Measurement of regional myocardial blood flow in rats by unlabeled microspheres and Coulter Channelyzer

Xuejun Wang, Faqian Li, Suleman Said, Joseph M. Capasso, A. Martin Gerdes

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A relatively inexpensive, expeditious, new nonradioactive microsphere method for measuring regional myocardial blood flow (RMBF) was developed with unlabeled microspheres and a Coulter Channelyzer. To validate the efficiency of this method, hearts from rats were perfused ex vivo by retrograde aortic cannulation. Unlabeled microspheres of varying size were injected into a side arm in the aortic cannula or added to blood samples collected from the rats. Microspheres were then recovered from the cardiac tissue and blood samples. It was found that >97% of perfused microspheres (diam >9.4 μm) were retained in the myocardium and that 94.8 ± 2.2% of the trapped microspheres were recovered and counted successfully using a Counter Channelyzer. The percent recovery of microspheres from 2- and 0.5-ml blood samples were 95.4 ± 2.3 and 95.3 ± 3.1%, respectively. Blood flow to the anterior and posterior halves of the ventricular free walls and septum were measured in six rats; excellent agreements were found between the results yielded by 10-, 15-, and 20-μm unlabeled microspheres injected simultaneously. The transmural flow gradients in the left ventricular free wall estimated by 10- and 15-μm spheres did not significantly differ from each other. Thus the method developed here provides a new alternative for measurement of RMBF, which currently allows at least three measurements for nontransmural gradient RMBF and at least two measurements for transmural gradient RMBF.

Original languageEnglish (US)
Pages (from-to)H1656-H1665
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number4 40-4
StatePublished - Oct 1996


  • Microsphere sizes
  • Transmural gradient


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