"We aren't at 100 percent," explained Dr. Julie Miller, a Hopkins cardiologist and the study's lead investigator. "Perhaps that's a high standard, but because it's so important to make sure the patient does or does not have a blockage, we can't say it's good enough to replace catheterization."
Still, she said, the study shows that CT and catheterization are equally useful in predicting the need for cardiac bypass surgery or angioplasty to restore blood flow.
And Miller thinks the heart CT can be better than other noninvasive tests such as stress tests or echocardiograms at diagnosing certain heart problems.
"We will begin to see the use of CT more as a first-line test in patients with chest pain in whom you suspect coronary artery disease," Miller predicted.
Dr. Kim Allen Williams, director of nuclear cardiology at the University of Chicago, is also a fan of the heart CT. "It's a tremendous test when applied to the right kind of people," he said.
But he doesn't think Miller's research will lead to more widespread use of the test, just the opposite.
Williams fears that the conclusions of the study - and an accompanying critical editorial - will actually mean fewer patients will be scanned because medical insurers, who have been reluctant to cover the unproven procedure, will have even more ammunition to justify refusing to pay for it.
Even though the study showed CT is 93 percent effective, by saying CT is not yet a replacement for conventional angiography, he said, "it's going to change the way payers look at it. That's what everyone is going to remember.
"They're looking at anything to try to improve the bottom line of their underwriting," said Williams, a spokesman for the American College of Cardiology who was not involved in the study.
Robert Mumma was - as a patient. For years, Mumma's doctors had worried about the health of his arteries. He had high cholesterol and a family history of heart trouble, and his doctors, worried about some test results, wanted him to undergo a catheterization.
He refused. A friend had died from a clot caused by the procedure, so "I'm aware of the downside of this," said the 62-year-old South Florida land developer, who spends part of his time in York County, Pa.
Then, his doctor recommended he have the CT scan done at Hopkins. In June 2007, Mumma did. The test, which revealed blockages, was bad news. Still, he refused a catheterization until that November when he started having chest pains. The CT, Mumma thinks, saved his life.
