Imaging Assessment of Endothelial Function: An Index of Cardiovascular Health

Figures

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  FIGURE 1. Coronary angiography for endothelial function assessment. Coronary angiography can be used for both epicardial and microvascular function assessment. Typically, acetylcholine is used as the endothelium dependent vasodilator for epicardial coronaries and adenosine is used for microcirculation assessment.

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  FIGURE 2. Example of coronary endothelial function (CEF) testing using non-contrast MRI with isometric handgrip exercise (IHE). Scout MRI (A) and cross-sectional cine (B–D) and phase-contrast images (E,F) in a healthy subject showing RCA in cross-section (red arrow). In the expanded inset sections, coronary area increases from rest (C) to IHE (D) and velocity and flow increase from rest (E) to stress (F) (note that increased darkness represents increased signal and thus velocity down through the imaging plane). (G) Stress MRI protocol for CEF measures for endpoints: change in coronary cross sectional area and blood flow velocity (%) from baseline to stress (continuous IHE for 5–8 min). (H) Example coronary flow velocity curve of RCA.

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  FIGURE 3. PET rest/stress images and coronary angiography in a patient with microvascular dysfunction. (A) Perfusion images demonstrate no evidence of stress (regadenoson)-induced myocardial ischemia. (B) Provides quantitative myocardial perfusion analysis with an overall reduced coronary flow reserve of 1.89, indicative of mild diffuse microvascular disease. The functional analysis for this patient showed normal wall motion. No obstructive coronary artery disease was seen on angiography of the left anterior descending (C), left circumflex (C) and right coronary (D) arteries.

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  FIGURE 4. Representative CT perfusion images and polar plots. Images demonstrate severe myocardial perfusion abnormalities in the lateral and posterolateral walls in a patient with history of myocardial infarction. (A) Depicts a cardiac four-chamber view with arrows pointing to hypodense areas in the subendocardial and mid myocardial levels, representing perfusion defects. In addition, thinning of the myocardium is consistent with prior infarct. (B) Provides a cross-sectional assessment of the same case. (C) (Polar plot) shows the corresponding perfusion indices, with the affected myocardial segments provided in (D).

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  FIGURE 5. Ultrasound Images Demonstrating Brachial Flow-Mediated Dilatation. (A) Shows the brachial artery at rest with arterial diameter of 3.88 mm. (B) Shows the artery 1 min after hyperemic stimulus with arterial diameter of 4.09 mm. Figure reproduced with permission from Corretti et al. (9) copyright JACC (Elsevier).