Praxis Medical Insights

Est. 2024 • Clinical Guidelines Distilled

Made possible by volunteer editors from the University of Calgary & University of Alberta

Last Updated: 11/1/2025

Myocardial Perfusion Imaging Recommendations for Suspected Coronary Artery Disease

Patient Selection Based on Pre-Test Likelihood

  • The European Society of Cardiology recommends myocardial perfusion imaging (MPI) for patients with moderate to high pre-test likelihood (>15-85%) of obstructive coronary artery disease (CAD) to diagnose myocardial ischemia and estimate the risk of major adverse cardiac events 1, 2, 3
  • For patients with moderate or high pre-test likelihood (>15-85%) of obstructive CAD, SPECT or preferably PET myocardial perfusion imaging is recommended to diagnose and quantify myocardial ischemia and/or scar, estimate risk of major adverse cardiac events, and quantify myocardial blood flow (with PET) 1, 3
  • For patients with low to moderate pre-test likelihood (>5-50%) of obstructive CAD, coronary computed tomography angiography (CCTA) is the preferred initial diagnostic test 3, 4
  • For patients with very high pre-test likelihood (>85%) of obstructive CAD, severe symptoms refractory to medical therapy, angina at low level of exercise, or high event risk, invasive coronary angiography is recommended 2, 3

Specific Clinical Scenarios for MPI

  • MPI is indicated when another non-invasive test is non-diagnostic in patients with low or moderate pre-test likelihood of CAD 3
  • In patients selected for PET or SPECT MPI, measurement of coronary artery calcium score from unenhanced chest CT (used for attenuation correction) is recommended to improve detection of both non-obstructive and obstructive CAD 1, 2
  • For patients with de novo symptoms highly suggestive of obstructive CAD occurring at low level of exercise, invasive coronary angiography with view toward revascularization is recommended as first diagnostic test after clinical assessment 2, 3

Technical Considerations for MPI

  • The American College of Radiology recommends technetium-99m labeled agents (sestamibi, tetrofosmin) over thallium-201 due to improved image resolution, higher count density, and more favorable dosimetry 5, 6
  • The diagnostic accuracy of stress SPECT MPI for detecting angiographically significant CAD is high with sensitivity of 87-89% and specificity of 73-75% 5, 6
  • A normal stress SPECT MPI in patients with intermediate to high likelihood of CAD predicts a very low rate of cardiac death or nonfatal myocardial infarction (1% per year) 6, 7

Contraindications and Precautions

  • Absolute contraindications for MPI include high-risk unstable angina, complicated acute coronary syndrome or acute myocardial infarction within 2 days, significant arrhythmias, and significant hypotension (systolic blood pressure <90 mmHg) 8

Hybrid Imaging Approaches

  • Hybrid SPECT/CCTA combines anatomic information from CT with functional perfusion evidence from SPECT, resulting in enhanced diagnostic accuracy (sensitivity 96%, specificity 95%) compared with SPECT (93%, 79%) or CCTA (98%, 62%) alone 6, 7
  • There is high agreement (92%) on the necessity of revascularization in treatment decisions based on hybrid SPECT/CCTA versus SPECT and coronary angiography alone 7

Alternative Imaging Modalities

  • The European Society of Cardiology recommends cardiac magnetic resonance (CMR) perfusion imaging for patients with suspected CAD and moderate or high pre-test likelihood of obstructive CAD to diagnose and quantify myocardial ischemia and/or scar and estimate risk of major adverse cardiac events 1, 2, 3
  • Stress echocardiography is recommended for patients with suspected CAD and moderate or high pre-test likelihood of obstructive CAD to diagnose myocardial ischemia and estimate risk of major adverse cardiac events 1, 2, 3
  • When selecting between imaging modalities, consider local expertise, availability, patient characteristics that influence test performance, and radiation exposure concerns, especially in younger patients 3, 9

