CORONARY FLOW AND FLOW RESERVE BY PET SIMPLIFIED FOR CLINICAL-APPLICATIONS USING RB-82 OR NITROGEN-13-AMMONIA

To validate routine, noninvasive determination of absolute myocardial perfusion and coronary flow reserve (CFR), cardiac PET was performed i n animals using a simplified imaging protocol, high-dose dipyridamole and a simplified quantitative algorithm specific for Rb-82 and N-13-am monia. Methods: One hundred thirty-five PET scans were obtained in eig ht dogs after intravenous N-13-ammonia or Rb-82 using serial dynamic P ET or a simple two-image dataset. A simple flow model using the two-im age dataset was developed for each radionuclide to account for varying arterial input function, flow-dependent myocardial extraction and inc reased permeability surface area (PS) product due to capillary recruit ment at high flows not incorporated into previous models. Myocardial p erfusion by the simple model was compared to standard, complete, two-c ompartment kinetic models validated by comparison to electromagnetic f low meter. Results: For N-13-ammonia, myocardial perfusion by the simp le PET model correlated with that by complete compartmental analysis o f multiple serial PET images with r=0.94, slope=0.96; CFR by compartme ntal analysis correlated with CFR by electromagnetic Row meter with r= 0.94, slope=0.97. For Rb-82, myocardial perfusion determined by the si mple model correlated with that determined by complete compartmental a nalysis of multiple serial PET images with r=0.98, slope=1.06; CFR det ermined by compartmental analysis correlated with CFR by electromagnet ic flow meter with r=0.88, slope=1.13. Conclusion: A simplified PET pr otocol using N-13-ammonia or Rb-82 and simple flow models provide noni nvasive measurement of CFR up to six times baseline flow throughout th e heart and diagnostic image quality for routine clinical application.