Frame rate requirement for tissue Doppler imaging in different phases of cardiac cycle: radial and longitudinal functions

Abstract

Tissue Doppler imaging (TDI) has been suggested for quantitative analysis of regional myocardial function. Myocardial movement included different mechanical phases with different duration and tissue velocity profiles need to high sampling rate in the acquisition of tissue velocity imaging for phases with shorter duration. The aim of this study is determining of frame rate requirement for myocardial tissue velocity imaging for longitudinal and radial functions separately. Tissue velocity imaging recorded from 29 healthy volunteers by use of the apical and para-sternal views. Off-line analysis performed for extracting tissue velocity profiles of the myocardial longitudinal and radial functions. The frequency and subsequently the frame rate calculated separately for all LV segments during two consequent cardiac cycles. Segmental distribution of the time intervals measured in all cardiac phases and the minimum frame rate requirement calculated for each segment. We found significant differences between radial and longitudinal functions (P < 0.001) except early diastolic phases. The presented normal frame rate values for LV segments may useful for accurate studies of myocardial longitudinal and radial functions in different cardiac phases. We conclude that data sampling at a rate of at least 105 and 118 frames per second need for longitudinal and radial functions respectively.

Tissue Doppler velocity imaging and event timings in neonates: a guide to image acquisition, measurement, interpretation, and reference values

“…These velocity measures have also been assessed in neonates, 11 , 12 but less frequently than the s′, e′, and a′. The time resolution is important because a low frame-rate might lead to under-sampling of velocities 13 and inaccurate assessments of time intervals, 14 in particular for diastolic velocities and isovolumic phases of the cardiac cycle.…”

“…The frame-rate requirements are probably more critical for short-time intervals and for diastolic velocities than for long-time intervals, systolic velocities, and displacements. 13 , 14 , 49 The sector should be narrow and shallow to keep the frame-rate high, but it must show the relevant structures throughout the cardiac cycle. Acquisition of several cardiac cycles will enable direct comparisons between heartbeats and is a prerequisite for averaging between heartbeats.…”

“…Although the angle of insonation is less important for time indices than for velocities and displacements, the sonographer should ensure a good angle of insonation because time indices will always need to be interpreted together with the velocities and displacements. In the velocity curves, the isovolumic contraction and relaxation phases each show a positive and a negative velocity peak, the negative peaks on each side of the ejection phase and the positive peaks on each side of the filling phase 14 (Fig. 2 ).…”

State diagrams of the heart – a new approach to describing cardiac mechanics

“…A relatively recently developed method with improved ability to measure cardiac events is Tissue Doppler Imaging (TDI), which allows for accurate measurement of cardiac phases generated by movement of the myocardium [ 7 ]. Different approaches of dividing the cardiac cycle into phases have been reported in the literature [ 8 - 11 ]. In a TDI-velocity curve, the most common way is to divide systole into two phases and diastole into four phases.…”