Figure 3. Maximum intensity projection reconstructions of 3D MR angiography (TR 3.7, TE 1.1, flip angle 40°) clearly depict stenosis of the lower left (arrow) and upper right (curved arrow) pulmonary artery, as well as a minor stenosis of the proximal lower right pulmonary artery (arrowhead). The locations of the stenoses correlate with the calcified hilar lymph nodes shown on CT. (b) Dynamic perfusion MR images (TR 2.5, TE 0.7) of the lung show a perfusion deficit of the upper zones of the right lung and the lower zones of the left lung (left-hand image). After 8 s the perfusion deficit is evened out (right-hand image). This finding results from the pulmonary artery stenoses.