Minimal starting time of data reconstruction for qualitative myocardial perfusion rubidium-82 positron emission tomography imaging

Objective Qualitative positron emission tomography (PET) myocardial perfusion imaging (MPI) scans are reconstructed with a delay after an injection of rubidium-82 (82 Rb) to ensure blood pool clearance and sufficient left ventricle to myocardium contrast. Our aim was to derive the minimal starting time of data reconstruction (STDR) after an injection of 82 Rb for which the diagnostic value and image quality remained unaffected. Materials and methods We retrospectively included 23 patients who underwent rest-stress 82 Rb PET MPI using 740 MBq. Patients fulfilling one of the two criteria indicating a slow blood pool clearance (ejection fraction <50% and/or cardiac output <3 l/min) were included in a consecutive manner. PET images using five different STDRs (1:15-2:15 min) were reconstructed and compared with reference images (STDR of 2:30 min). Differences in the summed rest score greater than or equal to 3 and total perfusion deficit greater than 3% were considered to significantly influence the diagnostic value. In addition, image quality was scored by two experts as not interpretable, inferior, adequate, or excellent. Results The summed rest score differed greater than or equal to 3 from the reference in seven or more patients (≥30%) using STDR less than or equal to 2:00 min (P<0.02). STDR less than or equal to 1:30 min resulted in six or more patients (≥26%) with a total perfusion deficit difference greater than 3% (P<0.03). In addition, STDR less than or equal to 2:00 min resulted in a lower image quality (P<0.002) and STDR less than or equal to 2:15 min resulted in greater than or equal to two scans with noninterpretable image quality. Conclusion STDR less than or equal to 2:15 min resulted in lower diagnostic value or insufficient image quality for qualitative PET MPI using 740 MBq 82 Rb. An STDR of 2:30 min can be considered for clinical adoption.