P286 Combined F18-FDG-PET-MRI-imaging: A promising tool for diagnostics of small bowel Crohn’s disease

Mattila, J.(1)*;Virtanen, J.(2);Nuutila, P.(3);Koffert, J.(1);

(1)Turku University Hospital, Department of Gastroenterology, Turku, Finland;(2)Turku University Hospital, Department of Radiology, Turku, Finland;(3)Turku University Hospital, Turku PET Centre, Turku, Finland; CD-PET


Diagnostics of small bowel Crohn’s disease (CD) may be difficult. Combined PET-MRI has been documented to be a reliable tool for evaluating intestinal metabolism, but clinical use has been limited due to accessibility, costs and lack of standardized methods to quantify inflammation. Our study aims to prove that combined PET-MRI can be used to detect active CD inflammation in small bowel.


25 patients with suspected ileal CD in ileocolonoscopy were recruited from Turku University Hospital’s outpatient clinic. The patients’ endoscopic findings in ileum were graded according to SES-CD- score (Simple Endoscopic Score for Crohn’s disease). A static PET-MRI was obtained with [18F]-FDG (fluorodeoxyglucose) tracer and gadolinium contrast agent (Dotarem®). Hemoglobin (Hb), C-reactive protein (CRP), serum albumin (Alb) and fecal calprotectin (FC) were measured. After PET-MRI, a small bowel capsule endoscopy was done and the findings graded along the CECDAI-system (Capsule Endoscopy Crohn’s disease Activity Index). The patient’s symptoms were scored with a validated questionnaire. Medication data was also collected. The MR images with a small bowel protocol and diffusion weighted imaging (DWI) were analyzed and the degree of inflammation graded on a visual scale of 1-4, from none to severe by an experienced abdominal radiologist. SUVmax (standardized uptake value) was measured from PET-sequences for each patient from terminal ileum. 


Twenty (80%) of the patients diagnosed with small bowel CD had mean SUVmax 3.40 (±1.54), while the 20% without CD diagnosis had lower SUVmax 2.15 (± 0.93) (p=0.047). Patients who were later treated with immunomodulators or biologics had higher SUVmax than patients who didn’t need medication or were treated with oral budesonide only (3.71 (±1.49) vs 2.07 (±0.82), p=0.0093). There was a correlation with SUVmax and visual MRI grading, CECDAI-score, ileal SES-CD-score and FC (r=0.406, p=0.049; r=0.504, p=0.056; r=0.419, p=0.042 and r=0.49, p=0.014 respectively). SUVmax correlated negatively with Alb (r=0.599, p=0.0025) but not with Hb, CRP or the symptom score of the patients.


In this study we have shown that SUVmax measured from terminal ileum in combined PET-MRI could be used for prediction of patients CD progression. SUVmax also correlated with SES-CD-score, fecal calprotectin and serum albumin. These findings suggest that combined PET-MRI can be used in the future in diagnostics of small bowel CD. Further analyses are needed to define threshold values for small intestine CD.