PET Scan for Diagnosis of Coronary Artery Disease

Diagnostic Performance and Indications

  • The European Society of Cardiology recommends PET myocardial perfusion imaging for patients with moderate to high pre-test likelihood (>15%-85%) of obstructive CAD who cannot exercise or have abnormal baseline ECGs, due to its superior diagnostic accuracy compared to SPECT 10, 11
  • PET myocardial perfusion imaging is indicated for patients with moderate or high pre-test likelihood (>15%-85%) of obstructive CAD to diagnose and quantify myocardial ischemia and/or scar, estimate risk of major adverse cardiac events, and quantify myocardial blood flow 10, 11
  • The American Academy of Family Physicians recommends PET as an initial diagnostic test in patients unable to exercise with intermediate likelihood of CAD 12, 13

Advantages Over SPECT and Technical Considerations

  • The European Society of Cardiology guidelines state that PET should be preferred over SPECT due to its higher diagnostic accuracy, with improved sensitivity and specificity compared to conventional nuclear techniques 10, 11, 14
  • PET provides quantification of myocardial blood flow and coronary flow reserve, which SPECT cannot provide 10, 11
  • The American College of Radiology recommends using adenosine or dipyridamole for pharmacologic stress in patients unable to exercise 10, 11, 12, 13

Prognostic Value and Comparison with Alternative Modalities

  • The American College of Radiology states that the extent and severity of ischemia and scarring provide incremental risk estimates of cardiac death beyond traditional risk factors 14
  • The American College of Cardiology recommends PET over SPECT when both are available, with randomized trial evidence showing lower rates of unnecessary invasive angiography with PET 15
  • The European Society of Cardiology recommends stress echocardiography and CMR as reasonable alternatives to PET, with Class I recommendations for the same patient population 10, 11

Cardiac PET Scan Indications and Applications

Primary Indications for Cardiac PET

  • The European Society of Cardiology recommends using cardiac PET for patients with moderate to high pre-test likelihood (>15-85%) of obstructive coronary artery disease to diagnose myocardial ischemia and estimate risk of major adverse cardiac events 16
  • The American College of Radiology suggests using FDG-PET for viability assessment in patients with ischemic heart failure or left ventricular dysfunction being considered for revascularization 17, 18
  • The American College of Radiology states that PET is the gold standard for detecting hibernating myocardium—dysfunctional but viable tissue that may recover function after revascularization 19

Heart Failure Evaluation

  • The American College of Radiology recommends using cardiac PET in heart failure of undetermined etiology to distinguish ischemic from non-ischemic cardiomyopathy 17, 18
  • The American College of Radiology indicates that FDG-PET/CT is used for follow-up imaging of heart failure related to cardiac sarcoidosis or other inflammatory conditions 18
  • The American College of Radiology notes that PET provides prognostic information with quantitative metrics of myocardial blood flow demonstrating modest but meaningful prognostic value in ischemic heart failure 18

Specific Clinical Scenarios

  • The European Society of Cardiology suggests selecting PET for patients unable to exercise who require pharmacologic stress testing with adenosine, dipyridamole, or regadenoson 16
  • The American College of Radiology recommends using PET for suspected multivessel disease, as it detects balanced ischemia that may appear normal on SPECT imaging 19

Hybrid PET/CT Applications

  • The American College of Radiology suggests combining PET perfusion imaging with coronary CT angiography to integrate functional perfusion data with anatomic coronary information, enhancing diagnostic accuracy 20
  • The European Society of Cardiology notes that non-contrast CT can be used for attenuation correction to simultaneously obtain coronary artery calcium scoring, providing additional risk stratification even with normal perfusion 16

Prognostic Value

  • The American College of Radiology states that extent and severity of ischemia on PET provide incremental risk estimates of cardiac death beyond traditional coronary risk factors 20
  • The European Society of Cardiology notes that low myocardial blood flow reserve measured by PET independently predicts mortality and helps identify patients with survival benefit from early revascularization 16

REFERENCES

8

Absolute Contraindications for Myocardial Perfusion Imaging [LINK]

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

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