Motion-Aware Mosaicing for Confocal Laser Endomicroscopy

International audienceProbe-based Confocal Laser Endomicroscopy (pCLE) provides physicians with real-time access to histological information during standard endoscopy procedures, through high-resolution cellular imaging of internal tissues. Earlier work on mosaicing has enhanced the potential of this imaging modality by meeting the need to get a complete representation of the imaged region. However, with approaches, the dynamic information, which may be of clinical interest, is lost. In this study, we propose a new mosaic construction algorithm for pCLE sequences based on a min-cut optimization and gradient-domain composition. Its main advantage is that the motion of some structures within the tissue such as blood cells in capillaries, is taken into account. This allows physicians to get both a sharper static representation and a dynamic representation of the imaged tissue. Results on 16 sequences acquired in vivo on six different organs demonstrate the clinical relevance of our approach

Smart Atlas for Supporting the Interpretation of probe-based Confocal Laser Endomicroscopy (pCLE) of Biliary Strictures: First Classification Results of a Computer-Aided Diagnosis Software based on Image Recognition

International audiencepCLE enables microscopic imaging of biliary strictures, in vivo and in real time, during an ERCP procedure. Results of a multicentric study (Meining et al., GIE 2011) have shown that pCLE allows endoscopists to diferentiate benign from malignant strictures in real time with high sensitivity and NPV. A computer-aided diagnosis software called Smart Atlas has been developed to assist endoscopists with the interpretation of pCLE sequences. This study aims at evaluating the performance of this software for the diferentiation of benign and malignant strictures

Smart Atlas for Supporting the Interpretation of needle-based Confocal Laser Endomicroscopy (nCLE) of Pancreatic Cysts: First Classification Results of a Computer-Aided Diagnosis Software based on Image Recognition

International audiencenCLE enables microscopic imaging of pancreatic cysts, in vivo and in real time, during an EUS-FNA procedure. Diferentiating branch duct-type Intraductal Papillary Mucinous Neoplasm (IPMN) and Serous Cystadenoma (SCA) of the pancreas can be difcult, especially in case of a solitary lesion without clear communication with the pancreatic duct. Recent studies (Konda et al., Endoscopy 2013; Napoléon et al., DDW 2013) have identifed reliable nCLE descriptive features (superfcial vascular network in SCA; fngerlike projections in IPMN), allowing endoscopists to discriminate between SCA and IPMN. In parallel, a computer-aided diagnosis software called Smart Atlas has been developed to assist endoscopists with the interpretation of nCLE video sequences. This study aims at evaluating the performance of this software for the diferentiation of SCA and IPMN cases

Smart Atlas for Supporting the Interpretation of probe-based Confocal Laser Endomicroscopy (pCLE) of Gastric Lesions: First Classification Results of a Computer-Aided Diagnosis Software based on Image Recognition

International audiencepCLE enables microscopic imaging of gastrointestinal mucosal lesions, in vivo and in real time, during an endoscopy procedure. Recent studies have demonstrated that pCLE enables accurate diagnosis of superfcial gastric neoplasia. In parallel, a computer-aided diagnosis software called Smart Atlas has been developed to assist endoscopists with the interpretation of pCLE sequences. This study aims at evaluating the performance of this software for the classifcation of gastric lesions into four pathological classes: healthy stomach, gastric intestinal metaplasia (GIM), dysplasia, and cancer

