Analysis of Image Sequence Data with Applications to Two-Dimensional Echocardiography

Digital two-dimensional echocardiography is an ultrasonic imaging technique that is used as an increasingly important noninvasive technique in the comprehensive characterization of the left ventricular structure and function. Quantitative analysis often uses heart wall motion and other shape attributes such as the heart wall thickness, heart chamber area, and the variation of these attributes throughout the cardiac cycle. These analyses require the complete determination of the heart wall boundaries. Poor image quality and large amount of noise makes computer detection of the boundaries difficult. An algorithm to detect both the inner and outer heart wall boundaries is presented. The algorithm was applied to images acquired from animal studies and from a tissue equivalent phantom to verify the performance. Different approaches to exploiting the temporal redundancy of the image data without making use of results from image segmentation and scene interpretation are explored. A new approach to perform image flow analysis is developed based on the Total Least Squares method. The result of this processing is an estimate of the velocities in the image plane. In an image understanding system, information acquired from related domains by other sensors are often useful to the analysis of images. Electrocardiogram signals measure the change of electrical potential changes in the heart muscle an d provide important information such as the timing data for image sequence analysis. These signals are frequently plagued by impulsive muscle noise and background drift due to patient movement. A new approach to solving these problems is presented using mathematical morphology. Experiments addressing various aspects of the problem, such as algorithm performance, choice of operator parameters, and response to sinusoidal inputs, are reported

Lv volume quantification via spatiotemporal analysis of real-time 3-d echocardiography

Abstract—This paper presents a method of four-dimensional (4-D) (3-D + Time) space–frequency analysis for directional denoising and enhancement of real-time three-dimensional (RT3D) ultrasound and quantitative measures in diagnostic cardiac ultrasound. Expansion of echocardiographic volumes is performed with complex exponential wavelet-like basis functions called brushlets. These functions offer good localization in time and frequency and decompose a signal into distinct patterns of oriented harmonics, which are invariant to intensity and contrast range. Deformable-model segmentation is carried out on denoised data after thresholding of transform coefficients. This process attenuates speckle noise while preserving cardiac structure location. The superiority of 4-D over 3-D analysis for decorrelating additive white noise and multiplicative speckle noise on a 4-D phantom volume expanding in time is demonstrated. Quantitative validation, computed for contours and volumes, is performed on in vitro balloon phantoms. Clinical applications of this spaciotemporal analysis tool are reported for six patient cases providing measures of left ventricular volumes and ejection fraction. Index Terms—Echocardiography, LV volume, spaciotemporal analysis, speckle denoising. I

Three-dimensional echocardiography for the assessment of congenital and acquired heart disease

Although conventional two-dimensional and Doppler blood-flow echocardiography are the standard imaging approaches in the assessment of heart disease they do not provide anatomic reconstructions in a form that resembles the cardiac morphology as visualized by the surgeon.The work presented in this thesis has explored the hypotheses that threedimensional echocardiography facilitates spatial recognition of intracardiac structures and therefore enhances the diagnostic confidence of echocardiography in congenital and acquired heart disease. The accuracy of three-dimensional reconstructions has been validated in vitro using two different phantoms and in vivo comparing the results with other established diagnostic techniques or surgical findings. Additionally, as the main limitation of transthoracic three-dimensional echocardiography is poor image quality in a substantial proportion of adult patients, Doppler myocardial imaging has been tested as a potentially superior method to conventional grey-scale imaging for transthoracic three-dimensional image acquisition.In vitro, using a virtual computer-generated phantom and a dynamic tissuemimicking phantom, the accuracy of both linear measurements and volume computation obtained from three-dimensional images was established. For both grey-scale and Doppler myocardial imaging, a detail of 1.0 mm dimension and two details separated from each other by a distance of 1.0 mm were the smallest structures and distances identified from a three-dimensional image. When testing the accuracy of volume measurements it appeared that both techniques marginally underestimated the true phantom volume (by approximately 1.0 ml for Doppler myocardial imaging and 4.0 ml for grey-scale imaging), but the systematic error was smaller and more constant in the case of Doppler myocardial imaging over the range of different true volumes.In vivo, the study was designed to compare the accuracy of grey-scale and Doppler myocardial imaging three-dimensional left ventricular volume measurements and cineventriculography. The differences were significantly smaller for the Doppler technique during both end-diastole and end-systole. A series of congenital heart lesions has also been studied. It has been shown that dynamic surgical reconstruction of the secundum atrial septal defect is feasible from the transthoracic approach in all patients. However, in adults, Doppler myocardial imaging proved more effective than grey-scale imaging in the accuracy of threedimensional defect reconstruction. In patients with sinus venosus atrial septal defect, transthoracic three-dimensional echocardiography was more accurate than standard echocardiography in diagnosing the defect including a detailed description of the abnormal pulmonary venous drainage. Finally, in children with atrio-ventricular septal defects, the 'unroofed' atrial reconstruction of the common valve accurately displayed dynamic valve morphology en face and the mechanism of valve reflux

