Scan-rescan reproducibility of ventricular and atrial MRI feature tracking strain

Background: A feature tracking (FT) was designed to simultaneously extract myocardial strains in main cardiac chambers from cine MRI images. Its inter-observer and scan-rescan reproducibility was assessed and sample sizes required to detect predefined longitudinal changes in strain values were provided. Method: FT was applied on left (LV) and right (RV) ventricles as well as left atrium (LA) of 21 individuals (66 10 years) who underwent 2 Mills 2 weeks apart. Global peaks for radial, circumferential, longitudinal strains, radial motion fraction (Mr), fractional area change (FAG) and tricuspid annular plane excursion (TAPSE) were estimated. Inter-operator and inter-exam reproducibility were evaluated using coefficients of variations (CV) and intra-class correlation coefficients (ICC). Results: Reproducibility of all measurements were good to excellent for inter-operator (LV:CV<6.5%, ICC>0.91; RV:CV<12%, ICC>0.86; LA:CV<14%, ICC>0.85) and inter-study (LV:CV<15%, ICC>0.65; RV:CV<20%, ICC>0.71; LA:CV<20.5%, ICC>0.83) evaluations. Reasonable sample sizes are required to detect a longitudinal difference of 10-15% in strain values (LV:5 to 33 individuals, RV:14 to 62 individuals, LA:4 to 65 individuals). Conclusions: FT-based functional evaluation of main heart chamber deformation from cine MRI is repeatable and thus suitable for follow-up. Strain measurements may help for the joint clinical evaluation of LV, RV or LA implication in various cardiomyopathies.