Noninvasive approach provides better "image".

• Position: Coronary Obstruction - Positron emission tomography myocardial perfusion imaging

Physicians need to know how badly heart vessels are blocked before they can decide how to treat patients at risk of having a heart attack. One standard approach to "imaging" suspected blockages involves injecting a radioactive substance with a very short half-life into the bloodstream. The patient subsequently undergoes an exercise stress test, and the radioactive material is tracked as it travels through the cardiovascular system, identifying narrowing or blockage. That process is called single photon emission computed tomography, or SPECT.

A study by Michael E. Merhige, clinical associate professor of nuclear medicine at the University at Buffalo (N.Y.) and medical director of The Heart Center at the Niagara Falls Memorial Medical Center, shows that a newer method, called positron emission tomography myocardial perfusion imaging, or PET MPI, provides a more accurate "picture" of coronary obstruction, costs 30% less, reduces the need for follow-up invasive procedures by 50%, and produces excellent clinical outcomes.

"Our evidence has shown that invasive procedures such as coronary arteriography [inserting a cardiac catheter into an artery in the upper arm or...