Figure 2a. Unilateral proximal interruption of the right pulmonary artery in a 52-year-old woman with progressive shortness of breath and hemoptysis. (a) Contrast material–enhanced CT scan shows only the proximal portion of the right pulmonary artery (arrowhead) and enlargement of the main and left pulmonary arteries that indicates pulmonary hypertension. (b) Contrast-enhanced CT scan at the level of the upper lobes shows serrated thickening of the right pleura because of enlarged intercostal collateral vessels (arrowheads). (c) CT scan obtained with a lung window setting shows multiple linear opacities perpendicular to the pleural surface that correspond to transpleural systemic vessels (arrowheads).