Effect of spectacular reflection on out‐of‐plane ultrasonographic images reconstructed from three‐dimensional data sets.

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/135445/1/jum2000196391.pd

Assessment of visual quality and spatial accuracy of fast anisotropic diffusion and scan conversion algorithms for real-time three-dimensional spherical ultrasound

Three-dimensional ultrasound machines based on matrix phased-array transducers are gaining predominance for real-time dynamic screening in cardiac and obstetric practice. These transducers array acquire three-dimensional data in spherical coordinates along lines tiled in azimuth and elevation angles at incremental depth. This study aims at evaluating fast filtering and scan conversion algorithms applied in the spherical domain prior to visualization into Cartesian coordinates for visual quality and spatial measurement accuracy. Fast 3d scan conversion algorithms were implemented and with different order interpolation kernels. Downsizing and smoothing of sampling artifacts were integrated in the scan conversion process. In addition, a denoising scheme for spherical coordinate data with 3d anisotropic diffusion was implemented and applied prior to scan conversion to improve image quality. Reconstruction results under different parameter settings, such as different interpolation kernels, scaling factor, smoothing options, and denoising, are reported. Image quality was evaluated on several data sets via visual inspections and measurements of cylinder objects dimensions. Error measurements of the cylinder's radius, reported in this paper, show that the proposed fast scan conversion algorithm can correctly reconstruct three-dimensional ultrasound in Cartesian coordinates under tuned parameter settings. Denoising via three-dimensional anisotropic diffusion was able to greatly improve the quality of resampled data without affecting the accuracy of spatial information after the modification of the introduction of a variable gradient threshold parameter

LV Volume Quantification via Spatiotemporal Analysis of Real-Time 3-D Echocardiography

This paper presents a method of four-dimensional (4-D) (3-D+Time) space-frequency analysis for directional denoising and enhancement of real-time three-dimensional (RT3D) ultrasound and quantitative measures in diagnostic cardiac ultrasound. Expansion of echocardiographic volumes is performed with complex exponential wavelet-like basis functions called brushlets. These functions offer good localization in time and frequency and decompose a signal into distinct patterns of oriented harmonics, which are invariant to intensity and contrast range. Deformable-model segmentation is carried out on denoised data after thresholding of transform coefficients. This process attenuates speckle noise while preserving cardiac structure location. The superiority of 4-D over 3-D analysis for decorrelating additive white noise and multiplicative speckle noise on a 4-D phantom volume expanding in time is demonstrated. Quantitative validation, computed for contours and volumes, is performed on in vitro balloon phantoms. Clinical applications of this spatiotemporal analysis tool are reported for six patient cases providing measures of left ventricular volumes and ejection fraction

A Three dimensional spatial reconstruction of the left ventricle and analysis of ventricular geometry / by Nicola L. Fazzalari

This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legalsThesis--University of Adelaide, Dept. of Pathology, 198

Automated Analysis of 3D Stress Echocardiography

__Abstract__ The human circulatory system consists of the heart, blood, arteries, veins and capillaries. The heart is the muscular organ which pumps the blood through the human body (Fig. 1.1,1.2). Deoxygenated blood flows through the right atrium into the right ventricle, which pumps the blood into the pulmonary arteries. The blood is carried to the lungs, where it passes through a capillary network that enables the release of carbon dioxide and the uptake of oxygen. Oxygenated blood then returns to the heart via the pulmonary veins and flows from the left atrium into the left ventricle. The left ventricle then pumps the blood through the aorta, the major artery which supplies blood to the rest of the body [Drake et a!., 2005; Guyton and Halt 1996]. Therefore, it is vital that the cardiovascular system remains healthy. Disease of the cardiovascular system, if untreated, ultimately leads to the failure of other organs and death