FHRWW Stress SPECT Protocol Reduces Radioactive Dosage and Increases Ischemia Detection
(MeSH): FHRWW, Sestamibi redistribution, heart function tests, Adverse cardiac events, Emission-computed, single-photon, Mathematical models, Tomography, Vulnerable plaque
ANZ Nuclear Medicine
BACKGROUND: Radioisotope manufacturers, nuclear camera manufacturers, standard guidelines for myocardial perfusion imaging, all assume rapid isotope uptake followed by an essentially static retention mechanism. Contrariwise, the historic first nuclear cardiology study found measurement of nuclear isotope blood flow kinetics to be diagnostic of heart disease. No clinical investigations appear to have followed that classic finding. We assessed the clinical diagnostic utility of time course myocardial perfusion measurements following single injections. METHOD: One hundred twenty patients suspected of having heart disease underwent Sestamibi stress images taken at 5 and at 60 minutes following completion of cardiac stress. Quantitative (FHRWW) redistribution differences between the images were assessed. FHRWW results were compared with angiographic findings. RESULT: Parabolic regression of stenosis on redistribution yielded an effect size of R(CI95%) = 0.72 to 0.95, (P=3.8x10-8). Fifteen percent of individuals with "normal" appearing 60 minute SPECT images were noted to having coronary artery disease using both redistribution data and coronary angiography requiring stent placement. These individuals had "wash in" of Sestamibi (isotope uptake greater at 60 minutes than 5 minutes) and signaled patients at risk of undergoing an acute cardiac event due to vulnerable plaques or tight lesions placing significant amounts of myocardium at risk of infarction. One of the individuals who did not require cardiac catheterization based upon the FHRWW data, underwent coronary angiography based upon rest-stress results AND had a major adverse event as a result of the subsequent cardiac catheterization. There was no detectable CAD, confirming the FHRWW findings and the need for caution in individuals undergoing invasive procedures. CONCLUSION: Dynamic "uptake /release" models appear to be a superior alternative to the common "uptake/retention" models of technetium-99m isotopes used in nuclear myocardial perfusion imaging. This sequential quantitative diagnostic model, reinforces the work by Blumgart, enabling more accurate diagnosis of coronary artery disease and providing for intervention in individuals requiring stents or bypass, whom would otherwise be missed on rest-stress imaging protocols while avoiding unnecessary coronary angiography among individuals with "normal" Sestamibi redistribution.
Original Publication Date
Fleming, Richard M. and Harrington, Gordon M., "FHRWW Stress SPECT Protocol Reduces Radioactive Dosage and Increases Ischemia Detection" (2010). Faculty Publications. 2037.