[An application of semiquantitative analysis of pulmonary scintigram to pulmonary tuberculosis sequelae]

We performed ventilation-perfusion scintigraphy in 13 patients with pulmonary tuberculosis sequelae and 21 with chronic obstructive pulmonary disease. We used 99mTc-MAA for perfusion scintigram and 133Xe gas for ventilation scintigram. We added the radioactivities during the rebreathing phase of the ventilation scintigram to make a computerized image of the lung volume. Regions of interest (ROIs) were derived from radioactivities on each image. ROIs included each whole lung on lung volume (L) image and areas where radioactivity was greater than 70% of the highest radioactivity on perfusion (P70) image. We counted the area of ROIs on L and P70, and used the ratio of perfusion to lung volume (P70/L) as a parameter of pulmonary perfusion. P70/L in patients with pulmonary tuberculosis sequelae was significantly higher than that in those with COPD. This suggested that the area of high pulmonary perfusion is larger in the patients with pulmonary tuberculosis sequelae as compared with those with COPD.