Quantitative measurement of lung density with x-ray CT and positron CT, (1)

Quantitative measurement of lung density was performed with X-ray CT (XCT) and Positron CT (PCT). Using XCT, total lung density could be measured quantitatively. The mean value was 0.25 +- 0.05 gcm-3. And profile analysis of CT numbers along the chest wall was useful to evaluate the distribution of lung blood volume. Using PCT, total lung density, lung blood volume, and extravascular lung density could be measured quantitatively. The mean values were 0.35 +- 0.03 gcm-3, 0.19 +- 0.01 mlcm-3 and 0.15 +- 0.02 gcm-3. We could evaluate lung density in detail. We believe that these methods provide many diagnostic informations to understand diffuse pulmonary diseases. (author)