Accurate quantification of myocardial blood flow using cardiac MR perfusion imaging requires a linear relationship between the arterial input function and myocardial signal intensity curves. Typically this condition is not fulfilled with standard contrast agent doses, but can be achieved using signal calibration techniques for direct contrast concentration quantification. These methods use a low flip angle (LFA) reference image for normalisation. However, normalisation based on a low SNR reference image results in poor precision of T1 estimates. In this study the use of a high flip angle reference image shows improved precision compared to a LFA technique.