History: chest pain
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Why not start out with a little twist?
Answer: Right sided aortic arch. Unfortunately I don’t have any cross-sectional images to determine the type, but you can read all about that here: https://radiopaedia.org/articles/right-sided-aortic-arch (my guess would be with an aberrant L subclavian since they made it to adulthood probably without a cyanotic heart defect).
And that’s likely just a gastric bubble with superimposed colon in the LUQ. Notice how thick the diaphragm is because it has the gastric wall next to it (versus the super thin diaphragm for free air).