Society for Cardiovascular Magnetic Resonance (SCMR) expert consensus for CMR imaging endpoints in clinical research: part I - analytical validation and clinical qualification by Puntmann, VO, Valbuena, S, Hinojar, R, Petersen, SE, Greenwood, JP, Kramer, CM, Kwong, RY, McCann, GP, Berry, C, Nagel, E, Neubauer, S