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

Ottawa Heart Institute Research Corporation66 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Conditions

Coronary Heart Disease

Interventions

single photon emission computed tomographyOTHER

Single photon emission computed tomography (SPECT) imaging will be done.

Eligibility

Sex: ALLMin age: 18 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Locations (1)

University of Ottawa Heart Institute

Ottawa, Ontario, Canada

Outcomes

Primary Outcomes

Difference Between Measurements of Myocardial Blood Flow Measured With PET and With SPECT

PET studies were acquired with either 82Rb or 13N-ammonia according to clinical protocol. The activity injected at both rest and stress was 10 MBq/kg (82Rb) or 5MBq/kg (ammonia). MBF was based on data acquired over 8 min (82Rb) or 4 min (ammonia). SPECT rest images were obtained for 11 min starting immediately before injection of 316 +/- 71 MBq of 99mTc-tetrofosmin. The patient returned at 45 min after injection for a 5 min static resting acquisition (corresponding to the standard time for myocardial perfusion imaging). Without repositioning, the patient was stressed using dipyridamole (0.14mg/kg/min for 5 minutes) with 11 minutes of list mode data acquired starting immediately before the injection of 1122 +/- 170 MBq of tetrofosmin. Both rest and stress injections were delivered mechanically over 30 seconds. A standard set of stress perfusion images were acquired at 45 mins after tracer injection. The myocardial blood flow obtained using SPECT was compared to the patient's PET.

Time frame: From enrollment to completion of imaging was a maximum of four weeks. The average difference in acquisition dates was 19 +/- 9 days.

Precision of Myocardial Blood Flow Measurements Between Two SPECT Scans

SPECT myocardial blood flow (MBF) was measured and repeated at a mean interval of 18 days to assess precision of MBF measurements between the two scans.

Time frame: From enrollment to completion of imaging was a maximum of four weeks.

Data from ClinicalTrials.gov

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