Abstract: A method of analysing MRI images is described. The method comprising the steps of: acquiring a first medical MR image, and a second medical MR image, of a subject at the same nominal magnetic field strength; analysing the first and second MR images to determine a wT1 map from the first and second images; applying a field strength correction based on modification of the nominal field strength used for the first and second MR image acquisitions, and an iron correction to correct for differences in the iron concentration from a normal level using a T2*map, to the wT1 map from the first and second images to generate a corrected wT1 map; using the corrected wT1 map to determine simulated signals for a subject with normal iron levels, and fitting the simulated signals to a standard cT1 to determine a standard cT1 image for the subject.