Comparison of longitudinal myocardial tissue velocity, strain, and strain rate measured by two-dimensional speckle tracking and by color tissue Doppler imaging in healthy dogs.

Objectives: Two-dimensional speckle tracking (2D-ST) is a new method to measure tissue velocity (TV), strain and strain rate (SR), but it is unclear if results are comparable to color tissue Doppler imaging (TDI). The objective was therefore to compare the two modalities 2D-ST and TDI.

Animals: 100 healthy dogs

Methods: TDI images were acquired from the interventricular septal wall (IVS) and the left ventricular free wall (LVFW) to measure longitudinal TV, strain, and SR, and grayscale images were collected for 2D-ST analysis. A software program was developed, that allowed extraction of single points (SP) from the 2D-ST data set to compare SP with averages of segments (AOS) results, which are usually displayed by the 2D-ST software.

Results: A good agreement was found between AOS and SP measurements using 2D-ST. Although most data were within limits of agreement, significant differences were found between TDI and 2D-ST measurements for selected parameters. The differences were small in the IVS, but higher and of clinical relevance in the LVFW. 2D-ST was feasible and reproducible in the IVS, but less reliable in the LVFW.

Conclusions: 2D-ST and color TDI can be used interchangeably in the IVS, but the methods reveal different results in the LVFW.