Correct!
4. Thoracic CT angiography (CTA)
While a mass is present at the left lung base, a referral for thoracic surgery is premature at this point. In particular, note the heavily vascular nature of the lesion on CT (Figure 2); therefore there may be significant risk surgically approaching this lesion without more definitive characterization of the blood supply to the lesion. Catheter angiography of the aorta could define the blood supply to this lesion, but is invasive and similar data can be obtained with thoracic CTA or MRA non-invasively. Choice 2 in this case is catheter angiography of the bronchial circulation, which will likely not provide diagnostically useful information and is not required therapeutically as the patient’s hemoptysis has resolved. Thoracic MRI and MRA could provide additional information, but MRI suffers from inferior anatomic resolution for lung parenchymal lesions compared with CTA, and thoracic CTA is therefore a better choice in this situation. 18FDG-PET scanning will not provide management-altering information in this situation- elevated tracer uptake is a non-specific finding that cannot discriminate between neoplastic and non-neoplastic etiologies for this patient’s lung mass, and the lack of tracer uptake will not obviate the need for further characterization of the lung mass. The suggestion of a prominent vascular supply on the presenting CT (Figures) raises the possibility of a specific cause for this lesion, but is not very well seen, and therefore thoracic CTA represents the best test to obtain for definitive characterization of this patient’s lesion.
The patient subsequently underwent thoracic CTA angiography (Figure 3).
Figure 3. Follow up contrast-enhanced axial (B-F) and coronal maximum intensity projected (G) and volume-rendered (H) thoracic CT obtained following antibiotic treatment shows resolution of the internal cavitation. The internal vascularity within the lesion is more conspicuous on this study. (click here for a movie of the thoracic CT scan)
What is the most likely diagnosis?
