Comparison of PET/CT SUV Metrics Across Different Clinical Software Platforms at UNMH

1391 Objectives: Fluorine-18-fluorodeoxyglucose (18F-FDG) PET/CT-derived parameters used in routine clinical practice are highly-dependent on the interpretation software systems employed. In a previous study, the authors found excellent correlation between two tested software reader platforms (Mirada and MIM Vista) for several PET-derived metrics in a dual-reader analysis1. We conducted a quality review of several clinical platforms available at our institution in order to assess the agreement of SUV metrics in the target lesion and liver across different software platforms. Methods: PET/CT images were reviewed on four different FDA-approved software platforms: syngoMMWP VE36A (Siemens Healthineers, Erlangen, Germany), Intellispace Portal 9.0 (Koninklijke Philips NV, Amsterdam, Netherlands), and Encore 6.7 (MIM Software Inc, Cleveland, OH). A volume of interest (VOI) was drawn around the primary tumor to determine lesion SUVmax for 10 subjects. A 3-cm diameter spherical VOI was placed in the right lobe of the liver to determine liver SUVmean and liver SUVmax for the same subjects. A two-tailed paired t-test and Bland-Altman analysis using the ratio method were used to compare SUV metrics measured on the current clinical platform, syngoMMWP VE36A, to the three other software platforms available at our institution. All statistical analysis was performed using Prism 7 software (GraphPad Software Inc, La Jolla, CA). Results: For lesion SUVmax, statistically significant differences were found for syngoMMWP VE36A vs syngo.via VB30A (p = 0.002), syngoMMWP VE36A vs Intellispace Portal 9.0 (p = 0.002), and syngoMMWP VE36A vs Encore 6.7 (p = 0.001), respectively. For liver SUVmax, a statistically significant difference was found for syngoMMWP VE36A vs syngo.via VB30A (p = 0.033) only, whereas for liver SUVmean, no statistically significant differences were determined. The bias ± SD and 95% Limits of Agreement (LOA) from the Bland-Altman analysis are reported in Table 1. A small systematic bias was observed between the current clinical platform and all other platforms for lesion SUVmax (Figure 1). This bias was not observed for liver SUVmean or liver SUVmax. Conclusions: Significant differences and systematic biases were observed when measuring lesion SUVmax using different reader software systems. Although these differences may not be clinically significant (max bias 6%), this bias could confound outcomes for quantitative, precision-research protocols. Hence, it is important for nuclear medicine departments to take SUV metric agreement into consideration, especially when transitioning to a new clinical platform. References: 1. Mhlanga, J. C., Chirindel, A., Lodge, M. A., Wahl, R. L. & Subramaniam, R. M. Quantitative PET/CT in clinical practice: assessing the agreement of PET tumor indices using different clinical reading platforms. Nuclear Medicine Communications39, 154-160 (2018). 2. O JH, Lodge MA, Wahl RL. Practical PERCIST: A Simplified Guide to PET Response Criteria in Solid Tumors 1.0. Radiology. 280, 576-84 (2016). 3. Arain Z, Lodge M, Wahl R. A comparison of SUV parameters across four commercial software platforms. Journal of Nuclear Medicine 56, 580 (2015). Table 1. Bland Altman analysis results comparing syngoMMWP to syngo.via, Intellispace Portal, and Encore, respectively. The bias ± SD and 95% limits of agreement (LOA) are shown for the SUV metrics (Lesion SUVmax, Liver SUVmean, Liver SUVmax). Figure 1. Bland Altman analysis plots comparing Lesion SUVmax values for syngoMMWP vs syngo.via, syngoMMWP vs Intellispace Portal, and syngoMMWP vs Encore, respectively. Data is plotted as ratio (A/B) vs average (A+B/2).