The effect of prednisolone and a short-term prednisolone discontinuation for the diagnostic accuracy of FDG-PET/CT in polymyalgia rheumatica-a prospective study of 101 patients

Andreas Wiggers Nielsen; Ib Tønder Hansen; Berit Dalsgaard Nielsen; Søren Geill Kjær; Jesper Blegvad-Nissen; Kate Rewers; Christian Møller Sørensen; Ellen-Margrethe Hauge; Lars Christian Gormsen; Kresten Krarup Keller

doi:10.1007/s00259-024-06697-8

The effect of prednisolone and a short-term prednisolone discontinuation for the diagnostic accuracy of FDG-PET/CT in polymyalgia rheumatica-a prospective study of 101 patients

Eur J Nucl Med Mol Imaging. 2024 Apr 2. doi: 10.1007/s00259-024-06697-8. Online ahead of print.

Authors

Andreas Wiggers Nielsen^{1

2

3}, Ib Tønder Hansen^{4

5}, Berit Dalsgaard Nielsen^{4

5

6}, Søren Geill Kjær⁷, Jesper Blegvad-Nissen⁷, Kate Rewers⁸, Christian Møller Sørensen⁶, Ellen-Margrethe Hauge^{4

5}, Lars Christian Gormsen^{5

9}, Kresten Krarup Keller^{4

5}

Affiliations

¹ Department of Rheumatology, Aarhus University Hospital, Led- Og Bindevævssygdomme, Palle Juul-Jensens Boulevard 59, 8200, Aarhus, Denmark. andrenie@rm.dk.
² Department of Clinical Medicine, Aarhus University, Aarhus, Denmark. andrenie@rm.dk.
³ Diagnostic Centre, Silkeborg Regional Hospital, Silkeborg, Denmark. andrenie@rm.dk.
⁴ Department of Rheumatology, Aarhus University Hospital, Led- Og Bindevævssygdomme, Palle Juul-Jensens Boulevard 59, 8200, Aarhus, Denmark.
⁵ Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
⁶ Department of Internal Medicine, Horsens Regional Hospital, Horsens, Denmark.
⁷ Diagnostic Centre, Silkeborg Regional Hospital, Silkeborg, Denmark.
⁸ Department of Nuclear Medicine and PET, Odense University Hospital, Odense, Denmark.
⁹ Department of Nuclear Medicine and PET, Aarhus University Hospital, Aarhus, Denmark.

PMID: 38563881
DOI: 10.1007/s00259-024-06697-8

Abstract

Purpose: 2-[18F]Fluoro-2-deoxy-D-glucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has been suggested as an imaging modality to diagnose polymyalgia rheumatica (PMR). However, the applicability of FDG-PET/CT remains unclear, especially following glucocorticoid administration. This study aimed to investigate the diagnostic accuracy of FDG-PET/CT before and during prednisolone treatment, as well as following short-term prednisolone discontinuation.

Methods: Treatment naïve suspected PMR patients were clinically diagnosed at baseline and subsequently had an FDG-PET/CT performed. Patients diagnosed with PMR were administered prednisolone following the first FDG-PET/CT and had a second FDG-PET/CT performed after 8 weeks of treatment. Subsequently, prednisolone was tapered with short-term discontinuation at week 9 followed by a third FDG-PET/CT at week 10. An FDG-PET/CT classification of PMR/non-PMR was applied, utilizing both the validated Leuven score and a dichotomous PMR score. The final diagnosis was based on clinical follow-up after 1 year.

Results: A total of 68 and 27 patients received a final clinical diagnosis of PMR or non-PMR. A baseline FDG-PET/CT classified the patients as having PMR with a sensitivity/specificity of 86%/63% (Leuven score) and 82%/70% (dichotomous score). Comparing the subgroup of non-PMR with inflammatory diseases to the PMR group demonstrated a specificity of 39%/54% (Leuven/dichotomous score). After 8 weeks of prednisolone treatment, the sensitivity of FDG-PET/CT decreased to 36%/41% (Leuven/dichotomous score), while a short-term prednisolone discontinuation increased the sensitivity to 66%/60%.

Conclusion: FDG-PET/CT has limited diagnostic accuracy for differentiating PMR from other inflammatory diseases. If FDG-PET/CT is intended for diagnostic purposes, prednisolone should be discontinued to enhance diagnostic accuracy.

Trial registration: ClinicalTrials.gov (NCT04519580). Registered 17th of August 2020.

Keywords: Diagnostic imaging; Effect of prednisolone; FDG-PET/CT; Polymyalgia rheumatica.

Associated data

ClinicalTrials.gov/NCT04519580