Shape Of Left Ventricle Research Articles

In vitro validation of tissue Doppler left ventricular regional wall velocities by using a novel balloon phantom.

To investigate the validity and accuracy of tissue Doppler imaging (TDI) using a novel balloon phantom, validation of TDI myocardial velocity measurements has been carried out indirectly from conventional M-mode images. However it is not a true and independent gold standard. We described a new TDI validation method by using a specially developed left ventricular balloon model mounted in a water bath and constructed using two pear-shaped balloons. It was connected to a pulsatile flow pump at 8 stroke volumes (50-85 ml/beat). The displacement and velocity of the balloon walls were recorded simultaneously by video imaging and TDI on a GE-Vingmed System Five with a 5 MHz phased array probe at the highest frame rates available. Conventional M-mode and 2-D imaging verified that our balloon model mimicked the shape and wall motion of left ventricle. There was a good correlation and agreement between the maximum video excursion of the anterior and posterior walls of the phantom and the results of the temporal integration of digital distance data by TDI (Anterior wall: r = 0.97, SEE = 0.24 mm, mean +/- s = 0.04 +/- 0.24 mm; Posterior wall: r = 0.95, SEE = 0.22 mm, mean +/- s = 0.03 +/- 0.24 mm). Analysis of the velocity profile by the TDI method showed that the velocity at each measured point was correlated well with the velocity obtained from the video images (Anterior wall: r = 0.97, SEE = 0.30 mm, mean +/- s = -0.04 +/- 0.28 mm; Posterior wall: r = 0.97, SEE = 0.30 mm, mean +/- s = 0.04 +/- 0.28 mm). Our balloon model provided a new independent method for the validation of TDI data. This study demonstrated that the present TDI system is reliable for measuring wall motion distance and velocity.

Transthoracic and Transesophageal Echocardiographic Indices Predictive of Sinus Rhythm Maintenance After Cardioversion of Atrial Fibrillation: An Echocardiographic Study During Direct Current Shock

Up to 57% of atrial fibrillation (AF) recurrences after cardioversion take place during the first 30 days following direct current shock (DCS) delivery. Previous echocardiographic studies on sinus rhythm (SR) maintenance after cardioversion have focused mainly on parameters recorded before DCS, while other studies have reported on the indices recorded soon after delivery of the shock. Therefore, we investigated 18 patients with nonrheumatic AF, selected to undergo DCS, by both transthoracic (TTE) and transesophageal (TEE) echocardiography performed within 10 minutes before and after the electrical shock delivery. TTE was utilized for the evaluation of left atrium and left ventricle shape as well as for mitral Doppler flow sampling, while TEE was used to evaluate left atrial appendage (LAA) morphology and function, to score the LAA spontaneous echo contrast, and to evaluate the flow of left superior pulmonary vein; the transesophageal probe was left in situ during the electrical procedure. Thirty days after cardioversion, 10 (55%) patients maintained SR (Group 1) while 8 (45%) reverted to AF (Group 2). We compared the mean values of the parameters recorded in the two groups both before and after DCS. Although many parameters of pre- and postcardioversion analysis proved to be significantly different between the two groups, the most marked differences were exhibited by the following postcardioversion indices: Peak Doppler flow velocity of the end-diastolic mitral flow (30.10 +/- 5.24 vs. 20.50 +/- 6.32 cm/sec, P = 0.003); sum of peak velocities of the end-diastolic contraction (A) and relaxation (A(1)) of LAA (A + A(1) = 58.20 +/- 17.02 vs. 31.25 +/- 9.27 cm/sec, P = 0.001); duration of A + A(1) (162.70 +/- 27.01 vs. 133.75 +/- 5.31 msec, P = 0.002); and sum of durations of the early diastolic forward (E) and reverse (E(1)) flow of LAA (101.90 +/- 35.15 vs. 53.33 +/- 16.33 msec, P = 0.006). Using a single echocardiographic examination during DCS and after induction of anesthesia, without further discomfort to patients, we were able to identify useful parameters for the prediction of future electrical activity of the heart before as well as soon after DCS. Postcardioversion indices, derived by both TTE and TEE, were even more predictive of SR maintenance after 1 month than precardioversion parameters.

A knowledge-based boundary delineation system for contrast ventriculograms.

