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Traumatic brain injury (TBI) is a pathologically heterogeneous disease, including injury to both neuronal cell bodies and axonal processes. Global atrophy of both gray and white matter is common after TBI. This study was designed to determine the relationship between neuroimaging markers of acute diffuse axonal injury (DAI) and cerebral atrophy months(More)
Diffusion tensor tractography is increasingly used to examine structural connectivity in the brain in various conditions, but its test-retest reliability is understudied. The main purposes of this study were to evaluate 1) the reliability of quantitative measurements of diffusion tensor tractography and 2) the effect on reliability of the number of gradient(More)
OBJECTIVE Several lines of evidence suggest that pathologic changes underlying Alzheimer disease (AD) begin years prior to the clinical expression of the disease, underscoring the need for studies of cognitively healthy adults to capture these early changes. The overall goal of the current study was to map the cortical distribution of β-amyloid (Aβ) in a(More)
OBJECTIVE Orbitofrontal cortex regional cerebral blood flow (rCBF) is lower in cocaine-dependent subjects than in non-cocaine-dependent subjects. Performance on the Gambling Task, a test of decision making, is a putative correlate of orbitofrontal cortex activity and is reportedly impaired in drug-dependent subjects. The authors tested the hypothesis that(More)
OBJECTIVE To examine the functional connectivity of hippocampal and selected frontal lobe circuits in patients with traumatic axonal injury (TAI). DESIGN Observational study. SETTING An inpatient traumatic brain injury unit. Imaging and neurocognitive assessments were conducted in an outpatient research facility. PARTICIPANTS Twenty-five consecutive(More)
BACKGROUND Diffuse axonal injury is a common consequence of traumatic brain injury that frequently involves the parasagittal white matter, corpus callosum, and brainstem. OBJECTIVE To examine the potential of diffusion tensor tractography in detecting diffuse axonal injury at the acute stage of injury and predicting long-term functional outcome. DESIGN(More)
Regional cerebral blood flow (rCBF) was assessed in 40 chronic male schizophrenic patients (20 medicated, 20 unmedicated) and 31 matched normal controls with Dynamic Single-photon Emission Computed Tomography (D-SPECT). Blind analyses of normalized color-coded tomograms revealed significant bifrontal and bitemporal rCBF deficits in the patient group.(More)
Stuttering is a poorly understood communication disorder with a 1% global prevalence. Recently, there has been a resurgence of interest in a neurogenic origin for the disorder, although no research has established clear neurological differences between "developmental" (stuttering onset in childhood) stutterers and nonstutterers. We have used xenon 133(More)
Although amyloid imaging with PiB-PET ([C-11]Pittsburgh Compound-B positron emission tomography), and now with F-18-labeled tracers, has produced remarkably consistent qualitative findings across a large number of centers, there has been considerable variability in the exact numbers reported as quantitative outcome measures of tracer retention. In some(More)
BACKGROUND The different clinical trajectories of cocaine-dependent men and women may be a consequence of distinct neurobiological substrates. Hypoperfusion of the orbitofrontal cortex (OFC) has previously been reported in individuals addicted to cocaine and has been posited as a biological mediator of relapse due to impulsivity or impaired decision making.(More)