18F-FDG PET-CT in rheumatoid arthritis patients tapering TNFi: reliability, validity and predictive value

Abstract

Objectives To investigate the reliability and validity of fluorine-18 fluorodeoxyglucose (18F-FDG) PET-CT scanning (FDG-PET) in RA patients with low disease activity tapering TNF inhibitors (TNFis) and its predictive value for successful tapering or discontinuation. Methods Patients in the tapering arm of the Dose REduction Strategies of Subcutaneous TNFi study, a randomized controlled trial of TNFi tapering in RA, underwent FDG-PET before tapering (baseline) and after maximal tapering. A total of 48 joints per scan were scored both visually [FDG-avid joint (FAJ), yes/no] and quantitatively [maximal and mean standardized uptake values (SUVmax and SUVmean)]. Interobserver agreement was calculated in 10 patients at baseline. Quantitative and visual FDG-PET scores were investigated for (multilevel) association with clinical parameters both on a joint and patient level and for the predictive value at baseline and the change between baseline and maximal tapering (Δ) for successful tapering and discontinuation at 18 months. Results A total of 79 patients underwent FDG-PET. For performance of identification of FAJs on PET, Cohen’s κ was 0.49 (range 0.35–0.63). For SUVmax and SUVmean, intraclass correlation coefficients were 0.80 (range 0.77–0.83) and 0.96 (0.9–1.0), respectively. On a joint level, swelling was significantly associated with SUVmax and SUVmean [B coefficients 1.0 (95% CI 0.73, 1.35) and 0.2 (0.08, 0.32), respectively]. On a patient level, only correlation with acute phase reactants was found. FDG-PET scores were not predictive of successful tapering or discontinuation. Conclusions Quantitative FDG-PET arthritis scoring in RA patients with low disease activity is reliable and has some construct validity. However, no predictive values were found for FDG-PET parameters for successful tapering and/or discontinuation of TNFi.

Fluorophore-conjugated 4-1BB antibody enables early detection of T-cell responses in inflammatory arthritis via NIRF imaging

“…Inappropriate T-cell activation and imbalanced T cell-related immune responses are critical mediators of the pathogenesis of RA [5], and the detection of activated T cells via noninvasive molecular imaging theoretically represents an ideal solution for the early diagnosis of RA. The most classic positron emission tomography (PET) tracer, 2-deoxy-2- 18 F-fluoro-D-glucose ( 18 F-FDG), has been tested in many studies [6][7][8]. Despite the achievements of 18 F-FDG, the carbohydrate metabolic pathway is also active in many other types of cells and tissues [9], which definitely causes false-positive results.…”

Extra-articular findings with FDG-PET/CT in rheumatoid arthritis patients: more harm than benefit

“…Scanning was done with a Siemens Biograph mCT FDG-PET/CT scanner according to the European Association of Nuclear Medicine procedure guidelines, as described by Boellaard et al [ 16 ]. The scanning protocol, arthritis scoring system and results on arthritis activity were reported elsewhere [ 17 ]. The scans were also read by experienced nuclear medicine specialists at the academic hospital immediately after they were performed for any unexpected extra-articular findings.…”

Fluorophore-conjugated 4-1BB antibody enables early detection of T-cell responses in inflammatory arthritis via NIRF imaging

“…Inappropriate T cell activation and imbalanced T cell-related immune response are critical mediators during RA pathogenesis [5], activated T cells detection via noninvasive molecular imaging theoretically represents an ideal solution for RA early detection. The most classic PET tracer, 2-deoxy-2-18 F-fluoro-D-glucose ( 18 F-FDG) had been tested in many studies [6][7][8]. Despite the achievements of 18 F-FDG, the carbohydrate metabolic pathway is also shared by many other types of cells and tissues [9], which would definitely lead to false-positive cases.…”