Prospective Comparison of Cardiac PET/CT, SPECT/CT Perfusion Imaging and CT Coronary Angiography With Invasive Coronary Angiography

Coronary artery disease (CAD) remains the leading cause of morbidity and mortality in Western civilized countries. Early detection of CAD allows optimal therapeutic management in order to decrease morbidity and mortality. In the Netherlands 80,000 invasive coronary angiographies are performed each year. Invasive coronary angiography (ICA), particularly in conjunction with fractional flow reserve (FFR) measurements, is considered the gold standard in diagnosing and evaluating the severity of CAD in the current era. FFR measurements during ICA are useful in determining whether a coronary stenosis is functionally important. An FFR < 0.80 is considered abnormal, reflecting a hemodynamic significant coronary stenosis. ICA has superior spatial and temporal resolution compared with non-invasive imaging techniques. However, ICA is an invasive procedure which is associated with a low, though significant, complication rate including bleeding, coronary artery dissections, cerebral embolism, cardiac arrhythmias, myocardial infarction and death. Moreover, ICA provides only limited information on the presence of atherosclerotic plaques not associated with luminal stenosis. Furthermore, conventional catheter angiography without the advent of FFR measurements, is not able to provide information about the hemodynamic significance of a significant luminal stenosis (≥ 70%), i.e. whether a coronary artery stenosis is leading to myocardial perfusion abnormalities. Therefore, there is a need for non-invasive imaging techniques for diagnosing and evaluating the hemodynamic significance of CAD. Non-invasive techniques can serve as a gatekeeper for invasive coronary angiographies in order to decrease the number of purely diagnostic invasive angiographies and associated morbidity and mortality. The detection and management of cardiovascular disease increasingly utilize non-invasive cardiac imaging in patients with suspected or known CAD. By more accurately identifying patients who are eligible for coronary revascularization with the use of non-invasive cardiac imaging, the number of unnecessary invasive diagnostic coronary angiographies can be decreased.

Study design

Positron emission tomography:

PET images will be acquired using a Gemini Time-of-Flight (TF) 64 scanner (Philips Healthcare, Best, The Netherlands). Quantitative myocardial perfusion at rest and during hyperemia in ml -1. min -1. g -1 of myocardial tissue will be measured using oxygen-15-labelled water (H215O). Pharmacological stress is induced by infusion of adenosine intravenously at a rate of 140 µg/kg/min. Two minutes after the start of adenosine vasodilation reaches a steady state and H215O will be given intravenously as a bolus followed with the start of a 6-minutes emission scan. Directly after the PET sequence, a low dose CT attenuation scan (CTAC) is acquired after which the infusion of adenosine is terminated. Technetium-99m sestamibi is injected intravenously after the second CTAC scan. A stress SPECT-scan is performed 45 minutes after the stress PET scan.

Single photon emission computed tomography: