TECHNETIUM-99M-MIBI SCINTIGRAPHY IN PULMONARY TUBERCULOSIS

We investigated the usefulness of Tc-99m-methoxyisobutylisonitrile sci ntigraphy in patients with known or suspected pulmonary tuberculosis ( PTB) in comparison with radiological and bacteriological findings. Met hods: Thirty-six patients aged 13-59 yr were scanned 15 and 60 min aft er intravenous injection of 370 MBq (10 mCi) Tc-99m-methoxyisobutyliso nitrile. Twenty-four patients had active PTB proven by chest radiograp h and sputum examinations, two had miliary tuberculosis and ten were s uspected of having relapsed PTB with negative sputum examinations and indeterminate chest radiographs, In 12 patients Tc-99m-MIBI imaging wa s repeated 1-3 mo after chemotherapy. Results: Of 24 patients with act ive localized PTB, 22 (92%) showed increased focal uptake of Tc-99m-MI BI, but two patients with minimal infiltration on chest radiographs ha d no accumulation of Tc-99m-MIBI. Both patients with miliary PTB showe d diffuse Tc-99m-MIBI uptake in the lungs. Among 10 patients with susp icion of relapse, Tc-99m-MIBI scans were true-positive in 4 of 5 patie nts (80%) with culture-proven tuberculosis and false-positive in 2 of 5 (40%) patients with negative sputum cultures, For repeat imaging, 6 of 10 patients with active localized PTB showed reduced MIBI uptake, w hich correlated with chest radiograph findings, and one patient had in creased MIBI uptake again concordant with clinical and radiological fi ndings which were suggestive of resistance to first line chemotherapy of tuberculosis. The other three patients showed no significant scinti graphic changes despite clinical and partial radiological regression. Conclusion: Active PTB granulomas generally present considerable Tc-99 m-MIBI uptake that is most probably related to disease activity. There fore, Tc-99m-MIBI scanning could be used in the detection and follow-u p of active PTB as a complement to routine techniques.