Overview
To evaluate the potential usefulness of 68Ga-FAPI PET/CT for the diagnosis and evaluation of systemic involvement in idiopathic inflammatory myopathies (IIM)/myositis, and compared the results with those of 18F-FDG PET/CT.
Description
Inflammatory myopathies (IIM), collectively known as myositis, are heterogeneous systemic autoimmune disorders characterized by muscle inflammation, and frequently accompanied by extra-muscular manifestations that affect the skin, lung, and joints. Prevalence of underlying malignancy is high in patients with IIM.
68Ga-FAPI has been developed as tracers specific for fibroblast-activation protein (FAP), which is overexpressed in activated fibroblasts in various type of cancers and autoimmune diseases, such as rheumatoid arthritis, IgG4-related diseases and interstitial lung diseases.
Recently the investigators have published articles of the application of 68Ga-FAPI in IgG4-related disease and rheumatoid arthritis, which showed it was more sensitive than FDG in detecting a certain type of inflammation, and the potential utility of FAP-targeted PET/CT imaging for disease assessment in myositis have been reported in a case recently.
Thus, this prospective study is going to investigate utility of 68Ga-FAPI PET/CT in diagnosis, disease assessment including skeletal muscle involvement, cardiac involvement, interstitial lung diseases and potential underlying cancer screening, response to treatment and prognosis, compared with 18F-FDG PET/CT.
Eligibility
Inclusion Criteria:
- A diagnosis of myositis according to American College of Rheumatology/European League Against Rheumatism 2017 (ACR/EULAR 2017) criteria
- Adult men or women 18 and ≤ 75 years of age at the time of signing the informed consent (ICF).
- Participants who were able to provide informed consent (signed by participant or legal representative) and assent according to the guidelines of the Clinical Research Ethics Committee.
- 68Ga-FAPI and 18F-FDG PET/CT were performed within two weeks.
Exclusion Criteria:
- Pregnancy;
- Breastfeeding;
- known allergy against FAPI;
- any medical condition that in the opinion of the investigator may significantly interfere with study compliance.