Tomografía computarizada de alta tecnología: no mala opción para prueba de arterias obstruidasContributed by: Anonymous · Views: 1,087
Contributed by: Anonymous · November 05, 2007 @ 09:49 AM MST · Views: 1,087
HIGH-TECH CT SCANS: NOT A BAD CHOICE TO TEST FOR CLOGGED ARTERIES
-- Catheterization still gold standard, but 64-slice scanners are coming on strong
Narrowed blood vessels shown by 64-CT scan
Researchers say the newer, 64-slice CT scans, first introduced in the United States in 2005 and initially tested at Hopkins, won’t replace the need for inspecting arteries by cardiac catheterization, also known as coronary angiography, but the scans will help cardiologists more quickly rule out those who can skip the more invasive procedures. Studies suggest that as much as 25 percent of the 1.3 million cardiac catheterizations performed each year in the United States may be unnecessary.
The latest study also showed that early detection with 64-CT is a good predictor of who will need angioplasty or coronary bypass surgery to open up new blood supply routes to the heart.
Results showed that on average 91 percent of patients with blockages were detected by 64-CT and that the scans were able to diagnose 83 percent of patients without blockages. This reliability, researchers say, allows them to accurately identify patients who need angioplasty or bypass surgery. More than a quarter million Americans undergo coronary bypass surgery each year.
In the study, investigators selected 291 men and women over the age of 40 who were already scheduled to have cardiac catheterization to check for blocked arteries. Each underwent a 64-CT scan prior to catheterization. Participants were then monitored through regular check-ups to identify who developed or did not develop coronary artery disease and who required subsequent bypass surgery or did not need surgery.
Color-image reconstruction of heart "slices" using 64-CT
In other measures, researchers found that 64-CT scans were 83 percent to 90 percent accurate, while tests using older, 16-CT scans were in some instances only 20 percent to 30 percent as precise.
“This study is the first step to realizing the full potential of CT imaging in predicting coronary artery disease, and these scans complement the arsenal of diagnostic tests available to physicians to prevent heart attacks,” says cardiologist Julie Miller, M.D., who led the study at Hopkins.
The new study also suggests that the new scanners, four times quicker than the more widely used 16-CT, may be a good alternative to cardiac stress testing, which evaluates heart function by measuring the effects of hard exercising. Exercise stress testing generally cannot safely be performed on the weak and elderly.
“Use of 64-CT scans will dramatically improve our ability to detect and treat people with suspected coronary disease and chest pain much earlier in their disease,” says cardiologist João Lima, M.D., senior investigator to the team whose findings will be presented Nov. 5 at the American Heart Association’s (AHA) annual Scientific Sessions in Orlando, Fla. “Cardiac catheterization is still the gold standard for evaluating clogged arteries, but our results show that this test could easily be the best backup or alternative.”
In cardiac catheterization, a thin tube is threaded into a blood vessel in the groin area to the heart’s arteries, where a dye is released to produce a clear X-ray image of the beating heart and its arterial blood supply. In CT imaging, computer-driven machinery passes X-rays through the body, producing digitized signals or “slices” that are detected and reconstructed for a precise picture.
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Credits: Johns Hopkins Medicine