Cardiovascular magnetic resonance is an important tool for patient care and is the best test for myocardial structure and function. Ischemia and scar imaging also provide key insights and focus attention on heart muscle – the site of most cardiac diseases. New ways of measuring abnormal muscle have been developed, including T1 mapping. Abnormal signal can be distinguished either without contrast (native T1), or post-contrast (extracellular volume measurement). Large changes occur in rare diseases (cardiac amyloidosis, Anderson-Fabry disease and iron overload) even at an early stage, while more subtle changes are seen in diffuse fibrosis where a robust test would be of major impact. This review presents the potential future clinical utility of T1 mapping – a technology to watch.