Various forms of ¹⁸F-FDG PET and PET/CT findings in patients with polymyalgia rheumatica

Abstract

Aim. Polymyalgia rheumatica (PMR) is a disease presenting with pain and stiffness, mainly in shoulders, hip joints and neck. Laboratory markers of inflammation may bolster diagnosis. PMR afflicts patients over 50 years old, predominantly women, and may also accompany giant cell arteritis. Patients and Methods. 67 patients, who fullfiled Healey´s criteria for PMR in the period between 2004 and 2013 and had positive FDG PET (PET/CT) findings were retrospectively evaluated. FDG uptake was assessed in large arteries, proximal joints (shoulders, hips and sternoclavicular joints), in extraarticular synovial structures (interspinous, ischiogluteal and praepubic bursae). Results. Articular/periarticular involvement (A) was detected in 59/67 (88.1%) patients and extrarticular synovial involvement (E) in 51/67 (76.1%) patients either individually or in combinations. Vascular involvement (V) was detected in 27/67 (40.3%) patients only in combination with articular (A) and/or extraarticular synovial (E) involvement. These combinations were: A+E involvement in 30/67 (44.8%) patients, A+V involvement in 8/67 (11.9%) patients, E+V involvement in 6/67 (9%) patients and A+E+V in 13/67 (19.4%) patients. Conclusions. PMR presents by articular/periarticular synovitis, extraarticular synovitis and can be accompanied by giant cell arteritis. All types of involvement have their distinct FDG PET (PET/CT) finding, which can be seen either individually or in any of their 4 combinations. FDG PET (PET/CT) examination seems to be an advantageous one-step examination for detecting different variants of PMR, for assessing extent and severity and also for excluding occult malignancy.

Predictors of positive 18F-FDG PET/CT-scan for large vessel vasculitis in patients with persistent polymyalgia rheumatica

“…Experts in the field consider that PET/CT scans may show LVV involvement in at least a third of patients with PMR [22][23][24]. The results of our study suggest that the prevalence of LVV in patients with well-defined PMR may be higher, reaching in our series up to 60%.…”

Response to: ‘A relationship between extracapsular involvement and response to steroid treatment in polymyalgia rheumatica: too soon to conclude?’ by Yang et al

“…Most early reports of musculoskeletal imaging in PMR focused on the shoulders 5. More recent 18-fluorodeoxyglucose positron emission tomography (18-FDG-PET)/CT studies have, like ours, identified focal 18-FDG uptake at capsular/entheseal sites distant from articular joints, including the hip pericapsular tissue and sites adjacent to the pubic symphysis 6. Although all these sites of focal 18-FDG uptake were termed ‘bursitis’, we are concerned that this term may lead to an assumption that the synovial lining of the bursa is the primary site of inflammation in PMR.…”

FDG-PET/CT(A) imaging in large vessel vasculitis and polymyalgia rheumatica: joint procedural recommendation of the EANM, SNMMI, and the PET Interest Group (PIG), and endorsed by the ASNC

“…Thereby, it can identify the presence of systemic LVV in patients with GCA and TA, and it can also show inflammation of peri-articular and extra-articular synovial structures in the case of PMR. Approximately 20% of patients with apparently isolated PMR show LVV on FDG-PET/CT [ 10 ], and this percentage can be even higher, depending on the presence of LVV symptoms [ 11 – 13 ]. It is important to realize that a negative temporal artery biopsy, an ultrasonography without a halo sign, or magnetic resonance imaging (MRI) without aortic wall thickening or edema does not definitively exclude the presence of LVV and should therefore not limit the use of FDG-PET/CT when LVV is clinically suspected [ 14 , 15 ].…”