The need for dedicated bifurcation quantitative coronary angiography (QCA) software algorithms to evaluate bifurcation lesions.

Single-vessel quantitative coronary angiography (QCA) software is inaccurate when used in bifurcation lesions due to the specific anatomical characteristics of bifurcations, including the natural step-down in diameters after every bifurcation. Dedicated bifurcation QCA software has been developed to overcome the limitations of single-vessel QCA in bifurcations. A phantom validation study has shown the superior accuracy of these bifurcation QCA algorithms compared to the single-vessel QCA software.

Clinical validation of the new T- and Y-shape models for the quantitative analysis of coronary bifurcations: an interobserver variability study.

Objectives: This article presents the results of an interobserver validation study of our new T- and Y-shape bifurcation models including their edge segment analyses.

Background: Over the last years, the coronary artery intervention procedures have been developed more and more toward bifurcation stenting. Because traditional straight vessel quantitative coronary arteriography (QCA) is not sufficient for these measurements, the need has grown for new bifurcation analysis methods.

QCA, IVUS and OCT in interventional cardiology in 2011.

Over the past 30 years, quantitative coronary arteriography (QCA) has been used extensively as an objective and reproducible tool in clinical research to assess changes in vessel dimensions as a result of interventions, but also as a tool to provide evidence to the interventionalist prior to and after an intervention and at follow-up when necessary. With the increasing complexities of bifurcation stenting, corresponding analytical tools for bifurcation analysis have been developed with extensive reporting schemes. Although intravascular ultrasound (IVUS) has been around for a long time as well, more recent radiofrequency analysis provides additional information about the vessel wall composition; likewise optical coherence tomography (OCT) provides detailed information about the positions of the stent struts and the quality of the stent placement.

Dedicated bifurcation analysis: basic principles.

Over the last several years significant interest has arisen in bifurcation stenting, in particular stimulated by the European Bifurcation Club. Traditional straight vessel analysis by QCA does not satisfy the requirements for such complex morphologies anymore. To come up with practical solutions, we have developed two models, a Y-shape and a T-shape model, suitable for bifurcation QCA analysis depending on the specific anatomy of the coronary bifurcation.

New approaches for the assessment of vessel sizes in quantitative (cardio-)vascular X-ray analysis.

This paper presents new approaches for the assessment of the arterial and reference diameters in (cardio-)vascular X-ray images, designed to overcome the problems experienced in conventional quantitative coronary and vascular angiography approaches. In single or "straight" vessel segments, the arterial and reference diameter directions were made independent of each other in order to be able to measure the minimal lumen diameter (MLD) more accurately, especially in curved vessel segments. For ostial segments, an extension of this approach was used, to allow measurement of ostial lesions in sidebranches more proximal than using conventional methods.

Coronary angiography enhancement for visualization.

High quality visualization on X-ray angiograms is of great significance both for the diagnosis of vessel abnormalities and for coronary interventions. Algorithms for improving the visualization of detailed vascular structures without significantly increasing image noise are currently demanded in the market. A new algorithm called stick-guided lateral inhibition (SGLI) is presented for increasing the visibility of coronary vascular structures.

Quantitative angiographic methods for bifurcation lesions: a consensus statement from the European Bifurcation Group.

The treatment of bifurcation lesions is complex and increasingly common. A growing number of dedicated bifurcation devices are under clinical evaluation, but no standardized methodology exists. Specifically, the angiographic analysis of bifurcation lesions is not standardized and current QCA packages are not designed for bifurcation lesions.

Evaluation of patients with previous coronary stent implantation with 64-section CT.

Purpose: To prospectively evaluate the diagnostic accuracy of 64-section computed tomography (CT) for the assessment of in-stent or peristent restenosis, with conventional coronary angiography as the reference standard.

Materials And Methods: The study was approved by the medical ethics committee, and informed consent was obtained in all 50 enrolled patients (40 men, 10 women; mean age, 60 years +/- 11 [standard deviation]). In addition to conventional coronary angiography with quantitative coronary angiography, 64-section CT was performed.

A new quantitative analysis system for the evaluation of coronary bifurcation lesions: comparison with current conventional methods.

