Fully-automated fetal left ventricular myocardial performance index measurement in pulsed-wave Doppler ultrasound based on tubular structure enhancement and intensity projection waveform peak detection: A feasibility study

Objective Measurement of fetal left ventricular myocardial performance index (MPI) in pulsed-wave Doppler (PWD) ultrasound is important while challenging, which relies on the localization of four peaks of mitral valve (MV) and aortic valve (AV) opening/closure clicks. The objective of this study is to explore a new method for automatic fetal MPI detection in PWD images. Methods We proposed a fully-automated method for fetal MPI measurement in PWD images based on tubular structure (TS) enhancement and intensity projection waveform peak detection. The four clicks were considered as TSs in PWD images and were significantly enhanced with a multiscale vesselness filter. Horizontal intensity projection (HIP) was performed to the TS-enhanced image to produce a TS intensity waveform, where local peaks were automatically detected as potential click peak locations. To identify the desired click peak locations, the proposed method also incorporated peak detection of main lobes and GS intensity waveforms based on HIP of PWD images. Results PWD images collected from 32 patients were included, with manually labeled MPI ranging from 0.41 to 0.71. The proposed method had a satisfying agreement with the manual method, with a mean absolute error of 0.06 and a mean absolute percentage error of 11.96 %. The average running time was 0.82 s. Conclusions The feasibility of the proposed method in automatically measuring fetal MPI on PWD images has been demonstrated. The findings of this study may shed light on the four click enhancement and may provide insight for automatic fetal left ventricular MPI measurement in PWD ultrasound.