"The CT scan convinced me and my doctors that I was really treading a thin line," he said this week. "So as soon as I had that chest pain, I knew it was time to go to the next step."
The same day Miller performed the catheterization, Mumma underwent triple bypass surgery.
The scanner used for the Hopkins study is called a "64-slice CT scan." As X-rays pass through the body, digitized signals or "slices" are reconstructed for a precise picture. These advanced scanners can measure blockages in blood vessels as small as 1.5 millimeters in diameter. There are 5,000 of these high-tech scanners in use in hospitals worldwide, according to Hopkins, meaning that four-fifths of diagnostic imaging centers are equipped to perform and read cardiac CTs.
The 64-slice machines aren't even the most modern scanners available. The University of Chicago uses a 256-slice machine, while Hopkins now has a 320-slice machine. Williams, who says the CT is a better test than catheterization at determining what kind of plaque is in the arteries and how dangerous it might be, thinks that as the technology keeps improving concerns should ease about the diagnostic use of CT scans.
Also, the faster machines give off less radiation per scan - less even than the X-ray used as part of catheterization, he said. There have been questions raised about the long-term health effects of the amount of radiation being given off by relatively routine medical tests.
Toshiba Medical Systems, a maker of CT scanning equipment, was among several organizations that paid for the study.
In the editorial accompanying the study in today's Journal, Dr. Rita F. Redberg, a cardiologist at the University of California, San Francisco Medical Center, and a colleague, Dr. Judith Walsh, write that the explosive use of cardiac CT has taken place without data showing it confers any medical benefit.
They say it is part of a "pay now, benefits may follow" approach that is contributing to the out-of-control costs of the nation's health care system.
"The use of cardiac imaging has been increasing 26 percent a year, despite a lack of evidence of outcome benefit," they write. "Without such evidence, a high-resolution cardiac CT angiographic image of the heart is just another pretty picture."
In an interview, Redberg said there is no reason that Medicare, for example, should be paying for the test.
