Abstract
Currently most stable patients referred for invasive angiography do not have obstructive disease, implying an enormous opportunity to avoid unnecessary, invasive, and expensive procedures. Cardiac positron emission tomography (PET) offers a robust and non-invasive tool for quantifying absolute blood flow as a “gatekeeper” to cardiac catheterization. It images the entire left ventricle down to branch vessels, permitting a “physiologic angiogram” while normalizing flow values for the amount of supplied myocardium. Flow imaging has been demonstrated to be accurate compared to invasive measurements, precise to 20% on test/retest assessment, and routinely achievable in >99% of daily clinical cases. Coronary flow capacity (CFC) integrates both resting and hyperemic flow together along the continuum from infarction to ischemia to normal levels. CFC predicts prognosis and identifies which patients benefit from revascularization. Emerging work allows cardiac PET to make an assessment of subendocardial hypoperfusion, relevant since this layer of the myocardium suffers “first and worst” from epicardial disease. A case example highlights many of the aspects of cardiac PET described in this review article.
