Detection of regional temporal abnormalities in left ventricular function during acute myocardial ischemia.

Echocardiographic diagnosis of myocardial ischemia is based on visualizing hypokinesis, which occurs late in the ischemic cascade. We hypothesized that temporal changes in endocardial motion may constitute sensitive early markers of ischemia. Two protocols were performed in 19 anesthetized pigs.

Effects of aging on left atrial reservoir, conduit, and booster pump function: a multi-institution acoustic quantification study.

Objective: To assess the feasibility of measuring left atrial (LA) function with acoustic quantification (AQ) and then assess the effects of age and sex on LA reservoir, conduit, and booster pump function.

Patients And Setting: 165 subjects without cardiovascular disease, 3-79 years old, were enrolled by six tertiary hospital centres.

Interventions: Continuous LA AQ area data were acquired and signal averaged to form composite waveforms which were analysed off-line.

Evaluation of Global and Regional Right Ventricular Function Using Automated Border Detection Techniques.

Quantitative evaluation of right ventricular (RV) function remains challenging due to the complex geometry of this chamber, which precludes the use of simple geometric assumptions. Automated border detection (ABD) techniques, which provide online changes in cardiac chamber dimensions, have been predominantly used for quantitative assessment of global as well as regional left ventricular function. Recently, acoustic quantification has been validated for quantitative evaluation of global RV function, and color kinesis has been used to objectively assess systolic and diastolic regional RV function.

Color Kinesis: New Technique or Just Another Display of Acoustic Quantification?

Color kinesis is a relatively new echocardiographic technique that allows color encoding of endocardial motion in real time. We briefly review the literature on the current clinical uses and limitations of this technique, as well as its potential future applications based on some of our results. The major advantage of this modality is that it provides the basis for objective and automated evaluation of regional systolic and diastolic function, which may have a direct impact on the diagnosis of various myocardial disease states and, in particular, coronary artery disease.

Acoustic Quantification Today and Its Future Horizons.

We briefly review previously published work based on the uses of acoustic quantification (AQ) or validation of this technology. We also discuss the limitations of AQ in a critical review of the literature, including operator dependency, signal noise, and low temporal resolution. We describe some enhancements made to AQ software to address these limitations and improve the accuracy of this technique, including digital beam processing, harmonic imaging, and signal averaging.

Evaluation of Left Ventricular Diastolic Performance Using Automated Border Detection.

Acoustic quantification (AQ) is a noninvasive technique which provides online left ventricular (LV) area/volume waveforms. The filling portion of the AQ waveform can be used to assess LV diastolic properties. Analysis of signal-averaged AQ curves enhances the waveforms and allows reliable, quantitative, and automated analysis.

Color Kinesis: Principles of Operation and Technical Guidelines.

Color kinesis is a new echocardiographic technique that aids in the assessment of global and regional left ventricular performance during either systole or diastole. Color kinesis uses automated border detection technology based on backscatter data to display both the magnitude and timing of endocardial motion in real time. The color kinesis display superimposes a color overlay on the two-dimensional echocardiographic image; the number of color pixels represents the magnitude of endocardial motion, while the different colors represent the timing of endocardial motion according to a predefined color scheme.

Electronic transmission of digital echocardiographic studies: effects of MPEG compression.

The acquisition, storage and retrieval of digital echocardiographic studies greatly facilitates image review and quantitation and permits the transmission of studies electronically. However, the considerable size of digital echocardiographic data files makes transmission over existing networks slow and impractical. Reduction in the size of these data files can be accomplished with digital image compression.

Normal values of regional left ventricular endocardial motion: multicenter color kinesis study.

Our goal was to establish normal values for quantitative color kinesis indexes of left ventricular (LV) wall motion over a wide range of ages, which are required for objective diagnosis of regional systolic and diastolic dysfunction. Color-encoded images were obtained in 194 normal subjects (95 males, 99 females, age 2 mo to 79 yr) in four standard views. Quantitative indexes of magnitude and timing of systolic and diastolic function were studied for age- and gender-related differences.

Power Doppler imaging as a basis for automated endocardial border detection during left ventricular contrast enhancement.

Echocardiographic evaluation of left ventricular (LV) systolic function relies on endocardial visualization, which can be improved when necessary using contrast enhancement. However, there is no method to automatically detect the endocardial boundary from contrast-enhanced images. We hypothesized that this could be achieved using harmonic power Doppler imaging.

Effects of inotropic stimulation on segmental left ventricular relaxation quantified by color kinesis.

Although myocardial ischemia impairs left ventricular (LV) relaxation before contractile function, regional LV diastolic dysfunction is difficult to evaluate by conventional echocardiography. Because beta-adrenergic stimulation enhances myocardial relaxation, we sought to characterize segmental LV diastolic function (by color kinesis) during dobutamine stress echocardiography and compare it with independently assessed segmental systolic function. We studied 22 patients with suspected coronary artery disease with color kinesis by acquiring digital images with endocardial motion display throughout diastole.

Spectral analysis of left ventricular area variability as a tool to improve the understanding of cardiac autonomic control.

Spectral analysis of the fluctuations in heart rate (HR) or blood pressure (BP) has been extensively used as a tool for the noninvasive assessment of autonomic control of the heart. The recently developed echocardiographic acoustic quantification allows noninvasive continuous measurement of the left ventricular cross-sectional area (LVA) signal. In this study, we investigated whether the LVA signal, and more specifically its fluctuations, can be reliably subjected to spectral analysis, and whether the results of such analysis may improve the understanding of the cardiovascular control mechanisms.

The role of echocardiographic harmonic imaging and contrast enhancement for improvement of endocardial border delineation.

