Hard to imagine any program topping Jefferson when it comes to sports imaging. They currently read for pretty much all of the local professional athletes including the Eagles, Sixers, Phillies, and Flyers. Emory seems to have a similar stronghold on the local teams in Atlanta handling the Falcons, Hawks, Braves (and more). While HSS has the Knicks and Nets, Giants, and Rangers plus they are the official imaging center for the US Olympic team, the historically lower degree of fellow autonomy puts them under Jeff IMO.
This is not all to say that reading out a few MRIs for professional athletes over the course of a year is paramount to good sports imaging training. Most of the other big names which have previously been mentioned in this thread are reading for the local D1 college and/or have a lot of other big orthopedic groups funneling into the system. But these departments that have built a good reputation and developed the trust of pro sports franchises are clearly doing something right.