Publications by authors named "Robert Delapaz"

Objective: To assess whether early changes in enhancing tumor volume (eTV) and relative cerebral blood volume (rCBV) 1 month after convection-enhanced delivery of topotecan in patients with recurrent malignant glioma correlated with 6-month disease progression status.

Methods: Sixteen patients were enrolled in a Phase Ib trial of convection-enhanced delivery of topotecan for recurrent malignant glioma. Each patient was evaluated with serial follow-up magnetic resonance imaging at baseline and at 4- to 8-week intervals.

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Patients with acute uncomplicated Plasmodium falciparum malaria have no evident neurologic disorder, vital organ dysfunction, or other severe manifestations of infection. Nonetheless, parasitized erythrocytes cytoadhere to the endothelium throughout their microvasculature, especially within the brain. We aimed to determine if 3 Tesla magnetic resonance imaging studies could detect evidence of cerebral abnormalities in these patients.

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Purpose: Outcome evaluation in ocular adnexal lymphoma (OAL) is based on clinical assessment and conventional volumetric changes in tumor size. The purpose of this retrospective study was to compare if changes in apparent diffusion coefficient (ADC) tumor values obtained by diffusion-weighted MRI corresponded to changes in enhancing tumor volume in the evaluation of early treatment response or failure in patients with OAL.

Methods: A retrospective case series analysis of conventional contrast-enhanced orbital MRI and diffusion-weighted sequences was performed on 8 pathologically confirmed OAL tumors before and after therapy.

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Stroke is the sudden onset of focal neurologic symptoms due to ischemia or hemorrhage in the brain. Current FDA-approved clinical treatment of acute ischemic stroke involves the use of the intravenous thrombolytic agent recombinant tissue plasminogen activator given <3 hours after symptom onset, following the exclusion of intracerebral hemorrhage by a noncontrast CT scan. Advanced MRI, CT, and other techniques may confirm the stroke diagnosis and subtype, demonstrate lesion location, identify vascular occlusion, and guide other management decisions but, within the first 3 hours after ictus, should not delay or be used to withhold recombinant tissue plasminogen activator therapy after the exclusion of acute hemorrhage on noncontrast CT scans.

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Background: Convection-enhanced delivery of chemotherapeutics for the treatment of malignant glioma is a technique that delivers drugs directly into a tumor and the surrounding interstitium through continuous, low-grade positive-pressure infusion. This allows high local concentrations of drug while overcoming the limitations imposed by toxicity and the blood-brain barrier in systemic therapies that prevent the use of many potentially effective drugs.

Objective: To examine the safety profile of a conventional chemotherapeutic agent, topotecan, via convection-enhanced delivery in the treatment of recurrent malignant gliomas and secondarily to assess radiographic response and survival.

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In cerebral ischemia, measurement of cerebral blood flow (CBF) alone is not a sensitive or specific predictor of tissue survival. Measurements of oxygen metabolism, which are directly related to cellular energy metabolism, are better predictors of tissue survival and the best of these is the "oxygen extraction fraction" (OEF). Elevation of OEF in Stage 2 hemodynamic failure, or "misery" perfusion, indicates that prolongation of this state or further reduction in blood flow will lead to failure of oxygen metabolism and cellular necrosis,making it a sensitive and specific biomarker for the "ischemic penumbra" and a predictor of impending cerebral infarction.

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This paper describes an individual who was diagnosed with obsessive-compulsive disorder (OCD) and body dysmorphic disorder (BDD) at age 17 when education was discontinued. By age 19, he was housebound without social contacts except for parents. Adequate trials of three selective serotonin reuptake inhibitors, two with atypical neuroleptics, were ineffective.

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Purpose: To determine radiation doses from coronary computed tomographic (CT) angiography performed by using a 320-detector row volume scanner and evaluate how the effective dose depends on scan mode and the calculation method used.

Materials And Methods: Radiation doses from coronary CT angiography performed by using a volume scanner were determined by using metal-oxide-semiconductor field-effect transistor detectors positioned in an anthropomorphic phantom physically and radiographically simulating a male or female human. Organ and effective doses were determined for six scan modes, including both 64-row helical and 280-row volume scans.

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Pneumocephalus in the absence of a recent intracranial or intrathecal procedure is a significant radiographic finding and may be clinically relevant. Pneumocephalus secondary to intravenous catheterization may be a more common finding than previously expected. Although pneumocephalus is often associated with pathological conditions, recognition of a characteristic pattern of intravenous pneumocephalus in the presence of intravenous catheterization may aid the clinician in determining a patient's underlying condition.

