Table 1 Fletcher’s PET and CT criteria for rating SPN
Category | Relationship between SPN18F-FDG uptake and likelihood of malignancy | Relationship between CT SPN characteristics and likelihood of malignancy |
|---|---|---|
Definitely benign | No increased uptake—uptake essentially the same as in reference lung tissue (generally corresponds to an SUV of 0.6–0.8) | Central laminated or diffuse calcification |
Popcorn pattern of calcification | ||
Lesion with cavitations and wall thickness < 1Â mm | ||
Probably benign | Uptake substantially less than in blood pool (general mediastinal activity) but greater than in reference lung tissue (SUV greater than 0.6–0.8 but less than 1.5–2.0) | Large (< ;2 cm) dominant nodule with satellite lesions |
Solid nodule with polygonal shape or smooth and well-defined margin | ||
Diameter < 10Â mm; lobulated margin contours | ||
Indeterminate | Uptake 2–3 times that in reference lung tissue but less than in blood pool (generally corresponds to SUV of 1.5–2.0 but less than 2.5) | All other characteristics not defined in other likelihood categories |
Probably Malignant | Uptake greater than in blood pool (blood pool generally corresponds to an SUV of 2.5) | Diameter > 2Â cm |
Ground-glass opacity with round shape | ||
Mixed ground-glass opacity with central zone of high attenuation | ||
Definitely Malignant | Uptake much greater than in blood pool—anything substantially greater than SUV of 2.5 | Densely spiculated margin, ragged margin Lesion with cavitations and wall thickness > 16 mm |