An exponential relationship exists between fatty acid uptake and myocardial blood flow
- Free Univ. Hospital, Amsterdam (Netherlands); and others
High lineair (lin) correlations have been reported between myocardial blood flow (MBF) and uptake of various fatty acid (FA) analogues. However, the positive intercept with the Y-axis is not physiologically explainable (FA uptake without flow). This study investigates the appropriateness of an exponential (exp) model function. Methods: In 10 open-chest dogs the left anterior descending coronary artery was cannulated and extra corporally bypass perfused at reduced flow. MBF was assessed with scandium-46 labeled microspheres. 40 Minutes after iv. injection of 37 MBq 15-(p-[I-125]-iodophenyl)-3,3-dirnethylpentadecanoic acid (DMIPP), the heart was excised and cut into 120 samples. In each sample MBF (ml/g*min) and DMIPP uptake were assessed.In each dog, MBF and DMIPP uptake data were normalized to die respective means of the normally perfused myocardium. Uptake data were fitted to an exp model A[1-exp(-MBF/Fc)] by adjusting the flow constant Fc for minimal residual variance and adapting the amplitude A to obtain a zero mean residual error. The goodness of each fit was expressed by the standard error of the estimate (SEE). The mean SEE of the 10 dogs was 0.12{+-}0.04 with the exp fit and 0.24{+-}0.07 with the lin fit: p<0.001, F-test. For pooled data, the SEE was 0.15 with the exp fit and 0.26 with the lin fit (fig). Lin fit without zero intercept revealed a SEE of 0.18, which is higher than the SEE of the exp fit. The intercept was 0.54. Conclusion: In the normal to low MBF range, uptake of (methyl branched) FA analogues shows an exponential relationship, which is more appropriate than a linear relationship from a physiological point of view.
- OSTI ID:
- 563334
- Report Number(s):
- CONF-970602-; ISSN 0161-5505; TRN: 97:004028-0006
- Journal Information:
- Journal of Nuclear Medicine, Vol. 38, Issue Suppl.5; Conference: 44. annual meeting of the Society of Nuclear Medicine, San Antonio, TX (United States), 2-5 Jun 1997; Other Information: PBD: May 1997
- Country of Publication:
- United States
- Language:
- English
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