Clin Physiol Funct Imaging. 2025 Jan;45(1):e12903.doi: 10.1111/cpf.12903. Epub 2024 Sep 23.

Sina Dalby ^1 2, Reza Piri ^2 3, Ole Graumann ^2 4, Oke Gerke ^2 3, Thomas Lund Andersen ⁵, Anne-Mette Walsted ⁶, Kirsten Risby ⁶, Rasmus Gaardskær Nielsen ¹, Anders Linnemann ¹, Poul Flemming Høilund-Carlsen ², Steffen Husby ²

Author information

¹Hans Christian Andersen Children's Hospital, Odense University Hospital, Odense, Denmark.

²Department of Clinical Research, University of Southern Denmark, Odense, Denmark.

³Department of Nuclear Medicine, Odense University Hospital, Odense, Denmark.

⁴Department of Radiology, Odense University Hospital, Odense, Denmark.

⁵Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, Copenhagen, Denmark.

⁶Department of Paediatrics, Kolding Hospital, Kolding, Denmark.

Abstract

Cross-sectional imaging supplements endoscopy in detecting disease manifestations in inflammatory bowel diseases (IBD). This study aimed to evaluate the accuracy of PET/MRI in a paediatric population suspected of IBD. This prospective study consecutively included patients aged 8-17 years under diagnostic evaluation for IBD. Forty-three patients underwent a PET/MRI scan and subsequent ileocolonoscopy, of whom 26 patients diagnosed with IBD participated in a follow-up scan, hereof 19 with Crohn's disease (CD), five with Ulcerative colitis and two with unclassified IBD. The results of PET alone, MRI alone, and PET/MRI combined were compared to a reference standard of endoscopy and histopathology. Of the 208 intestinal segments analysed, 109 showed inflammation, and 99 had no inflammation. In the per-segment analysis PET had a sensitivity of 0.83 (95% CI 0.73-0.93), specificity of 0.59 (95% CI 0.47-0.71), and area under the receiver operating characteristic curve (AUROC) of 0.73 (95% CI 0.67-0.80). MRI had a sensitivity of 0.52 (95% CI 0.41-0.64), specificity 0.89 (95% CI 0.82-0.96), and AUROC of 0.72 (95% CI 0.66-0.77). PET/MRI had a sensitivity of 0.83 (95% CI 0.74-0.94), specificity of 0.57 (95% CI 0.44-0.69), and AUROC of 0.77 (95% CI 0.71-0.84). At follow-up, PET and MRI scores decreased, and the change in MRI was able to identify patients with a clinical response. The accuracy of the PET/MRI scan in detecting inflammation in the terminal ileum and colon was moderate and not superior to either modality alone. With technological advances and combined reading, PET/MRI may still be valuable in selected cases.