Application of technetium-99m-sestamibi in differentiation of active from inactive pulmonary tuberculosis using a...

We studied the usefulness of 99mTc-methoxyisobutylisonitrile (MIBI) scintigraphy for differentiation between active and inactive pulmonary tuberculosis.

Thirty-six patients (aged 27-82 years, 16 males and 20 females) were included in our study. Each patient was injected with 740 MBq (20 mCi) 99mTc-MIBI and both planar and single photon emission computed tomography (SPECT) imaging were performed 15 and 60 min after injection. Twenty-four patients had active pulmonary tuberculosis (proven by sputum culture), and the remainder 12 had negative sputum culture. Semiquantitative as well as visual assessments were done on all sets of images.

All of the 12 patients in the control group had negative scintigraphy on both planar and SPECT images. Twenty patients with active pulmonary tuberculosis had positive 99mTc-MIBI scintigraphy on planar images (sensitivity of 87.5%). SPECT images were positive in 23 patients with active pulmonary tuberculosis (sensitivity of 95.8%). Both semiquantitative and visual assessment of planar and SPECT images showed statistically significant differences between active and inactive pulmonary tuberculosis patients (P<0.001). Comparison of 15 and 60 min image sets did not show any statistically significant difference (P=0.956 and 0.457 for planar and SPECT images, respectively).

99mTc-MIBI has significant uptake in the active tuberculosis lesions and can be used to differentiate between active and inactive tuberculosis. The SPECT method is especially useful because of its higher sensitivity.