Objective: Speckle tracking is a new imaging modality capable of providing information about myocardial motion in all three directions: longitudinal, circumferential and radial. There are many software packages with their unique tracking algorithms and user interfaces in the market. We aimed to evaluate the feasibility of QLAB software in clinical practice and speckle based myocardial velocities in healthy subjects.
Methods: Thirty-two subjects were enrolled in the study. Images from apical four-chamber, apical two-chamber, parasternal short-axis (mitral valve-apical levels) views were acquired and analyzed offline with QLAB. We measured speed and velocity data in longitudinal, circumferential and radial directions. Time percent of these events were also calculated. In the final data analysis 825 of 832 segments (99.2%) were included. Mann Whitney U, Student's t and Kendall's tau-b coefficient tests were used for statistical analysis.
Results: We determined that circumferential speed was significantly higher (p<0.001) than radial velocity in both parasternal short-axis views. Likewise, longitudinal speed was higher (p<0.001) than radial velocity in apical views. Notwithstanding the speed and velocity data, time percent of radial velocity were significantly lower (p<0.001 for all) than their longitudinal or circumferential counterparts. We also notified that apex was the segment reaching its maximum speed at earliest time. QLAB measurement time was relatively long (8.1+/-1.7 min) and intraobserver agreement was lost in 3% of the segments.
Conclusion: In addition to these findings, we consider QLAB software package for speckle tracking needs some improvements to shorten measurement time and decrease user intervention.