Evaluation of Quantitative PET/MR Enterography Biomarkers for Discrimination of Inflammatory Strictures from Fibrotic Strictures in Crohn Disease

Abstract

PET/MR enterography offers a potential noninvasive technique for the differentiation of purely fibrotic strictures from mixed or inflammatory strictures. A hybrid biomarker that incorporates both MR and PET information performed better for stricture evaluation than either modality alone.

Role of molecular imaging in the management of patients affected by inflammatory bowel disease: State-of-the-art

“…As such, it is crucial to discriminate those lesions likely to benefit from surgical treatment (the predominantly fibrotic ones) from those still medically treatable (the inflammatory ones). With this regard, some authors suggested a possible role for 18 F-FDG-PET, although data are still limited and controversial[2,4,5]. While Shyn and colleagues reported no significant difference in SUV max between the strictures deserving or not a surgical resection, although in a small patient sample[21], Holtmann et al[2] showed that both hydro-MRI and 18 F-FDG-PET have very high accuracy in detecting and characterizing strictures.…”

“…More recently, a retrospective study of Catalano et al[5] investigated the role of 18 F-FDG-PET/MR enterography in discriminating between inflammatory and fibrotic strictures associated with CD, by using “quantitative” methods. Nineteen patients surgically treated within one month from imaging were evaluated and the following parameters were recorded for each resected bowel segment: The “SI” on T2 weighted sequences, the “apparent diffusion coefficient (ADC)”, the SUV max and the values obtained by multiplying the first two parameters by SUV max (SI × SUV max and ADC × SUV max , respectively).…”

“…Specifically, endoscopy is an invasive procedure associated with increased risk of bowel perforation, if performed during the acute phase of disease[1,3,4]. Moreover, it cannot study the deepest layers of intestinal wall and discover possible extra-intestinal alterations[5]. Finally, in case of CD complicated by strictures, endoscopic exploration often remains incomplete, due to difficulties in going beyond narrowed bowel segments and in exploring the distal side of the strictures[4].…”

Combined PET/MRI: from Status Quo to Status Go. Summary Report of the Fifth International Workshop on PET/MR Imaging; February 15–19, 2016; Tübingen, Germany

“…Some of the potential clinical areas of application named for combined PET/MRI included soft tissue inflammation, GI inflammation (inflammatory bowel disease) [54, 55], cardiovascular processes such as acute myocarditis and sarcoidosis, rheumatoid arthritis [56], type-1-diabetes [57], giant cell arteritis, and spondylodiscitis [58]. It was noted that, yet again, CXCR4 and CD25 are expressed on most infiltrating cells in many of these processes and hence provide a PET target.…”

Imaging of intestinal fibrosis: current challenges and future methods

“…A recent study showed that PET-MR in 19 patients undergoing elective bowel resection was able to predict the histology of resected segments (fibrosis alone vs. a mixed fibroinflammatory disease), albeit with underwhelming diagnostic accuracy (sensitivity 0.67, specificity 0.73). 25 Lenze and colleagues prospectively evaluated PET-CT, MR-enteroclysis, and B-mode ultrasound for characterizing stricturing disease and predicting therapeutic outcomes. While non-significant trends in their data suggested some ability of all modalities to predicting medical response vs. surgical management within 6 months, no single technique was superior.…”