Automated left-ventricle (LV) boundary delineation from contrast ventriculograms has been studied for decades. Unfortunately, no accurate methods have ever been reported. A new knowledge based multistage method to automatically delineate the LV boundary at end diastole (ED) and end systole (ES) is discussed in this paper. It has a mean absolute boundary error or about 2 mm and an associated ejection fraction error of about 6%. The method makes extensive use of knowledge about LV shape and movement. The processing includes a multiimage pixel region classification, shape regression, and rejection classification. The method was trained and cross-validated tested on a database of 375 studies whose ED and ES boundary had been manually traced as the ground truth. The cross-validated results presented in this paper show that the accuracy is close to and slightly above the interobserver variability.

Relaxation of epicardial strains after volume changes in the isolated guinea pig left ventricle

Cardiac muscle is a porous viscoelastic material, exhibiting stress relaxation and hysteresis after being passively stretched. We investigated whether these material properties are also manifested in relaxation of epicardial segment lengths of the passive diastolic left ventricle (LV). For this purpose LV pressure and biaxial epicardial strains were measured simultaneously in isolated guinea pig hearts, arrested in diastole and instrumented to manipulate LV volume. Our study confirmed the existence of epicardial strain relaxation in both axial and circumferential directions, though it was much less expressed than LV pressure relaxation. Since the volume calculated from the segment lengths also revealed relaxation phenomena, our findings suggest that epicardial strain relaxation was connected with exchange of fluid from the LV cavity into the tightened epicardial vessels and back and not with the transformation of the LV shape.

Knowledge Based Automated Boundary Detection for Qualifying of LV Function in Low Contrast Angiographic Images

A Cardiac function is evaluated quantitatively by analyzing a shape change of the heart wall boundaries in angiographic images. To begin with, a boundary detection of end systolic left ventricle (ESLV) and end diastolic left ventricle (EDLV) is essential for the quantitative analysis of the cardiac function. Conventional methods for the boundary detection are almost semi-automatic, and a knowledgeable human operator’s intervention is still required. Manual tracing of the boundaries is currently used for subsequent analysis and diagnosis. However, these methods do not cut excessive time, labor, and subjectivity associated with manual intervention by a human operator. Generally, EDLV images have noncontiguous and ambiguous edge signal on some boundary regions. In this paper, we propose a new method for an automated detection of left ventricle (LV) boundaries in noncontiguous and ambiguous EDLV images. The proposed boundary detection scheme is based on a priori knowledge information and is divided into two steps. The first step is to detect EDLV boundary using ESLV boundary. The second step is to correct the detected EDLV boundary using the left ventricle (LV) shape information. We compared the proposed method with the manual method to detect the EDLV boundary. And through the experiments of the proposed method, we verified the usefulness of this method.

Relaxation of epicardial strains after volume changes in the isolated guinea pig left ventricle.

Cardiac muscle is a porous viscoelastic material, exhibiting stress relaxation and hysteresis after being passively stretched. We investigated whether these material properties are also manifested in relaxation of epicardial segment lengths of the passive diastolic left ventricle (LV). For this purpose LV pressure and biaxial epicardial strains were measured simultaneously in isolated guinea pig hearts, arrested in diastole and instrumented to manipulate LV volume. Our study confirmed the existence of epicardial strain relaxation in both axial and circumferential directions, though it was much less expressed than LV pressure relaxation. Since the volume calculated from the segment lengths also revealed relaxation phenomena, our findings suggest that epicardial strain relaxation was connected with exchange of fluid from the LV cavity into the tightened epicardial vessels and back and not with the transformation of the LV shape.

Assessment of left ventricular cardiac shape by the use of volumetric curvature analysis from 3D echocardiography

A method for three-dimensional shape analysis of left ventricle (LV) is presented in this article. The method uses three-dimensional transesophageal echocardiography (TEE) as the source to derive the 3D wire-frame model and the related shape descriptors. The shape descriptors developed in this article include regional surface changing (RSC), global surface curvature (GSC), surface distance (SD), normalized surface distance (ND), and effective radius (ER) of the endocardial surface. Based on these shape descriptors, the shape of LV could be sketched in both static and dynamic manner. The results show that the new approach provides a robust but easy method to quantify regional and global LV shape from 2D and 3D echocardiograms.

Tracking the left ventricle in echocardiographic images by learning heart dynamics

In this paper a temporal learning-filtering procedure is applied to refine the left ventricle (LV) boundary detected by an active-contour model. Instead of making prior assumptions about the LV shape or its motion, this information is incrementally gathered directly from the images and is exploited to achieve more coherent segmentation. A Hough transform technique is used to find an initial approximation of the object boundary at the first frame of the sequence. Then, an active-contour model is used in a coarse-to-fine framework, for the estimation of a noisy LV boundary. The PCA transform is applied to form a reduced ordered orthonormal basis of the LV deformations based on a sequence of noisy boundary observations. Then this basis is used to constrain the motion of the active contour in subsequent frames, and thus provide more coherent identification. Results of epicardial boundary identification in B-mode images are presented.

