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Las exploraciones de CT podían “cambiar el paradigma” para la enfermedad cardíaca

por Brendon Nafziger, DOTmed News Associate Editor | November 18, 2010
CT scan
of the heart. (Image courtesy
Johns Hopkins Medicine)
SPECT nuclear medicine scans have long been the gold standard for gauging the sluggish blood flow indicating heart disease. And angiograms are the standard tool for discovering blocked arteries.

But now a group of Johns Hopkins University doctors suggest a combination of two ultra-high-slice CT scans can produce results nearly as accurate as both tests, with a mite less radiation and in less time.

In a study presented earlier this week at the American Heart Association's annual meeting in Chicago, scientists said two scans using a high-powered 320-slice CT scanner identified most of the patients picked out as having heart disease by SPECT imaging and angiograms.

"This shows the kind of results that could really change the paradigm for diagnosing coronary artery disease," lead researcher Dr. Richard George, a cardiologist and assistant professor of medicine with Johns Hopkins, told DOTmed News.

The researchers hope the combined CT scans could help make treatment planning simpler for the many Americans who suffer from coronary artery disease, or CAD. Every year, around 800,000 Americans suffer a heart attack due to CAD, with 150,000 of them dying, according to Johns Hopkins.

For the study, the researchers examined 50 patients who came to Johns Hopkins Hospital in Baltimore complaining of chest pain. All patients got a SPECT scan. Nineteen of the patients, those suspected of having hardening arteries, also received an angiogram, a somewhat invasive test which involves threading a catheter up blood vessels.

In addition to the traditional heart disease tests, the patients received two CT scans with the Aquilion One, an advanced CT scanner made by Toshiba America Medical Systems of Tustin, Calif., which also helped fund the study.

The two scans were a CT angiogram, or CTA, to gauge arterial plaque build-up, and a CT perfusion test, or CTP, to measure blood flow. For CTP scans, doctors have to inject iodine to make blood flow visible, and they also have to inject adenosine to cause the heart to pump faster.

How did the modalities stack up? CTA plus CTP had 71 percent sensitivity in identifying patients with reduced blood flow. The CT scans were also able to rule out 90 percent of the patients who did not have blood flow problems.

The CT scan combination also had 90 percent accuracy in detecting patients with clogged arteries, with 89 percent specificity. (For specific blood vessels, CTA and CTP were 75 percent as sensitive as the other tests, and 91 percent as specific.)