Absolute Quantitation of Myocardial Blood Flow in Human Subjects With or Without Myocardial Ischemia Using Dynamic Flurpiridaz F 18 PET

• Published in: Journal of Nuclear Medicine Vol. 55; no. 9; pp. 1438 - 1444
• Main Authors: Packard, René R.S., Huang, Sung-Cheng, Dahlbom, Magnus, Czernin, Johannes, Maddahi, Jamshid
• Format: Journal Article
• Language: English
• Published: United States Society of Nuclear Medicine 01.09.2014
• Subjects: Aged; Cardiovascular disease; Coronary Circulation; Female; Fluorine Radioisotopes; Heart attacks; Humans; Ischemia; Male; Myocardial Ischemia - physiopathology; Nuclear medicine; Positron-Emission Tomography - methods; Pyridazines; Radiometry; Stress response; Tomography; MBF; MFR; flurpiridaz; human; PET
• ISSN: 0161-5505; 1535-5667; 2159-662X; 1535-5667
• DOI: 10.2967/jnumed.114.141093

Absolute quantitation of myocardial blood flow (MBF) by PET is an established method of analyzing coronary artery disease (CAD) but subject to the various shortcomings of available radiotracers. Flurpiridaz F 18 is a novel PET radiotracer that exhibits properties of an ideal tracer. A new absolute perfusion quantitation method with flurpiridaz was developed, taking advantage of the early kinetics and high first-pass extraction by the myocardium of this radiotracer, and the first-in-human measurements of MBF performed in 7 healthy subjects and 8 patients with documented CAD. PET images with time-activity curves were acquired at rest and during adenosine stress. In healthy subjects, regional MBF between coronary artery territories did not differ significantly, leading to a mean global MBF of 0.73 mL/min/g at rest and 2.53 mL/min/g during stress, with a mean global myocardial flow reserve (MFR) of 3.70. CAD vascular territories with <50% stenosis demonstrated a mean MBF of 0.73 at rest and 2.02 during stress, leading to a mean MFR of 2.97. CAD vascular territories with ≥50% stenosis exhibited a mean MBF of 0.86 at rest and 1.43 during stress, leading to a mean MFR of 1.86. Differences in stress MBF and MFR between normal and CAD territories, as well as between <50% and ≥50% stenosis vascular territories, were significant (P < 0.01). Absolute quantitation of MBF in humans with the novel PET radiotracer flurpiridaz is feasible over a wide range of cardiac flow in the presence or absence of stress-inducible myocardial ischemia. The significant decrease in stress MBF and ensuing MFR in CAD territories allows a clear distinction between vascular territories exhibiting stress-inducible myocardial ischemia and those with normal perfusion.