Tomographic left ventricular volume determination in the presence of aneurysm by three-dimensional echocardiographic imaging. I: Asymmetric model hearts

To improve the accuracy of measurements of left ventricular volume in the presence of an aneurysm, we used three-dimensional echocardiographic imaging to analyze the shape of left ventricles in 23 asymmetric model hearts with eccentric aneurysms of different sizes, shapes, and localizations. A standard 3.75 MHz ultrasound probe with a rotation motor device was used to obtain a three-dimensional data set. By rotating the probe stepwise 1 degree, 180 radial ultrasound pictures were digitized. On the basis of the three-dimensional data set, the following parameters were determined and compared with the dimensions of the model hearts obtained by direct measurement: total left ventricular volume (LVV), aneurysm volume, area of the aneurysm's base, the longest aneurysm long diameter, and the longest aneurysm cross diameter. In addition, quantification of LVV by three-dimensional echocardiography was compared with biplane two-dimensional echocardiographic measurement according to the disk method. Good agreements were found for LVV measured by both techniques, three-dimensional echocardiographic and direct measurement (mean of differences = 0.91 ml; SD of differences = ±6.23 ml; line of regression y ≐ 1.07 x − 14.24 ml; r = 0.968; standard error of the estimate [SEE] = ±6.17 ml), aneurysm volume (mean of differences = 0.43 ml; SD of differences = ±2.14 ml; line of regression y = 1.05 x −0.81 ml; r = 0.996; SEE = ±1.96 ml), area of the aneurysm's base (mean of differences = 0.24 cm 2; SD of differences = ±1.72 cm 2; line of regression y = 1.02 x −0.02 cm 2; r = 0.981; SEE = ±1.75 cm 2), the longest aneurysm long diameter (mean of differences = −0.26 mm; SD of differences = ±1.60 mm; line of regression y = 0.97 x + 1.34 mm; r = 0.996; SEE = ±1.54 mm), and the longest aneurysm cross diameter (mean of differences = 1.35 mm; SD of differences = ±3.94 mm; line of regression y = 0.95 x + 3.17 mm; r = 0.941; SEE = ±3.99 mm). In contrast, in these extremely asymmetric-shaped model hearts, agreement between biplane two-dimensional echocardiographic and both direct LVV measurement (mean of differences = 7.8 ml; SD of differences = ±20.8 ml; line of regression y = 1.48 x − 92.45 ml; r = 0.874; SEE = ±18.36 ml) and three-dimensional echocardiographic measurements (mean of differences = −7.6 ml; SD of difference = ±18.1 ml; line of regression y = 0.59 x + 80.98 ml; r = 0.908; SEE = ±10.36 ml) was poor. Thus tomographic three-dimensional echocardiography allowed accurate volume determination of asymmetric model hearts in the shape of left ventricles with eccentric aneurysms.

Realistic three-dimensional left ventricular ejection determined from computational fluid dynamics

A realistic model of the left ventricle of the human heart was constructed using a cast from a dog heart which was in diastole. A coordinate measuring machine was used to measure and digitize the coordinates of the left ventricle. From the complex measured left ventricle shape values, a three-dimensional finite volume representation was constructed using a simulation package. The left ventricular walls moved towards the centre of the aortic outlet in order to study the effects of time-varying left ventricular ejection. The left ventricular wall motion was assumed to follow the blood flow and the wall grid was reformed 25 times during the calculation. The 25.8 cm 3 ventricular volume was reduced by 75% in 0.25 s. Centreline and cross-sectional velocity vectors greatly increased in magnitude at the aortic outlet, and most of the pressure occurred in the top 15% of the heart. The computational method should make it possible to compare simulation results with important measurement techniques such as ultrasound and magnetic resonance imaging, and this should allow a finer detail of flow understanding than is presently available using either a modelling or imaging method alone.

