Diagnostic Validity of [18F]FSPG PET for the Assessment of Disease Activity in Inflammatory Bowel Disease

Inclusion Criteria: * Subject is aged between 19 and 79 years and male or female of any race/ethnicity. * Subject has had ulcerative colitis or Crohn's disease diagnosed by clinical, endoscopic and histologic evidence at least 3 months prior to screening. * Subject has symptoms suggestive of active disease at the time of enrollment. * Subject is scheduled to undergo sigmoidoscopy or colonoscopy for ulcerative colitis or Crohn's disease within 7 days prior to or after the planned study with \[18F\]FSPG administration. Exclusion Criteria: * Subject or subject's legally acceptable representative does not provide written informed consent. * Subject displays clinical signs of ischemic colitis or has an evidence of pathogenic bowel infection. * Subject is diagnosed as having inflammatory bowel disease unclassified. * Subject has been treated with sulfasalazine or intravenous corticosteroids within the previous four weeks prior to the planned study with \[18F\]FSPG administration. * Dose escalation of the current inflammatory bowel disease drugs or starting a new oral aminosalicylate, corticosteroid, immunomodulator, biologics, antibiotics, probiotics, or topical preparations is scheduled from the study enrollment to the scheduled sigmoidoscopy or colonoscopy, or 24 hours after \[18F\]FSPG administration . The dose escalation or starting a new antidiarrheal and/or analgesic drug is allowed. * Female subject is pregnant or nursing. Exclusion of the possibility of pregnancy is made by one of the following: 1) Woman is physiologically post-menopausal (cessation of menses for more than 2 years), 2) woman is surgically sterile (has had a documented bilateral oophorectomy and/or documented hysterectomy, or 3) if the woman is of childbearing potential, a serum or urine pregnancy test performed within 24 hours immediately prior to administration of \[18F\]FSPG has to be negative and the women is advised to apply contraceptive measures during her participation in this study. * Subject has concurrent severe and/or uncontrolled and/or unstable medical disease (e.g. congestive heart failure, acute myocardial infarction, severe pulmonary disease, chronic renal or hepatic disease which could compromise participation in the study) in the judgment of the investigator. * Subject is a relative of the investigator, student of the investigator or otherwise dependent. * Subject has received any investigational drugs or devices within four weeks prior to the study enrollment. * Subject has been previously included in this study. * Subject has any other condition or personal circumstances that, in the judgment of the investigator, might make collection of complete data difficult or impossible. * Subject is allergic to hyoscine or any of ingredients of hyoscine butylbromide, or has myasthenia gravis, megacolon, closed angle glaucoma, or obstructive prostatic hypertrophy.