High frequency of capsular knee involvement in polymyalgia rheumatica/giant cell arteritis patients studied by positron emission tomography.

Marco A. Cimmino, Dario Camellino, Francesco Paparo, Silvia Morbelli, Michela Massollo, Maurizio Cutolo, Gianmario Sambuceti

Research output: Contribution to journalArticle


Peripheral arthritis has been described in up to 50% of PMR patients, with knee involvement in the majority. This study was designed to evaluate by PET/CT the knees of patients with PMR and GCA and to identify the knee structures involved by inflammation. Twenty-five consecutive patients with PMR (19) or GCA (6) were studied in comparison with 25 age- and sex-matched controls who underwent PET/CT for initial staging of cancer. Clinical features, ESR and CRP were evaluated. Simultaneous FDG-PET and CT imaging from the skull base to the knee was performed after injection of 4.8-5.2 MBq of [(18)F]FDG per kilogram body weight. The knee anatomical structures being evaluated included joints, fibrous capsule, synovial recesses and bursae. At PET/CT, 21/25 patients (84%) showed bilateral diffuse uptake at the knees. The tracer clearly outlined the contour of the fibrous capsule. In 50 knees, 90% of capsular sites were involved by inflammation in comparison with 23% of intracapsular sites and 4.7% of extracapsular sites (P <0.0001). No correlation was found between PET/CT results and ESR or CRP. FDG uptake, with a pattern similar to that observed in 96% of PMR/GCA patients, was seen in 20% of controls (P = 0.03). Our findings suggest that bilateral capsulitis of the knee is detectable in most PMR/GCA patients if a sensitive imaging technique such as PET/CT is used.

Original languageEnglish
Pages (from-to)1865-1872
Number of pages8
Issue number10
Publication statusPublished - Oct 2013


ASJC Scopus subject areas

  • Medicine(all)

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