Intra- and interobserver reproducibility in off-line extracted cardiac tissue Doppler velocity measurements and derived variables

Using post-processing software it is possible to extract tissue velocities from colour-coded Doppler information in numerous positions in the myocardial wall. From velocity other variables such as displacement and deformation (strain) can be calculated. For adequate clinical assessment multiple measurements are needed. This is why reproducibility of the method must be evaluated. A moderately experienced observer measured systolic and diastolic basal velocity, displacement, strain rate and strain in right and left ventricular walls in 14 patients. The measurements were compared to those acquired by an experienced observer. The inter-observer variability for the systolic longitudinal and radial velocity was 6.9% and 12.0% for the right and 5.8% and 11.9% for the left ventricle respectively. The results with the least reproducibility were obtained for the radial strain rate where the inter-observer variability was 27.9% and 16.2% for the right and left ventricles respectively. Left ventricular velocity measurements had slightly better reproducibility than right ventricular. Derived calculations had a larger variation. In conclusion, basal velocity measurements and displacement calculations could be performed in the clinical routine by different observers with high reproducibility. Derived variables depending on multiple measuring locations could still be performed but with a method uncertainty of almost 15%.