Characterizing Inflammatory Bowel Disease With 68Ga-FAPI PET/CT

Inflammatory bowel disease (IBD) is comprised of two major disorders: ulcerative colitis (UC) and Crohn's disease(CD).CD is an autoimmune condition resulting in chronic gut inflammation that can be complicated by intestinal fibrosis and stricture formation. Ulcerative colitis is characterized by recurring episodes of inflammation limited to the mucosal layer of the colon. It commonly involves the rectum and may extend in a proximal and continuous fashion to involve other parts of the colon. Studies identified FAP to be overexpressed in uninflamed strictures compared with nonstrictured colonic regions in biopsies taken from Crohn's disease patients. But preliminary studies showed FAP was not overexpressed in colonic biopsies taken from healthy individuals or individuals with ulcerative colitis.68Ga-FAPI has been developed as a tumor-targeting agent as fibroblast activation protein is overexpressed in cancer-associated fibroblasts and inflammation. Recently we have published an article of the application of 68Ga-FAPI in IgG4-related disease which showed it was more sensitive than FDG in detecting a certain type of inflammations. Thus this prospective study is going to investigate whether 68Ga-FAPI PET/CT may be superior for diagnosis, therapy response assessment and follow-up of IBD than 18F-FDG PET/CT.