Stress Adenosine Cardiac Magnetic Resonance (MR) Comparison With Single Photon Emission Computed Tomography (SPECT) Imaging

Myocardial SPECT imaging will be performed 10-12 minutes after the stress injection of Tl-201, at 4 hours, and at 18-24 hours in patients with non-reversible or partially reversible defect on 4-hour imaging. Images will be obtained with a rotating single- or dual-head gamma camera equipped with low-energy high resolution collimators. Energy windows of 20% and 10% will be centered on the 70 KeV and 167 KeV peaks of Tl-201, respectively. Thirty images will be obtained (40 seconds each for the stress and 4-hour redistribution imaging, and 60 seconds each for the 18-24-hour imaging) over 180° extending from the 45° right anterior oblique to the 45° left posterior oblique projections.Localization of the disease in the left anterior descending artery (LAD), left circumflex (Cx) and right coronary artery (RCA) will be performed using a quantitative analysis software.

CMR will be performed using a 3-T scanner and a dedicated eight-element cardiac phased-array coil Cine CMR will be performed using steady state free precession in the short-axis, two chamber, three chamber and four-chamber, 8 mm thick, separated by 0-mm gaps. Adenosine perfusion CMR: Adenosine will be administered intravenously at 140 µg/kg/min over 6 min. Four minutes into the infusion (or earlier if angina is provoked), a bolus (0.1 mmol/kg at 5 ml/s) of Gadolinium DTPA will be administered. Patients will be instructed to hold their breath. Stress perfusion images will be acquired in the short axis plane (parameters and planning will be similar for stress and rest perfusion evaluation). The patients will be monitored by vector ECG, noninvasive sphygmomanometry, pulse oximetry and capnography.