Despite advances in imaging technology, many myocardial segments remain poorly visualized with echocardiography; however, both contrast enhancement and harmonic imaging have shown promise for improving endocardial definition. Fifty subjects with technically limited echocardiograms were studied with fundamental and harmonic imaging as well as during echocardiographic contrast injection. Overall endocardial visualization scores improved with both techniques compared with fundamental imaging.

Effects of MPEG compression on the quality and diagnostic accuracy of digital echocardiography studies.

The advantages of digital echocardiography studies include ease of retrieval, review, comparison, duplication, and quantitation as well as the potential for moving studies over networks. However, the large amounts of data associated with digital echocardiography studies have posed new problems. Reduction of the amount of data can be accomplished with image compression, in particular MPEG-1 (Moving Pictures Expert Group), which is designed for dynamic image sequences.

Three-dimensional echocardiography in adult patients: comparison between transthoracic and transesophageal reconstructions.

Background: Three-dimensional (3D) echocardiography is a relatively new technique typically implemented with transesophageal imaging with multiplane transducers.

Objectives: The goals of this study were (1) to test the feasibility of 3D reconstruction with a new transthoracic multiplane transducer in adult subjects with excellent quality of 2-dimensional images and (2) to compare these reconstructions with those obtained in the same patients with the transesophageal approach.

Methods: Transthoracic multiplane image acquisition was performed in 37 patients who were selected on the basis of the quality of their 2-dimensional images.

Identification of cardiac masses and abnormal blood flow patterns with harmonic power Doppler contrast echocardiography.

Power Doppler is an ultrasound technique that color-encodes the change in amplitude of the ultrasound signal, which reflects changes in the position of scatterers between ultrasound pulses. Power Doppler can be used with echocardiographic contrast agents in a harmonic imaging mode to opacify a cardiac chamber. The opacification of a cardiac chamber can aid in visualizing the silhouette of intracardiac masses and displaying blood flow patterns.

Objective evaluation of regional left ventricular wall motion during dobutamine stress echocardiographic studies using segmental analysis of color kinesis images.

Objectives: To test the feasibility of objective and automated evaluation of echocardiographic stress tests, we studied the ability of segmental analysis of color kinesis (CK) images to detect dobutamine-induced wall motion abnormalities and compared this technique with inexperienced reviewers of conventional gray-scale images.

Background: Conventional interpretation of stress echocardiographic studies is subjective and experience dependent.

Methods: CK images were obtained in 89 of 104 consecutive patients undergoing clinical dobutamine stress studies and were analyzed using custom software to calculate regional fractional area change in 22 segments in four standard views.

Quantitative assessment of regional right ventricular function with color kinesis.

We used color kinesis, a recent echocardiographic technique that provides regional information on the magnitude and timing of endocardial wall motion, to quantitatively assess regional right ventricular (RV) systolic and diastolic properties in 76 subjects who were divided into five groups, as follows: normal (n = 20), heart failure (n = 15), pressure/volume overload (n = 14), pressure overload (n = 12), and RV hypertrophy (n = 15). Quantitative segmental analysis of color kinesis images was used to obtain regional fractional area change (RFAC), which was displayed in the form of stacked histograms to determine patterns of endocardial wall motion. Time curves of integrated RFAC were used to objectively identify asynchrony of diastolic endocardial motion.

Quantitative evaluation of left ventricular function in a TransgenicMouse model of dilated cardiomyopathy with 2-dimensional contrast echocardiography.

The study of transgenic mouse models of human cardiovascular disease has been limited by the small size and high heart rate of the mouse heart. Advances in digital echocardiographic imaging equipment have provided the high spatial and temporal resolution necessary for 2-dimensional (2D) in vivo imaging of the mouse heart. The goal of this study was to test the use of contrast-enhanced 2D echocardiography to quantitatively assess left ventricular (LV) size and function in normal and transgenic mice with dilated cardiomyopathy.

Age dependency of left atrial and left ventricular acoustic quantification waveforms for the evaluation of diastolic performance in left ventricular hypertrophy.

We evaluated diastolic performance in 50 normal subjects and 50 patients with concentric left ventricular (LV) hypertrophy. Age-dependent normal values were determined for LV and left atrial (LA) acoustic quantification parameters. Pulsed wave Doppler echocardiography was also performed on all subjects.

Acoustic quantification indexes of left ventricular size and function: effects of signal averaging.

Background: The aim of this study was to evaluate the clinical utility of using signal-averaged acoustic quantification (SAAQ) waveforms for improved assessment of left ventricular (LV) size and function.

Methods And Results: Four separate protocols were performed in 47 subjects. SAAQ waveforms were used to assess alterations in LV function induced by dobutamine (15 microg/kg per minute) and esmolol (200 microg/kg per minute) in eight normal subjects.

Use of color kinesis for evaluation of left ventricular filling in patients with dilated cardiomyopathy and mitral regurgitation.

Objectives: We tested the feasibility of using analysis of color kinesis images to objectively assess global and regional left ventricular (LV) diastolic function in patients with dilated cardiomyopathy (DCM). In addition, the ability of this technique to track drug-induced changes on LV diastolic properties was studied.

Background: Diastolic dysfunction contributes to symptomatology in patients with DCM.

Quantitative evaluation of global and regional left ventricular diastolic function with color kinesis.

Background: Diastolic wall motion asynchrony is a major determinant of impaired left ventricular (LV) filling in patients with concentric hypertrophy and coronary artery disease. We evaluated the ability of Color Kinesis, a new echocardiographic technique that color-encodes endocardial motion, to quantitatively assess global and regional LV filling properties.

Methods And Results: Color Kinesis images and mitral and pulmonary vein flow Doppler data were acquired in 29 patients with LV hypertrophy and 29 age-matched control subjects.