The researchers achieved two breakthroughs in MRI imaging to develop the new test. They created computer software to control the scanner and analyze data that made it possible -- for the first time -- to measure blood flow in the small vessels leading to the heart.
Second, they used this imaging technique to measure flow while the heart is stressed, or beating close to capacity. This is the ideal time to assess whether a blockage requires treatment. Patients take a drug to temporarily speed up their heart rate for the test. As the heart rate increases, blood flow should also increase. When the results show that flow isn't increasing to meet the heart's demands, the patient's physician may recommend heart bypass surgery or artery-opening procedures such as angioplasty.
"If the patient holds his breath for 8 to 15 seconds, we get clear pictures of the beating heart," said Kerry Link, M.D., associate professor of radiology and cardiology and a member of the research team. "We can tell not only what percentage the artery is blocked, but can measure how the blockage affects flow."
The MRI test cannot currently replace the cardiac catheterization as a "roadmap" to performing angioplasty or bypass surgery, but the researchers believe it has promise in the future to provide the detail necessary for these procedures.
Other members of the research team are Robert J. Applegate, M.D., associate professor of cardiology; Steve Darty, radiation technologist; Craig Hamilton, Ph.D., assistant professor of radiology; David M. Herrington, M.D., associate professor of cardiology; Kim Lane, sonographer; Tiffany Salido, engineer, and, Mark Thomas, R.N.
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Contact: Karen Richardson, Robert Conn or Jim Steele
krchrdsn@wfubmc.edu
336-716-4587
Wake Forest University Baptist Medical Center
29-Jun-1999