Noninvasive pressure measurement with 4D phase contrast MRI in patients with aortic coarctations

Background Aortic coarctation (CoA) is defined as a congenital narrowing of the descending thoracic aorta severe enough to create pressure gradient. In clinical routine, invasive catheter pressure measurements are considered the gold standard. Pressure gradients can also be estimated noninvasively from Doppler ultrasound (US) or 2D phase contrast (PC) MRI using a simplified Bernoulli equation [1]. However, thoracic US measurements are not always possible, results can be user dependent, and do not provide information regarding temporal and spatial variations. 4D PC MRI with three-directional velocity encoding can be used to measure the spatial and temporal distribution of pressure gradients [2] as well as other hemodynamic parameters (Fig. 1). The purpose of this study was to compare pressure measurements made with US to those made with a radially undersampled 4D PC-MRI sequence in patients with coarctations.