Alveolar Integrity in Pulmonary Emphysema Using Technetium-99m-DTPA and Technetium-99m-HMPAO Radioaerosol Inhalation Lung Scintigraphy

The alveolar integrity (AI) in 17 male patients with pulmonary emphysema (EMPH) diagnosed by chest x-ray was measured by 99mTc-DTPA and 99mTc-HMPAO radioaerosol inhalation lung scintigraphy. The patients were divided into two groups: (A) nine patients with pulmonary emphysema and normal carbon monoxide diffusion capacity (DLCO) and (B) eight patients with pulmonary emphysema and abnormal DLCO. The degree of AI damage in EMPH was presented as the slope of the time-activity curves from the dynamic left lung imagings in DTPA and HMPAO. The AI of EMPH patients were compared with the AI of 16 normal controls. The results show that: (1) the slope of DTPA is larger than that of HMPAO in each of the portions of the left lung for any of the study groups; (2) statistical differences were found between the normal controls and EMPH patients in HMPAO but not in DTPA; and (3) the correlation was not good between DLCO and DTPA/HMPAO in EMPH patients. Our results suggest that: (1) at least two different mechanisms in the lungs were at work; (2) the AI damage in EMPH developed mainly in the lipophilic part of the alveoli; and (3) the AI damage presented as slopes of DTPA/HMPAO in our study was different from the traditional pulmonary function such as DLCO.