All MRIs of the first 10 patients before (left), and at intervals after, with the diameter of greatest change shown in red. All MRIs of the first 10 patients before (left), and at intervals after, with the diameter of greatest change shown in red. Duplicate measurements of 37 anonymised MRI images of Marfan aortic roots were presented with those of the patients in a random sequence.4 The black circles show the read-reread variation in the controls, and the largest difference in the patients in red. The variability in read-reread is amplified by choosing to display the one of three diameters with the largest difference, but illustrates the degree of imprecision that should be allowed for when clinical decision are being made. The reduction in size of eight out of ten supported aortas because the aorta is held at the size it was on the operating table illustrates the potential for restoration of aortic valve competence. Tom Treasure et al. Heart 2014;100:969-975 Copyright © BMJ Publishing Group Ltd & British Cardiovascular Society. All rights reserved.