Differentiation of fibrotic and inflammatory component of Crohn's disease-associated strictures

Abstract

Patients with Crohn's disease (CD) commonly develop bowel strictures, which may contain various degrees of inflammation and fibrosis. While predominantly inflammatory strictures may benefit from a medical anti-inflammatory treatment approach, fibrotic strictures would require endoscopic balloon dilation or surgery. Cross-sectional imaging surpasses endoscopy for characterization of stenotic segments and potentially may contribute to the optimal clinical management of these patients. This short review aims to discuss the potentialities and limitations of cross-sectional imaging techniques for assessing bowel fibrosis in patients with CD.

Keywords: Crohn disease; Elastography; Magnetic resonance; Ultrasound.

Fig. 1.

Images in a 57-year-old woman with CD with past history of ileocecal resection and new stricture on the neo-terminal ileum. Axial diffusion-weighted images with b=800 sec/mm² (A) and hypointensity on corresponding apparent diffusion coefficient (ADC) map (ADC=923 mm² /sec) (B) are shown in the same segment (arrow). Axial magnetization transfer (MT) imaging without (C) and with MT pulse and (D) demonstrate MT effect of neo-terminal ileum (arrow) to be similar to that of skeletal muscle.

Fig. 2.

Real-time shear wave ultrasound image of stenotic bowel wall (left image) overlaying conventional ultrasound gray-scale images (right image) in a 38-year-old woman with CD. Multiple circular region of interest (ROI) are depicted over the bowel wall (T1–T3 and T4 [not seen on this image]) and in perienteric fat (R1). The quantitative data (average stiffness value in kPa and SD of each ROI, and ratio between bowel wall and fat) is automatically calculated. The color scale inside the box on the left image indicates the distribution of the measured elasticity within the area of interest. Ave, average.