Saline-push improves rubidium-82 PET image quality.

Introduction: Rubidium-82 (⁸²Rb) PET is used widely for myocardial perfusion imaging (MPI). The purpose of this study was to investigate if an additional saline-push following the ⁸²Rb elution improves PET image quality.

Methods: ⁸²Rb PET scans were acquired with/without 29±3 mL saline-push in 10 patients as part of a continuous quality improvement (CQI) program. Dynamic images were analyzed to measure the total activity delivered to the superior vena cava (SVC) and retained in the left ventricle (LV) myocardium. Tracer uptake images were used to measure blood background coefficient-of-variation (COV), myocardium-to-blood signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) to assess image quality. Results: Similar eluted activity was measured with/without the saline-push (830 vs. 795 MBq; p=0.24). The activity delivered to the heart and retained in the myocardium was consistently increased more than 2-fold (SVC: +114% and LV: +104%; p<0.001) with the saline-push. Image quality was improved in all patients, with lower background noise (COV: −19%), higher SNR (+24%) and CNR (+27%) (all p&#8804;0.01). Conclusions: The 30-mL saline-push used to flush ⁸²Rb activity out of the patient injection and intravenous access lines consistently increased the activity delivered to the heart by 2-fold. This technique is recommended to maximize image quality with ⁸²Rb PET.

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