SAT0048 THE CLINICAL USE OF F-18 NAF BONE PET/CT FOR EVALUATING DISEASE ACTIVITY IN PATIENTS WITH RHEUMATOID ARTHRITIS
Authors: H. J. Park, J. W. Lee
Journal: Annals of the Rheumatic Diseases (2020)

Background: Bone positron emission tomography/computed tomography (PET/CT) using F-18 sodium-fluoride (NaF) has been widely used in various bone and joint diseases. However, only a few studies had evaluated the clinical implication of F-18 NaF bone PET/CT in patients with rheumatoid arthritis 1 . Table 1. Risk factors for DWH after orthopedic surgery in RA patients treated with bDMARDs Univariable Multivariable OR (95% CI) p value OR (95% CI) p value Age 1.012 (0.967-1.059) 0.610 Disease duration 1.053 (1.010-1.099) 0.016 1.035 (0.980-1.093) 0.220 Surgical site hand and wrist Ref ref elbow and shoulder n.c. n.c. hip and knee n.c. n.c. foot and ankle 7.091 (2.130-23.603) 0.001 6.915 (1.914-24.976) 0.003 Smoking 0.708 (0.085-5.905) 0.749 Diabetes Mellitus 0.698 (0.150-3.252) 0.647 DAS28-CRP 0.558 (0.302-1.029) 0.062 HAQ-DI 0.986 (0.923-1.054) 0.686 use of PSL 1.039 (0.343-3.147) 0.946 bDMARDs TNF inhibitors ref ref tocilizumab 0.286 (0.093-0.881) 0.029 0.265 (0.074-0.953) 0.042 abatacept 0.370 (0.072-1.889) 0.232 0.515 (0.085-3.107) 0.469 PNI 0.986 (0.896-1.084) 0.767 CONUT 0.892 (0.594-1.338) 0.580 Objectives: The aim of our study is to investigate the clinical usefulness of F-18 NaF bone PET/CT for evaluating disease activity in patients with rheumatoid arthritis. Methods: Seventeen patients with rheumatoid arthritis prospectively enrolled. All patients underwent whole-body F-18 NaF bone PET/CT and ultrasonography simulataneously. The baseline disease activity score with 28 joints using erythrocyte sedimentation rate (DAS28-ESR) and the results of blood tests were collected. From F-18 NaF bone PET/CT images, uptake of the 28 joints used in DAS28-ESR, expressed as standardized uptake value (SUV), and joint-to-normal bone uptake ratios of those joints were measured for each patient. Using SUV and joint-to-normal bone uptake ratios of the 28 joints, the relationship of bone PET/CT findings with clinical factors and ultrasonography findings were assessed. Results: SUVs and joint-to-normal bone uptake ratios in the joints with active synovitis were significantly higher than those in the joints without definite synovitis (p &lt; 0.05). The sum of SUVs and joint-to-normal bone uptake ratios of 28 joints showed significant positive correlations with DAS28-ESR as shown in Figure 1 and Figure 2 (p &lt;0.001 and correlation coefficient 0.775 for SUV; p &lt; 0.001 and correlation coefficient = 0.828 for joint-to-normal bone uptake ratio) and patient global assessment score (p = 0.002 and correlation coefficient 0.697 for SUV; p = 0.002 and correlation coefficient = 0.705 for join-to-normal bone uptake ratio). On correlation analysis with blood test results, only serum ESR level showed a positive correlation with the sum of joint-to-normal bone uptake ratios of the 28 joints (p = 0.047; correlation coefficient = 0.470) and other serum markers showed no significant association with bone PET/CT results (p &gt; 0.05). On correlation analysis with ultrasonography findings, both power Doppler and gray-scale joint inflammation scores showed significant positive correlations with both the sum of SUVs and joint-to-normal bone uptake ratios of ultrasonography-examined joints (p &lt; 0.05). Conclusion: The sum of joint uptake on F-18 NaF bone PET/CT has significant positive correlations with DAS28-ESR, serum ESR level, and ultrasonography findings in patients with rheumatoid arthritis. The findings on F-18 NaF bone PET/CT might be used as an imaging biomarker for disease activity of rheumatoid arthritis. References: [1] Watanabe T, Takase-Minegishi K, Ihata A, et al. 18 F-FDG and 18 F-NaF PET/CT demonstrate coupling of inflammation and accelerated bone turnover in rheumatoid arthritis. Mod Rheumatol. 2016;26:180-7. Funding: Research relating to this abstract was funded by the National Research Foundation of Korea (NRF) grant funded by the Korea government (Ministry of Science and ICT) (grant number: NRF-2017R1C1B5075905). Disclosure of Interests: None declared