(A-C) A serial of ECG-gated spin echo T1-weighted image. At the carinal level (A), a moderate degree of stenosis (arrow) of left pulmonary artery was noted. At right pulmonary artery level (B), the dilated right pulmonary artery shows rapid tapering (asterisk). Note the left pulmonary artery shows post-stenotic dilatation (arrow). At the lower lung level (C), the right pulmonary artery is tiny (curved arrow), in contrast to the left lower pulmonary artery (arrowhead). Ao: aorta; PT: pulmonary trunk. (D) Catheter angiography with contrast medium injection from right ventricle shows dilated PT, left pulmonary artery (arrowhead) and right pulmonary artery with an abrupt tapering (asterisk). Note there is a tiny branch with decrease flow (curved arrow) in the right lower lung. (E). DCE-MRI after bolus injection. ROIs were chosen to cover the whole left lung (red) and right lung (green). Pixels with high intensity were considered as vessels and excluded from ROIs. (F) SI-time curves obtained from DCE-MRI for the left and right lungs. (G) Tc99M-MAA pulmonary perfusion scintigraphy (posterior-anterior view) shows almost no detectable perfusion in the right lung. (Right, 97.3%, Left, 2.7%). (H) rPBV map of whole lungs showed a small but observable flow in the right lung. (I) rPBViw map of the whole lungs was similar to PS and showed no detectable flow in the right lung.