Intraventricular Pressure Gradients - Vector Flow Imaging versus Color M-Mode

Abstract

Non-invasive estimation of intraventricular pressure differences (IVPD) can be of clinical value for the assessment of diastolic function. We investigate the potential of estimating IVPD using Euler's equation and 2-D velocity fields from blood speckle tracking (BST). Separate Color Doppler M-mode (CMM) recordings are done for comparison. Using a clinical scanner, high-frame-rate recordings based on plane wave imaging gave duplex frame rates above 70 frames-per-second (fps) for BST analysis of the left ventricle. Data from 20 healthy children were analyzed. On average, CMM measured 0.29 mmHg higher peak negative IVPD in diastole than BST. Decimating the BST data to frame rates of 50–70 fps and 30–50 fps reduced the estimated peak negative IVPD with 11% and 23%, respectively, and increased the mean difference between CMM and BST to 0.71mmHg and 0.87 mmHg, confirming the need of having higher frame rates than in conventional color flow imaging to achieve comparable results to CMM. In contrast to CMM, BST analysis allows 2-D integration along inflow streamlines for IVPD estimation and is thus not dependent on a low beam-to-flow angle. In addition, the estimated pressure gradients can be visualized in 2-D for further evaluation.