3D Reconstruction Of Coronary Arteries Research Articles

Optimal 3D reconstruction of coronary arteries for 3D clinical assessment

A novel method is presented for 3D reconstruction of the coronary arteries. The algorithm refines the point correspondences between the arteries visible in a pair of monoplane X-ray fluoroscopy images acquired at different incidences. Traditional computer vision techniques use the RANSAC methods to discard outliers in a list of corresponding points. However, as these methods work for rigid motion primarily, we introduce a curvature constraint that relates the 2D and 3D Frenet information of the coronary artery centerlines. This constraint takes into account non-rigid movement of the arteries and also serves as a refinement tool to discard potential outlier points. Results show that for synthetic experiments with left–right anterior oblique (LAO/RAO) and posterior–left lateral (PA/LAT) viewing angles, the average 3D RMS errors are respectively 3.1 mm and 1.9 mm for the RANSAC method, and decrease to 2.8 mm and 1.1 mm by using our curvature constraint methodology. Similarly, clinical validation is performed on two datasets and the average 2D retroprojection errors are 3.34 pixels and 2.24 pixels, respectively.

A method for 3D reconstruction of coronary arteries using biplane angiography and intravascular ultrasound images

The aim of this study is to describe a new method for the three-dimensional reconstruction of coronary arteries and its quantitative validation. Our approach is based on the fusion of the data provided by intravascular ultrasound images (IVUS) and biplane angiographies. A specific segmentation algorithm is used for the detection of the regions of interest in intravascular ultrasound images. A new methodology is also introduced for the accurate extraction of the catheter path. In detail, a cubic B-spline is used for approximating the catheter path in each biplane projection. Each B-spline curve is swept along the normal direction of its X-ray angiographic plane forming a surface. The intersection of the two surfaces is a 3D curve, which represents the reconstructed path. The detected regions of interest in the IVUS images are placed perpendicularly onto the path and their relative axial twist is computed using the sequential triangulation algorithm. Then, an efficient algorithm is applied to estimate the absolute orientation of the first IVUS frame. In order to obtain 3D visualization the commercial package Geomagic Studio 4.0 is used. The performance of the proposed method is assessed using a validation methodology which addresses the separate validation of each step followed for obtaining the coronary reconstruction. The performance of the segmentation algorithm was examined in 80 IVUS images. The reliability of the path extraction method was studied in vitro using a metal wire model and in vivo in a dataset of 11 patients. The performance of the sequential triangulation algorithm was tested in two gutter models and in the coronary arteries (marked with metal clips) of six cadaveric sheep hearts. Finally, the accuracy in the estimation of the first IVUS frame absolute orientation was examined in the same set of cadaveric sheep hearts. The obtained results demonstrate that the proposed reconstruction method is reliable and capable of depicting the morphology of coronary arteries.

Three-dimensional coronary artery reconstruction using fusion of intravascular ultrasound and biplane angiography

We have developed an efficient method for 3D reconstruction of coronary arteries. Our approach is based on the fusion of intravascular ultrasound (IVUS) and biplane angiography. The method includes an efficient algorithm for the automatic identification of the regions of interest in IVUS images and a novel methodology for the extraction of the catheter path from biplane angiographies. The estimation of IVUS frames relative twist and the computation of first IVUS frame absolute orientation is also investigated. To assess the performance of the method, a validation procedure is introduced. Several metrics are obtained to verify the reliability of our method in the description of coronary artery morphology.

True 3-dimensional reconstruction of coronary arteries in patients by fusion of angiography and IVUS (ANGUS) and its quantitative validation.

