Comparison of 67Ga planar imaging and SPECT for the evaluation of activity in undetermined minimal pulmonary tuberculosis

An, Min; Chang, Won Kyu; Kim, Kyoung Gon; Kim, Sung Min; Kim, Yun Kwon; Kim, Young Jung; Park, Byung Yik; Cho, Min Koo; Lee, Gwon Jun

Abstract

BACKGROUND
We have studied the 67Ga SPECT to determine the activity of pulmonary tuberculosis, especially in patients with minimal extent of the disease on chest radiographs. Because active minimal pulmonary tuberculosis is sometimes difficult to diagnose by means of initial chest X-ray, sputum examination and 67Ga planar imaging, we compared 67Ga planar imaging with SPECT to evaluate minimal pulmonary tuberculosis activity.
METHODS
67Ga planar imagings and SPECTs of 69 patients suspected of minimal pulmonary tuberculosis by the initial chest X-ray were performed and compared to each other. Active pulmonary tuberculosis was defined by a positive AFB smear and/or culture in the sputum and changes shown on the serial chest X-ray findings.
RESULTS
1)67Ga planar imaging imagings showed positive uptakes in 24 patients and no uptakes in 13 patients, which confirms active pulmonary tuberculosis. But SPECT imagings showed positive uptakes in 25 patients and no uptakes in 12 patients. 2) Patients confirmed with inactive pulmonary tuberculosis showed no up-take on 67Ga planar imaging. Only one of the 32 patients confirmed as having inactive pulmonary tuberculosis showed positive uptake on 67Ga SPECT imaging.
CONCLUSIONS
According to the results of our study, 67Ga planar imaging and SPECT are both sensitive in detecting the activity of minimal pulmonary tuberculosis. The difference between the two methods is not statistically significant, and the negative predictive value of the 67Ga SPECT is not higher than that of 67Ga planar imaging.