Search results for "Imaging"
showing 10 items of 6802 documents
Choroidal thickness in glaucoma patients and glaucoma suspects measured by spectral domain coherence optical tomography
2012
Purpose: The aim of our study was to evaluate and compare retro-foveolar choroidal thickness (RFCT) of healthy subjects, individuals with intraocular hypertension, patients with primary open-angle glaucoma (POAG), patients with normal tension glaucoma (NTG) and patients with primary angle-closure glaucoma (PACG) by spectral domain optical coherence tomography (SD-OCT).Methods: Sixty-five healthy eyes, 30 eyes with intraocular hypertension, 90 eyes with POAG, 30 eyes with NTG and 20 eyes with PACG were included in this cross-sectional study. RFCT, foveolar retinal thickness and average retinal nerve fiber layer thickness (RNFL) were measured by SD-OCT (Spectralis HRA-OCT, Heidelberg Engineer…
Anatomical and functional macular changes after rhegmatogenous retinal detachment with macula off
2011
International audience; Purpose: To evaluate the correlation between morphologic changes in the outer retina and visual function after successful repair of rhegmatogenous retinal detachment with macula off. Methods: Thirty patients (30 eyes) with successful repair of rhegmatogenous retinal detachment (RD) after macula off and a minimum 6-month follow-up after the surgery were examined. Preoperative characteristics of the RD (visual acuity and duration) were collected. Postoperative visual acuity measurement with ETDRS scale and fundus autofluorescence (FAF) were performed. Spectral-Domain Optical Coherence Tomography (HRA OCT) of outer retina was performed to analyse the number of disrupted…
Contributions à l’imagerie polarimétrique et à ses applications en vision pour la robotique
2019
Ce mémoire présente le bilan de l'ensemble de mes travaux de recherche effectués de septembre 2006 à juin 2019 au sein de l'équipe Creusotine du laboratoire Le2i devenue équipe Vibot ERL CNRS 6000 depuis janvier 2018. Les principales activités de recherche que j'ai menées au cours de ces 10 dernières années autour de l'imagerie polarimétrique, de la vision omnidirectionnelle et de leurs applications en vision pour la robotique seront particulièrement détaillées dans ce document. Elles seront présentées selon deux grandes parties : la première concernera plutôt l'aspect mise en œuvre et calibrage des caméras et la seconde se concentrera sur les applications potentielles en vision pour la rob…
Contributions à l'analyse et à l'interprétation des images : Extraction et représentation de caractéristiques
2016
Ce mémoire, rédigé en vue de l'obtention de l'Habilitation à Diriger des Recherches (HDR), offre un aperçu des travaux de recherche et d’encadrement que j’ai pu mener depuis l'obtention de mon doctorat. Il montre la diversité des champs d’application et de recherche (en vision et en imagerie médicale) que j’ai pu couvrir , ainsi que mon implication dans l’encadrement doctoral.Mes activités de recherche se divisent en deux grandes parties. D'une part, l'analyse de scènes dynamiques, à savoir la détection de regions d'intérêt dans des séquences d'images, pour réduire la taile des données à traiter, et la détection et le suivi d'objets mobiles à l'aide de caméras de diverses natures (perspecti…
A method for measuring wetting and swelling of bentonite using X-ray imaging
2022
A non-invasive method based on X-ray imaging for measuring deformation and water transport in wetting and swelling bentonite samples is introduced. Sequential X-ray images taken of the samples were used to calculate the attenuation coefficient and deformation. These results, together with careful calibration, allowed finding the dry density and water content distributions and their temporal evolution in the wetting and swelling samples. A specific correction technique, based on regularly taking reference X-ray images of aluminum plates of varying thickness, was developed and used to take into account X-ray beam instabilities and thus to improve the accuracy of density analysis. Large deform…
Ultrasound bioeffects in rats: quantification of cellular damage in the fetal liver after pulsed Doppler imaging
2011
Objective To determine whether pulsed Doppler examination of the ductus venosus in rat fetuses could damage exposed tissue. Methods On gestational day 18, the livers of a mean of approximately five fetuses per mother (n = 5.14, SD = 1.6), in a cohort of 35 pregnant female rats, were exposed individually to pulsed Doppler and these were considered the 'exposed group'. The remaining fetuses in each pregnant rat (n = 5.16, SD = 2.1) formed the 'control group'. We tested for 600, 300, 60, 20, 15, 10 and 3 s of exposure of the fetal ductus venosus and the damage was evaluated measuring a cell death index of apoptotic activity at 7 h post-exposure (n = 16). In addition, subgroups of mothers were …
Intravenous Contrast Material for Cardiac Computed Tomography
2023
Purpose: The Italian Registry of Contrast Material use in Cardiac Computed Tomography (iRCM-CCT) is a multicenter, multivendor, observational study on the use of contrast media (CM) in patients undergoing cardiac computed tomography (CCT). The aim of iRCM-CCT is to assess image quality and safety profile of intravenous CM compounds. Materials and methods: iRCM-CCT enrolled 1842 consecutive patients undergoing CCT (≥50 per site) at 20 cluster sites with the indication of suspected coronary artery disease. Demographic characteristics, CCT, and CM protocols, clinical indications, safety markers, radiation dose reports, qualitative (ie, poor vascular enhancement) and quantitative (ie, HU attenu…
An International Survey of Quality and Safety Programs in Radiology
2021
Purpose: The aim of this study was to determine the status of radiology quality improvement programs in a variety of selected nations worldwide. Methods: A survey was developed by select members of the International Economics Committee of the American College of Radiology on quality programs and was distributed to committee members. Members responded on behalf of their country. The 51-question survey asked about 12 different quality initiatives which were grouped into 4 themes: departments, users, equipment, and outcomes. Respondents reported whether a designated type of quality initiative was used in their country and answered subsequent questions further characterizing it. Results: The re…
Automated Detection of Microaneurysms Using Scale-Adapted Blob Analysis and Semi-Supervised Learning
2014
International audience; Despite several attempts, automated detection of microaneurysm (MA) from digital fundus images still remains to be an open issue. This is due to the subtle nature of MAs against the surrounding tissues. In this paper, the microaneurysm detection problem is modeled as finding interest regions or blobs from an image and an automatic local-scale selection technique is presented. Several scale-adapted region descriptors are then introduced to characterize these blob regions. A semi-supervised based learning approach, which requires few manually annotated learning examples, is also proposed to train a classifier to detect true MAs. The developed system is built using only…
Microchimerism in multiple sclerosis: The association between sex of offspring and MRI features in women with multiple sclerosis
2023
AimsDuring pregnancy, fetal cells can migrate to the mother via blood circulation. A percentage of these cells survive in maternal tissues for decades generating a population of fetal microchimeric cells (fMCs), whose biological role is unclear. The aim of this study was to investigate the association between the sex of offspring, an indirect marker of fMCs, and magnetic resonance imaging (MRI) features in women with multiple sclerosis (MS).MethodsWe recruited 26 nulliparous MS patients (NPp), 20 patients with at least one male son (XYp), and 8 patients with only daughters (XXp). Each patient underwent brain MR scan to acquire 3D-T2w FLAIR FatSat and 3D-T1w FSPGR/TFE. Lesion Segmentation To…