Cadmium-zinc-telluride (CZT) Imaging of Myocardial Blood Flow (MBF) (SPECT MBF)

Comparison of Myocardial Blood Flow Measurements With Dedicated Solid State SPECT Camera Imaging and 99mTc-Tetrofosmin Versus PET Imaging and Rubidium-82

This study is being done to compare the blood flow measurements obtained with the SPECT and PET imaging scans. Measurements such as myocardial blood flow (MBF) and myocardial flow reserve (MFR) are analyzed on PET scans. These measurements give the doctors more precise information in diagnosing heart problems. SPECT scans, with new camera technology and computer software, now have the potential to also give this additional information. The study is investigating how well the blood flow measurements from SPECT compared to PET.

Absolute myocardial blood flow (MBF) and myocardial flow reserve (MFR) are calculated measurements that are obtained using positron emission tomography (PET) nuclear imaging, from a myocardial perfusion imaging (MPI) stress test, due to the advanced capabilities of the PET camera technology. These calculations provide more diagnostic and prognostic information for patients. Single photon emission computed tomography (SPECT) nuclear imaging is more widely done due to the availability and lower costs, but in the past has not been able to provide the additional information needed to perform the MBF and MFR calculations. SPECT cameras have now been developed and are in use, as well as software for the cameras that have shown that these measurements can be obtained from SPECT. The goal of this study is to compare SPECT and PET measurement of MBF and MFR and determine the reproducibility of SPECT MFR measurements.

The study will be done in 3 Phases, with recruitment done over 3 years. Phase 1 and 2 will be done over the first 2 years, with Phase 3 planned following Phases 1 and 2, in the 3rd year of recruitment.

Phase 1: patients with coronary artery disease, who are coming to the University of Ottawa Heart Institute (UOHI) for MPI stress testing will have both a PET and SPECT MPI for comparison of the measurements of MBF and MFR. The PET scan will be done as the clinical, reportable test.

Phase 2: patients with coronary artery disease, who are coming to UOHI for SPECT MPI testing will have the SPECT repeated to see how reproducible the measurements are.

Phase 3: normal, healthy volunteers will have both a PET and SPECT scan for the comparison of the measurements of MBF and MFR.

No change to any patient care will be done in Phases 1 and 2. Phase 1 and Phase 2 participants will have 1 research scan and Phase 3 participants will have 2 research scans.

Rubidium (Rb-82) Elution System Performance Data will be collected on the elution pump system, used to deliver the Rb-82 isotope, to support the system performance documentation for Health Canada Authorization.

Inclusion Criteria:

For all participants

• Age ≥ 18 years old
• BMI ≤ 40 kg/m2
• Able and willing to comply with the study procedures
• Written informed consent Participants with intermediate to high probability of CAD
• Suspected or known CAD on a stable medication regime. Healthy volunteers without known heart disease
• Low risk of CAD (ACC Guidelines Pre-test Probability of Coronary Disease by Symptoms, Gender and Age)

Exclusion Criteria:

• History or risk of severe bradycardia (heart rate < 50 beats per minute) not related to chronotropic drugs
• Known second- or third-degree AV block without pacemaker
• Dyspnea (NYHA III/IV), wheezing asthma or COPD
• Coronary artery bypass graft (CABG) surgery within 60 days prior to screening or at any time after consent
• Percutaneous coronary intervention (PCI) within 30 days prior to screening or at any time following consent
• Acute myocardial infarction or acute coronary syndrome within 60 days prior to screening or at any time following consent
• Recent use of dipyridamole, dipyridamole-containing medications (e.g. Aggrenox)
• Known hypersensitivity to dipyridamole
• Breastfeeding or pregnancy
• Claustrophobia or inability to lie still in a supine position
• Unwillingness or inability to provide informed consent