Case 5 Answer

Answer: femoral speudoaneurysm ( ok.. it’s a bit of a gimme but this was a pretty one and now everyone will have seen this).

Notice the nice neck and the so-called “yin-yang” sign of the swirling blood.

And yes, this was about 4-5 days post catheterization

Reference: http://radiopaedia.org/articles/false-aneurysm