Why do cardiac positron emission tomography (PET) scans?

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Last updated: July 5, 2025 • View editorial policy

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From the Guidelines

Cardiac positron emission tomography (PET) scans are primarily performed to evaluate heart function, blood flow, and metabolism with exceptional precision, particularly for diagnosing coronary artery disease and assessing myocardial viability. The main goal of cardiac PET scans is to provide accurate and detailed information about the heart's structure and function, which is essential for diagnosing and managing various heart conditions. Some of the key benefits of cardiac PET scans include:

  • Higher spatial resolution and improved diagnostic accuracy compared to other imaging techniques, with sensitivity >90% and specificity >85% for coronary artery disease 1
  • Lower radiation exposure than SPECT imaging
  • Ability to quantify absolute myocardial blood flow, which helps identify balanced triple-vessel disease that might be missed by other tests 1
  • Ability to assess individuals with known or suspected diffusely impaired myocardial blood flow, such as those with multivessel CAD or microvascular dysfunction 1 The procedure typically takes 1-2 hours, during which the patient lies still on an examination table while the scanner detects gamma rays emitted by the tracer. The use of cardiac PET scans is recommended for patients with suspected or known coronary artery disease, as it provides valuable information for diagnosing and managing the condition, and can help identify patients who may benefit from early revascularization with PCI or coronary artery bypass grafting (CABG) 1. Patients should fast for 4-6 hours before metabolic imaging with FDG and avoid caffeine for 24 hours before perfusion studies to ensure accurate results. The latest guidelines, such as the 2024 ESC guidelines for the management of chronic coronary syndromes, support the use of cardiac PET scans for diagnosing and managing coronary artery disease, and highlight the importance of quantifying absolute myocardial blood flow in this context 1.

From the FDA Drug Label

Ammonia N 13 Injection USP is a radioactive diagnostic agent for Positron Emission Tomography (PET) indicated for diagnostic PET imaging of the myocardium under rest or pharmacologic stress conditions to evaluate myocardial perfusion in patients with suspected or existing coronary artery disease (1). Ammonia N 13 Injection USP is indicated for diagnostic Positron Emission Tomography (PET) imaging of the myocardium under rest or pharmacologic stress conditions to evaluate myocardial perfusion in patients with suspected or existing coronary artery disease. Ammonia N 13 Injection USP is a radioactive diagnostic agent for Positron Emission Tomography (PET) indicated for diagnostic PET imaging of the myocardium under rest or pharmacologic stress conditions to evaluate myocardial perfusion in patients with suspected or existing coronary artery disease (1).

Cardiac Positron Emission Tomography (PET) scans are done to:

  • Evaluate myocardial perfusion in patients with suspected or existing coronary artery disease.
  • Perform diagnostic PET imaging of the myocardium under rest or pharmacologic stress conditions 2, 2, 2.

From the Research

Cardiac Positron Emission Tomography (PET) Scans

  • Cardiac PET scans are used for the diagnosis and prognosis of ischemic heart disease, offering higher resolution and enhanced diagnostic accuracy compared to single-photon emission computerized tomography (SPECT) 3.
  • They allow for the measurement of myocardial blood flow (MBF) and myocardial flow reserve (MFR), aiding in the diagnosis of multivessel disease or identifying non-responders 3.
  • Cardiac PET imaging is also useful in diagnosing coronary artery disease (CAD) in specific populations, such as patients with prior COVID-19 infection, cardiac transplant, and other comorbidities 3.
  • Additionally, cardiac PET can help diagnose nonischemic cardiomyopathies, including sarcoidosis, amyloidosis, and myocarditis, and offers crucial information for the treatment of ischemic cardiomyopathy 4.

Advantages of Cardiac PET Scans

  • Higher sensitivity and specificity than myocardial perfusion SPECT for the detection of coronary artery disease (CAD) 5, 6.
  • Ability to detect subclinical coronary stenosis, define the extent and severity of CAD, and detect ischemia when there is balanced reduction in myocardial perfusion due to three-vessel or main stem CAD 5.
  • Lower radiation exposure compared to SPECT 3, 6.
  • Ability to measure myocardial viability, offering crucial information for the treatment of ischemic cardiomyopathy 4, 5.

Clinical Applications of Cardiac PET Scans

  • Diagnosis and management of heart failure 4.
  • Detection of coronary artery disease with high accuracy 4, 5, 6.
  • Diagnosis of nonischemic cardiomyopathies, including sarcoidosis, amyloidosis, and myocarditis 4.
  • Assessment of myocardial viability and detection of hibernating/viable myocardium 5.
  • Identification of calcium deposition in atherosclerotic plaques and cardiac amyloid involvement 5.

References

1
Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

5
Research

Cardiac applications of PET.

Nuclear medicine communications, 2015

6
Research

Myocardial perfusion imaging with PET.

Imaging in medicine, 2013

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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