Search results for "resolution."
showing 10 items of 1825 documents
Diffusion-tensor MR imaging at 1.5 and 3.0 T: initial observations.
2001
Diffusion-tensor MR imaging was compared at 1.5 and 3.0 T. With sufficient signal-to-noise ratio, we found no differences in fractional anisotropy. With a 40% higher signal-to-noise ratio at 3.0 T, higher resolution could be obtained without introduction of noise-related errors, albeit at the cost of increased geometric distortions caused by 3.0-T magnetic field inhomogeneities.
Management of benign paroxysmal positional vertigo of lateral semicircular canal by Gufoni's manoeuvre
2009
Abstract Benign paroxysmal positional vertigo (BPPV) of lateral semicircular canal (LSC) is one of the rarer forms of BPPV as compared to posterior semicircular canal BPPV. Various particle repositioning manoeuvres have been described in the literature as a mode of treating this condition. Purpose Evaluation and discussion of the procedure of the Gufoni's manoeuvre and its advantages in the treatment of BPPV of LSC. Material and methods Prospective study of 58 patients affected by LSC BPPV who were office-treated with Gufoni's manoeuvre. Results Seventy-nine percent of the patients so treated had complete resolution of symptoms, and 6.9% did not show any improvement in their symptoms. The r…
Multisectorial changes in the ciliary muscle during accommodation measured with high-resolution optical coherence tomography
2019
ABSTRACT Purpose: To measure changes in the anterior ciliary muscle during accommodation at the nasal, superior, temporal, and inferior sectors by means of an anterior chamber optical coherence tomographer, and correlate them with vergence changes. Methods: Twenty-four subjects with healthy, phakic eyes, whose mean age was 27.1 ± 8.9 years, underwent measurement with an anterior chamber optical coherence tomographer. The anterior ciliary muscle was measured at the nasal, temporal, superior, and inferior sectors for 0, -1, -2, and -3 D of vergence. A linear model was used to assess the correlation of each eye parameter with the accommodative demand. Results: The anterior ciliary muscle area …
Impaired conflict resolution and vigilance in euthymic bipolar disorder.
2015
Abstract Difficulty attending is a common deficit of euthymic bipolar patients. However, it is not known whether this is a global attentional deficit or relates to a specific attentional network. According to the attention network approach, attention is best understood in terms of three functionally and neuroanatomically distinct networks-alerting, orienting, and executive control. In this study, we explored whether and which of the three attentional networks are altered in euthymic Bipolar Disorder (BD). A sample of euthymic BD patients and age-matched healthy controls completed the Attention Network Test for Interactions and Vigilance (ANTI-V) that provided not only a measure of orienting…
Evaluation of esophagogastric junction relaxation by 4-second Integrated Relaxation Pressure in achalasia using High Resolution Manometry with water-…
2014
Background Relaxation of the esophagogastric junction (EGJ) is now evaluated calculating 4-second integrated relaxation pressure (4-s IRP) by high resolution manometry (HREPT). Solid-state catheters have been used to define abnormal values. Our aim was to evaluate 4-s IRP in esophageal achalasia using HREPT with perfused catheters. Methods From June 2009 to June 2013, 936 HREPT studies have been performed in our unit. Of these, 194 patients having treated achalasia were excluded. Control group was constituted by 695 patients without achalasia, and 47 patients with untreated achalasia constituted the study group. HREPT was performed with water-perfused catheters. To establish the cut-off val…
Accuracy of staging in early oesophageal cancer using high resolution endoscopy and high resolution endosonography: a comparative, prospective, and b…
2004
The increasing use of endoscopic resection for curative treatment of early oesophageal cancers requires accurate staging before therapy. In a prospective blinded trial, we compared staging of early oesophageal carcinoma using high resolution endoscopy (HR-E) with staging using high resolution endosonography (HR-EUS).A total of 100 patients (89 men, 11 women; mean age 63.9 (10.8) years (range 31-91)) with a suspicion of early oesophageal adenocarcinoma (n = 81) or squamous cell carcinoma (n = 19) were enrolled in the study. After endoscopic staging with high resolution video endoscopy by two experienced endoscopists, HR-EUS was performed by an experienced endosonographer who was blinded to t…
Role of high-resolution ultrasonography without and with real-time spatial compound imaging in evaluating the injured posterior cruciate ligament: pr…
2009
This study sought to compare high-resolution ultrasonography (HRUS) without and with compound imaging in evaluating the injured posterior cruciate ligament (PCL). Thirteen patients with a magnetic resonance imaging (MRI) diagnosis of PCL lesions (ten acute and three chronic) and 20 healthy controls underwent conventional and compound HRUS performed by the same radiologist who was blinded to the subjects' case-control status. The PCL was scanned in a longitudinal direction in all cases. HRUS images were assessed for PCL thickness by two other radiologists blinded to the number and type of PCL injury. PCLs were classified as normal or injured, and the latter as having acute or chronic injurie…
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…
Benign and Atypical Meningioma Metabolic Signatures by High-Resolution Magic-Angle Spinning Molecular Profiling
2008
Meningiomas are neoplasms that arise from the leptomeningeal covering of the brain and spinal cord, accounting for 15%-20% of CNS tumors. The WHO classifies meningiomas into three histological grades: benign, atypical, and anaplasic in accordance with the clinical prognosis. Atypical and anaplasic meningiomas tend to recur. Sometimes, meningiomas with histological diagnosis of benign meningioma show clinical characteristics of atypical meningioma. In this context, high-resolution magic-angle spinning (HR-MAS) spectroscopy of intact tissue from brain tumor biopsies has shown great potential as a support diagnostic tool. In this work, we show differences between benign and atypical meningioma…
The effect of spherical aberration on visual performance and refractive state for stimuli and tasks typical of night viewing
2018
Purpose: The aim of this work was to examine the impact of Seidel spherical aberration (SA) on optimum refractive state for detecting and discriminating small bright lights on a dark background. Methods: An adaptive-optics system was used to correct ocular aberrations of cyclopleged eyes and then systematically introduce five levels of Seidel SA for a 7-mm diameter pupil: 0, ± 0.18, and ± 0.36 diopters (D) mm−2. For each level of SA, subjects were required to detect one or resolve two points of light (0.54 arc min diameter) on a dark background. Refractive error was measured by adjusting stimulus vergence to minimize detection and resolution thresholds. Two other novel focusing tasks for si…