99. Nuclear and Multimodality Imaging – Coronary Ischemia

CardioNerd Amit Goyal is joined by Dr. Erika Hutt (Cleveland Clinic general cardiology fellow), Dr. Aldo Schenone (Brigham and Women’s advanced cardiovascular imaging fellow), and Dr. Wael Jaber (Cleveland Clinic cardiovascular imaging staff and co-founder of Cardiac Imaging Agora) to discuss nuclear and complimentary multimodality cardiovascular imaging for the evaluation of coronary ischemia. Show notes were created by Dr. Hussain Khalid (University of Florida general cardiology fellow and CardioNerds Academy fellow in House Thomas). To learn more about multimodality cardiovascular imaging, check out Cardiac Imaging Agora! 

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Show Notes & Take Home Pearls

Five Take Home Pearls

1. We can broadly differentiate non-invasive testing into two different categories—functional and anatomical. Functional tests allow us to delineate the functional consequence of coronary disease rather than directly characterizing the burden of disease. Anatomical tests such as coronary CTA, on the other hand, allow us to directly visualize obstructive epicardial disease.

2. In general PET imaging provides higher quality images than SPECT imaging for a variety of reasons, including a higher “keV” of energy in PET radiotracers

3. If using a SPECT camera, we should use cameras that have attenuation correction. Without attenuation correction, the specificity of a SPECT camera drops to 50-60%.

4. In evaluating ischemic heart disease, cardiac nuclear imaging can provide a wide range of information including myocardial perfusion (rest and stress), ejection fraction assessment (rest and stress), absolute myocardial blood flow with quantitative flow reserve in all coronary territories (PET), assessment of myocardial viability (PET), and calcium score with CT attenuation correction.

5. To select the best non-invasive test, we should consider a variety of factors such as pretest probability of obstructive epicardial disease, patient-specific factors (e.g., ability to exercise) and whether a functional or an anatomical test will provide the best answer for our clinical question.

Detailed Show Notes

What are the basic non-invasive testing categories for evaluation of coronary artery disease?  We have a variety of different non-invasive testing modalities that can be broadly separated into functional tests and anatomical tests.  The basic principle underlying functional stress testing is to induce ischemia or coronary vasodilation (discussed below), followed by a functional assessment by different techniques (e.g., EKG, echocardiography, radionuclide imaging) to detect flow-limiting obstructive coronary artery disease. These tests delineate the functional consequence of the coronary disease, rather than directly characterizing the burden of disease itself.  Functional tests can also allow us to assess the nature of a patient’s symptoms. For example, by having a patient exercise on a treadmill we can evaluate whether we can reproduce a patient’s chest pain syndrome. Anatomical tests allow us to visualize the presence of obstructive epicardial disease. For example, obtaining a Coronary Computed Tomography Angiography (CCTA) for a patient with chest pain would allow you to directly visualize possible obstructive epicardial disease.  

How do we induce ischemia for functional stress testing?  To induce ischemia (and/or coronary vasodilation), we have many different stressors that can be broadly separated into exercise stressors and pharmacologic stressors. Treadmill exercise via standardized protocols is the most common method for inducing ischemia and has the advantage of assessing functional capacity,