Something like 10% of stent placements in the US are validated by FFR/FM. In Japan it's 80%+ and I think it's like 40% in Europe. That is an awful lot of room to grow into.
High resolution intravascular imaging is sexy as hell; nobody is too sure what it's good for, but it looks like every cath lab wants it. That'll be hitting in a couple of years.
VOLC probably isn't going to charge upward any time soon; they're moving manufacturing from California to Costa Rica, and investing heavily in research. Expensive items in the next year, but likely to pay off well. I think this is their second year in the black, and they've said that they could productively spend more on research, only they do want to keep those black numbers.
This is one you buy a little of to keep your attention on it. One other tease: Volcano has been cooperating with Medtronic lately, and Volcano's serious competitors are Boston Scientific and St Jude. Medtronic might decide to take over the whole thing some day.