Our investigation used a Siemens 1.5-Tesla Avanto MRI system, manufactured by Siemens Medical Systems, Malvern, New Jersey. After localizers in multiple planes, a stack of static, steady-state free precession axial images were acquired spanning the entire thorax and neck. These images evaluated cardiovascular anatomy and were used for localized through-plane velocity mapping. The effective repetition time was the R-R interval (range 450 to 650 ms). The echo time was 1.5 to 3 ms, the number of segments per heartbeat was 29, the number of excitations was 3, the image matrix size was pixels, interpolated to , with a field of view ranging from 180 to 200 mm and slice thickness of 3 mm. Multiplanar reconstruction, a software package resident on the Siemens MRI system, used the transverse images to calculate the exact slice position and double-oblique angles to obtain a ventricular outflow tract view and long-axis images of the jugular veins and superior vena cava. If two ventricular outflow tracts were present, each one was obtained separately. An imaging plane perpendicular to flow was then determined for the ventricular outflow tract at the sinotubular junction, right and left common jugular veins above the superior vena cava and the superior vena cava proximal to the pulmonary artery anastomosis and distal to the innominate and subclavian veins. The retrospective phase encoded velocity mapping sequence was then performed with a repetition time of 35 ms, echo time of 3 ms, number of segments per heartbeat of 3, field of view of 180 mm, a slice thickness of 5 mm, obtaining 20 to 23 phases depending upon the heart rate utilizing parallel imaging and 5 averages. VENC MRI encoding was 60 to .