The relationships between the radionuclide alveolar integrity study and the pulmonary function test

This study evaluated the relationships between the alveolar integrity and the pulmonary function in 33 male subjects, including 18 COPD patients, 10 normal volunteers and 5 NIDDM patients. Alveolar integrity was evaluated by dynamic Tc-99m DTPA/HMPAO radioaerosol lung scintigraphies. The speed of radioaerosol clearance is represented as a slope from the lungs to the blood stream. Comprehensive pulmonary function tests included forced expiratory volume, flow-volume loop, and diffusion capacity of a single breath CO method. The results showed the following: that (1) there are no correlations between the slopes and the parameters of pulmonary function tests, and (2) that the clearance of DTPA aerosols is faster than the clearance of HMPAO, and that these differences are significant. In conclusion, the radionuclide alveolar integrity study should be considered as a new method for evaluating lung function, and should be differentiated from traditional pulmonary function tests, and, secondly, lipophilic HMPAO aerosols are slower to clear than those of hydrophilic DTPA, which suggests at least two different clearance mechanisms for radioaerosols.