Correct!
1. Obtain 18FDG-PET scan
Among the choices listed, 18FDG-PET scanning may represent the least invasive, most effective approach to nodule management for this patient. Performing contrast-enhanced thoracic CT using a nodule enhancement protocol could prove useful- negative findings, typically defined as less than 15 HU enhancement within the nodule at all 4, 1-minute time points, compared to baseline unenhanced imaging nodule attenuation, strongly predicts that the nodule is benign. However, false positive results are not uncommon and may occur with infectious granulomas (a consideration for this patient), and the nodule should be followed anyway to exclude growth even if the contrast-enhanced CT results are negative, limiting the utility of this approach. In contrast, positive 18FDG-PET scanning results may prompt biopsy, whereas negative results predict that a solitary nodule is likely benign (although the nodule is still typically followed to assure stability or resolution); furthermore, 18FDG-PET scanning can detect additional findings that may impact the relevant differential diagnostic considerations and also reveal abnormal findings that would be more readily accessible to a tissue diagnosis than the pulmonary nodule. Should the nodule prove to represent a bronchogenic malignancy, 18FDG-PET scanning is of proven value for lung cancer staging as well. The lesion is peripherally located and, while possibly accessible using navigational bronchoscopy, would probably be better approached using transthoracic percutaneous needle biopsy should a tissue diagnosis be desired. Surgical lung biopsy would no doubt be diagnostic but is needlessly invasive at this point. As noted previously, thoracic MRI has limited utility for the assessment of a solitary pulmonary nodule.
The patient underwent 18FDG-PET scanning (Figure 4).
Figure 4. Representative images from 18FDG-PET scanning.
Which of the following represents the most accurate assessment of the 18FDG-PET findings? (Click on the correct answer to proceed to the seventh of ten pages)