Recovery of the 3-D shape of the left ventricle from echocardiographic images

A computational method is reported which allows the fully automated recovery of the three-dimensional shape of the cardiac left ventricle from a reduced set of apical echo views. Two typically ill-posed problems have been faced: 1) the detection of the left ventricle contours in each view, and 2) the integration of the detected contour points (which form a sparse and partially inconsistent data set) into a single surface representation. The authors' solution to these problems is based on a careful integration of standard computer vision algorithms with neural networks. Boundary detection comprises three steps: edge detection, edge grouping, and edge classification. The first and second steps (which are typical early-vision tasks not involving specific domain-knowledge) have been performed through fast, well-established algorithms of computer vision. The higher level task of left ventricle-edge discrimination, which involves the exploitation of specific knowledge about the left ventricle silhouette, has been performed by feedforward neural networks. Following the most recent results in the field of computer vision, the first step in solving the problem of recovering the ventricle surface has been the adoption of a physically inspired model of it. Basically, the authors have modeled the left ventricle surface as a closed, thin, elastic surface and the data as a set of radial springs acting on it. The recovery process is equivalent to the settling of the surface-plus-springs system into a stable configuration of minimum potential energy. The finite element discretization of this model leads directly to an analog neural-network implementation. The efficiency of such an implementation has been remarkably enhanced through a learning algorithm which embeds specific knowledge about the shape of the left ventricle in the network. Experiments using clinical echographic sequences are described. Four apical views (each with a different rotation of the probe) have been acquired during a heartbeat from a set of seven normal subjects. These images have been utilized to set the various processing modules and test their capabilities.

Ventricular interaction in the pathologic heart. A model based study.

The effects of direct ventricular interaction and interaction mediated by the pericardium on the diastolic left ventricle (LV) were quantified using idealized models of five pathologic conditions. Two-dimensional (2D) mathematical models were constructed in long and short axis views of four pathologic LV conditions and the normal heart (NL): dilated cardiomyopathy (DCM), concentric LV hypertrophy (HYP), chronic anterior-apical infarction in a normal shaped LV (CAINL), and CAI in a dilated LV (CAID). To assess the effects of RV pressure increase on the LV mechanical state, RV pressure was systematically increased for several LV pressures and changes in the LV diastolic pressure-area relationships, and LV free wall and septal principal stresses and strains were quantified. At higher RV pressures, with pericardial effects included in the models, the pressure-area relationship was similar for all models, indicating that, at these higher pressures, the effects of RV and pericardial pressures are more important than global LV shape, wall thickness, or material properties in determining the pressure-area relationship. There were significant differences among models in the changes in LV free wall and septal stress and strain after an increase in RV pressure. These models may be of use in predicting interaction in the corresponding clinical state.

Shape preserving three-dimensional display of myocardial scintigraphic data

A three-dimensional display has been developed which is specifically suited to the visualization of myocardial single photon emission tomographic (SPET) data. A set of radial maxima voxels, representative of the whole left ventricle uptake and shape is first extracted by cylindrical and spherical sampling of the short axis slices. A three-dimensional representation of these voxels is then obtained, with hues depicting the uptake amount and shades (i.e. intensity and saturation) depicting the shape. This technique is suitable for 201Tl and 99TCm-hexakis-2-methoxyisobutyl isonitrile (99TCm-sestamibi) myocardial images. It is proposed as an aid to interpreting myocardial SPET as it enables the physician to distinguish simultaneously the actual shape, the extent and the severity of perfusion defects on a single frame.

Modeling, analysis, and visualization of left ventricle shape and motion by hierarchical decomposition

This paper presents an approach to the modeling, analysis, and visualization of left ventricle motion and deformation. The authors' modeling of left ventricle shape and motion as a hierarchical representation enables them to develop a promising noninvasive technique for monitoring heart dynamics where both image analysis and image synthesis are involved. The proposed hierarchical motion model of left ventricle is constructed by combining several existing simple models and is able to capture major motion and deformation components of the left ventricle. The hierarchical decomposition characterizes the left ventricle motion and deformation in a coarse-to-fine fashion and leads to computationally efficient estimation algorithms. The authors estimate the global rigid motion of the left ventricle by establishing a time-varying object-centered coordinate system. The global deformations of the left ventricle are obtained by fitting the given data to superquadric modeling primitives. The local deformations are estimated by a tensor-description approach that is based on the locally deformable surface obtained by constructing spherical harmonic local surface from the residues of global shape estimation. The authors also describe in this paper methods of image synthesis and dynamic animation for visualizing the estimated results of the time-varying left ventricle shape, motion, and deformations. These animation results are consistent with the apparent motion pattern of the left ventricle and therefore show the success of the authors' hierarchical decomposition based approach.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Subepicardial fiber strain and stress as related to left ventricular pressure and volume.

