Menachem Halmann

Dynamic analysis of left-ventricular shape based on curvature function

SummaryThe local curvature function is defined as the change in curvature around the circumference of the LV silhouette. The local instantaneous curvature function is used here to quantify regional left-ventricular (LV) performance throughout the cardiac cycle. Left ventriculography images, taken in the right anterior oblique (RAO) view from nine patients with normal ventricular contraction, and eight patients with anterior hypokinesis (AHK) are used. The local curvature around the circumference of the LV is calculated for each heart throughout the ejection period. The dynamic increase in the curvature of the apex, defined as apical sharpening, is a typical feature of LV contraction. Apical sharpening from end-diastole to end-systole is closely related to the degree of hypokinesis. Normal hearts show larger apical sharpening (128 ± 57%, SD) than do AHK hearts (46 ± 13%, p = 0.002). The ratio between apical and anterior curvatures at ES has been found to be 7 ± 3.5 for normal hearts and 2.3 ± 0.6 for AHK hearts (p = 0.003). Linear regression between the ventricular volume and apical curvature yields a significant relationship for the normal hearts (r = 0.82 ± 0.06, average p = 0.07), but not for the AHK hearts (r = 0.72 ± 0.2, average p = 0.24). Thus, the information inherent in the local curvature of the LV and its dynamic change throughout the cardiac cycle may be used to distinguish between normal and anterior hypokinetic hearts.

Microcomputer-based system for 3D reconstruction, analysis and 3D animation of the heart and its coronary arteries

A system for 3D reconstruction, analysis, and dynamic animation of the heart and the coronary arteries was developed on an IBM/PC-compatible computer. The system utilizes data from MRI (magnetic resonance imaging), cine-CT (computer tomography), ultrasound, or angiography. The endocardium and epicardium of both the left and right ventricles are first traced from the video monitor. Three-dimensional reconstruction is done from planar slices (MRI, CT) or long axis images (echocardiography). The coronary tree is superimposed on the 3D epicardial surface by means of anatomical markers. The location and severity of the stenosed vessels are then marked. Graphical capabilities include dynamic animation, wireframe, solid shading, semitransparent shading, color mapping of the 3D shape according to local function, and anatomical cross-sectional views. Analysis of global and local ventricular function is achieved by calculating LV volume, ejection fraction, regional thickening, and wall motion.<<ETX>>

Microcomputer based system for 3D reconstruction, simulation and dynamic animation of the heart

A system for 3-D reconstruction, analysis, simulation and dynamic animation of the heart and the coronary arteries is reported. Using magnetic resonance cross-sectional or ultrasonic and angiographic long-axis imagers of the heart, the endocardial and epicardial contours are traced, interpolated and reconstructed in 3-D. The coronary tree is then superimposed on the 3-D shape using anatomical markers. Graphical capabilities include real-time animation, utilizing wire-frame, solid shading, semitransparent shading and different viewing angles. Simulation of geometrical deformations caused by variations in the arterial flow is achieved by defining the risk area of each coronary vessel, the flow-thickening relationship function and the actual relative flow in the simulated stenosed vessel and using these to simulate local ischemia by varying the dynamic 3-D shape of a normal heart. Assessment of local myocardial function is achieved by calculating local parameters such as thickening or wall motion.<<ETX>>

Three dimensional display of the heart and coronaries relating stenosis shape and severity to regional function

It is shown that displaying and animating the dynamic, three-dimensional (3-D) shape of the beating heart, including the global layout of the coronary tree and the local shape of the stenosed vessel, can help in assessing the severity of coronary artery disease, particularly in cases where several vessels are obstructed. The coronary tree is superimposed on the 3-D shape of the heart by using the anatomical markers of the anterior and posterior interventricular grooves and the ventriculoatrial groove. The program is also geared to zoom in on the stenosis and yield a 3-D surface reconstruction of the stenosis from biplane angiography. When the obstruction in the vessel occurs near a bifurcation in the coronary tree, the 3-D shape of the stenosed area can be too complicated for reconstruction as a surface, and a voxel space model is used to reconstruct and display the entire region of the stenosis, including the bifurcation. The regional function of the heart, estimated by the local wall thickening, is color coded and displayed on the epicardial surface.<<ETX>>