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

Completed

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

Brief Summary: 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: 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.

Recruitment & Eligibility

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

Arm && Interventions

Group	Intervention	Description
N13-ammonia Cardiac Rest/Stress PET/CT	N-13 ammonia	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.
N13-ammonia Cardiac Rest/Stress PET/CT	Cardiac Perfusion Rest/Stress Digital PET/CT	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.
N13-ammonia Cardiac Rest/Stress PET/CT	Regadenoson	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.

Primary Outcome Measures

Name	Time	Method
CFR measurement using PET/CT	an estimated average of 2 hours	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.
RFR measurement using PET/CT	an estimated average of 2 hours	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.
MBF measurement using PET/CT	an estimated average of 2 hours	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.

Secondary Outcome Measures

Name	Time	Method
Overall Exam Time	an estimated average of 2 hours	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.
Effective radiation dose	an estimated average of 2 hours	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.
NM Physician diagnostic confidence of 13N-NH3 PET/CT	an estimated average of 2 hours	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).