Cardiac T1 mapping in congenital heart disease: bolus versus infusion protocol for measurement of myocardial extracellular volume

Background Measurement of myocardial extracellular volume fraction (ECV) with T1 mapping cardiac magnetic resonance (CMR) before and after the application of a gadolinium-based extracellular contrast agent enables the assessment of diffuse myocardial fibrosis. The equilibrium between blood and myocardium contrast concentration required for ECV measurements can be achieved with a primed contrast infusion (equilibrium contrastCMR). In healthy volunteers it could be shown that a single bolus may also be sufficient to reach equilibrium. We hypothesized that equilibrium between blood and myocardium contrast distribution can be achieved with the bolus-only technique to accurately measure diffuse myocardial fibrosis in patients with congenital heart disease (CHD).