A new approach to the assessment of regional myocardial blood flow and fractional oxygen extraction has been developed using 15O-water (H2- 15O) and 15O-hemoglobin (15O-Hb). Bolus doses (1 mCi) of H2-15O and 15O- Hb were injected 10 minutes apart into the left main coronary artery of 12 normal dogs. Sequential images of regional myocardial tracer clearance were obtained over 5 minutes with a positron camera. Myocardial blood flow calculated from the monoexponential washout of H2- 15O after background correction was 78 +/- 6 (SE) ml/100 g per min. Functional images of regional blood flow in which the image of peak activity was divided by the integrated image of H2-15O washout were derived by computer processing. These images demonstrated homogeneous blood flow in the normal myocardium. Fractional myocardial O2 extraction was determined from an image of initial distribution of O2 used (obtained by extrapolating back to time zero the series of images obtained after 15O-Hb administration), divided by initial distribution of O2 delivered (obtained by back extrapolating H2-15O washout). These functional images showed uniform distribution of fractional O2 extraction in the normal myocardium. Thus, these studies show that regional myocardial blood flow and regional oxygen extraction can be measured simultaneously by sequential imaging after serial intracoronary injections of H2-15O and 15O-Hb.

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Article may be found at: http://circres.ahajournals.org/cgi/reprint/42/4/511 Supported in part by National Institutes of Health Grant HL-15860, Ischemic SCOR Grant HL-17665-02, and Grant-in-Aid 76-942 from the American Heart Association.ISSN:0009-7330 Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

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Department, Program, or Center

School of Chemistry and Materials Science (COS)


RIT – Main Campus