Meta-Analysis of the Test-Retest Repeatability of [18F]-Fluorodeoxyglucose Standardized Uptake Values:Implications for Assessment of Tumor Response

PURPOSE: Currently, guidelines for positron emission tomography with 18F-fluorodeoxyglucose (FDG-PET) interpretation for assessment of therapy response in oncology primarily involve visual evaluation of FDG-PET/CT scans. However, quantitative measurements of the metabolic activity in tumors may be even more useful in evaluating response to treatment. Guidelines based on such measurements, including the European Organisation for Research and Treatment of Cancer (EORTC) Criteria and PET Response Criteria in Solid Tumors (PERCIST), have been proposed. However, more rigorous analysis of response criteria based on FDG-PET measurements is needed to adopt regular use in practice.EXPERIMENTAL DESIGN: Well-defined boundaries of repeatability and reproducibility of quantitative measurements to discriminate noise from true signal changes is a needed initial step. An extension of the meta-analysis from de Langen et al. (2012) of the test-retest repeatability of quantitative FDG-PET measurements, including mean, maximum, and peak standardized uptake values (SUVmax, SUVmean, and SUVpeak, respectively), was performed. Data from 11 studies in the literature were used to estimate the relationship between the variance in test-retest measurements with uptake level and various study-level, patient-level, and lesion-level characteristics.RESULTS: Test-retest repeatability of percentage fluctuations for all three types of SUV measurement (max, mean and peak) improved with higher FDG uptake levels. Repeatability in all three SUV measurements varied for different lesion locations. Worse repeatability in SUVmean was also associated with higher tumor volumes.CONCLUSIONS: Recommendations regarding SUV measurements for assessing minimal detectable changes based on repeatability and reproducibility are proposed and should be applied to differentiate between response categories for FDG-PET-based criteria.