Detection and differentiation of inflammatory versus fibromatous Crohn's disease strictures: prospective comparison of 18F-FDG-PET/CT, MR-enteroclysis, and transabdominal ultrasound versus endoscopic/histologic evaluation.

BACKGROUND

Differentiation between inflammatory and fibromatous strictures in Crohn's disease (CD) is difficult but crucial for therapeutic decisions. The aim of this study was to assess the best noninvasive imaging method for the detection and differentiation of inflammatory and fibromatous stenoses in CD in comparison to endoscopic and histologic evaluation.

METHODS

Patients with suspected CD strictures were included. According to a formalized endoscopic and histologic protocol, strictures were classified as inflammatory, mixed, and fibrostenotic. Strictures were further analyzed using fluorine 18-labeled fluoro-2-deoxy-D-glucose ((18) FDG) / positron emission tomography (PET) low-dose computed tomography (CT), magnetic resonance (MR) enteroclysis and transabdominal ultrasound using standardized scoring systems.

RESULTS

Thirty patients with 37 strictures were evaluated (inflamed n = 22; mixed n = 12, fibromatous n = 3). (18) FDG-PET/CT detected 81%, MR-enteroclysis 81%, and ultrasound 68% of the strictures. Correct differentiation rates of strictures were 57% for MRE, 53% for (18) FDG-PET/CT, and 40% for ultrasound. Differences of detection rates and differentiation rates were not statistically significant. When combining transabdominal ultrasound with (18) FDG-PET/CT or MR-enteroclysis all strictures that required invasive treatment were detected.

CONCLUSIONS

Detection rates of the strictures were not significantly different between (18) FDG-PET/CT, MR-enteroclysis, and ultrasound. Despite good stricture detection rates relating to our gold standard, (18) FDG-PET/CT nor MR-enteroclysis nor ultrasound can accurately differentiate inflamed from fibrotic strictures. A combination of MR-enteroclysis and ultrasound as well as a combination of (18) FDG-PET/CT and ultrasound resulted in a 100% detection rate of strictures requiring surgery or endoscopic dilation therapy, suggesting the combination of these methods as an alternative to endoscopy at least in the group of patients not able to perform an adequate bowel preparation.