Background: Objective conventional quantitative angiographic systems are designed to automatically follow the contours of straight vascular segments and not of bifurcations. Recently a new analysis method was specifically developed for bifurcation lesions, able to automatically divide the lesion into three separate segments. In this study, we aimed to assess whether the smaller interaction required by the analyst could reduce the analysis time and inter and intra observer variability when compared with a conventional analysis.

Is there an effect of flat-panel-based imaging systems on quantitative coronary and vascular angiography?

Objectives: To study the possible effects on quantitative coronary or vascular analyses (QCA and QVA) on images of a flat-panel-based (FP-based) system.

Background: Since a few years, more and more cardiovascular X-ray imaging systems are equipped with flat-panel detectors, replacing the conventional image intensifiers in combination with CCD cameras for the creation of the angiographic images.

Methods: To assess any differences in QCA and QVA results from these two types of digital X-ray imaging systems, we performed a quantitative comparison study on images of the Medis coronary and vascular phantom, respectively.

A new approach to contour detection in x-ray arteriograms: the wavecontour.

Objectives: We sought to develop a novel approach (the Wavecontour) for the detection of contours in vascular x-ray images, designed to eliminate any systematic underestimation or overestimation for vessel sizes in the range of 0.5 to 15 mm and further minimize the influence of the user-defined start points and end points.

Materials And Methods: This method is based on the Wavefront Propagation principle in a 2-stage approach.

Cardiac multidetector-row computed tomography in patients with unstable angina.

Ideally, information on coronary artery stenosis and left ventricular (LV) function is obtained in patients who have unstable angina to allow optimal risk stratification. The value of multidetector-row computed tomography (MDCT) was evaluated for a simultaneous assessment of coronary artery disease and global/regional LV function using a single acquisition. Twenty-five patients who had unstable angina underwent a single multidetector-row computed tomographic acquisition using a 4-slice multidetector-row computed tomographic system.

Validation of a new method for the detection of pathlines in vascular x-ray images.

This article presents the validation of a new pathline approach, based on the wavefront propagation principle, on a large variety of vascular images. The purpose of the novel approach, called wavepath, was to minimize the variability of the measurements in the quantitative vascular analysis by reducing the variability that is introduced by manually placing the start and end points of the vessel segment. This results in a robust and reproducible pathline detection that is subsequently used in the analysis and lesion quantification.

A novel measurement technique to assess the effects of coronary brachytherapy in clinical trials.

This paper presents a novel measurement technique to assess the effects of coronary brachytherapy. This new technique is based upon the conventional quantitative coronary analysis (QCA) technique, which is accepted worldwide as an accurate and reliable analysis tool for clinical trials. This paper provides the definitions and main issues important for correct brachytherapy analysis.

A novel approach for the detection of pathlines in X-ray angiograms: the wavefront propagation algorithm.

This article presents a new pathline approach, based on the wavefront propagation principle, and developed in order to reduce the variability in the outcomes of the quantitative coronary artery analysis. This novel approach, called wavepath, reduces the influence of the user-defined start- and endpoints of the vessel segment and is therefore more robust and improves the reproducibility of the lesion quantification substantially. The validation study shows that the wavepath method is totally constant in the middle part of the pathline, even when using the method for constructing a bifurcation or sidebranch pathline.

Advanced contour detection for three-dimensional intracoronary ultrasound: a validation--in vitro and in vivo.

Intracoronary ultrasound (ICUS) provides high-resolution transmural images of the arterial wall. By performing a pullback of the ICUS transducer and three-dimensional reconstruction of the images, an advanced assessment of the lumen and vessel wall morphology can be obtained. To reduce the analysis time and the subjectivity of boundary tracing, automated segmentation of the image sequence must be performed.

One core laboratory at two international sites, is that feasible? An inter-core laboratory and intra-observer variability study.

To assess the magnitude of differences in QCA outcomes between two cooperating core laboratories in a single trial, we have carried out an inter-core laboratory variability study. Two QCA experts at the Montreal Heart Institute and Heart Core Leiden both analyzed 32 lesions (pre- and post-intervention) in accordance with previously agreed upon standard operating procedures. One of the experts analyzed the whole image set twice to determine the intraobserver variability.