In a mathematical model of the mechanics of the left ventricle (LV) by Arts et al. (1), assuming uniformity of fiber stress (sigma f) and fiber strain (delta epsilon f) in the wall during the ejection phase, fiber stress and fiber strain were related to LV cavity pressure (Plv), LV cavity volume (Vlv) and wall volume (Vw) by the following pair of equations: sigma f = Plv (1 + 3 Vlv/Vw) and delta epsilon f = 1/3 delta ln (1 + 3 Vlv/Vw). The ratio of Vlv to Vw appeared to be the most important geometric parameter, whereas the actual LV shape was of minor importance. The relationships on fiber strain and stress were evaluated experimentally in six anesthetized open-chest dogs during normal and elevated (volume loading) end-diastolic LV pressure. Subepicardial fiber strain was measured simultaneously in 16 adjacent regions of the LV anterior wall, using optical markers that were attached to the epicardial surface and recorded on video. Changes in Vlv were measured by use of four inductive coils sutured to the LV in a tetrahedric configuration. Vw was measured postmortem. During control as well as hypervolemia the following results were found. At the anterior free wall of the LV, the slope of the estimated linear relationship between measured and calculated fiber strain was 1.017 +/- 0.168 (means +/- SD), which is not significantly different from unity. Calculated fiber stress corresponded qualitatively and quantitatively with experimental results reported on isolated cardiac muscle. Calculated subepicardial contractile work per unit of tissue volume was not significantly different from global pump work as normalized to Vw. These findings support the assumption of homogeneity of muscle fiber strain and stress in the left ventricular wall during the ejection phase. Furthermore, average values of fiber stress and strain can be estimated on the basis of measured left ventricular pressure and volume.

Natural history and patterns of recovery of contractile function in single left ventricle after Fontan operation.

Before the era of the Fontan procedure, the typical course of patients with single left ventricle (LV) consisted of heart failure and death during the second or third decade of life. Despite the advent of effective palliative therapy, ventricular dysfunction remains a significant clinical problem for these patients. To investigate the causes of ventricular dysfunction in these patients and to determine whether Fontan-type repair reverses deterioration of LV function, the ventricular dimensions, volume, shape, wall stress, and systolic function were determined by echocardiography in 84 patients 0.2-35 years old with double-inlet single LV or tricuspid atresia. Measurements were obtained in 67 patients after palliation (arterial shunt or pulmonary artery band) and in 47 patients a median of 4.4 years after a Glenn (n = 9) or a Fontan operation (n = 38). Before a Fontan procedure, ventricular volumes were 2 to 3 times normal. Ventricular afterload, assessed as circumferential and meridional end-systolic wall stress, became abnormal after 2 years of age. With age, LV shape changed progressively from ellipsoidal to spherical, as indicated by the decrease in long axis:short axis ratio from normal (1.9) toward unity. Concomitantly, the ratio of circumferential to meridional end-systolic wall stress fell from 1.3 to unity, the ratio of a sphere at equilibrium. This age-related change in shape and load occurred in concert with progressive deterioration of LV systolic function and contractility. Aortic oxygen saturation, an indicator of pulmonary blood flow and therefore volume work in single-ventricle physiology, was inversely and independently correlated with contractility. In the group of patients in whom a Glenn or a Fontan operation was performed at < 10 years of age, ventricular dimensions, volumes, and wall stress diminished and LV function and contractility improved after surgery (p < 0.001). In patients undergoing surgery after 10 years of age, few had improvement of LV function after surgery. Postoperative ventricular function and contractility were inversely related to age at surgery and to aortic oxygen saturation measured before surgery. Although Fontan-type repair of single ventricle early in life is associated with reversal of the abnormal contractile mechanics associated with age and volume load, this capacity for recovery diminishes with age at surgery.

Regional three-dimensional geometry and function of left ventricles with fibrous aneurysms. A cine-computed tomography study.