Reconstruction 3D of the anterior eye segment by echography high frequency

Une des applications de l’échographie médicale est celle de l’ophtalmologie qui pose de nombreux problèmes spécifiques liés en partie à la faible dimension de l’oeil et à la précision importante que requièrent les mesures intraoculaires. En effet, avec le développement de la chirurgie réfractive qui regroupe ensemble des techniques capables de corriger les erreurs de réfraction et l’avènement des implants intraoculaires, le chirurgien ophtalmologiste est amené à surveiller la tolérance et les effets secondaires de ces implants sur les structures du segment antérieur. L’échographie à haute fréquence apporte la résolution suffisante pour cette tâche. Cependant, le développement de l’échographie 3D permet une extension des applications ophtalmologiques notamment pour le dimensionnement des implants en préopératoire. La modélisation 3D du segment antérieur permet d’étudier le comportement des implants et surtout de dessiner à terme un implant « sur mesure » pour le patient. C’est dans ce contexte que nous présentons une méthode originale de segmentation et de reconstruction 3D du segment antérieur par échographique haute fréquence en utilisant l’ajustement de modèles 3D. Nous utilisons un système échographique 3D de type main-libre, composé d’une sonde échographique haute fréquence, et d’un module de localisation actif comprenant une caméra et des marqueurs infrarouges. Ce système échographique 3D nous permet d’obtenir des images avec des informations de positionnement dans l’espace tridimensionnel associées. Nous avons ainsi pu mettre en place toute une chaîne d’acquisitions et de traitements des images échographiques. Nous créons, à partir d’images échographiques du segment antérieur oculaire, des modèles de référence 3D réalistes. Nous proposons ainsi une méthode d’ajustement de modèles 3D de référence sur des données 3D échographiques via l’utilisation de l’algorithme de recalage ICP. Nous avons également sélectionné et adapté différentes méthodes pour l’évaluation de l’approche de reconstruction proposée. Ces méthodes permettent de mettre en valeur la précision de ces reconstructions.Ophthalmology is one of the clinical application fields of ultrasound imaging, for which numerous specific issues arise, related in part to the eye’s small anatomical dimensions combined with the high level of accuracy requirements associated with intraocular measurements. Indeed, since the development of refractive surgery including all the techniques dedicated to the correction of refractive errors, as well as the emergence of intraocular lens (IOL), ophthalmic surgeons have to monitor overall acceptance as well as secondary effects related to these implants on the structures of the anterior eye segment. High frequency ultrasound imaging provides the required spatial resolution for this task. However, the development of 3D ultrasound imaging allows for the development of new applications in ophthalmology, for instance pre-operative dimensioning of the lens. 3D modelling of the anterior eye segment therefore allows studying the IOL behaviour and may help designing future personalized IOL tailored for each patient. Within this context, we present an original 3D segmentation and reconstruction method based on 3D models registration, dedicated to the anterior eye segment acquired in high frequency ultrasound imaging. We used a 3D ultrasound free-hand acquisition system, composed of a high frequency ultrasound probe and a localization module based on a camera and infrared markers. This 3D ultrasound system provides images along with associated 3D spatial positioning information. We were therefore able to develop an entire ultrasound images acquisition and processing chain. This allowed us creating realistic reference 3D models from sequences of ultrasound images of the anterior eye segment. We thus propose a method based on the iterative closest point (ICP) algorithm for the registration of the 3D reference models to 3D ultrasound acquired data. We have also selected and adapted various methods for the evaluation of the proposed reconstruction process. These methods highlight the accuracy of the obtained reconstructions

Semi-automated query construction for content-based endomicroscopy video retrieval

International audienceContent-based video retrieval has shown promising results to help physicians in their interpretation of medical videos in general and endomicroscopic ones in particular. Defining a relevant query for CBVR can however be a complex and time-consuming task for non-expert and even expert users. Indeed, uncut endomicroscopy videos may very well contain images corresponding to a variety of different tissue types. Using such uncut videos as queries may lead to drastic performance degradations for the system. In this study, we propose a semi-automated methodology that allows the physician to create meaningful and relevant queries in a simple and efficient manner. We believe that this will lead to more reproducible and more consistent results. The validation of our method is divided into two approaches. The first one is an indirect validation based on per video classification results with histopathological ground-truth. The second one is more direct and relies on perceived inter-video visual similarity ground-truth. We demonstrate that our proposed method significantly outperforms the approach with uncut videos and approaches the performance of a tedious manual query construction by an expert. Finally, we show that the similarity perceived between videos by experts is significantly correlated with the inter-video similarity distance computed by our retrieval system

Reconstruction 3D du segment antérieur du globe oculaire par l'utilisation de données radio-fréquence échographique et d'un modèle déformable

Cette étude vise à reconstruire le segment antérieur du globe oculaire (SA) afin de mieux définir la taille des implants phakes. La méthode proposée adapte un modèle générique 3D sur les données radio fréquence (RF)