Added value of coronary artery calcium score in the reporting of SPECT versus PET myocardial perfusion imaging

J Nucl Cardiol. 2021 Sep 3. doi: 10.1007/s12350-021-02789-2. Online ahead of print.


Background: Knowledge of coronary artery calcium score (CACS) influences the interpretation of myocardial perfusion imaging (MPI) with SPECT; however, the impact on PET interpretation remains unclear. We compared the added value of CACS to reporting MPI using SPECT vs PET.

Methods: We retrospectively included 412 patients. 206 patients who underwent Rb-82 PET were propensity-based matched to a cohort of 4018 patients who underwent cadmium-zinc-telluride SPECT MPI to obtain a comparable group of 206 SPECT patients. Next, we created four image sets: SPECT MPI-only, PET-only, SPECT + CACS, and PET + CACS. Two physicians interpreted the 824 images as normal, equivocal, or abnormal for ischemia or irreversible defects. Additionally, event rates were compared between PET and SPECT groups during 30-month follow-up.

Results: PET yielded more scans interpreted as normal than SPECT (88% vs 80%, respectively, P = 0.015). Adding CACS to SPECT increased the percentage of normal scans to 86% (P = 0.014), whereas this effect was absent for PET (90%, P = 0.77). Annualized event rates for images interpreted as normal did not differ and varied between 0.7 and 2.0% (P > 0.084).

Conclusion: Adding CACS correctly increased the percentage of normal scans for SPECT MPI but not for PET, possibly limiting the effect of adding CACS to reporting PET.

Keywords: PET Rubidium-82; SPECT; coronary artery calcium; image quality; myocardial perfusion imaging.