Fast simulation of stent deployment with plastic beam elements.

Coronary stent deployment is a reference cardiology intervention, used to treat atherosclerosis and prevent heart attacks. The outcomes of the intervention highly depend on the accuracy of the stent apposition, which could benefit from per-operative prediction tools. In this paper, we propose a fast and mechanically realistic 3D simulation of a coronary stent expansion.

Computed and Subjective Blue Scleral Color Analysis as a Diagnostic Tool for Iron Deficiency: A Pilot Study.

Iron deficiency (ID) is the most common nutritional deficiency. ID diagnosis requires ferritin measurement because clinical findings are poor and nonspecific. We studied the diagnostic value of blue sclera, which was scarcely reported as a specific and sensitive sign of ID.

Contour segmentation of the intima, media, and adventitia layers in intracoronary OCT images: application to fully automatic detection of healthy wall regions.

Purpose: Quantitative and automatic analysis of intracoronary optical coherence tomography images is useful and time-saving to assess cardiovascular risk in the clinical arena.

Methods: First, the interfaces of the intima, media, and adventitia layers are segmented, by means of an original front propagation scheme, running in a 4D multi-parametric space, to simultaneously extract three non-crossing contours in the initial cross-sectional image. Second, information resulting from the tentative contours is exploited by a machine learning approach to identify healthy and diseased regions of the arterial wall.

Estimation of Myocardial Strain and Contraction Phase From Cine MRI Using Variational Data Assimilation.

This paper presents a new method to estimate left ventricle deformations using variational data assimilation that combines image observations from cine MRI and a dynamic evolution model of the heart. The main contribution of the model is that it embeds parameters modeling the contraction / relaxation process. It estimates myocardial motion and contraction parameters simultaneously, providing accurate complementary information for diagnosis.

Improved Estimation of Cardiac Function Parameters Using a Combination of Independent Automated Segmentation Results in Cardiovascular Magnetic Resonance Imaging.

This work aimed at combining different segmentation approaches to produce a robust and accurate segmentation result. Three to five segmentation results of the left ventricle were combined using the STAPLE algorithm and the reliability of the resulting segmentation was evaluated in comparison with the result of each individual segmentation method. This comparison was performed using a supervised approach based on a reference method.

Automated peroperative assessment of stents apposition from OCT pullbacks.

This study's aim was to control the stents apposition by automatically analyzing endovascular optical coherence tomography (OCT) sequences. Lumen is detected using threshold, morphological and gradient operators to run a Dijkstra algorithm. Wrong detection tagged by the user and caused by bifurcation, struts'presence, thrombotic lesions or dissections can be corrected using a morphing algorithm.

Nonsupervised ranking of different segmentation approaches: application to the estimation of the left ventricular ejection fraction from cardiac cine MRI sequences.

A statistical methodology is proposed to rank several estimation methods of a relevant clinical parameter when no gold standard is available. Based on a regression without truth method, the proposed approach was applied to rank eight methods without using any a priori information regarding the reliability of each method and its degree of automation. It was only based on a prior concerning the statistical distribution of the parameter of interest in the database.

Comparison of different segmentation approaches without using gold standard. Application to the estimation of the left ventricle ejection fraction from cardiac cine MRI sequences.

A statistical method is proposed to compare several estimates of a relevant clinical parameter when no gold standard is available. The method is illustrated by considering the left ventricle ejection fraction derived from cardiac magnetic resonance images and computed using seven approaches with different degrees of automation. The proposed method did not use any a priori regarding with the reliability of each method and its degree of automation.

Spatial distribution of neo-intimal hyperplasia 6 months after zotarolimus-eluting stent implantation, analysed by optical coherence tomography.

Background: Optical coherence tomography is a high-resolution imaging technology that allows in vivo assessment of neointimal hyperplasia and strut coverage after coronary stenting.

Aim: Assessment of spatial distribution of healing, 6 months after zotarolimus-eluting stent implantation.

Methods: Forty-two zotarolimus-eluting stents were monitored by optical coherence tomography 6 months after implantation.

High-resolution coronary imaging by optical coherence tomography: Feasibility, pitfalls and artefact analysis.

Background: Optical coherence tomography is an imaging method that enables cardiologists to study atheromatous plaques, and to check the implantation and evolution of coronary stents. It is an invasive technique, providing high-resolution (10 microm) in vivo images, but with limitations and artefacts that need to be understood before the field of application can be extended.

Aim: To determine the feasibility and limitations of optical coherence tomography coronary imaging from a single-centre experience.

In vivo supervised analysis of stent reendothelialization from optical coherence tomography.

The aim of this study is to interactively assess reendothelialization of stents at an accuracy of down to a few micrometer by analyzing endovascular optical coherence tomography (OCT) sequences. Vessel wall and stent struts are automatically detected by using morphological, gradient, and symmetry operators coupled with active contour models; alerts are issued to ask for user supervision over some extreme irregular geometries caused by thrombotic lesions or dissections. A complete distance map is then computed from sparse distances measured between wall and struts.

Comparative analysis of neointimal coverage with paclitaxel and zotarolimus drug-eluting stents, using optical coherence tomography 6 months after implantation.

Background: Intrastent thrombosis, while rare, has a poor prognosis. Strut non-coverage is one causal factor, especially in cases of resistance to or premature discontinuation of dual antiplatelet therapy.

Aim: To compare neointimal coverage with paclitaxel and zotarolimus drug-eluting stents, using optical coherence tomography (OCT).

Contact position analysis of deep brain stimulation electrodes on post-operative CT images.

Purpose: Groups performing deep brain stimulation advocate post-operative imaging [magnetic resonance imaging (MRI) or computer tomography (CT)] to analyse the position of each electrode contact. The artefact of the Activa 3389 electrode had been described for MRI but not for CT. We undertook an electrode artefact analysis for CT imaging to obtain information on the artefact dimensions and related electrode contact positions.

In vivo OCT coronary imaging augmented with stent reendothelialization score.

The aim of this study is to automatically assess reendothelialization of stents at an accuracy of down to a few microns by analyzing endovascular optical coherence tomography (OCT) sequences. Vessel wall and struts are automatically detected and complete distance map is then computed from sparse distances measured between wall and struts by thin-plate spline (TPS) interpolation. A reendothelialization score is mapped onto the geometry of the coronary artery segment.

Early detection and monitoring of cartilage alteration in the experimental meniscectomised guinea pig model of osteoarthritis by 99mTc-NTP 15-5 scintigraphy.

Purpose: This study in the meniscectomised guinea pig aimed to demonstrate that the radiotracer (99m)Tc-NTP 15-5 would have pathophysiological validity for in vivo osteoarthritis imaging.

Methods: The specificity of (99m)Tc-NTP 15-5 for cartilage was determined in healthy animals (n = 13), by tissue radioactivity counting, joint autoradiography and scintigraphy. (99m)Tc-NTP 15-5 scintigraphy was performed at 20, 50, 80, 115, 130, 150 and 180 days after medial meniscectomy (n = 10 MNX) or sham operation (n = 5), and scintigraphic ratios (operated/contralateral) were calculated for femoral (F) and tibial (T) areas.

Radiographic stereometry for non-metal-backed acetubular cups: 3D wear estimation and related uncertainty.

The aim of this work was to assess the 3D wear of non-metal-backed acetubular cups from two conventional digitized radiographs. The centers of the femoral head and the metal ring in the equatorial plane of the cup are located using 3D pose techniques for spheres and circles from sampled points in the images. The method used to locate these points of interest and also estimate their covariance is fully described in previous work.