T1 mapping for myocardial extracellular volume measurement by cardiovascular magnetic resonance: bolus only vs primed infusion technique

Background Myocardial ECV can be measured using T1 mapping before and after contrast if the contrast agent distribution between blood:myocardial is at equilibrium. Equilibrium distribution can be achieved with a primed contrast infusion (EQ-CMR), or may be approximated by the dynamic equilibration achieved by delayed post bolus measurement. This bolus only approach is highly attractive but currently limited data support its use. We compared the bolus only technique with two gold standards: collagen volume fraction (CVF) from myocardial biopsy in aortic stenosis (AS), and the infusion technique in five representative conditions.