Quantitative 13N-Ammonia Cardiac Rest/Stress Digital PET/CT

Study Overview
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Brief Summary
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Accurate measurements from a non-invasive test like myocardial perfusion positron emission tomography/ computed tomography (PET/CT) may decrease the need for invasive procedures such as cardiac catheterization.The investigators wish to see if the measurements from cardiac catheterization can be predicted using a non-invasive 13N-NH3 digital PET/CT scan.

Detailed Description
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Cardiac imaging using standard-of-care Nuclear Medicine techniques assess the relative radiopharmaceutical distribution from coronary arteries to cardiac tissue. This standard interpretation however, lacks the clinical utility of modern quantitative techniques that are now routinely obtained during cardiac catheterization, such as fractional flow reserve (FFR). Cardiologists routinely base critical management decisions, including the choice for revascularization, stenting, or angioplasty, on these measurements. Non-invasive measurements of MBF (Myocardial Blood Flow), CFR (Coronary Flow Reserve) and RFR (Relative Flow Reserve) using PET/CT have been investigated, but have yet to reach clinicl use. Given the inherent gains in sensitivity and resolution, digital PET/CT, may allow for a more robust and accurate platform to obtain quantitative measurements of MBF, CFR and RFR which may greatly enhance the clinical utility of cardiac PET/CT for management of coronary artery disease.

Official Title
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Quantitative Rest/Stress Cardiac Perfusion Digital PET/CT: Comparison Between Noninvasive Imaging and Invasive Coronary Angiography.

Conditions
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Coronary Artery Disease

Intervention / Treatment
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* Diagnostic Test: Cardiac Perfusion Rest/Stress Digital PET/CT
* Drug: N-13 ammonia
* Drug: Regadenoson


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patient is ≥ 18 years old at the time of the scan Patient has known or suspected coronary artery disease Patient has had a recent or will be scheduled for a diagnostic coronary angiogram Patient provides written informed consent Patient is referred for myocardial perfusion scan Patient is capable of complying with study procedures Patient is able to remain still for duration of imaging procedure (approximately 60 minutes total for both PET/CT) Exclusion Criteria: Patients who are pregnant or breast feeding Patients with contraindications to regadenoson

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| N13-ammonia Cardiac Rest/Stress PET/CT<br>Patients with coronary artery disease (CAD) undergo a Cardiac Perfusion Rest/Stress Digital PET/CT scan using the radiopharmaceutical N13-ammonia and Regadenoson (Lexiscan) to induce pharmacologic stress. | Diagnostic Test: Cardiac Perfusion Rest/Stress Digital PET/CT<br>* Patients with coronary artery disease undergo a N-13 ammonia rest/stress PET/CT scan. These patients are given: One 5-10 mCI N13-ammonia (13N-NH3) intravenously and undergo a rest digital PET/CT scan of  20 minute duration. A dose of 0.4 mg regadenoson (Lexiscan) intravenously over 10 seconds to increase blood flow to the heart One 5-10 mCi N13-ammonia (13N-NH3) intravenously and undergo a stress digital PET/CT scan of  20 minute duration Total patient time will take approximately up to 120 minutes.<br>Drug: N-13 ammonia<br>* 5-10 mCi intravenous injection of N-13 ammonia radiopharmaceutical at rest and at stress<br>Drug: Regadenoson<br>* 0.4 mg/5mL intravenous injection to induce pharmacologic stress (Astellas Pharma US, Inc.)<br>* Other names: Lexiscan;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| MBF measurement using PET/CT | Non-invasive measurements of myocardial blood flow (MBF) in milliliter/minute/gram using PET/CT scanner will be compared to invasive cardiac angiography values (current gold standard). MBF values are obtained using image-derived time activity curves from the left ventricular blood and myocardial tissue regions. These values represent radiotracer exchange between the blood and the tissue over time. The rate of radiotracer uptake into the myocardial tissue provides an estimate of MBF. Processing software will then use the time-activity curves to calculate MBF at rest and at stress. | an estimated average of 2 hours | 
| CFR measurement using PET/CT | Non-invasive measurements of coronary flow reserve (CFR) using digital PET/CT scanner will be compared to the gold standard evaluation from invasive cardiac angiography. Discrepancy between PET measurements and cardiac angiography results will be reported. CFR is the ratio of MBF at peak blood flow to resting MBF. | an estimated average of 2 hours | 
| RFR measurement using PET/CT | Non-invasive measurements of relative flow reserve (RFR) using digital PET/CT scanner will be compared to the gold standard evaluation from invasive cardiac angiography. Discrepancy between PET measurements and cardiac angiography results will be reported. RFR is the ratio of MBF during stress in an affected region of the left ventricle (LV) to MBF during stress in a normal region of the LV. | an estimated average of 2 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| NM Physician diagnostic confidence of 13N-NH3 PET/CT | Nuclear medicine physician diagnostic confidence will be assessed using a 5-point Likert scale. NM Physicians will compare images obtained from the 13N-NH3 PET/CT to images obtained from single photon emission computed tomography/CT (SPECT/CT). | an estimated average of 2 hours | 
| Overall Exam Time | Overall study time as counted from initial administration of radiopharmaceutical to completion of image acquisition will be measured and compared to SPECT/CT overall exam time. | an estimated average of 2 hours | 
| Effective radiation dose | Total radiation dose (measured in mSv) from 13N-NH3 PET/CT will be measured and compared to the dose typically given to patients during standard myocardial perfusion imaging SPECT/CT studies. | an estimated average of 2 hours |