To assess the extent and nature of the dysfunction surrounding aneurysms of the left ventricle (LV), we examined the parameters of local and global three-dimensional shape, size, and function of LVs of eight patients with histologically confirmed anterior fibrous aneurysms. Three-dimensional reconstructions of each LV were made from 10-12 short-axis fast cine-angiographic computed tomography (cine-CT) slices encompassing the entire heart at end diastole and end systole. Regional three-dimensional wall thickness, thickening, motion, curvature, and stress index were calculated for 84 elements encompassing the entire LV. The aneurysmal border was defined by a sharp decrease in end-diastolic wall thickness and separated the LV into an aneurysmal zone and a normal zone that was further divided into adjacent normal (AN) and remote normal (RN) zones. As expected, thickening was negligible in both the aneurysmal and the border zones. Although both the AN and the RN zones had normal wall thickness (1.05 +/- 0.20 and 1.09 +/- 0.20 cm, respectively), thickening was depressed in the AN (0.22 +/- 0.08 cm) but not the RN (0.44 +/- 0.19 cm) zones. The size of the dysfunction zone (defined as less than 2 mm thickening) was found to be considerably greater than the anatomic size of the aneurysm (60.9 +/- 13.7% versus 33.6 +/- 7.6% of the left ventricular endocardial area, respectively; p less than 0.001). In addition, the AN zone had a smaller curvature and a higher stress index than the RN zone. LVs with fibrous aneurysms are characterized by a relatively large region of nonfunction that encompasses the thin aneurysmal area and its transitional border zone, a normally functioning remote zone, and an intermediate region of normal wall thickness but with reduced function, which may be attributed to its low curvature and high stress index.

Differences in the Shape of the Normal, Cardiomyopathic, and Volume Overloaded Human Left Ventricle

A transformation from the normal elliptical shape of the left ventricle that may accompany various disease states and that may be indicative of myocardial remodeling, has not been completely addressed in part because of the need for a descriptor of shape that is independent of chamber size. Accordingly, the goal of this study was twofold: to derive dimensionless echocardiographic descriptors of left ventricle chamber shape that are independent of chamber volume and to use these descriptors to quantitatively compare the shape of left ventricles that were either of normal size (81 ± 17 ml, 19 patients) or were enlarged secondary to idiopathic caridomyopathy, (194 ± 61 ml, 46 patients) or chronic aortic or mitral valve incompetence (196 ± 67 ml, 14 patients). Two-dimensional and M-mode determined descriptors, of left ventricle shape based on its width, length, and area were found to be independent of left ventricle volume. These descriptors were significantly greater in cardiomyopathy compared with the normal or dilated left ventricle secondary to valvular incompetence, indicating that the left ventricle had become nearly spherical. A spherical shape of the left ventricle was not observed with valvular incompetence. The ability to classify a patient as hawing either a normal or a cardiomyopathic left ventricle by discriminant function analysis was enhanced when both left ventricle size and shape were considered. In a prospective study using discriminant function and fractional shortening, we found that patients with valvular incompetence could be classified as having either a normal discriminant function and fractional shortening, an abnormal discriminant function and normal fractional shortening, or an abnormal discriminant function and fractional shortening. The clinical utility of this discriminant function analysis with descriptors of left ventricle shape and size in the prediction of myocardial remodeling needs to be determined.

A new method of three dimensional analysis of left ventricular wall motion

The three dimensional (3D) shape of left ventricles (LV) was reconstructed from gated blood pool emission computed tomography (GECT) to assess regional LV wall motion. The 3D LV shape was created using LV boundaries detected by a threshold method. Based on the length from each LV boundary to the end diastolic LV center of mass, regional percent shortening and phase of the first harmonic by Fourier analysis were calculated to create 3D functional images. These images clearly demonstrated the 3D extent of wall motion abnormality. In addition, the same 3D analysis was applied to biplane X-ray left ventriculography (LVG) by assuming that LV short axis sections were elliptic. Results of planar imaging, 3D analysis of GECT, 3D analysis of LVG and conventional LVG findings correlated well with each other. The 3D analysis of GECT is useful for non invasive quantitative analysis of LV wall motion.

An analytical descriptor of three-dimensional geometry: application to the analysis of the left ventricle shape and contraction.

A novel method to describe the instantaneous three-dimensional (3-D) geometry of the left ventricular (LV) endocardial surface by an analytical time-varying scalar function of Fourier spectrum coefficients is suggested. The method utilizes experimental echocardiographic data and uses a helical coordinate system to transform the 3-D data into a unidimensional numerical function. The instantaneous numerical function is then represented by its Fourier sine series which serves as an analytical shape descriptor from which the 3-D shape is reconstructed. The procedure can also be applied to data compression (spatial low-pass filtering), spectral analysis, and the evaluation of geometric similarity of 3-D shapes. When applied to the endocardial surface of the LV at end-diastole (ED) and end-systole (ES) this technique gives a quantitative analysis of the global LV contraction of the real heart.