Axillary lymph-node metabolic activity assessment on ¹⁸F-FDG-PET/CT in rheumatoid arthritis patients treated with biologic therapies

Abstract

Objective: Recent studies have provided new insights into the role of lymph nodes (LNs) in rheumatoid arthritis (RA). The aim of this study was to evaluate the metabolic activity of the axillary LNs in relation to that of the upper limb joints and the clinical assessment of disease activity in RA patients treated with biologic therapies.

Method: ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (¹⁸F-FDG-PET/CT) scans were acquired for 64 patients with RA at baseline and after 6 months of biologic therapy, and the patients’ clinical status was evaluated. The maximum standardized uptake value (SUV_max), metabolic active volume, and total lesion glycolysis (TLG) were used to assess glucose metabolism in the LNs and 12 joints. Clinical evaluations included serum markers and the Disease Activity Score based on 28-joint count–erythrocyte sedimentation rate (DAS28-ESR).

Results: Changes in the SUV_max and TLG for the axillary LNs correlated significantly with those of the ipsilateral wrist joints. There was a positive correlation between the changes in the three metabolic parameters of the axillary LNs and the changes in disease activity after treatment. After 6 months of biologic therapy, all metabolic parameters for the axillary LNs in patients with a DAS28-ESR < 3.2 were significantly lower than those of patients with a DAS28-ESR ≥ 3.2.

Conclusion: A relationship between the glucose metabolism of the axillary LNs and the ipsilateral wrist joints was demonstrated by the ¹⁸F-FDG-PET/CT parameters. The metabolic activity and active volume of axillary LNs may reflect the therapeutic response to the biologic treatment of RA.

Disclosure statement

No potential conflict of interest was reported by the authors.

Supporting Information

Additional Supporting Information may be found in the online version of this article.

Supplementary table S1. Metabolic parameters for the axillary lymph nodes and 12 joints at baseline and 6 months.

Supplementary table S2. Correlations between the changes in the metabolic parameters of the axillary LNs and ipsilateral lower limb joints.

Supplementary table S3. Correlations between the metabolic parameters for the 12 joints and the clinical evaluations of the disease activity.

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