Correlation between right ventricular Tei index by tissue Doppler imaging and pulsed Doppler imaging in fetuses

The aim was to compare the right ventricular (RV) Tei index obtained by the tissue Doppler imaging (TDI) method with that obtained by the pulsed Doppler method in 29 fetuses aged 24-39 weeks (29.9 +/- 4.0 weeks). From pulsed Doppler recordings, the tricuspid closing-to-opening time (a) and RV ejection time (b) were measured. The Tei index determined by the pulsed Doppler method was calculated as (a - b)/b. From TDI recordings, the time interval during diastole (a') and the duration of the systole S-wave (b') were measured. The modified Tei index obtained by TDI was calculated as (a' - b')/b'. The time a' correlated strongly with a (r = 0.90, p < 0.0001). The mean difference between a' and a was 0.3 +/- 5.0 ms. There was also a strong correlation between b' and b (r = 0.94, p < 0.0001). The mean difference between b' and b was 0.5 +/- 3.3 ms. The TDI-Tei index correlated with the pulsed Doppler-Tei index (r = 0.83, p < 0.0001). The mean difference between the TDI-Tei index and the pulsed Doppler-Tei index was -0.003 +/- 0.04. This study demonstrated that the TDI-Tei index correlates well with the Tei index determined by pulsed Doppler in fetuses, suggesting that the TDI-Tei index is a feasible approach to assess global RV function in fetuses.