Authors:

SS Koenders¹ , JA Van Dalen² , PL Jager¹ , M Mouden³ , CH Slump⁴ , JD Van Dijk¹ , ¹Isala Clinics, Nuclear Medicine - Zwolle - Netherlands (The) , ²Isala Clinics, Medical Physics - Zwolle - Netherlands (The) , ³Isala Clinics, Cardiology - Zwolle - Netherlands (The) , ⁴University of Twente, MIRA: Institute for Biomedical Technology and Technical Medicine - Enschede - Netherlands (The) ,

Citation:

Introduction: The use of PET in myocardial perfusion imaging (MPI) is increasing rapidly due to its increased availability, high resolution, high sensitivity and specificity and the possibility of quantifying myocardial blood flow (MBF). Currently, conventional photomultiplier technology is used in PET. Philips recently introduced its first PET system with digital photon counting technology. This system is possibly the first Philips system suitable for MBF quantification using Rubudium-82 (Rb-82) due to its high count rate capability.

Purpose: To evaluate the feasibility of MBF quantification using a new digital PET system.

Methods: We performed a prospective pilot study using intra-individual comparison in 18 patients who underwent rest and regadenoson-induced stress MPI using Rb-82 on a conventional PET system (Discovery 690, GE Healthcare) and a digital PET system (Vereos, Philips Healthcare) within 3 weeks. Time activity curves were derived for the left ventricle and the whole myocardium. Subsequently, MBFs were calculated using Lortie’s one-tissue compartment model (Corridor4DM, INVIA, v2016). Moreover myocardial flow reserve (MFR) was calculated by the ratio of MBF during stress and rest. For each patient rest MBF, stress MBF and MFR measurements  were compared between both PET systems. The digital PET system was considered  suitable for MBF and MFR quantification if the test-retest precision, defined as the SD of the relative difference between measurements, was =21%, as previously derived.

Results: The mean rest MBF, stress MBF and MFR did not differ between both cameras as illustrated in Figure 1. The mean rest MBFs were 0.9 ± 0.3 ml/min/g for conventional PET and 0.9 ± 0.2 ml/min/g for digital PET, respectively (p=0.8). The mean stress MBFs were 2.1 ± 0.6 ml/min/g and 2.2 ± 0.7 ml/min/g, respectively (p=0.6). The MFR for conventional PET was 2.5 ± 0.6 and for digital PET 2.6 ± 0.8 (p=0.4). Test-retest precision for rest MBF was 20%, for stress MBF 14% and for MFR 21%.

Conclusion: MBF and MFR measurements using Rb-82 PET are comparable between a conventional and a recently introduced digital PET system. Hence, this digital PET camera can be used for reliable MBF quantification.