On-line assessment of ventricular function by automatic boundary detection and ultrasonic backscatter imaging

Abstract

To provide an approach suitable for on-line analysis of ventricular function, a conventional two-dimensional ultrasound imaging system was modified to detect and track blood-tissue interfaces in real time based on their quantitative acoustic properties. This modification permitted on-line display of the left ventricular cavity area, fractional area change, volumes and ejection fraction on a beat by beat basis. Images were obtained from 54 patients and 12 normal subjects with broad ranges of ventricular dimensions and systolic function. On-line measurements of cavity areas were compared with off-line measurements of cavity areas (analysis of videotaped conventional images). Left ventricular cavity areas measured on-line from short-axis views correlated closely with off-line views as did areas from apical views. On-line fractional area change correlated well with ejection fraction calculated off-line. More than 70% of patients could be studied adequately with the approach developed. Thus, automatic boundary detection based on quantitative assessment of tissue acoustic properties permits on-line quantitation of ventricular cavity areas and indexes of function.

Quantification of flow volume with a new digital three‐dimensional color Doppler flow approach: an in vitro study.

“…For ultrasonography, pulsed wave, continuous wave, power Doppler, ACM, and 3D reconstruction flow methods have been reported. [1][2][3][4][7][8][9][10][11][12][21][22][23][24] Most commonly, such flows are determined from pulsed wave Doppler velocity data obtained from the centerline of flow, and the cross-sectional area of the annulus or vessel at this point obtained from the diameter measured from 2D ultrasonographic imaging. This single pulsed wave Doppler sample volume does not allow estimation of a velocity profile across the entire flow area but, by virtue of the limited lateral resolution, nonetheless probably obtains the spatial mean velocity.…”

“…This single pulsed wave Doppler sample volume does not allow estimation of a velocity profile across the entire flow area but, by virtue of the limited lateral resolution, nonetheless probably obtains the spatial mean velocity. 1,6,15 The velocity profile is determined by physical characteristics such as the driving pressure, blood viscosity, frictional forces from the wall surface structure, and geometry of vessels or the valve annulus and leaflets. 15 In addition, the shape of this profile and the size and shape of the vessel may change over the cardiac cycle.…”

“…Abbreviations ACM, automated cardiac output measurement; MRI, magnetic resonance imaging; SEE, standard error of the estimate; TEE, transesophageal echo; 3D, three-dimensional; 2D, two-dimensional ccurate, noninvasive measurement of blood flow in the inflow and outflow tracts of the heart and great arteries continues to be an important clinical goal in the assessment of cardiac function, shunt flows in congenital cardiac defects, and regurgitation in the presence of valvular disease. [1][2][3][4][5][6][7][8][9][10][11][12] Noninvasive methods for the quantification of blood flow include magnetic resonance imaging (MRI) and combinations of M-mode and two-dimensional (2D) echocardiography and spectral Doppler flow. 13 Phase-encoded MRI velocity methods have been used for quantifying flow across…”

“…[1][2][3][4][5][6][7][8][9][10][11][12] Noninvasive methods for the quantification of blood flow include magnetic resonance imaging (MRI) and combinations of M-mode and two-dimensional (2D) echocardiography and spectral Doppler flow. 13 Phase-encoded MRI velocity methods have been used for quantifying flow across semilunar and atrioventricular valves and do not have the inherent angle dependency, window restrictions, or attenuation limitations that exist for Doppler ultrasonography.…”

Automated grading of left ventricular segmental wall motion by an artificial neural network using color kinesis images

“…Acoustic quantification (10,11) is an automated edge detection method incorporated into a commercially available ultrasound system which provides real-time, objective and reproducible estimation of ventricular area and volume (10)(11)(12)(13)(14)(15)(16). Color kinesis is a new technique (17) based on acoustic quantification, developed to display on-line timing and extension of endocardial motion by creating a color map of regional wall motion.…”