Richard B. Schwartz

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OBJECTIVE A major shortcoming of image-guided navigational systems is the use of preoperatively acquired image data, which does not account for intraoperative changes in brain morphology. The occurrence of these surgically induced volumetric deformations ("brain shift") has been well established. Maximal measurements for surface and midline shifts have been(More)
The signal decay with increasing b-factor at fixed echo time from brain tissue in vivo has been measured using a line scan Stejskal-Tanner spin echo diffusion approach in eight healthy adult volunteers. The use of a 175 ms echo time and maximum gradient strengths of 10 mT/m allowed 64 b-factors to be sampled, ranging from 5 to 6000 s/ mm2, a maximum some(More)
OBJECTIVE The neurotoxic effects of cyclosporine therapy are well known but poorly understood. Imaging studies typically show subcortical edema predominantly affecting the posterior regions of the brain. We sought to determine the causes for these findings by comparing radiographic data with various clinical parameters. MATERIALS AND METHODS In a 3-year(More)
BACKGROUND No age-adjusted or histologic-adjusted assessments of the association between extent of resection and risk of either recurrence or death exist for neurosurgical patients who undergo resection of low-grade glioma using intraoperative magnetic resonance image (MRI) guidance. METHODS The current data included 156 patients who underwent surgical(More)
OBJECTIVE We describe the development and implementation of a new open configuration magnetic resonance imaging (MRI) system, with which neurosurgical procedures can be performed using image guidance. Our initial neurosurgical experience consists of 140 cases, including 63 stereotactic biopsies, 16 cyst drainages, 55 craniotomies, 3 thermal ablations, and 3(More)
Hypertensive encephalopathy is a syndrome consisting of headache, seizures, visual changes, and other neurologic disturbances in patients with elevated systemic blood pressure. The purpose of this study was to analyze the imaging findings in 14 patients with hypertensive encephalopathy. CT (n = 13), MR (n = 12), and single-photon emission computed(More)
PURPOSE To investigate the clinical parameters that are associated with the development of brain edema of hypertensive encephalopathy in patients with preeclampsia-eclampsia. MATERIALS AND METHODS Twenty-eight patients with preeclampsia-eclampsia and neurologic symptoms underwent magnetic resonance (MR) imaging. Clinical parameters recorded at the time of(More)
BACKGROUND Hypertensive encephalopathy (HTE) is a syndrome typified by headache, seizures, and neurologic signs associated with increased systemic blood pressures; edema in the subcortical white matter is seen on imaging studies and is usually reversible, although infarction or hemorrhage may supervene. Based on previous work, we theorize that HTE is(More)
PURPOSE To review preliminary experience with an open-bore magnetic resonance (MR) imaging system for guidance in intracranial surgical procedures. MATERIALS AND METHODS A vertically oriented, open-configuration 0.5-T MR imager was housed in a sterile procedure room. Receive and transmit surface coils were wrapped around the patient's head, and images(More)
PURPOSE Hypertensive encephalopathy, a complex of cerebral disorders, including headache, seizures, visual disturbances, and other neurologic manifestations, is associated with a variety of conditions in which blood pressure rises acutely. It has been ascribed to either exuberant vasospasm with ischemia/infarction or breakthrough of autoregulation with(More)