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.
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.
Study Type
OBSERVATIONAL
Enrollment
15
Patients with coronary artery disease undergo a N-13 ammonia rest/stress PET/CT scan. These patients are given: 1. One 5-10 mCI N13-ammonia (13N-NH3) intravenously and undergo a rest digital PET/CT scan of \~20 minute duration. 2. A dose of 0.4 mg regadenoson (Lexiscan) intravenously over 10 seconds to increase blood flow to the heart 3. 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.
5-10 mCi intravenous injection of N-13 ammonia radiopharmaceutical at rest and at stress
0.4 mg/5mL intravenous injection to induce pharmacologic stress (Astellas Pharma US, Inc.)
Stanford University
Stanford, California, United States
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.
Time frame: 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.
Time frame: 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.
Time frame: an estimated average of 2 hours
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).
Time frame: an estimated average of 2 hours
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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.
Time frame: 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.
Time frame: an estimated average of 2 hours