Correct!
1. 18FDG-PET
A contrast-enhanced thoracic CT scan using a nodule enhancement protocol can be useful for the assessment of non-calcified, indeterminate pulmonary nodules- the lack of contrast enhancement exceeding 15 Hounsfield units at any one of 4, 1-minute intervals following intravenous contrast administration, compared to the unenhanced nodule attenuation, renders the nodule indeterminate for malignancy, but lack of such enhancement is a strong predictor that the nodule is benign. This protocol, however, is typically employed for solitary indeterminate nodules (≤3 cm size), not multiple nodules or pulmonary masses (˃3 cm size), the latter largely due to the high prevalence of malignancy in lesions of this size.
Thoracic MRI is not typically employed for the evaluation of pulmonary parenchymal abnormalities, particularly if contrast-enhanced thoracic CT has already been obtained. 68Ga-citrate scintigraphy has relatively few thoracic applications, but may occasionally be used for the assessment of diffuse lung abnormalities, but is not typically employed for nodules or masses. Finally, serial thoracic CT is useful for the assessment of small pulmonary nodules, to determine if intervention is required; such an approach is not useful when large nodules or frank pulmonary masses are present. 18FDG-PET scan can be useful when multiple indeterminate pulmonary nodules, or even masses, are found as a means of prioritizing interventions or for the detection of sites of unsuspected disease that may more be more amenable to tissue sampling than pulmonary nodules.
The patient underwent further evaluation with 18FDG-PET scanning (Figure 3).
Figure 3: Axial 18FDG-PET scanning.
Which of the following regarding this examination is correct? (Click on the correct answer to proceed to the sixth of nine panels)