Mismatch Between Gallium-67 Uptake and CT Findings in a Case of Pulmonary Alveolar Proteinosis

Gallium-67 citrate (67Ga) scintigraphy has been used as an indicator of activity of diffuse interstitial lung diseases. However, little has been mentioned in pulmonary alveolar proteinosis (PAP). Here we present a 53-year-old man with PAP showing patchy 67Ga uptake by single photon emission computed tomography (SPECT). Interestingly, the strong 67Ga uptake was observed in areas where ground-glass opacities were faint on chest CT. The uptake persisted after whole-lung lavage while the ground-glass opacity improved markedly. Although the precise mechanism of 67Ga uptake remains unclear, 67Ga SPECT findings may reflect the different pathological condition of PAP than that shown by CT.