TO Illustrate: In my third year medicine clerkship we had a presentation on difficult venous access. We were told that before three call IR, after three and on weekends call surgery. I'm not saying that there aren't dedicated IR guys, but that disgusted me. Plus what happens when you have a problem with a PICC line at 6:00 on a Saturday? I truly hope that my experience is not the rule.
To be clear, I honestly never considered IR. It isn't too useful for mission work.
All for now, go back to your mini wheats.