THE ROLE OF (67)GALLIUM SCINTIGRAPHY AND HIGH-RESOLUTION COMPUTED-TOMOGRAPHY AS PREDICTORS OF DISEASE-ACTIVITY IN SPUTUM SMEAR-NEGATIVE PULMONARY TUBERCULOSIS

SETTING: University Hospital, Kuala Lumpur, Malaysia. OBJECTIVE: To de termine whether (67)Gallium (Ga) scintigraphy and high resolution comp uted tomography (HRCT) of the lung improve the diagnostic accuracy of sputum smear-negative active pulmonary tuberculosis. DESIGN: Patients suspected of having active pulmonary tuberculosis but who were sputum smear-negative underwent Ga-67 scintigraphic and HRCT scanning of the lung, Results of these scans were correlated with results of bacteriol ogy and histopathology as well as clinical data on follow-up. RESULTS: Although none of the patients was culture-positive for Mycobacterium tuberculosis, 14 were considered to have active disease either because of positive direct smears of respiratory tract specimens other than s putum, positive histopathology, or clinical and radiological improveme nt following antituberculosis chemotherapy, A positive Ga-67 scan had a sensitivity of 100% and a specificity of 83% for active pulmonary tu berculosis. Of the HRCT findings, the presence of centrilobular lesion s had a 93% sensitivity and 100% specificity in determining disease ac tivity in this group of patients. CONCLUSION: Both Ga-67 scintigraphic and HRCT scans are helpful in determining disease activity in sputum smear-negative pulmonary tuberculosis.