INR includes angiograms of the head and neck, cerebral and spinal circulation and related procedures (aneurysm coiling, embolization, angioplasty, stenting), and spinal interventional procedures (myelography, fluoro-LP, vertebroplasty) as well as percutaneous biopsy in the head and neck and spine (not intracranially) under imaging guidance.
(Please fill in if I have missed anything).
Interventional radiologists work longer hours than most radiologists, and have more rigorous on-call duties (emergency angio). In some places this may approach a typical neurosurgeon's hours, but many are able to work out a happy medium.
The pay is excellent, usually in the order of 400-600K although some outliers make a lot more by working inhuman hours.
You should also be aware that most INRs do at least some diagnostic radiology as part of their practice. In addition, there are opportunties for neurosurgeons to train in neuroangiography, so the specialty distinctions are becoming a bit blurred.