Image reconstruction and analysis of atherosclerosis imaging by [¹⁸F]FDG PETCT using digital PET technology

Digital PETCT scanners have improved spatial resolution and sensitivity. This may have implications for reconstruction parameters and atherosclerosis assessment using [¹⁸F]FDG. On a contemporary digital scanner, we assessed European Association of Nuclear Medicine's (EANM)-recommended reconstruction parameters and blood pool methods, compared with a locally-optimised protocol using fewer iterations and subsets than recommended by EANM.

Using clinical PETCT and phantom analysis, we quantitatively assessed two reconstructions ('EANM' and 'local') for atherosclerotic assessment using mean contrast recovery (MCR), absolute error and coefficient of variation (CoV). We assessed the impact of each reconstruction on tissue-to-background ratio (TBR). We also assessed the differences within four blood pool regions on repeated imaging over 24-weeks.

EANM reconstruction yielded higher TBRmax, 4.28 ± 0.65 vs 1.81 ± 0.24 p < 0.0001, than local reconstruction. Phantom data demonstrated a higher RCmax curve with EANM vs local reconstruction. EANM MCR was 1.87 vs 1.23 with local reconstruction, with higher absolute error (2.23 vs 0.61) and variation (7.63% vs 4.14%), vs local reconstruction. Superior vena cava (SVC) offered the most reproducible and reliable blood pool data. Internal jugular vein had lower FDG-uptake compared to other regions, resulting in higher TBRmax, but was less reproducible between scans over 24 weeks.

Local reconstruction, with fewer iterations and subsets compared to EANM recommendations, resulted in more accurate atherosclerotic assessment on a contemporary digital scanner. Metrics for assessing reconstructions, such as absolute error and CoV, provided valuable information. The blood pool region used affects TBR. SVC appears to provide the most reliable blood pool region.