As I have not seen your x-ray, I can only speculate about what you were seeing (by now, hopefully, you have the Radiologist's report, and your concerns will hopefully have been addressed by this report). One possible explanation is the circular appearance of the aorta where it curves down towards the back of the chest after arising from the heart.
Sincerely/ Robert A. Wascher, MD, FACS
www.doctorwascher.com
www.oncoguard.com