Interstudy variability in cardiac magnetic resonance imaging measurements of ventricular volume, mass, and ejection fraction in repaired tetralogy of fallot: A prospective observational study

Purpose To assess the interstudy variability of cardiac magnetic resonance imaging (CMR) parameters of ventricular size and function in repaired tetralogy of Fallot (TOF). Materials and Methods Patients with TOF (n = 30, median age 23.5 years, 43% male) were enrolled prospectively. Each patient underwent two consecutive CMR examinations on the same day. Each examination was analyzed for ventricular size and function by two observers and multiple comparisons were made with assessment of agreement using Bland-Altman analysis and intraclass correlation coefficients (ICC). Results Agreement for most measures of ventricular size and function was high when a single observer analyzed both studies. Agreement was worse when different observers analyzed sequential studies. This effect was most prominent on measurements of right ventricular (RV) mass and there was slight improvement when mass was measured during systole. Aside from ventricular mass, agreement was similar for RV and left ventricular (LV) parameters. Conclusion CMR measures of ventricular size and function have acceptable repeatability across serial examinations in patients with repaired TOF. Measurements of RV mass are subject to higher variability. For most parameters, agreement limits are wider when measurements are performed by multiple operators. These results will aid in the interpretation of study-to-study variations in the follow-up of individual patients and in designing future clinical trials.