Color Tissue Doppler to Analyze Fetal Cardiac Time Intervals: Normal Values and Influence of Sample Gate Size

摘要

Purpose To assess the time intervals of the cardiac cycle in healthy fetuses in the second and third trimester using color tissue Doppler imaging (cTDI) and to evaluate the influence of different sizes of sample gates on time interval values. Materials and Methods Time intervals were measured from the cTDI-derived Doppler waveform using a small and large region of interest (ROI) in healthy fetuses. Results 40 fetuses were included. The median gestational age at examination was 26 + 1 (range: 20 + 5 – 34 + 5) weeks. The median frame rate was 116/s (100 – 161/s) and the median heart rate 143 (range: 125 – 158) beats per minute (bpm). Using small and large ROIs, the second trimester right ventricular (RV) mean isovolumetric contraction times (ICTs) were 39.8 and 41.4 ms (p = 0.17), the mean ejection times (ETs) were 170.2 and 164.6 ms (p Conclusion Isovolumetric time intervals can be analyzed precisely and relatively independent of ROI size. In the near future, automatic time interval measurement using ultrasound systems will be feasible and the analysis of fetal myocardial function can become part of the clinical routine.