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OBJECTIVE The ECAT EXACT HR is a newly designed CTI-Siemens PET scanner with high spatial resolution. Its physical performance with respect to resolution, count rate efficiency, and scatter was investigated and evaluated with phantom studies. MATERIALS AND METHODS The new tomograph consists of three rings of 112 BGO block detectors (50 mm x 23 mm x 30 mm(More)
We studied the functional anatomy of affect-laden autobiographical memory in normal volunteers. Using H2 15O positron emission tomography (PET), we measured changes in relative regional cerebral blood flow (rCBF). Four rCBF measurements were obtained during three conditions: REST, i.e.,, subjects lay at rest (for control); IMPERSONAL, i.e., subjects(More)
A new diagnostic indicator of FDG PET scan abnormality, based on age-adjusted t statistics and an automated voxel-based procedure, is presented and validated in a large data set comprising 110 normal controls and 395 patients with probable Alzheimer's disease (AD) that were studied in eight participating centers. The effect of differences in spatial(More)
As previous functional neuroimaging studies could not settle the controversy regarding the contribution of dominant and subdominant hemisphere to recovery from poststroke aphasia, language performance was related to H2(15)O-positron emission tomographic activation patterns in 23 right-handed aphasic patients 2 and 8 weeks after stroke. In patients(More)
Activation studies in patients with aphasia due to stroke or tumours in the dominant hemisphere have revealed effects of disinhibition in ipsilateral perilesional and in contralateral homotopic cortical regions, referred to as collateral and transcallosal disinhibition. These findings were supported by studies with selective disturbance of cortical areas by(More)
The brain may use two strategies to recover from poststroke aphasia: the structural repair of primarily speech-relevant regions or the activation of compensatory areas. We studied the cortical metabolic recovery in aphasic stroke patients with positron emission tomography (PET) at rest and during word repetition. The left supplementary motor area (SMA)(More)
The microPET R4 scanner is a dedicated positron emission tomograph (PET) for studies of rodents. A number of scanner parameters such as spatial resolution, sensitivity, scatter, and count rate performance were determined in this work, which showed that the microPET R4 is a suitable PET scanner for small animals like mice and rats. In the center of the field(More)
Disturbance of neurologic function in disorders of the central nervous system is expressed as an altered activation pattern in functional networks employed by specific tasks and can be studied by functional imaging modalities, e.g., positron emission tomography. Language, a complex brain function, is based on the interplay of a distributed network in which(More)
OBJECTIVE To assess neurochemical deficits in patients with Parkinson disease (PD) associated dementia (PDD) in vivo. METHODS The authors performed combined PET with N-[11C]-methyl-4-piperidyl acetate (MP4A) and 18F-fluorodopa (FDOPA) for evaluation of cholinergic and dopaminergic transmitter changes in 17 non-demented patients with PD and 10 patients(More)
Deep brain stimulation of the subthalamic nucleus (STN-DBS) is a highly effective surgical treatment in patients with advanced Parkinson's disease (PD). Because the STN has been shown to represent an important relay station not only in motor basal ganglia circuits, the modification of brain areas also involved in non-motor functioning can be expected by(More)