True 3D reconstruction of coronary arteries in patients based on intravascular ultrasound (IVUS) may be achieved by fusing angiographic and IVUS information (ANGUS). The clinical applicability of ANGUS was tested, and its accuracy was evaluated quantitatively. METHODS AND REUSLTS: In 16 patients who were investigated 6 months after stent implantation, a sheath-based catheter was used to acquire IVUS images during an R-wave-triggered, motorized stepped pullback. First, a single set of end-diastolic biplane angiographic images documented the 3D location of the catheter at the beginning of pullback. From this set, the 3D pullback trajectory was predicted. Second, contours of the lumen or stent obtained from IVUS were fused with the 3D trajectory. Third, the angular rotation of the reconstruction was optimized by quantitative matching of the silhouettes of the 3D reconstruction with the actual biplane images. Reconstructions were obtained in 12 patients. The number of pullback steps, which determines the pullback length, closely agreed with the reconstructed path length (r=0.99). Geometric measurements in silhouette images of the 3D reconstructions showed high correlation (0.84 to 0.97) with corresponding measurements in the actual biplane angiographic images. With ANGUS, 3D reconstructions of coronary arteries can be successfully and accurately obtained in the majority of patients.

3D-reconstruction of coronary arteries in view of flow measurement.

An angiographic method for measurement of absolute coronary blood flow in patients was developed. It is based on 3D-reconstruction of the left or right coronary tree from digitized biplane coronary cineangiograms. The apparatus is presently composed of a 35 mm cinefilm projector with a video camera and a 512 x 512 x 8 bits image array processor controlled by a VAX-11/750 computer. First, the parameters of the two angiographic projections are determined in form of two 4 x 3 matrices from a pair of cineframes showing a 4 cm cube bearing markers. The cube is filmed after the coronary injection, with unchanged geometric configuration. The coronary arteries of interest are then 3D-reconstructed from a pair of cineframes showing them fully opacified. This allows to compute the intravascular volumes needed for flow determination. In vitro experiments showed that the obtained volume are reasonably accurate. For the measurement of coronary flow, the concentration of contrast medium along the involved arteries is computed (in arbitrary units) from two cineframes taken one (or two) cardiac cycle after onset of the injection. This yields a 'concentration-distance' curve per artery. The volume of fluid (contrast medium mixed with blood) which flows into the arteries during this (or these two) cardiac cycle is determined by applying a concentration threshold to the obtained concentration-distance curves. Measurements performed on a constant flow model were satisfying. Preliminary measurements in 12 patients showed that flow values obtained angiographically into the left anterior descending coronary artery correlate well with the values measured simultaneously by thermodilution in the great cardiac vein (Qangio = 0.83 x Qthermo + 16.1 ml, r = 0.87, n = 29).

Spatial reconstruction of coronary arteries from angiographic images

A method for 3D reconstruction of coronary arteries from two angiographic projection views is presented (cinefilm 35 mm, 50 images/s). The geometric information defining the two projections is secured by filming a cube bearing 15 steel markers in the approximate location of the heart. For 3D reconstruction, a pair of images of the cube and two simultaneous images of the coronary tree are digitized on a computer assisted system. Two matrices describing the two projections are obtained from the 15*2*2 image coordinates of the cube markers. Next, the operator draws with a mouse the approximate centre lines of the coronary arteries to be 3D reconstructed. The program then determines the centre lines and the edges of the vessels in the two images accurately. The 3D centre lines are reconstructed and the true local vessel diameters determined. Intravascular volumes are obtained by summation of elementary volumes. The reconstructed arteries are visualized on a colour TV monitor.

An expert system for the labeling and 3D reconstruction of the coronary arteries from two projections

In this paper we present a rule-based expert system for the automatic delineation and 3D reconstruction of the left coronary artery on standard RAO and LAO angiographic projections. The approach is based on the application of a general blood vessel model and on anatomical models which take into account the normal variations of the coronary artery structure. In a first step, the arteries are delineated by detecting the maximum intensity on the centerline of the vessels. Then, we label the blood vessel segments according to an anatomical model of the left coronary artery. In general, only 1-2 labels remain for each blood vessel segment. Finally, these results are used for an automatic 3D reconstruction of the left coronary artery from two projections. Results from clinical RAO and LAO angiograms will be presented.