Ventilation-perfusion lung imaging in diaphragmatic paralysis.

Clinical, radiological, physiological, and lung imaging findings from a patient with paralysis of the diaphragm are described. Dyspnea, hypoxemia and hypercapnia increased when the patient changed from the upright to the supine positions. Ventilation (V) and perfusion (P) images of the right lung appeared to be relatively normal and remained nearly the same in the upright and supine positions. In contrast, V/P images of the left lung were smaller than those of the right lung in the upright position and decreased further in the supine position. In addition, the size of the ventilation image was much smaller than that of the perfusion.