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.
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.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
50
Intravenous injection of one dosage of 111-185 MBq (3-5 mCi) 68Ga-FAPI. Tracer doses of 68Ga-FAPI will be used to image IIM lesions in skeletal muscle, heart, lung, skin and potential tumor by PET/CT.
The first affiliated hospital of Xiamen University
Xiamen, Fujian, China
RECRUITINGTo define the distribution pattern of 68Ga-FAPI in patients with IIM
To quantify 68Ga-FAPI positron emission tomography (PET) tracer biodistribution in diseased tissue including muscle, heart, lung and normal background organs. 68Ga-FAPI positron emission tomography (PET) tracer biodistribution will be assessed by semi-quantitative analysis (unit/metrics = standardized uptake values (SUV)).
Time frame: 60 minutes following injection
Correlation between uptake of 68GA-FAPI and other parameters associated with disease activity
The Standardized uptake value (SUV) of 68Ga-FAPI was calculated and analyzing the correlation between pathological results and parameters associated with disease activity.
Time frame: 30 days
68Ga-FAPI and disease progression
To evaluate whether the 68Ga-FAPI biodistribution in the diseased tissues can be associated with disease progression under therapies.
Time frame: Up to 2 years
Therapy response
To evaluate whether the change of 68Ga-FAPI uptake in diseased tissue can be associated with disease activity after therapy.
Time frame: Up to 2 years
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