Impact of Bayesian penalized likelihood reconstruction on quantitative and qualitative aspects for pulmonary nodule detection in digital 2-[F]FDG-PET/CT.

To evaluate the impact of block sequential regularized expectation maximization (BSREM) reconstruction on quantitative and qualitative aspects of 2-[F]FDG-avid pulmonary nodules compared to conventional ordered subset expectation maximization (OSEM) reconstruction method. Ninety-one patients with 144 2-[F]FDG-avid pulmonary nodules (all ≤ 20 mm) undergoing PET/CT for oncological (re-)staging were retrospectively included. Quantitative parameters in BSREM and OSEM (including point spread function modelling) were measured, including maximum standardized uptake value (SUV). Nodule conspicuity in BSREM and OSEM images was evaluated by two readers. Wilcoxon matched pairs signed-rank test was used to compare quantitative and qualitative parameters in BSREM and OSEM. Pulmonary nodule SUV was significantly higher in BSREM images compared to OSEM images [BSREM 5.4 (1.2-20.7), OSEM 3.6 (0.7-17.4); p = 0.0001]. In a size-based analysis, the relative increase in SUV was more pronounced in smaller nodules (≤ 7 mm) as compared to larger nodules (8-10 mm, or > 10 mm). Lesion conspicuity was higher in BSREM than in OSEM (p < 0.0001). BSREM reconstruction results in a significant increase in SUV and a significantly improved conspicuity of small 2-[F]FDG-avid pulmonary nodules compared to OSEM reconstruction. Digital 2-[F]FDG-PET/CT reading may be enhanced with BSREM as small lesion conspicuity is improved.