Findings: chest radiographs show post-operative changes in the left hemithorax, with surgical clips in the mid-field and residual pleural effusion. There is a para-mediastinal tubular structure, better seen in the immediate post-operative film (A, B, arrows). As the majority of you mentioned, a tubular structure in the lungs suggests a vascular lesion. Muppet investigated the clinical history and it corresponds to a graft between the subclavian artery and descending aorta in a patient with aortic coarctation. The surgeon found a hypertrophic Adamkiewicz artery with marked collateral circulation and was afraid to resect the coarctation and cause damage to the spinal cord (thus the graft).

Muppet checked the pre-op films (Fig. 2) and there were no imaging findings suggestive of coarctation: no rib notching, non-prominent ascending aorta and unremarkable aortic knob. This normal appearance may be related to collateral circulation going through Adamkiewicz artery.

Final diagnosis: aortic coarctation corrected with bypass graft.

Teaching point: tubular images in the lung should suggest three possibilities: vascular, bronchial impaction and herniated bowel loops.