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Object: Pediatric neurosurgeons are increasingly called on to provide prognostic data regarding the antenatal diagnosis of ventriculomegaly. This study was designed to determine if there is a correlation between prenatal MR imaging results and the need for ventricular shunt placement during the neonatal period.

Methods: The authors retrospectively reviewed the prenatal MR imaging data of 38 consecutive patients who had been referred for neurosurgical consultation following the diagnosis of ventriculomegaly.

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Eosinophilic vasculitis has been described as part of the Churg-Strauss syndrome, but affects the central nervous system (CNS) in <10% of cases. A 39-year-old woman with a history of migraine without aura presented to an institution in an acute confusional state with concurrent headache and left-sided weakness. Laboratory evaluation showed an increased cerebrospinal fluid (CSF) protein level, but otherwise unremarkable serologies.

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Purpose: To determine the incidence and associated risk factors of nephrogenic systemic fibrosis (NSF) in patients who undergo gadolinium-based contrast agent (GBCA)-enhanced magnetic resonance (MR) imaging.

Materials And Methods: Institutional review board approval was obtained for retrospective review of the medical records from two hospitals to identify all cases of biopsy-confirmed NSF and all patients administered a GBCA from January 1, 1997, to June 30, 2007. Informed patient consent was not required.

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Introduction: Retroperitoneal abscesses have been previously reported to cause infectious meningitis. Cerebral infarction is a known complication of basilar meningitis.

Summary Of Case: We present a case where a comatose patient with a known retroperitoneal abscess was diagnosed via Magnetic Resonance Imaging (MRI) with extensive brainstem infarction secondary to basilar meningitis.

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Objective: Neurocognitive dysfunction has been shown to occur in roughly 25% of patients undergoing carotid endarterectomy (CEA). Despite this, little is known about the mechanism of this injury. Recently, several groups have shown that new diffusion weighted imaging (DWI)-positive lesions are seen in 20% of patients undergoing CEA.

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This study evaluated the role of proton magnetic resonance spectroscopic imaging (1H MRSI) in assessing the response of low-grade brain tumors to a chemotherapy-only treatment regimen. Specifically, it was of interest to assess if 1H MRSI could detect early tumor response to therapy prior to magnetic resonance imaging (MRI) changes, and to establish which spectral markers were sensitive to regional changes within and around a heterogeneous tumor mass. A total of 14 patients with lower-grade gliomas were evaluated by multislice 1H MRSI, MRI and clinical examination.

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All procedures and protocols were approved by the institutional animal care and use committee of Columbia University. To determine whether transfemoral catheterization of the carotid arteries can be performed entirely with real-time magnetic resonance (MR) imaging guidance, the authors catheterized the carotid arteries in six domestic pigs by using active-tracking catheters and guidewires and MR tracking software created for neurovascular procedures. The carotid arteries were successfully catheterized 24 times, on average within 5 minutes after insertion of the catheter into the femoral artery.

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All examinations were performed with approval from the institutional animal care and use committee of Columbia University. To assess the feasibility of real-time magnetic resonance (MR) imaging-guided neurovascular intervention in a swine model, the authors placed stents in the carotid arteries of five domestic pigs. Seven-French vascular sheaths were placed in the target carotid arteries via femoral access by using active MR tracking.

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The study aimed to identify task-related brain activation networks whose change in expression exhibits subject differences as a function of differential susceptibility to sleep deprivation. Brain activity during a non-verbal recognition memory task was investigated in an event-related functional MRI paradigm both prior to and after 48 h of sleep deprivation. Nineteen healthy subjects participated.

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Precise assessment of stroke outcome is critical for pre-clinical testing of cerebroprotective strategies. Differences in stroke volume measured by various magnetic resonance imaging (MRI) techniques are documented in humans, but not well described in experimental primate stroke. This study characterizes changes in stroke volume using serial MRI scans in a baboon model of reperfused cerebral ischemia.

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Over the last two decades, interventional neuroradiologists have developed powerful techniques for the treatment of cerebrovascular disorders and brain tumors. Current interventional neuroradiological procedures are performed under X-ray fluoroscopy, which has allowed for high temporal and spatial resolution. However, these imaging techniques do not provide the treating physician with vital anatomic and functional information regarding vessel walls and the surrounding brain tissue.

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There is epidemiologic and imaging evidence for the presence of cognitive reserve, but the neurophysiologic substrate of CR has not been established. In order to test the hypothesis that CR is related to aspects of neural processing, we used fMRI to image 19 healthy young adults while they performed a nonverbal recognition test. There were two task conditions.

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Memory function commonly declines in later life. Whether memory decline represents a disease process or whether it is part of normal aging remains unknown. Here we answer this question by assessing the function of multiple subregions that make up the hippocampal circuit across the human life span.

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