A 64-year-old man with a history of aortic arch dissection and repair 9 years prior, presents after surveillance of the chest and abdomen with MR imaging. Intravenous contrast was not used because of the ordering physician's renal concerns. What will be the most likely underlying etiology and diagnosis?

What should be the mode of treatment? *This image based case is from Docplexus editorial team for educative purpose only. Source: The American College of Radiology