Search results for "Image."
showing 10 items of 6790 documents
Frontoparietal cortex and cerebellum contribution to the update of actual and mental motor performance during the day
2016
AbstractActual and imagined movement speed increases from early morning until mid-afternoon. Here, we investigated the neural correlates of these daily changes. Fifteen subjects performed actual and imagined right finger opposition movement sequences at 8 am and 2 pm. Both actual and imagined movements were significantly faster at 2 pm than 8 am. In the morning, actual movements significantly activated the left primary somatosensory and motor areas, and bilaterally the cerebellum; in the afternoon activations were similar but reduced. Contrast analysis revealed greater activity in the cerebellum, the left primary sensorimotor cortex and parietal lobe in the morning than in the afternoon. Im…
Laterality effects in motor learning by mental practice in right-handers.
2014
Converging evidences suggest that mental movement simulation and actual movement production share similar neurocognitive and learning processes. Although a large body of data is available in the literature regarding mental states involving the dominant arm, examinations for the nondominant arm are sparse. Does mental training, through motor-imagery practice, with the dominant arm or the nondominant arm is equally efficient for motor learning? In the current study, we investigated laterality effects in motor learning by motor-imagery practice. Four groups of right-hander adults mentally and physically performed as fast and accurately as possible (speed/accuracy trade-off paradigm) successive…
Correlation between fatigue and brain atrophy and lesion load in multiple sclerosis patients independent of disability.
2007
Abstract Background Fatigue is a major problem in multiple sclerosis (MS), and its association with MRI features is debated. Objective To study the correlation between fatigue and lesion load, white matter (WM), and grey matter (GM), in MS patients independent of disability. Methods We studied 222 relapsing remitting MS patients with low disability (scores ≤ 2 at the Kurtzke Expanded Disability Status Scale). Lesion load, WM and GM were measured by fully automated, operator-independent, multi-parametric segmentation method. T1 and T2 lesion volume were also measured by a semi-automated method. Fatigue was assessed by the Fatigue Severity Scale (FSS), and patients divided in high-fatigue (FS…
Semi-automated retinal vessel analysis in nonmydriatic fundus photography.
2013
Purpose Funduscopic assessment of the retinal vessels may be used to assess the health status of microcirculation and as a component in the evaluation of cardiovascular risk factors. Typically, the evaluation is restricted to morphological appreciation without strict quantification. Our purpose was to develop and validate a software tool for semi-automated quantitative analysis of retinal vasculature in nonmydriatic fundus photography. Methods matlab software was used to develop a semi-automated image recognition and analysis tool for the determination of the arterial–venous (A/V) ratio in the central vessel equivalent on 45° digital fundus photographs. Validity and reproducibility of the r…
Disturbed structural connectivity is related to inattention and impulsivity in adult attention deficit hyperactivity disorder
2010
Inattention and impulsivity are the most prominent clinical features of attention deficit hyperactivity disorder (ADHD) in adulthood. Structural and functional neuroimaging studies of subjects with ADHD have demonstrated abnormalities in several brain areas, including fronto-striatal and fronto-cerebellar networks. Mostly, these studies were based on volumetric measurements and have been conducted in children. We investigated white matter (WM) integrity and correlation with measures of attention and impulsivity in adult patients with ADHD adopting diffusion tensor imaging (DTI). N = 37 (21 males) never-medicated adult patients with ADHD combined subtype and N = 34 (16 males) healthy control…
Automatic detection and quantification of ground-glass opacities on high-resolution CT using multiple neural networks: comparison with a density mask.
2000
We compared multiple neural networks with a density mask for the automatic detection and quantification of ground-glass opacities on high-resolution CT under clinical conditions.Eighty-four patients (54 men and 30 women; age range, 18-82 years; mean age, 49 years) with a total of 99 consecutive high-resolution CT scans were enrolled in the study. The neural network was designed to detect ground-glass opacities with high sensitivity and to omit air-tissue interfaces to increase specificity. The results of the neural network were compared with those of a density mask (thresholds, -750/-300 H), with a radiologist serving as the gold standard.The neural network classified 6% of the total lung a…
Characterization of benign hepatic tumors arising in fatty liver with SonoVue and pulse inversion US.
2007
Background: We describe the spectrum of contrast-enhancement patterns of benign hepatic tumors arising in fatty liver on contrast-enhanced ultrasound (US). Methods: Sixteen patients (12 women and four men) with 27 benign hepatic tumors (17 hemangiomas, eight focal nodular hyperplasias, and two hepatocellular adenomas) arising in fatty liver underwent baseline and pulse inversion US after administration of SonoVue. Two experienced radiologists evaluated baseline echogenicity and dynamic enhancement pattern of each lesion in comparison with adjacent liver parenchyma. Results: After administration of SonoVue, in the arterial phase 13 of 17 hemangiomas showed peripheral globular enhancement and…
Heterogeneous delayed enhancement of hepatic parenchyma after intravenous infusion of sonographic contrast agent: a new hypothesis
2007
Purpose. The aim of this paper was to report a heterogeneous latephase hepatic enhancement pattern observed after administration of a sonographic contrast agent and to present an aetiological hypothesis for the phenomenon. Materials and methods. A total of 1,729 (1,012 women and 717 men; age range 28–82; mean age 51) patients underwent contrastenhanced sonography of the liver. The examination was performed with a low mechanical index (MI <0.09) after injection of sulphur-hexafluoride-filled microbubbles, using different fonographic equipment and different contrast-specific algorithms. Results. Heterogeneous delayed liver enhancement was observed in six patients in the late phase (180 s), wi…
Do we truly see what we think we see? The role of cognitive bias in pathological interpretation
2008
In the histomorphological grading of prostate carcinoma, pathologists have regularly assigned comparable scores for the architectural Gleason and the now-obsolete nuclear World Health Organization (WHO) grading systems. Although both systems demonstrate good correspondence between grade and survival, they are based on fundamentally different biological criteria. We tested the hypothesis that this apparent concurrence between the two grading systems originates from an interpretation bias in the minds of diagnostic pathologists, rather than reflecting a biological reality. Three pathologists graded 178 prostatectomy specimens, assigning Gleason and WHO scores on glass slides and on digital im…
Evaluation of robot-guided minimally invasive implantation of 2067 pedicle screws
2017
ObjectiveRecent studies have investigated the role of spinal image guidance for pedicle screw placement. Many authors have observed an elevated placement accuracy and overall improvement of outcome measures. This study assessed a bi-institutional experience following introduction of the Renaissance miniature robot for spinal image guidance in Europe.MethodsThe medical records and radiographs of all patients who underwent robot-guided implantation of spinal instrumentation using the novel system (between October 2011 and March 2015 in Mainz and February 2014 and February 2016 in Regensburg) were reviewed to determine the efficacy and safety of the newly introduced robotic system. Screw posit…