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Brain imaging techniques have provided substantial insight into the pathophysiology of hepatic encephalopathy (HE). Magnetic resonance imaging gave hint to the fact that there is an increased deposition of manganese especially in the basal ganglia. Single photon emission computed tomography (SPECT) and positron emission tomography (PET) showed that the(More)
Studies of resting regional cerebral glucose consumption (rCMRGlc) in nondemented patients with Parkinson's disease (PD) have produced conflicting results, reporting both reduced and normal metabolism in advanced disease and reduced or normal metabolism after dopaminergic therapy. To investigate these issues, [(18)F]fluorodeoxyglucose (FDG) positron(More)
OBJECTIVE To evaluate the effects of levodopa and the dopamine D2 agonist cabergoline on striatal dopamine turnover estimated as the inverse of the effective dopamine distribution volume ratio (EDVR) measured by (18)F-dopa PET in de novo Parkinson disease (PD). METHODS Single-center, parallel-group, randomized, observer-blinded study of cabergoline (3(More)
A multilinear reference tissue approach has been widely used recently for the assessment of neuroreceptor-ligand interactions with positron emission tomography. The authors analyzed this "multilinear method" with respect to its sensitivity to statistical noise, and propose regularization procedures that reduce the effects of statistical noise. Computer(More)
AIM Evaluation of a dedicated software tool for automatic delineation of 3D regions of interest in oncological PET. PATIENTS, METHODS The applied procedure encompasses segmentation of user-specified subvolumes within the tomographic data set into separate 3D ROIs, automatic background determination, and local adaptive thresholding of the background(More)
PURPOSE To evaluate the feasibility of PET/MRI (positron emission tomography/magnetic resonance imaging) with FDG ((18)F-fluorodeoxyglucose) for initial staging of head and neck cancer. METHODS The study group comprised 20 patients (16 men, 4 women) aged between 52 and 81 years (median 64 years) with histologically proven squamous cell carcinoma of the(More)
PURPOSE Partial volume (PV) effects are caused by limited spatial resolution and significantly affect cerebral blood flow investigations with arterial spin labeling. Therefore, accurate PV correction (PVC) procedures are required. PVC is commonly based on PV maps obtained from segmented high-resolution T1 -weighted images. Segmentation of these images is(More)
OBJECTIVE To investigate the predictive value of striatal dopamine turnover in patients with de novo Parkinson disease (PD) for the onset of later motor complications. METHODS This retrospective, observer-blinded cohort study followed up 31 patients with early PD who completed quantitative (18)F-dopa PET imaging to measure striatal (18)F-dopa uptake(More)
OBJECTIVE Evaluation of the quantitative accuracy of MR-based attenuation correction (MRAC) in the Philips Ingenuity TF whole-body PET/MR. MATERIALS AND METHODS In 13 patients, PET emission data from the PET/MR were reconstructed using two different methods for attenuation correction. In the first reconstruction, the vendor-provided standard MRAC was(More)
OBJECTIVES Findings in local cerebral blood flow (rCBF) in Normal pressure hydrocephalus (NPH) have always been challenged by the variable and inconsistent relation to clinical symptoms before and after shunt treatment. [(15)O]H(2)O PET data from a consecutive cohort of 65 idiopathic NPH patients were retrospectively analyzed questioning whether the(More)