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

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.