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

Overview

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.

Full Title of Study: “Quantitative Rest/Stress Cardiac Perfusion Digital PET/CT: Comparison Between Noninvasive Imaging and Invasive Coronary Angiography.”

Study Type

  • Study Type: Observational
  • Study Design
    • Time Perspective: Prospective
  • Study Primary Completion Date: March 31, 2020

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.

Interventions

  • Diagnostic Test: Cardiac Perfusion Rest/Stress Digital PET/CT
    • 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.
  • Drug: N-13 ammonia
    • 5-10 mCi intravenous injection of N-13 ammonia radiopharmaceutical at rest and at stress
  • Drug: Regadenoson
    • 0.4 mg/5mL intravenous injection to induce pharmacologic stress (Astellas Pharma US, Inc.)

Arms, Groups and Cohorts

  • N13-ammonia Cardiac Rest/Stress 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.

Clinical Trial Outcome Measures

Primary Measures

  • MBF measurement using PET/CT
    • Time Frame: 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.
  • CFR measurement using PET/CT
    • Time Frame: 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
    • Time Frame: 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.

Secondary Measures

  • NM Physician diagnostic confidence of 13N-NH3 PET/CT
    • Time Frame: 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).
  • Overall Exam Time
    • Time Frame: 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
    • Time Frame: 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.

Participating in This Clinical Trial

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

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Stanford University
  • Collaborator
    • GE Healthcare
  • Provider of Information About this Clinical Study
    • Principal Investigator: Guido A. Davidzon, MD, SM, Clinical Assistant Professor – Stanford University
  • Overall Official(s)
    • Guido Davidzon, MD, MS, Principal Investigator, Stanford University

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