This is the peer reviewed version of the following article: Higgins, D. M., Keeble, C. , Juli, C. , Dawson, D. K. and Waterton, J. C. (2019), Reference range determination for imaging biomarkers: Myocardial T1. J Magn Reson Imaging, 50: 771-778., which has been published in final form at https://doi.org/10.1002/jmri.26683. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.