TY - JOUR T1 - Quantification of Subendocardial and Subepicardial Blood Flow Using <sup>15</sup>O-Labeled Water and PET: Experimental Validation JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 163 LP - 172 VL - 47 IS - 1 AU - Ornella Rimoldi AU - Klaus P. Schäfers AU - Ronald Boellaard AU - Federico Turkheimer AU - Lars Stegger AU - Marilyn P. Law AU - Adriaan A. Lammerstma AU - Paolo G. Camici Y1 - 2006/01/01 UR - http://jnm.snmjournals.org/content/47/1/163.abstract N2 - The purpose of this study was to assess the feasibility and accuracy of quantifying subendocardial and subepicardial myocardial blood flow (MBF) and the relative coronary flow reserves (CFR) using 15O-labeled water (H215O) and 3-dimensional–only PET. Methods: Eight pigs were scanned with H215O and 15O-labeled carbon monoxide (C15O) after partially occluding the circumflex (n = 3) or the left anterior descending (n = 5) coronary artery, both at rest and during hyperemia induced by intravenous dipyridamole. Radioactive microspheres were injected during each of the H215O scans. Results: In a total of 256 paired measurements of MBF, ranging from 0.30 to 4.46 mL·g−1·min−1, microsphere and PET MBF were fairly well correlated. The mean difference between the 2 methods was −0.01 ± 0.52 mL·g−1·min−1 with 95% of the differences lying between the limits of agreement of −1.02 and 1.01 mL·g−1·min−1. CFR was significantly reduced (P &lt; 0.05) in the ischemic subendocardium (PET = 1.12 ± 0.45; microspheres = 1.09 ± 0.50; P = 0.86) and subepicardium (PET = 1.2 ± 0.35; microspheres = 1.32 ± 0.5; P = 0.39) in comparison with remote subendocardium (PET = 1.7 ± 0.62; microspheres = 1.64 ± 0.61; P = 0.68) and subepicardium (PET = 1.79 ± 0.73; microspheres = 2.19 ± 0.86; P = 0.06). Conclusion: Dynamic measurements using H215O and a 3-dimensional–only PET tomograph allow regional estimates of the transmural distribution of MBF over a wide flow range, although transmural flow differences were underestimated because of the partial-volume effect. PET subendocardial and subepicardial CFR were in good agreement with the microsphere values. ER -