Discrepancy between Ga-67 citrate and F-18 fluorodeoxyglucose positron emission tomographic scans in pulmonary infection

The authors describe a patient with the acquired immunodeficiency syndrome who had active pulmonary tuberculosis and was receiving anti- tuberculosis treatment. High-grade fever and a right-sided pleural effusion had recently developed. Results of a Ga-67 scan were negative for any focal infection in the chest. Fluorine-18 fluorodeoxyglucose positron emission tomography showed increased uptake in the right lower lung field, which correlated with the diagnosis of concomitant bacterial pneumonia. Anti- tuberculosis treatment can decrease the sensitivity of the Ga-67 scan and could have contributed to this discrepancy. The authors predict that the fluorine-18 fluorodeoxyglucose positron emission tomographic scan will play an important diagnostic role in the management of such a selected group of patients.