Lung scintigraphy in differential diagnosis of peripheral lung cancer and community-acquired pneumonia

Abstract

Ventilation/perfusion lung scintigraphy was performed in 39 patients with verified diagnosis of community-acquired pneumonia (CAP) and in 14 patients with peripheral lung cancer. Ventilation/perfusion ratio, apical-basal gradients of ventilation (U/L(V)) and lung perfusion (U/L(P)), and alveolar capillary permeability of radionuclide aerosol were determined based on scintigraphy data. The study demonstrated that main signs of CAP were increases in ventilation/perfusion ratio, perfusion and ventilation gradient on a side of the diseased lung, and two-side increase in alveolar capillary permeability rate for radionuclide aerosol. Unlike this, scintigraphic signs of peripheral lung cancer comprise an increase in ventilation/perfusion ratio over 1.0 on a side of the diseased lung with its simultaneous decrease on a contralateral side, normal values of perfusion and ventilation gradients of both lungs, and delayed alveolar capillary clearance in the diseased lung compared with the intact lung.