R M Lang

Learn More
We tested the feasibility of real-time three-dimensional (3D) echocardiographic (RT3DE) imaging to measure left heart volumes at different gravity during parabolic flight and studied the effects of lower body negative pressure (LBNP) as a countermeasure. Weightlessness-related changes in cardiac function have been previously studied during spaceflights(More)
Tissue Doppler is used to evaluate mitral annulus (MA) dynamics. This technique has two major limitations: it is two-dimensional and angle-dependent. To solve these limitations, our aim was to develop and test a tool for automated 3D tracking and quantification of the MA motion throughout the cardiac cycle by using real-time 3D echocardiography (RT3DE). The(More)
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(More)
OBJECTIVE To develop a technique for volumetric analysis of real time three dimensional echocardiography (RT3DE) data aimed at quantifying left ventricular (LV) mass and to validate the technique against magnetic resonance (MR) assumed as the reference standard. DESIGN RT3DE, which has recently become widely available, provides dynamic pyramidal data(More)
Left ventricular (LV) volumes obtained from RT3DE datasets are underestimated compared to cardiac magnetic resonance (CMR). We sought to study the accuracy and reproducibility of this technique in a multicenter setting, the inter-institutional differences in these variables in relationship with investigators' experience, and the potential sources of(More)
Parabolic flight (PF) elicits changes in hydrostatic pressure gradients, resulting in increase (at 0Gz) or decrease (at 1.8Gz) in cardiac preload. The magnitude of these changes on left ventricular (LV) and atrial (LA) volumes, as well as on myocardial velocities, strain and strain rates, is largely unknown. Using real-time 3D (RT3DE) and Doppler tissue(More)
We developed a method for automated quantification of myocardial perfusion from cardiac magnetic resonance (CMR) images. Our approach uses region-based and edge-based level set techniques for endocardial and epicardial border detection combined with non-rigid registration achieved by a 2D multi-scale cross-correlation and contour adaptation. This method was(More)
The recently developed echocardiographic matrix array transesophageal (mTEE) transducer provides real-time 3D images of high spatial and temporal resolution that may be suitable for detailed simultaneous study of functional anatomy of the mitral and aortic valves. We developed software that detects and tracks throughout the cardiac cycle mitral and aortic(More)
Cardiac magnetic resonance imaging (CMRI) is the standard for estimates of LV volumes, ejection fraction and mass. These computations are based on extensive manual tracing of endocardial and epicardial borders and are subjective and time-consuming. We developed a new technique for semi-automated surface detection for the measurement of LV end-systolic and(More)
We developed an automated technique for non-rigid image registration as a basis for tracking the heart in contrast-enhanced cardiac magnetic resonance (CMR) image sequences. The goal of the present work was to validate this technique against conventional manual analysis. Our approach is based on a multi-scale extension of the normalized 2D cross-correlation(More)