A tree-topology preserving pairing for 3D/2D registration

Information Processing in Computer-Assisted Interventions (IPCAI) 2015 Special IssueInternational audiencePurpose: Fusing pre-operative and intra-operative information into a single space aims at taking advantage of two complementary modalities and necessitates a step of registration that must provide good alignment and relevant correspondences. This paper addresses both purposes in the case of 3D/2D vessel tree matching. Method: We propose a registration algorithm endorsing this vascular tree nature by providing a pairing procedure that preserves the tree topology and by integrating this pairing into an iterative algorithm maintaining pairing coherence. In addition, we define two complementary error measures quantifying the resulting alignment error and pairing error. Both are based on manual ground-truth that is independent of the type of transformation to retrieve. Results: Experiments were conducted on a database of 63 clinical cases, evaluating robustness and accuracy of our approach with respect to the iterative closest point algorithm. Conclusion: The proposed method exhibits good results both in term of pairing and alignment as well as low sensitivity to rotations to be compensated (up to 30 degrees)

Using occluding contours for 3D object modeling

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Suivi temporel 3D de vaisseaux coronaires dans les projections rayons X

International audienceFusing pre-operative CT angiography with per-operative an-giographic and fluoroscopic images is considered by physicians as a potentially useful tool for improved guidance. To be adopted, this tool requires the development of tracking methods adapted to the deformations of the arteries caused by the cardiac motion. Here, we propose a 3D/2D temporal tracking of one coronary vessel, based on a spline deformation, using pairings with a controlled 2D stretching or contraction along the paired curves and a preservation of the length of the 3D curve. Experiments were conducted on a database of 10 vessels from 5 distinct patients, with dedicated metrics assessing both the global registration and the local coherency of the position along the vessel. The proposed results demonstrate the efficiency of the proposed method, with an average standard deviation of 2 mm for the localization of landmarks

Iterative Closest Curve: a Framework for Curvilinear Structure Registration Application to 2D/3D Coronary Arteries Registration

International audienceTreatment coronary arteries endovascular involves catheter navigation through patient vasculature. The projective angiography guidance is limited in the case of chronic total occlusion where occluded vessel can not be seen. Integrating standard preoperative CT angiography information with live fluoroscopic images addresses this limitation but requires alignment of both modalities. This article proposes a structure-based registration method that intrinsically preserves both the geometrical and topological coherencies of the vascular centrelines to be registered, by the means of a dedicated curve-to-curve distance pairs of closest curves are identified, while pairing their points. Preliminary experiments demonstrate that the proposed approach performs better than the standard Iterative Closest Point method giving a wider attraction basin and improved accuracy

Reconstruction of Coronary Arteries from One Rotational X-Ray Projection Sequence

Cardiovascular diseases remain the first death cause in developed countries. In most cases, exploration of possibly underlying coronary artery pathologies is performed using injected X-ray coronary angiography imaging modality. Current clinical routine in coronary angiography is directly conducted in 2-D from angiograms acquired from several static points of view. However, for diagnosis and treatment purposes, coronary arteries reconstruction is highly suitable. In this report, we propose a novel method to reconstruct coronary arteries from one single rotational X-ray projection sequence. The purpose of this study is to provide physicians with a 3-D model of coronary arteries, e.g. for absolute tridimensional measures for lesion assessment, instead of direct projective measures deducted from the images, which are highly dependent on the point of view. Our method is split in 3 sequential steps: (1) 3-D stereoscopic reconstruction of coronary arteries centerlines, including respiratory motion compensation, (2) coronary arteries 4-D motion computation, and (3) 3-D tomographic reconstruction of coronary arteries, involving compensation for respiratory and cardiac motions. We have successfully tested it on the datasets from a synthetic phantom and16 patients

Machine precision assessment for 3D/2D digital subtracted angiography images registration

Colloque avec actes et comité de lecture.During an interventional neuroradiology exam, knowing the exact location of the catheter tip with respect to the patient can dramatically help the physician. An image registration between digital subtracted angiography (DSA) images and a volumic pre-operative image (magnetic resonance or computed tomography volumes) is a way to infer this important information. This mono-patient multimodality matching can be reduced to finding the projection matrix that transforms any voxel of the volume onto the DSA image plane. This modelization is unfortunately not valid in the case of distorted images, which is the case for DSA images. A classical angiography room can now generate 3D X-ray angiography volumes (3DXA). Since the DSA images are obtained with the same machine, it should be possible to deduce the projection matrix from the sensor data indicating the current machine position. We propose an interpolation scheme, associated to a pre- operative calibration of the machi

Recalage automatique d'images d'angiographie

Colloque avec actes et comité de lecture. nationale.National audienceAujourd'hui des volumes d'angiographie tridimensionnelle sont générées en routine à partir de séquences d'angiographie rotationnelle. Nous avions dans un précédent travail étudié la précision d'un recalage de ces volumes avec des images d'angiographie 2D classique, en nous basant uniquement sur les capteurs d'état de la machine. Cet estimé initial permet de poser le problème du recalage final comme l'estimation d'une translation d'amplitude quelconque associée à une petite rotation dans l'espace. Nous décrivons ici la stratégie que nous avons suivie afin de résoudre ce problème. Nous comparons en deux étapes l'image d'angiographie à la projection MIP ( Maximum Intensity Projection ) conique du volume angiographique. Dans un premier temps, la translation est estimée en maximisant la corrélation. La deuxième étape résout les paramètres du petit mouvement résiduel grâce à une technique de flux optique modifiée. Nous décrivons également comment accélérer le processus d'optimisation en nous basant sur une analyse des équations mises en oeuvre. Notre algorithme a été validé sur 17 images de fantômes et 2 patients. La mesure manuelle de l'erreur 3D indique qu'elle est inférieure à 1 mm. Le recalage est atteint en 1 mn 30 s par image. Un prototype a été installé dans un environnement clinique pour une validation plus approfondie

Découverte d’un territoire et de son patrimoine à travers le cadastre napoléonien et son intégration dans un système d’information géographique

Les démarches pour découvrir le patrimoine d’un territoire sont nombreuses et aujourd’hui connues pour être mises en application par des spécialistes, professionnels et amateurs. Qu’il s’agisse du dépouillement d’archives ou de prospection sur le terrain, ces recherches, longues et parfois fastidieuses, sont l’œuvre de passionnés. Les techniques modernes permettent aujourd’hui de faciliter le travail mais offrent surtout les moyens d’une restitution et d’un accès plus large au public de ces p..

Topological and geometrical corners by watershed

International audienc