We have the future of medicine," boasts Dr. Barry Stein, a leader of the Society of Interventional Radiology. Not so fast, doctors in other specialties would reply--while most of us might ask, "Just what is interventional radiology?"

Consider repair of a brain aneurysm. The swelling, like a tiny balloon, protrudes from an artery in the brain and throbs with each beat of the heart. If it is not treated, it could burst, flooding the surrounding tissue with blood. The result would be a horribly disabling or even fatal hemorrhagic stroke. Before the repair, a radiologist takes a series of images on MR or CT. These days they are spectacular--three-dimensional color pictures revealing the brain anatomy in exquisite detail. The doctor can rotate them, zoom in and out and map a precise plan for treatment.

Not long ago the next step would be brain surgery to clip off the aneurysm. But now, interventional radiology (IR) offers an alternative. A radiologist, perhaps the same one who took the diagnostic images, watches the brain with live X-ray pictures as he threads a thin tube (called a catheter) from a tiny incision above the patient's leg all the way into the artery in the brain. There, he unravels a tiny wire coil which provides a scaffolding that prevents the aneurysm from bursting. Brain surgery would have meant sawing open the patient's skull and slicing into the brain, a week or more in the hospital and months of recovery. With IR, the patient goes home in a day or less, ready to return immediately to an active life. And yes--the medical bill is less than half as big.

Most people are familiar with angiograms, angioplasties and stents--procedures from interventional radiology adopted by cardiologists to open clogged arteries to the heart. But interventional radiologists can also open arteries in the legs that might lead to an amputation if not treated and arteries in the neck that can cause a stroke. They can reopen critical blood flow to the kidney or liver, drain excess bile from the gall bladder, stop life-threatening internal bleeding and repair ruptured discs in the back. Most recently, they have begun to attack certain kinds of cancer by running a tube right to the tumor and either blocking its blood supply with a kind of glue or killing the cells with lasers or microwaves.

There are now more than 5,000 IR physicians practicing in the United States. Often, these procedures take business from surgeons--and in some cases, while the protocols continue to develop, there are turf wars.

There are often sound medical reasons for choosing one medical procedure over another. For example, a brain aneurysm may occur in a place accessible only through surgery, or a leg artery can be blocked so severely that it cannot be opened by IR, and needs to be bypassed. But whether a patient gets surgery or an IR procedure for a particular condition can often depend on the biases of the doctor who first diagnosed the case and the policies of the hospital (which might consider which procedure generates the most income). "These things have a political agenda, a scientific agenda and financial agenda," explains Dr. John Pile-Spellman, who performs IR on the brain at New York-Presbyterian/Columbia University Medical Center. "The science can be way out ahead of the political or the financial."

One of the biggest battles centers on uterine arterial embolization, or UAE, a treatment for fibroids, noncancerous tumors of the uterus that can be extremely painful. Like most IR treatments, it involves far less pain and recovery time than the surgical alternative, in this case myomectomy (removal of the fibroids) or hysterectomy (removal of the uterus). In UAE, the uterus remains intact. Thousands of women have learned about the IR alternative from friends or on the Internet, but not from their gynecologists, who are trained as surgeons. Gynecologists perform 200,000 hysterectomies in the United States every year for fibroids, and for many it remains the treatment of choice. A study at Northwestern Medical Center found that 79 percent of women who got the nonsurgical alternative learned of it from a source other than a gynecologist.

What is the future of IR? As surgeons realize how effective the techniques are, they may simply adopt them; indeed, this is already happening with vascular surgery. But at some enlightened medical centers there is an effort to make sure patients get the alternative that works best. And most experts agree that as the quality of medical imagining continues to improve, the opportunities for interventional radiology can only grow.