Repeatability of @entity419 PET/CT in Advanced XXXX : Prospective Assessment in 2 Multicenter Trials.

@entity1 @entity8984 @entity419 @entity5 @entity75 @entity1149 @entity344 @entity413
PET/CT with the @entity413 analog @entity419 has several potential applications for monitoring @entity5 response to therapy in @entity1 with @entity1149 ( @entity1149 ). A prerequisite for many of these applications is detailed knowledge of the repeatability of quantitative parameters derived from @entity8984 -FDG PET/CT studies. METHODS: The repeatability of the @entity8984 -FDG signal was evaluated in 2 prospective multicenter trials. @entity1 with advanced @entity1149 ( @entity5 stage III-IV) underwent two @entity419 PET/CT studies while not receiving therapy. @entity5 @entity419 uptake was quantified by measurement of the maximum standardized uptake value within a lesion (SUVmax) and the average SUV within a small volume of interest around the site of maximum uptake (SUVpeak). Analysis was performed for the lesion in the chest with the highest @entity419 uptake and a size of at least 2 cm ( @entity75 ) as well as for up to 6 additional lesions per @entity1 . Repeatability was assessed by Bland-Altman plots and calculation of 95% repeatability coefficients (RCs) of the log-transformed SUV differences. RESULTS: Test-retest repeatability was assessed in 74 @entity1 (34 from the ACRIN 6678 trial and 40 from the Merck MK-0646-008 trial). SUVpeak was 11.57    7.89 g/mL for the ACRIN trial and 6.89    3.02 for the Merck trial. The lower and upper RCs were -28% (95% confidence interval [CI], -35% to -23%) and +39% (95% CI, 31% to 54%) in the ACRIN trial, indicating that a decrease of SUVpeak by more than 28% or an increase by more than 39% has a probability of less than 2.5%. The corresponding RCs from the Merck trial were -35% (95% CI, -42% to -29%) and +53% (95% CI, 41% to 72%). Repeatability was similar for SUVmax of the @entity75 , averaged SUVmax, and averaged SUVpeak of up to 6 lesions per @entity1 . CONCLUSION: The variability of repeated measurements of @entity5 @entity419 uptake in @entity1 with @entity1149 is somewhat larger than previously reported in smaller single-center studies but comparable to that of @entity344 in a previous multicenter trial. The variability of measurements supports the definitions of @entity5 response according to PET Response Criteria in @entity5 .
