The Clinical Value of Myocardial Blood Flow Measurement

Abstract

PET provides robust and reproducible measurements of regional myocardial blood flow in milliliters per minute per gram of tissue, providing unique pathophysiologic and diagnostic information on the function of the coronary macro-and microcirculation. There is compelling evidence to suggest that in many instances abnormalities of global myocardial perfusion are demonstrated in individuals with either coronary risk factors for coronary artery disease or different myocardial diseases in the absence of angiographically demonstrable stenosis of the epicardial coronary arteries. In this context, measurement of myocardial blood flow gives unique diagnostic information regarding the function of the coronary microcirculation and provides a quantitative surrogate endpoint against which the efficacy of treatments can be established.

PET imaging of cardiac hypoxia: Opportunities and challenges

“…2. While the "earliest" approach would perhaps be to quantify reductions in blood flow or perfusion [43,44], imaging a decrease in supply without reference to demand gives little insight into its pathophysiological importance. Several studies describe earlier and more severe endocardial damage during demand ischemia with arterial stenosis, despite having comparable or greater blood flow than the rest of the heart.…”

Structural epicardial disease and microvascular function are determinants of an abnormal longitudinal myocardial blood flow difference in cardiovascular risk individuals as determined with PET/CT

“…1,2 As hyperemic MBFs during pharmacologic vasodilation comprise up to 21-25% flow-mediated and, thus, endothelium-related vasodilatory effects, it is also reported as the ''total integrated coronary circulatory function.'' 1,2,5,6 Conversely, functional and/or structural abnormalities of the coronary arterial wall may impair flow-mediated coronary vasodilation predominantly of the epicardial artery. [7][8][9][10] Such functional alterations or diffuse epicardial narrowing of the epicardial arteries, 7,9,11 commonly accompanied by an impairment of flow-mediated vasodilation, have been suggested as cause for a more recently described longitudinal decrease in myocardial perfusion or MBF during pharmacologically stimulated hyperemia.…”

“…1,2 Shear sensitive components of the coronary endothelium, however, contribute through flow-mediated coronary vasodilation to the overall hyperemic flow during pharmacologic vasodilation. 1,2 As hyperemic MBFs during pharmacologic vasodilation comprise up to 21-25% flow-mediated and, thus, endothelium-related vasodilatory effects, it is also reported as the ''total integrated coronary circulatory function.'' 1,2,5,6 Conversely, functional and/or structural abnormalities of the coronary arterial wall may impair flow-mediated coronary vasodilation predominantly of the epicardial artery.…”

“…[1][2][3][4] Hyperemic MBFs are considered to denote predominantly endothelium-independent flow responses owing to the relaxation of the vascular smooth muscle cells of the arteriolar vessels during pharmacologic vasodilation. 1,2 Shear sensitive components of the coronary endothelium, however, contribute through flow-mediated coronary vasodilation to the overall hyperemic flow during pharmacologic vasodilation.…”

“…[1][2][3][4] Hyperemic MBFs are considered to denote predominantly endothelium-independent flow responses owing to the relaxation of the vascular smooth muscle cells of the arteriolar vessels during pharmacologic vasodilation. 1,2 Shear sensitive components of the coronary endothelium, however, contribute through flow-mediated coronary vasodilation to the overall hyperemic flow during pharmacologic vasodilation. 1,2 As hyperemic MBFs during pharmacologic vasodilation comprise up to 21-25% flow-mediated and, thus, endothelium-related vasodilatory effects, it is also reported as the ''total integrated coronary circulatory function.''…”