A new type of heart scan may offer doctors a realistic, three-dimensional view of clogged arteries without invasive procedures.
A new study shows the scan, known as multislice computed tomography (MSCT), is nearly as accurate as conventional, invasive coronary angiograms at spotting clogged arteries in need of repair.
Researchers say the results suggest that the new, noninvasive imaging technique may offer an alternative to angiograms for some people with suspected heart disease.
Detecting Heart Disease
Coronary angiogram is the recommended method to evaluate heart disease. In a coronary angiogram, a thin, flexible tube called a catheter is inserted in a blood vessel, usually in the groin, and guided toward the heart. Then a dye is injected into the blood vessel to make it more visible on an X-ray.
The risks associated with coronary angiograms are small, but serious and potentially deadly complications can occur such as stroke, damage to the arteries, or internal bleeding. The test also causes some discomfort and requires follow-up care.
MSCT is a new type of X-ray scanning technique designed to detect heart disease. This new technique takes many more images within a few seconds than a traditional CT scan.
A computer then processes this information and turns it into three-dimensional images of the arteries. This procedure eliminates the risk and discomfort associated with angiograms, but there are the usual risks associated with exposure to X-ray radiation.
Comparing Detection Methods
In this study, researchers compared the accuracy of the recently developed MSCT to conventional coronary angiogram. Over a 10-month period 103 adults with suspected heart disease underwent both tests.
The study showed that compared to angiograms, the heart scan was 95 percent accurate in detecting significant artery blockages. The results appear in the May 25 issue of The Journal of the American Medical Association.
Researchers say the results of the MSCT and angiograms agreed in most cases and identified patients who would have benefited from heart surgery to repair clogged arteries.
A New Alternative?
With this rapidly improving technology, researchers say MSCT may evolve from a useful complement of invasive angiography to a viable alternative.
In an editorial that accompanies the study, Mario J. Garcia, MD, of The Cleveland Clinic, says these results are promising and there are many people at risk for heart disease for whom MSCT may be useful.
But Garcia says there are also several limitations to the new technology and it's too soon to say if it will replace angiograms for the majority of patients.
For example, he says the dose of radiation used in MSCT is two to three times that used in angiograms, which raises a concern about repetitive use in younger people or women of childbearing age.
Garcia says it's also not clear how MSCT should be used.
"Should it be used as a first test for the evaluation of chest pain or as a complementary test in patients with equivocal stress test results? In either case, adequate patient selection will be critically important," says Garcia.
SOURCE: Hoffman, M. The Journal of the American Medical Association, May 25, 2005; vol 293: pp 2471-2478.