REPRODUCIBILITY OF MEASUREMENTS OF REGIONAL RESTING AND HYPEREMIC MYOCARDIAL BLOOD-FLOW ASSESSED WITH PET

PET with N-13-ammonia permits the noninvasive quantification of myocar dial blood flow (MBF) in humans, The present study was done to assess the reproducibility of quantitative blood flow measurements at rest an d during pharmacologically induced hyperemia in healthy individuals. M ethods: Thirty healthy volunteers (26 men, 4 women) were studied. Pair ed measurements of MBF at rest (n = 21), during adenosine (n = 15) and during dipyridamole (n = 7) were performed using a two-compartment mo del for N-13-ammonia PET, The mean difference between baseline and fol low-up blood flow (% difference) was calculated to assess reproducibil ity. Results: No significant difference was observed between resting b lood flow at baseline or follow-up (15.8% +/- 15.8%; p = ns), Baseline and follow-up resting blood flow were linearly correlated (r = 0.63, p < 0.005). Normalization of resting blood flow to the rate pressure p roduct improved the reproducibility significantly (15.8% +/- 15.8% ver sus 10.1% +/- 10.5%, p < 0.05), Baseline and follow-up hyperemic myoca rdial blood flow did not differ (11.8% +/- 9.4%; p = ns) and were line arly correlated (r = 0.69, p < 0.0005). Conclusion: MBF at rest can be measured reproducibly with N-13-ammonia PET, The individual response to pharmacologic stress appears to be relatively consistent. Thus, ser ial blood flow measurements with N-13-ammonia PET can be used to quant ify the effect of Various interventions on MBF and vasodilatory reserv e.