We read with great interest the article by Hager et al (October 2004),1 who report comparable usefulness of helical CT (HCT) scanning and cardiovascular MRI (CMR) for the noninvasive evaluation of the thoracic aorta in patients with aortic coarctation.1However, CMR not only allows detailed imaging of the entire aorta, but it also allows quantification of parameters of left ventricular function, aortic valve function, and collateral circulation in aortic coarctation patients. Steady-state free precession CMR is the most accurate imaging modality for measuring ventricular volumes, owing to its high accuracy and good reproducibility. It allows calculation of left ventricular systolic, diastolic, stroke volumes, and ejection fraction. Assessment of left ventricular mass—a parameter with prognostic significance—by CMR has also been shown much more reproducible and accurate than echocardiography, and has an excellent correlation with postmortem ventricular weights.2CMR velocity mapping can be used to quantify the degree of stenosis and/or regurgitation of frequently found bicuspid aortic valves. Insight in the functional significance of native aortic coarctation or residual aortic stenosis can be gained by assessing the recruitment of collateral circulation by comparing the flow volume through the aorta just distal to the stenosis with the flow volume through the descending aorta at the level of the diaphragm.3So, in agreement with Therrien et al,4 we believe that for the postoperative assessment of aortic coarctation patients, CMR is very much the preferred imaging modality and that aortic coarctation patients should be cared for in a specialized center with experience and appropriate CMR imaging facilities.