Aortic coarctation is a relatively common cardiovascular condition with high associated mortality if not treated. Even with successful repair, however, close follow up is needed as late complications can result in significant cardiovascular morbidity. MRI, with is ability to provide both anatomic and hemodynamic information, is becoming the imaging option of choice for post-intervention surveillance. Time-resolved, three-dimensional phase contrast magnetic resonance velocity (4D Flow) profiling enables the acquisition of multidirectional blood velocity data. The technique is well suited for evaluation of blood flow patterns in the thoracic aorta. By comparing aortic flow patterns in patients status post coarctation repair with those of healthy volunteers using 4D Flow, this study intends to characterize abnormal flow patterns in these patients with the eventual goal of better understanding and predicting late complications so that preemptive intervention may be taken.