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Updated: Mar 18, 2026
Author Spotlight: Enhancing Rheumatoid Arthritis Research Through HR-pQCT Imaging Analysis
Published on: October 6, 2023
Differentiation between Polymyalgia Rheumatica (PMR) and Elderly-Onset Rheumatoid Arthritis Using
Daisuke Wakura1, Takuya Kotani1, Tohru Takeuchi1
1Department of Internal Medicine (I), Osaka Medical College, Takatsuki, Osaka, Japan.
Background:
It is difficult to differentiate polymyalgia rheumatica (PMR) from elderly-onset rheumatoid arthritis (EORA) in clinical practice. We compared FDG-PET/CT findings between patients with PMR and those with EORA and extracted factors useful for differentiating the two disorders.
Methods:
We compared abnormal FDG accumulation sites and maximum standardized uptake value (SUVmax) between 15 patients with PMR and 7 with EORA in whom FDG-PET/CT was performed.
Results:
The proportion of patients in the PMR group with abnormal FDG accumulation at the following 9 sites on FDG-PET/CT was significantly higher than that in the EORA group: periarticular region of the scapulohumeral joint, enthesis of the pectineus muscle, vicinity of the enthesis of the rectus femoris muscle, lateral side of the greater trochanter, ischial tuberosity, hip joint, spinous process of the lower cervical vertebra, intervertebral joint of the lumbar vertebra, and spinous process of the lumbar vertebra. The PET/CT score was evaluated at 9 sites consisting of the abovementioned sites. The median score in the PMR group was 8, which was significantly higher than that of 0 in the EORA group (P = 0.0003). ROC curve analysis was performed with the PET/CT scores, and a score of 5 was shown to maximize the area under the ROC curve (sensitivity: 86.7%, specificity: 86.7%).
Conclusions:
FDG-PET/CT is useful for differentiating PMR from EORA. In patients with PMR, abnormal FDG accumulation was observed at the entheses, suggesting the presence of enthesitis in addition to bursitis and synovitis.
Insights
Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) can differentiate polymyalgia rheumatica (PMR) from elderly-onset rheumatoid arthritis (EORA). PMR patients show significantly higher abnormal FDG accumulation at specific sites, indicating enthesitis.
Area of Science:
- Rheumatology
- Nuclear Medicine
- Diagnostic Imaging
Background:
- Differentiating polymyalgia rheumatica (PMR) from elderly-onset rheumatoid arthritis (EORA) presents clinical challenges.
- FDG-PET/CT imaging offers a potential tool for distinguishing these conditions.
Purpose of the Study:
- To compare FDG-PET/CT findings between PMR and EORA patients.
- To identify imaging features that aid in differentiating PMR from EORA.
Main Methods:
- A comparative study involving 15 PMR patients and 7 EORA patients who underwent FDG-PET/CT.
- Analysis of abnormal FDG accumulation sites and SUVmax between the two groups.
- Evaluation of a PET/CT score across 9 specific anatomical sites.
Main Results:
- Significantly higher FDG accumulation was observed in PMR patients at 9 specific sites, including joints and entheses.
- The median PET/CT score was significantly higher in the PMR group (8) compared to the EORA group (0).
- ROC analysis indicated a PET/CT score of 5 achieved 86.7% sensitivity and 86.7% specificity for differentiating PMR from EORA.
Conclusions:
- FDG-PET/CT is a valuable imaging modality for differentiating PMR from EORA.
- Abnormal FDG uptake at entheses in PMR patients suggests the presence of enthesitis, alongside bursitis and synovitis.
