Enhanced Risk Stratification With Noninvasive Measurement of Coronary Flow Reserve Using Positron Emission Tomography

Major progress has been made in the development and clinical application of dynamic imaging and tracer kinetic models to accurately measure absolute blood flow and coronary flow reserve (CFR) using quantitative positron emission tomography (PET) myocardial perfusion imaging (MPI) in patients with known or suspected coronary artery disease (CAD).1–6 Assessing CFR provides significantly greater separation of low- and high-risk subsets of patients compared with conventional single photon emission tomography or PET, imaging in which only relative tracer uptake is evaluated after exercise or pharmacological stress. Certainly, the traditional semiquantitative techniques used for many years for conventional single photon emission tomography and PET MPI have provided valuable diagnostic and prognostic information, particularly when extensive focal defects are identified on poststress images, which normalize on resting studies. In addition, the annual cardiac death or infarction rate is reported to be quite low ( 1 coronary supply region. Another indication that multivessel or left main CAD may …