Figure 4.

A-D, Confirmatory chest imaging. Contrast to enhance the pulmonary arteries disclosed multiple regions smaller-then-normal pulmonary artery caliber. A, Apical segment of the right upper lobe. The pulmonary artery (long arrow) is smaller in caliber than the corresponding vein (short arrow). B, Superior segment of the left lower lobe. The pulmonary artery (long arrow) is smaller in caliber than the corresponding vein (short arrow). C, Superior branch of the lingular pulmonary artery. An eccentric filling defect (arrow) is apparent on the anterior wall of the artery. D, Descending branch of the left pulmonary artery. A web-like filling defect (arrow) is present on the lateral aspect of the artery.