Pharmacologic stress rubidium-82 PET: A quantitative comparison of segmental perfusion using regadenoson bolus versus dipyridamole infusion

154 Objectives Regadenoson (Reg) is an A2a specific receptor agonist administered as a rapid (10s) bolus recently validated for myocardial perfusion (MP) SPECT detection of CAD. The rapid rise to peak hyperemia combined with the efficiency of Rb-82 PET suggest this combined approach may have clinical benefits over current methods. In this study, we performed a quantitative analysis of perfusion patterns acquired with bolus Reg with early (90s post-Rb) imaging and the current Dipyridamole (DP) stress protocol. Methods 30 patients (8F, 22M) referred for clinically-indicated DP rest/stress Rb PET, providing informed (IRB) consent and having no change in clinical status had a repeat Reg Rb PET study. Time between scans was 22.8 +/12 d. All rest/stress imaging used 60 mCi Rb (Bracco Diagnostics, Princeton, NJ). DP was infused for 4 min followed by Rb infusion (25 sec) and 90 sec delay. For Reg, Rb infusion began a mean of 18s post bolus, and imaging began 90 sec later. All images were acquired on a Biograph™-16 or -64 (Siemens Medical, Erlangen, Germany). 17-segmental perfusion scores were recorded using QPS™ (Cedars-Sinai, Los Angeles, CA). Bland-Altman (BA) and linear correlation analysis were applied to the paired data. Results Paired left ventricular segmental perfusion scores were highly correlated; Stress: DP = 0.9874Reg + 1.2469, r = 0.89, Rest: DP = 0.8057Reg + 14.162, r = 0.73. Mean of absolute differences for all segments (n = 510) relative to their respective mean segment score (DP and Reg) was 4.8 +/ 3.2% (stress) and 5.8% +/ 4.7% (rest) (p = NS). Greater than 90% of all segments had paired differences less than 8% between Reg and DP. BA analysis indicated a trend toward increased severity of abnormal segments with Reg vs. DP, but was not statistically significant. Conclusions In this preliminary analysis, stress Rb-82 PET perfusion patterns, using a rapid bolus regadenoson injection and early imaging correlate highly with the current DP infusion and imaging protocol. Research Support Astellas Pharma