Search results for "Image processing"
showing 10 items of 3285 documents
Baseline [18F]-FDOPA kinetics are predictive of haloperidol-induced changes in dopamine turnover and cognitive performance: A positron emission tomog…
2007
The telencephalic dopamine innervations contribute to the modulation of cognitive processing. However, the relationship between cognitive effects of D(2/3)-receptor antagonism and dopamine transmission is not described in healthy subjects. We therefore tested effects of acute haloperidol (5 mg/d over 3 days) on continuous performance task (CPT) performance and 6-[(18)F]-fluoro-l-DOPA (FDOPA) PET parameters. Nine physically and mentally healthy male men performed two FDOPA-PET scans including arterial plasma withdrawal. Over 3 days before the second scan, all subjects were treated with 5 mg/d haloperidol orally. Using our novel steady-state analysis, we calculated the intrinsic rate of the c…
VBM-DTI correlates of verbal intelligence: a potential link to Broca's area.
2012
Abstract Human brain lesion studies first investigated the biological roots of cognitive functions including language in the late 1800s. Neuroimaging studies have reported correlation findings with general intelligence predominantly in fronto-parietal cortical areas. However, there is still little evidence about the relationship between verbal intelligence and structural properties of the brain. We predicted that verbal performance is related to language regions of Broca's and Wernicke's areas. Verbal intelligence quotient (vIQ) was assessed in 30 healthy young subjects. T1-weighted MRI and diffusion tensor imaging data sets were acquired. Voxel-wise regression analyses were used to correla…
Functional MRI of galvanic vestibular stimulation with alternating currents at different frequencies.
2004
Abstract Functional MRI was performed in 28 healthy volunteers to study the effects of galvanic vestibular stimulation with alternating currents (AC-GVS) of different frequencies on brain activation patterns. The aims of this study were (1) to identify specific areas within the vestibular cortical network that are involved in the processing of frequency-specific aspects by correlation analyses, (2) to determine the optimal frequency for stimulation of the vestibular system with respect to perception, and (3) to analyze whether different frequencies of AC-GVS are mediated in different cortical areas or different sites within the vestibular cortex. AC-GVS was performed using sinusoidal stimul…
Modulating phonemic fluency performance in healthy subjects with transcranial magnetic stimulation over the left or right lateral frontal cortex.
2017
Abstract A growing body of evidence have suggested that non-invasive brain stimulation techniques, such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS), can improve the performance of aphasic patients in language tasks. For example, application of inhibitory rTMS or tDCs over the right frontal lobe of dysphasic patients resulted in improved naming abilities. Several studies have also reported that in healthy controls (HC) tDCS application over the left prefrontal cortex (PFC) improve performance in naming and semantic fluency tasks. The aim of this study was to investigate in HC, for the first time, the effects of inhibitory repetitive TMS (rTMS…
Colorectal Polyps: Detection with Dark-Lumen MR Colonography versus Conventional Colonoscopy
2005
To prospectively compare dark-lumen magnetic resonance (MR) colonography with conventional colonoscopy in the detection of colorectal polyps.Local ethical committee approval and informed consent were obtained. One hundred consecutive patients (56 men, 44 women; mean age +/- standard deviation, 67.7 years +/- 14.7; range, 25-82 years) who were referred for conventional colonoscopy from January 2003 to January 2004 underwent MR colonography and conventional colonoscopy after standard precolonoscopic bowel cleansing. Colonoscopy was performed immediately after MR colonography. For MR colonography, the colon was filled with approximately 2000 mL of tap water. Imaging was performed with a 1.5-T …
Computed Virtual Chromoendoscopy for Classification of Small Colorectal Lesions: A Prospective Comparative Study
2007
Standard colonoscopy offers no reliable discrimination between neoplastic and nonneoplastic colorectal lesions. Computed virtual chromoendoscopy with the Fujinon intelligent color enhancement (FICE) system is a new dyeless imaging technique that enhances mucosal and vascular patterns. This prospective trial compared the feasibility of FICE, standard colonoscopy, and conventional chromoendoscopy with indigo carmine in low- and high-magnification modes for determination of colonic lesion histology.Sixty-three patients with 150 flat or sessile lesions less than 20 mm in diameter were enrolled. At colonoscopy, each lesion was observed with six different endoscopic modalities: standard colonosco…
Comparison of running kinematics between elite and national-standard 1500-m runners.
2009
The aim of this study was to determine whether elite 1500-m runners differ in their running kinematics from national-standard 1500-m runners. Six national-standard male runners (seasonal best: 3 min 49.2 s +/- 3.2 s) were assessed during the second lap of a 1500-m race. Their running kinematics was then compared with those of five elite runners (seasonal best: 3 min 35.6 s +/- 2.6 s) analysed during the second lap of the men's 1500-m final at the 2005 World Championships. Data were collected using two high-speed cameras operating at 200 Hz with a three-dimensional pan and tilt system. Running speed was the same for both groups. Despite the similar contact times, the minimum knee angle durin…
Resovist enhanced MR imaging of the liver: Does quantitative assessment help in focal lesion classification and characterization?
2009
Purpose: To improve characterization of focal liver lesions by a prospective quantitative analysis of percentage signal intensity change, in dynamic and late phases after slow (0.5 mL/s) Resovist administration. Materials and Methods: Seventy-three patients were submitted on clinical indication to MR examination with Resovist. Signal intensity of 92 detected focal lesions (5–80 mm) were measured with regions of interest and normalized to paravertebral muscle in arterial, portal, equilibrium and T1/T2 late phases, by two observers in conference. Five values of percentage variations per patient were obtained and statistically evaluated. Results: The enhancement obtained on dynamic study is mo…
Assessment of the relationship between lung parenchymal destruction and impaired pulmonary perfusion on a lobar level in patients with emphysema.
2006
Abstract Purpose To assess the relationship between lung parenchymal destruction and impaired pulmonary perfusion on a lobar level using CT and MRI in patients with emphysema. Material and methods Forty-five patients with severe emphysema (GOLD III and IV) underwent inspiratory 3D-HRCT and contrast-enhanced MR-perfusion (1.5T; 3.5 mm × 1.9 mm × 4 mm). 3D-HRCT data was analyzed using a software for detection and visualization of emphysema. Emphysema was categorized in four clusters with different volumes and presented as overlay on the CT. CT and lung perfusion were visually analyzed for three lobes on each side using a four-point-score to grade the abnormalities on CT (1: predominantly smal…
Influence of heart rate in the selection of the optimal reconstruction window in routine clinical multislice coronary angiography
2008
Purpose. The aim of our study was to assess the influence of heart rate on the selection of the optimal reconstruction window with 40-slice multidetector-row computed tomography (40-MDCT) coronary angiography. Materials and methods. We studied 170 patients (114 men, age 60 +/- 11.3 years) with suspected or known coronary artery disease with 40-MDCT coronary angiography. Patients [mean heart rate (HR) 62.9 +/- 9.3 bpm, range 42-94 bpm] were clustered in two groups (group A: HR <= 65 bpm; group B: HR >65 bpm). Multiphase reconstruction data sets were obtained with a retrospective electrocardiogram (ECG)-gated 40-MDCT coronary angiography scan from 0% to 95% every 5% of the R-R interval.…