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P176 Correlation of biomarkers to simultaneous positron emission tomography with 18F-fluorodeoxyglucose with magnetic resonance imaging enterography and endoscopy for monitoring activity of inflammation in patients with Crohn’s disease

J. Langhorst*1, J. Boone2, A. Rueffer3, G. Dobos4, K. Beiderwellen5, T. Lauenstein6

1University of Duisburg-Essen, Integrative Gastroenterology, Kliniken Essen-Mitte, Essen, Germany, 2Tech Lab Inc, Blacksburg, United States, 3Labor L+S, Enterosan, Bad Bocklet-Grossenbrach, Germany, 4University of Duisburg-Essen, Integrative and Internal Medicine, Essen, Germany, 5University of Duisburg-Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany, 6University Duisburg-Essen, Department of Diagnostic and Interventional Radiology and Neuroradiology, Essen, Germany

Background

The combination of positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG) with magnetic resonance imaging (MRI) as integrated PET/MRI in one examination is a new cutting-edge technology for the non-invasive assessment of the inflammatory activity in patients with Crohn’s disease (CD). In CD, a manifestation throughout the gastrointestinal tract is possible. Therefore, a comprehensive diagnostic work-up including endoscopy and an extended exploration of the small intestine is recommended. Non-invasive biomarkers such as lactoferrin and calprotectin are increasingly popular. In the presented study, we compared the performance of lactoferrin, calprotectin, and other non-invasive biomarkers to PET/MRI and colonoscopy in patients with CD.

Methods

In every patient, a PET/MRI including the maximum standardised uptake value (SUVmax) and a colonoscopy including an endoscopy index (SES-CD) was performed. The PET/MRI protocol was optimised for small bowel and proximal colon investigation results of colonoscopy were rated as pivotal in the rectum and sigma. Harvey–Bradshaw-Index (HBI) was calculated as symptom based index. Lactoferrin (LF > 7.25 µg/g, TechLab), calprotectin (Cal > 50 µg/g, Immundiagnostik), PMN-elastasis (PMN-e > 0.062 µg/g, Immundiagnostik), as well as CRP (≥ 0.5 mg/dl) were correlated to the SUVmax. Sensitivity, specificity, and diagnostic accuracy for the biomarkers were calculated using optimised cut-offs.

Results

Included were 30 patients (17 female), mean age 45.6 ± 13.4 years (range 21–67) with known CD were included in the study. N = 15 patients showed signs of active disease in colonoscopy and/or PET/MRI (4 exclusively in the small bowel proximal the term ileum); n = 10 patients showed at least 1 stenosis. SUVmax was correlated significantly with the SES-CD (Spearman cc 0.500; p = 0.009, excluding pts with exclusively small bowel involvement) and the HBI (cc 0.382; p = 0.037). Lactoferrin showed a significant correlation to the SUVmax (cc 0.47; p = 0.009). The median levels (inactive/active) of LF were 3.9/18.0 µg/g (p = 0.009), Cal 103.9/128.7 µg/g, PMN-E 0.100/0.160 µg/g, and CRP 0.4/0.3 mg/dl. Using optimised cut-offs sensitivity, specificity, and diagnostic accuracy for LF was 73.3%/71.4%/70% optimised cut-off: 10.4 µg/g (Chi2, p = 0.028); CAL 66,7%/64,3%/63.3%; 114,9 µg/g (p = 0.096); PMN-e 53.3%/57.1%/56.6%; 0.1155 µg/g (p = ns); CRP 46.7%/57.1%/50%; 0.45 mg/dl (p = ns).

Conclusion

Faecal biomarkers outperform CRP for detecting active CD using combined PET/magnetic resonance (MR) enterography and endoscopy as the gold standard. Lactoferrin levels were significantly correlated to the SUVmax, which was significantly correlated with SES-CD. Further studies are needed to assess the performance of faecal biomarkers in CD identified by PET/MRI.