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Abstract Cerebral blood flow was measured using positron emission tomography (PET) in three experiments while subjects performed mental imagery or analogous perceptual tasks. In Experiment 1, the subjects either visualized letters in grids and decided whether an X mark would have fallen on each letter if it were actually in the grid, or they saw letters in(More)
BACKGROUND Previous studies have reported a high prevalence of mitral-valve prolapse among patients with embolic stroke (28 to 40 percent), especially among young patients (those < or =45 years old); this finding has practical implications for prophylaxis. However, diagnostic criteria for prolapse have changed and are now based on three-dimensional analysis(More)
BACKGROUND AND PURPOSE Tissue signatures from acute MR imaging of the brain may be able to categorize physiological status and thereby assist clinical decision making. We designed and analyzed statistical algorithms to evaluate the risk of infarction for each voxel of tissue using acute human functional MRI. METHODS Diffusion-weighted MR images (DWI) and(More)
PURPOSE To evaluate acute stroke with conventional, multisection diffusion-weighted (DW), and hemodynamically weighted (HW) magnetic resonance (MR) imaging. MATERIALS AND METHODS The three MR imaging techniques were performed in 11 patients within 10 hours of the onset of acute hemiparesis. The volume of DW and HW abnormalities were compared with infarct(More)
BACKGROUND Percutaneous transcatheter closure of patent foramen ovale (PFO) is used as an alternative to surgery or long-term anticoagulation for the treatment of patients with paradoxical embolism and PFO. METHODS AND RESULTS We report the immediate and long-term clinical and echocardiographic outcome of 110 consecutive patients (58 males, mean age(More)
OBJECTIVE To investigate the causes of fever in subarachnoid hemorrhage (SAH) and examine its relationship to outcome. BACKGROUND Fever adversely affects outcome in stroke. Patients with SAH are at risk for cerebral ischemia due to vasospasm (VSP). In these patients, fever may be both caused by, and potentiate, VSP-mediated brain injury. METHODS The(More)
The risks to patients with metal surgical implants who are undergoing nuclear magnetic resonance (NMR) imaging and the artifacts caused by such implants were studied. Twenty-one aneurysm and other hemostatic clips and a variety of other materials (e.g., dental amalgam, 14 karat gold) were used. Longitudinal forces and torques were found to be exerted upon(More)
OBJECTIVE Massive cerebral infarction is often accompanied by early death secondary to transtentorial herniation. We have tested the hypothesis that decompressive hemicraniectomy for massive nondominant cerebral infarction is lifesaving in a series of 14 patients presenting with right hemispheric infarction and clinical signs of uncal herniation and(More)
BACKGROUND AND PURPOSE Therapies that transiently prevent ischemic neuronal death can potentially extend therapeutic time windows for stroke thrombolysis. We conducted a pilot study to investigate the effects of high-flow oxygen in acute ischemic stroke. METHODS We randomized patients with acute stroke (<12 hours) and perfusion-diffusion "mismatch" on(More)
OBJECTIVE To determine the relationship between blood glucose levels (mg/dL) and occurrence of symptomatic vasospasm (VSP) and clinical outcomes after aneurysmal subarachnoid hemorrhage. DESIGN Retrospective observational study of 352 patients with subarachnoid hemorrhage admitted within 48 hrs of ictus between January 1995 and June 2002. SETTING(More)