P977 Combined F18-FDG-PET-MRI-imaging can predict clinical remission in small bowel Crohn’s disease

Abstract Background Diagnostics and follow-up of small bowel Crohn’s disease (CD) can be difficult. Combined PET-MRI enterography (MRE) can be used to evaluate intestinal inflammation. Lack of standardized methods and diagnostic thresholds has limited its clinical use in diagnostics and monitoring of small bowel CD. There is no previous data on the use of PET-MRI in follow-up of small bowel CD. Methods 34 patients with suspected CD in small bowel were recruited from Turku University Hospital’s outpatient clinic. A static PET-MRE was obtained with [18F]-FDG (fluorodeoxyglucose) tracer. CD diagnosis was confirmed with small bowel capsule endoscopy. Patients diagnosed with CD were started with appropriate treatment chosen by clinicians. Endoscopic findings including histopathology, laboratory results (Hb, CRP, serum albumin (Alb) and fecal calprotectin (FC)) and medication data were collected. Patients diagnosed with CD (N=16) went through control PET-MRE median 105 days after initial imaging. Highest SUVmax (standardized uptake value) in small intestine was measured and MRE-images with diffusion weighted imaging (DWI) were analyzed by an experienced abdominal radiologist and severity of inflammation was graded from 1-4. Hb, CRP, Alb and FC were measured from the patients at the time of imaging. Results Median SUVmax was significantly lower after three months of medical treatment (3.2 vs. 2.1) (p=0.016). FC was significantly lower at the time of control imaging (p=0.030) (median 725 ug/g vs. 141 ug/g). 10 patients had FC