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

Abstract

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 loss and kinetic energy. However, velocity quantification using BSI has scarcely been studied in vivo.

Methodology: Maximum aortic valve velocities by conventional Doppler echocardiography were compared with those derived from BSI in healthy children. BSI-derived velocities were extracted via a custom Python code. Agreement between methods was assessed using Pearson correlation and Bland-Altman analysis. Inter-observer reproducibility of BSI analysis was evaluated in a randomly selected subset.

Results: Seventy-seven Doppler acquisitions from 33 patients were analysed. The median age was 84 months, and maximum velocity was 1.19 m/s. Modest correlation (R = 0.53, p-value<0.001) was found between BSI and Doppler velocities. Age-stratified analysis showed good correlation in younger children (<6.5 years; R = 0.59, p-value<0.001), whereas no significant correlation was found in older subjects. A non-significant trend towards BSI underestimating velocities, more marked in older children, was noted. Discrepancies between methods increased at higher velocities. Inter-observer reproducibility of BSI velocities was good (R = 0.7, p-value = 0.006).

Discussion and conclusion: Aortic valve velocities by BSI technique show moderate correlation with Doppler in healthy children, with better performance in younger subjects, and good inter-observer reproducibility. Overall, the findings support BSI echocardiography for aortic valve maximum velocity assessment in healthy children, but further research is warranted to determine its utility in patients with aortic valve disease.

Keywords: Aorta; Blood speckle imaging; Echocardiography; Pediatric cardiology; Velocity.