Search results for " Computer"
showing 10 items of 6910 documents
Direct Objective Quantification of Corneal Haze after Excimer Laser Photorefractive Keratectomy for High Myopia
1996
Purpose: The purpose of the study is to measure regional distribution differences in corneal haze after excimer laser photorefractive keratectomy for high myopia. Methods: The authors developed computerized gradient edge detectors with which were analyzed digitized anterior slit-lamp photographs of 40 eyes, an average of 21.0 plus or minus 14.5 weeks after photorefractive keratectomy for high myopia (−6 to −22 diopters). A treated area and an adjacent untreated area on the anterior corneal surface, each containing six regions, were quantified, and the difference was correlated with various parameters. Results: Mean differences between scarred and clear areas for haze grade 0.5, 1.0, 2.0, 3.…
Virtual Unenhanced Images at Dual-Energy CT: Influence on Renal Lesion Characterization
2019
Background Dual-energy (DE) CT allows reconstruction of virtual noncontrast (VNC) images from a single-phase contrast agent-enhanced examination, potentially reducing the need for multiphasic CT to characterize renal lesions. However, data regarding diagnostic performance of VNC images for the characterization of renal lesions are limited. Purpose To determine whether renal mass CT performed by using VNC images allows for reliable identification of renal lesions and differentiation of contrast-enhanced from unenhanced lesions, compared with unenhanced images. Materials and Methods This is a retrospective study of 293 patients (105 women [mean age, 65 years; age range, 18-91 years] and 188 m…
The effectiveness of a novel optical probe in subgingival calculus detection
2008
: Objectives: The aim of the present study was to evaluate the effectiveness of a novel optical calculus detection system under in vivo conditions. Methods: One hundred and seventy-six tooth surfaces from 44 adult teeth that were indicated for extraction were selected for the present study. The patients were randomly assigned to one of the two experimental groups. In group A (n = 96), clinical presence or absence of subgingival calculus deposits was determined using the light-emitting diode-based optical probe (OP). In group B (n = 80), the subgingival deposits were first recorded with the OP followed by root surface debridement until no subgingival deposits could be detected by the devi…
Motor Activity Improves Temporal Expectancy
2015
International audience; Certain brain areas involved in interval timing are also important in motor activity. This raises the possibility that motor activity might influence interval timing. To test this hypothesis, we assessed interval timing in healthy adults following different types of training. The pre- and post-training tasks consisted of a button press in response to the presentation of a rhythmic visual stimulus. Alterations in temporal expectancy were evaluated by measuring response times. Training consisted of responding to the visual presentation of regularly appearing stimuli by either: (1) pointing with a whole-body movement, (2) pointing only with the arm, (3) imagining pointi…
Voxel-based morphometry depicts central compensation after vestibular neuritis.
2010
Objective Patients who have had vestibular neuritis (VN) show a remarkable clinical improvement especially in gait and posture >6 months after disease onset. Methods Voxel-based morphometry was used to detect the VN-induced changes in gray and white matter by means of structural magnetic resonance imaging. Twenty-two patients were compared an average 2.5 years after onset of VN to a healthy sex-and age-matched control group. Results Our analysis revealed that all patients had signal intensity increases for gray matter in the medial vestibular nuclei and the right gracile nucleus and for white matter in the area of the pontine commissural vestibular fibers. A relative atrophy was observed in…
Usability and Trust in E-Banking
2007
This study assessed the role of usability in trust of e-banking services. A questionnaire was administered to 185 Italian undergraduate working students who volunteered for the experiment (M age = 30.5 yr., SD = 3.1). Participants were differentiated on computer ability (Expert, n=104; Nonexpert, n = 81) and e-banking use (User, n = 93; Nonusers, n = 92). Analysis showed that the website usability of e-banking services did not play a very important role for the User group. Instead, institution-based trust, e.g., the trust in the security policy of the Web merchant, customers, and the overall trust of the bank were the crucial factors in the adoption of e-banking. © Psychological Reports 200…
Using Tic-Tac software to reduce anxiety-related behaviour in adults with autism and learning difficulties during waiting periods: A pilot study
2013
Deficits in the perception of time and processing of changes across time are commonly observed in individuals with autism. This pilot study evaluated the efficacy of the use of the software tool Tic-Tac, designed to make time visual, in three adults with autism and learning difficulties. This research focused on applying the tool in waiting situations where the participants exhibited anxiety-related behaviour. The intervention followed a baseline and intervention (AB) design, and a partial interval recording procedure was used to code the presence of stereotypes, nervous utterances, wandering or other examples of nervousness during the selected waiting situations. The results showed that t…
FAIR and dynamic susceptibility contrast-enhanced perfusion imaging in healthy subjects and stroke patients.
2002
Purpose To compare dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) and the flow-sensitive alternating inversion recovery (FAIR) technique for measuring brain perfusion. Materials and Methods We investigated 12 patients with acute stroke, and 10 healthy volunteers with FAIR and DSC maps of regional cerebral blood volume (rCBV), mean transit time (MTT), and regional cerebral blood flow (rCBF). Results In volunteers good gray/white-matter contrast was observed in FAIR, rCBF, and rCBV maps. Regions with high signal intensities in FAIR matched well with high values of rCBV and rCBF. In ischemic stroke patients a high correlation (r = 0.78) of the ipsi- to contralate…
Functional imaging of sympathetic activation during mental stress
2010
Activation of the sympathetic nervous system (SNS) is essential in adapting to environmental stressors and in maintaining homeostasis. This reaction can also turn into maladaptation, associated with a wide spectrum of stress-related diseases. Up to now, the cortical mechanisms of sympathetic activation in acute mental stress have not been sufficiently characterized. We therefore investigated cerebral activation applying functional magnetic resonance imaging (fMRI) during performance of a mental stress task with graded levels of difficulty, i.e. four versions of a Stroop task (Colour Word Interference Test, CWT) in healthy subjects. To analyze stress-associated sympathetic activation, skin c…
Computer assisted evaluation of retinal vessels tortuosity in Fabry disease.
2012
. Purpose: Fabry Disease (FD) is a rare X-linked metabolic disorder characterized by diffuse deposition of sphingolipids in many tissues. Retinal vessel tortuosity is a common ocular manifestation in FD and may represent a useful marker for the disease. Unfortunately its clinical evaluation is poorly reproducibile and alternative means of evaluation may be of interest. We tested a new semi-automatic software measuring retinal vessel tortuosity from eye fundus digital images in a group of FD patients. Methods: Observational case-control study evaluating four mathematical parameters describing tortuosity (relative length, sum of angle metric [SOAM], product of angle distance [PAD], triangul…