The purpose of this study is to delineate the association of the 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) detected vasculitis pattern of the large vessels (PET positivity) and the clinical picture of Polymyalgia Rheumatica (PMR)/Giant Cell Arteritis (GCA) .

Introduction:

Polymyalgia Rheumatica (PMR) and Giant Cell Arteritis (GCA) are common inflammatory conditions. The diagnosis of PMR/GCA poses many challenges since there are no specific diagnostic tests. Recent literature emphasizes the ability of 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) to assess global disease activity and/or inflammation burden. 18F-FDG PET/CT may lead to make diagnosis at an earlier stage than conventional imaging and assess response to therapy. With respect to the management of PMR/GCA, there are three significant areas of concern as follows: Vasculitis process/vascular stiffness, malignancy and osteoporosis.

Methods and Analysis:

Patients: All patients with the suspicion of PMR/GCR will be offered to participate in the study. The current protocol consists of 4 separate studies including: I) The association of clinical picture of PMR/GCA with PET detected vasculitis II) Evaluating validity of 18F-FDG PET/CT scan for diagnosis of PMR/GCA compared to temporal artery biopsy III) Incidence of new diagnosed malignancies in patients with PMR/GCA, or PMR like syndrome with the aim of PET/CT scan and Chest X ray/Abdominal ultrasound IV) Impact of disease process as well as steroid treatment on bone mineral density, body composition and vasculitis/vascular stiffness in PMR/GCA patients.

Inclusion Criteria:

• At least five (A-E) components of the PMR diagnostic criteria, including:

  • A. Age ≥50 years,
  • B. Bilateral shoulder or hip pain,
  • C. Morning stiffness lasting >45 min,
  • D. Elevated erythrocyte sedimentation rate (ESR),
  • E. Elevated C-reactive protein (CRP),
  • F. Disease duration >2weeks, should be met to suspect PMR.

• For GCA following criteria's must be seen: Age > 50 years, ESR/CRP > 50, as well as at least two symptoms related to vasculitis (scalp tenderness, vision disturbances, headache (new or changed), jaw claudication, tenderness of the temporal arteria) if patients do not simultaneously have PMR. If the patient is suspected for PMR, one cranial symptom is enough to suspect GCA.

Exclusion Criteria:

• Dementia
• Inability to communicate in Danish
• Infections or malignancy when prednisolone is permanently unsuitable
• Contraindication to imaging studies (allergy to contrast materials, reduced kidney function, pregnancy and Blood Sugar (BS) >8 mmol/l after 6 hours fasting)
• Initiation of steroid treatment before the PET scan
• Inability to provide informed consent

All new patients with clinical suspicion of PMR/GCA.