Blood speckle imaging for the assessment of aortic valve velocity in healthy children: Reproducibility and comparison with Doppler echocardiography

INTRODUCTION Blood speckle imaging (BSI) in paediatrics is a promising novel echocardiography technique that allows complex blood flow assessment via qualitative visualization and analysis of vorticity, energy gloss and kinetic energy. However, velocity quantification has scarcely been studied in vivo, albeit in children at the aortic valve level. METHODOLOGY Comparison of conventional Doppler and BSI velocities at the aortic valve level in healthy children by echocardiography. BSI maximal velocity was extracted via a custom code in Python. Analysis was performed using Pearson correlation and Bland Altman analysis. An inter-observer study variability for BSI analysis was also performed in a randomly selection of subjects. RESULTS A total of 77 Doppler acquisitions in 33 patients were obtained. The median age was 84 months, and maximal velocity was 1.19 m/s. Modest correlation (R = 0.53, p-value<0.001) was found between maximal velocity by BSI and Doppler. When age-stratified, the younger subgroup (<6.5 years) showed good correlation (R = 0.59, p-value<0.001) whereas it was not significant in the older subjects. A non-significant trend towards BSI underestimating velocities was found, more marked in the older subgroup. Also, discrepancies between BSI and Doppler were higher in the older subjects. There was good inter-observer reproducibility of BSI analysis (R = 0.7, p-value = 0.006). DISCUSSION AND CONCLUSION The BSI technique shows moderate correlation with Doppler in healthy children, with better performance at lower body size. A non-significant trend towards greater discrepancies at higher velocities was observed. Good BSI analysis inter-observer variability was found. The BSI echocardiography allows quantification of aortic valve maximum velocity in healthy children.