Beyond late gadolinium enhancement: the key role of diffuse myocardial fibrosis in severe aortic stenosis - an Equilibrium Contrast CMR study by Mcgregor Christopher, Pellerin Denis, Lawrence David, Banypersad Sanjay M, Hausenloy Derek, Huttin Olivier, Quarta Giovanni, Sado Dan M, Flett Andrew S, Taylor Andrew M, Moon James C