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 (H2 15O) 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 < 0.05) in the ischemic subendocardium (PET = 1.12 ± 0.45; microspheres 5 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 5 1.64 6 0.61; P 5 0.68) and subepicardium (PET = 1.79 ± 0.73; microspheres = 2.19 ± 0.86; P = 0.06). Conclusion: Dynamic measurements using H2 15O 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.
|Number of pages||10|
|Journal||Journal of Nuclear Medicine|
|Publication status||Published - 1 Jan 2006|