Correct!
1. 18FDG-PET scan
18FDG-PET scanning is the most appropriate procedure among those listed above for the evaluation of this patient. 18FDG-PET scanning has the ability to assess for additional sites of hypermetabolic tissue, perhaps outside of the thorax and potentially unsuspected, that may change the differential diagnostic considerations or provide an additional target for tissue sampling. 68Ga-citrate scanning (aka “gallium” scan) could show uptake in the opacities, but such uptake is relatively non-specific, and may be seen with inflammatory or malignant etiologies, and negative results would not provide any useful data. Repeating the thoracic CT is unlikely to be of benefit when two recent thoracic CTs have shown progressive abnormalities; the addition of intravenous contrast is unlikely to add any management-altering information. Ventilation-perfusions scanning plays a role in the assessment of suspected thromboembolic disease and assessing lung function prior to surgery, and, rarely evaluation patients for shunts to the systemic circulation, but such disorders are not among the differential diagnostic considerations for this patient. Finally, while assessment of pulmonary function may benefit this patient, such assessment is not germane as regards determining the next step in the evaluation of this patient’s worsening status.
Further clinical course: The patient subsequently underwent 18FDG-PET scanning (Figure 8), which showed evidence of variable, primarily mild-to-moderate, metabolic in many of the pulmonary opacities, but no extrathoracic sites of hypermetabolic tissue.
Figure 8. 18FDG-PET scanning shows mild-to-moderate metabolic activity in several of the pulmonary opacities (arrows).
Which of the following represents the most appropriate next stepfor the management of this patient? (Click on the correct answer to proceed to the next panel)