Search results for "positron"
showing 10 items of 1346 documents
Dysfunction of attention switching networks in amyotrophic lateral sclerosis
2019
Objective To localise and characterise changes in cognitive networks in Amyotrophic Lateral Sclerosis (ALS) using source analysis of mismatch negativity (MMN) waveforms. Rationale The MMN waveform has an increased average delay in ALS. MMN has been attributed to change detection and involuntary attention switching. This therefore indicates pathological impairment of the neural network components which generate these functions. Source localisation can mitigate the poor spatial resolution of sensor-level EEG analysis by associating the sensor-level signals to the contributing brain sources. The functional activity in each generating source can therefore be individually measured and investigat…
SPM-based count normalization provides excellent discrimination of mild Alzheimer's disease and amnestic mild cognitive impairment from healthy aging☆
2008
Statistical comparisons of [(18)F]FDG PET scans between healthy subjects and patients with Alzheimer's disease (AD) or amnestic mild cognitive impairment (aMCI) using Statistical Parametric Mapping (SPM) usually require normalization of regional tracer uptake via ROIs defined using additional software. Here, we validate a simple SPM-based method for count normalization. FDG PET scans of 21 mild, 15 very mild AD, 11 aMCI patients and 15 age-matched controls were analyzed. First, we obtained relative increases in the whole patient sample compared to controls (i.e. areas relatively preserved in patients) with proportional scaling to the cerebral global mean (CGM). Next, average absolute counts…
Choice of reference area in studies of Alzheimer's disease using positron emission tomography with fluorodeoxyglucose-F18
2007
At present, there is still no consensus on the choice of the reference area in positron emission tomography (PET) studies of Alzheimer's disease (AD). In this study, PET scans with fluorodeoxyglucose-F18 were carried out in the following groups of subjects: 47 patients with probable AD, 8 patients with mild cognitive impairment, and 15 age-similar healthy subjects. Scans normalized to the cerebral global mean (CGM), cerebellum (CBL), and the primary sensorimotor cortex (SMC). We evaluated the effect of the different count normalization procedures on the accuracy of (18)F-FDG PET to detect AD-specific metabolic abnormalities (voxel-based group comparison) and to differentiate between patient…
Peptide Receptor Radionuclide Therapy Combined With Chemotherapy in Patients With Neuroendocrine Tumors
2019
Combinations of therapies may enhance therapeutic effects without significantly increasing the incidence of adverse events. However, there are few data regarding survival after concomitant chemotherapy and peptide receptor radionuclide therapy (PRRT) with [Lu]Lu-octreotate in patients with neuroendocrine tumors (NETs). Thus, we explored the outcome of this combination of therapies.Fifteen patients with somatostatin receptor-positive, rapidly progressive G2/G3 NETs during chemotherapy or PRRT alone from 2 German cancer centers were included in the retrospective analysis. The patients received a combination of PRRT and chemotherapy with temozolomide (n = 3) or temozolomide plus capecitabine (…
Physical Activity and Amyloid-β Brain Levels in Elderly Adults with Intact Cognition and Mild Cognitive Impairment
2015
Objectives To examine the associations between amyloid-β brain deposition and physical activity (PA) in elderly adults without dementia and to investigate whether the association has a dose-response relationship. Design Cross-sectional study. Setting French community-dwelling people. Participants Elderly adults with normal or mildly impaired cognition (mean age 74.7 ± 4.2; 60.4% female) with available information on current self-reported PA and amyloid-β brain deposition measured using positron emission tomography (PET) using the PET-ligand florbetapir F 18 (n = 268). Measurements A standardized uptake value ratio (SUVR) was obtained for each subject. Participants were divided according to …
Focal or whole-gland salvage prostate brachytherapy with iodine seeds with or without a rectal spacer for postradiotherapy local failure: How best to…
2016
International audience; PURPOSE: Salvage prostate permanent implant (sPPI) for postradiation local failure provides high rates of biochemical control. The cumulative dose delivered to the prostate and the rectum is still unknown. METHODS AND MATERIALS: We reviewed the postimplant CT-based dosimetry of 18 selected patients who underwent sPPI with I-125 seeds for isolated biopsy-proven local failure several years after external beam radiation therapy. Ten patients had whole-prostate sPPI, and 8 patients had multiparametric MRI-based focal sPPI. In 8 patients, hyaluronic acid (HA) gel was injected into the prostate rectum space. RESULTS: The median cumulative biological effective dose after EB…
Validating the DemTect with 18-Fluoro-2-Deoxy-Glucose Positron Emission Tomography as a Sensitive Neuropsychological Screening Test for Early Alzheim…
2005
<i>Objectives:</i> The first study to validate the diagnostic value of the DemTect, a short neuropsychological screening test for dementia (8–10 min), using 18-fluoro-2-deoxy-glucose positron emission tomography (FDG-PET) in patients of a memory clinic. <i>Methods:</i> DemTect results were compared to the clinical diagnosis and to FDG-PET as a reference method for the early in vivo detection of Alzheimer’s disease (AD). <i>Results:</i> 38 patients (age 65.2 ± 9.8 years, 16 men, 22 women) were investigated using clinical standard examination, FDG-PET, and cranial magnetic resonance imaging. According to NINCDS-ADRDA and Petersen’s criteria, 18 patients had…
Limited agreement between biomarkers of neuronal injury at different stages of Alzheimer's disease
2013
Abstract New diagnostic criteria for Alzheimer's disease (AD) treat different biomarkers of neuronal injury as equivalent. Here, we quantified the degree of agreement between hippocampal volume on structural magnetic resonance imaging, regional glucose metabolism on positron emission tomography, and levels of phosphorylated tau in cerebrospinal fluid (CSF) in 585 subjects from all phases of the AD Neuroimaging Initiative. The overall chance-corrected agreement was poor (Cohen κ, 0.24–0.34), in accord with a high rate of conflicting findings (26%–41%). Neither diagnosis nor APOE e4 status significantly influenced the distribution of agreement between the biomarkers. The degree of agreement t…
Progressive necrotic encephalopathy following tacrolimus therapy for liver transplantation.
2009
Previously described neurologic damage induced by immunosuppressive treatments includes transient or reversible central nervous system involvement. We describe a 57-year-old man who underwent liver transplantation and was started on immunosuppressive therapy with tacrolimus (FK506). Six months later, he started complaining of a progressive motor and sensory impairment of the left side, together with cognitive impairment. Brain MRI showed an enlarging lesion of the white matter with peripheral contrast enhancement. PET study indicated severe hypometabolism in the right hemisphere and spectroscopic MRI showed a peak of choline and relative reduction of other metabolites. Findings of CSF exami…
Association of elevated phospho-tau levels with alzheimer-typical 18F-Fluoro-2-Deoxy-D-Glucose positron emission tomography findings in patients with…
2003
Abstract Background Mild cognitive impairment is considered to be a transitional stage between normal aging and dementia. Phosphorylated tau protein in cerebrospinal fluid and even more decrements of cerebral glucose metabolism in parietal, temporal, or cingulate regions have shown favorable specificity for the diagnosis of Alzheimer dementia and could be useful supplementary tools to determine Alzheimer pathology in early stages. Methods We measured cerebrospinal fluid tau phosphorylated at threonine 181 protein, cerebrospinal fluid total tau, and cerebral glucose metabolism using 18F-fluoro-2-deoxy-D-glucose positron emission tomography in 16 patients with mild cognitive impairment and ag…