulation, collation and comparison. Standardization of the format provides for later computer analysis of increasing numbers of diverse infarcts. This method may be extended to any other type of pathology, although successful analysis of different lesions may require partitioning the gray and white matter zones in different ways.

Magnetic resonance imaging of intracranial hypotension syndrome with pathophysiological correlation.

OBJECTIVE: To correlate the pathophysiology of intracranial hypotension syndrome with abnormalities in the brain and spine found through magnetic resonance imaging. METHODS: In a series of 11 patients with intracranial hypotension syndrome, brain magnetic resonance scans were evaluated for the thickness, distribution, morphology, and pattern of meningeal enhancement coincident with subdural fluid collections and the descent of the brain toward the skull base. Spinal magnetic resonance studies were reviewed for extra-arachnoid fluid collections, meningeal enhancement, and distended epidural veins. RESULTS: Diffuse, continuous dural-arachnoid enhancement was present in all patients with abnormal brain studies. The dura was thickest in patients with very low intracranial pressures. Subdural fluid collections and descent of the brain were seen in patients with the thickest meninges and were not present in the absence of meningeal enhancement. Extra-arachnoid or paraspinal fluid collections were found in all patients who had spinal magnetic resonance scans. CONCLUSIONS: In the brain, diffuse dural-arachnoid enhancement is the most common imaging abnormality and is probably the earliest magnetic resonance manifestation of intracranial hypotension syndrome, while subdural fluid collections and descent of the brain are indicators of a more severe hypotensive state. Extra-arachnoid fluid collections are common spinal imaging abnormalities.

MR of Toxoplasma encephalitis: signal characteristics on T2-weighted images and pathologic correlation.

PURPOSE: Our goal was to determine if there are any T2-weighted MR signal characteristics of Toxoplasma encephalitis that might be useful in diagnosis and/or in gauging the effectiveness of medical therapy. METHOD: We retrospectively analyzed the MR, CT, thallium-201 SPECT brain scans, and medical records of 27 patients with medically proven (26) and biopsy proven (1) Toxoplasma encephalitis, supplemented by autopsy findings in 4 additional patients, 2 of whom had postmortem MR correlation. The neuropathologic literature was also reviewed. RESULTS: Among the 27 patients, we discovered three distinct imaging patterns. Ten (37%) patients had predominantly T2-weighted hyperintense lesions and had been on medical therapy an average of 3 days (excluding one outlier). Ten (37%) patients had T2-weighted isointense lesions and had received medical therapy an average of 61 days. Seven (26%) patients had lesions with mixed signal on T2-weighted images and had been on treatment an average of 6 days. Analysis of autopsy material from the four additional patients revealed the presence of organizing abscesses in three and necrotizing encephalitis in one, while the patient who had a brain biopsy demonstrated both types of pathologic lesions. In both cases having postmortem MRI, organizing abscesses appeared isointense to hypointense on T2-weighted images. CONCLUSION: There is a definite variation in the appearance of lesions of Toxoplasma encephalitis on T2-weighted images that precludes a definitive diagnosis based on signal characteristics alone. Pathologically, our data suggest that T2-weighted hyperintensity correlates with necrotizing encephalitis and T2-weighted isointensity with organizing abscesses. Furthermore, in patients on medical therapy the T2-weighted MR appearance may be a transition from hyperintensity to isointensity as a function of a positive response to antibiotic treatment, indicating that the signal change might be used to gauge the effectiveness of medical therapy.

Neurosyphilis in HIV-positive and HIV-negative patients: neuroimaging findings.

PURPOSE: To evaluate and describe the neuroimaging findings of patients with neurosyphilis. METHODS: The neuroimaging studies of 35 patients with documented neurosyphilis were reviewed. Diagnosis was established in 34 patients with cerebrospinal fluid for a Venereal Disease Research Laboratory test, complemented by autopsy in 1 and brain biopsy in 1. All patients had reactive fluorescent treponemal antibody tests with absorption in their sera. Imaging studies included plain and contrast-enhanced CT of the brain, plain and gadolinium-enhanced MR, MR angiography, and conventional angiography. Imaging findings were also correlated with the relevant pathologic findings at autopsy in three additional patients with neurosyphilis who did not have brain imaging studies. RESULTS: Of the 35 patients with imaging studies, 32 tested human immunodeficiency virus (HIV)-seropositive, and 3 were HIV-seronegative. Eleven (31%) of 35 patients had normal radiographic findings. Cerebral infarctions were seen in 8 (23%) of 35 patients, and nonspecific white matter lesions in 7 (20%) of 35. Cerebral gummas and extraaxial enhancement indicating meningitis were noted in 2 (6%) of 35 patients, respectively. Arteritis was demonstrated in 2 (50%) of 4 patients who underwent either MR angiography or conventional angiography. The 3 subjects who had autopsy but not imaging studies were found to have manifestations of meningovascular syphilis, including syphilitic leptomeningitis and an obliterative endarteritis. CONCLUSION: We conclude that findings of vascular occlusive disease manifested as infarction or arteritis, enhancing cortical lesions with or without adjacent meningeal enhancement, focal or diffuse extraaxial enhancement, and white matter disease, although nonspecific, in the proper clinical setting should prompt appropriate testing for neurosyphilis, a treatable disease, in patients with and without HIV infection.

Normal magnetic resonance imaging and abnormal discography in lumbar disc disruption.

STUDY DESIGN: This report describes a clinical series of seven patients who had surgically proven internal disc disruption, normal magnetic resonance imaging, and abnormal discograms morphologically. SUMMARY OF BACKGROUND DATA: Numerous reports in the literature have described the utility of magnetic resonance imaging and discography in diagnosing degenerative disease within lumbar intervertebral discs. RESULTS: Discography may be useful in patients with persistent symptoms despite a normal or equivocal magnetic resonance imaging study.

Waste disposal tangled by liability and conflicting regulations.

In this issue HMM examines the problem of trash disposal. What are hospitals doing with their wastes? In many areas landfills are either running out of space or increasingly unwilling to accept hospital wastes. The next HMM Price Exclusive will survey the prices materials managers are paying for wound closures. Read the next HMM Price Exclusive and see what kinds of contracts and deals materials managers are getting for these important supplies.

Exam glove shortage leaves MMs searching for supplies.

In this issue HMM examines the impact of AIDS on the price and availability of disposable gloves. Materials managers are facing higher prices and uncertain supplies as more and more health care workers use gloves and other protective apparel.