Fdg avid lesion

 

Fdg avid lesion

Lung cancer is very FDG-avid. This uptake becomes even more conspicuous as there is relatively low uptake in the surrounding aerated lung as opposed to other soft tissues. Non-aerated lung may have about three times the activity of aerated lung. As lung tissue is less "dense", an area of atelectasis would have relatively higher uptake per volume of tissue compared to surrounding normal lung. This would hold true for a lung nodule as well. Therefore nodules should not be compared to surrounding aerated lung, but rather to other solid soft tissue to assess for relatively increased uptake. Comparison typically can be made with mediastinal soft tissues or blood pool.

Standardized Uptake Value takes into account the differences between normalizing for body weight, for lean body mass, or for surface area.

SUV calculation: SUV = [mCi/ml (decay corrected) in tissue] / [mCi of tracer injected/body weight (grams)]

Precise lymph node localization is useful for staging as well as for communication with the bronchoscopist or surgeon. A numbering system has been adopted to describe the various lymph node locations 5 .