EVALUATION OF INTRAPULMONARY NODULES BY P OSITRON EMISSION TOMOGRAPHY

Positron emission tomography (PET) with fluor-18-labeled deoxyglucose (FDG) enables metabolically oriented imaging of intrapulmonary lesions . PET is currently not used for the detection of lung metastases, but for further diagnostic differentiation of nodules that have already be en detected. The diagnostic accuracy of FDG-PET is currently dependent on the size of the metastatic lesions and the uptake intensity. Signi ficantly increased FDG uptake is strongly suggestive of malignant dise ase whatever the size of lesion concerned. Differentiation of a solita ry metastasis from a primary lung tumor is not possible. Slightly elev ated FDG uptake can also be found in tuberculosis, sarcoidosis and oth er granulomatous or inflammatory processes. Exclusion of metastatic di sease with PET is currently only reliably possible for lesions larger than 2.0 cm in diameter, owing to respiratory motion and effects of pa rtial volume.