Table 1.

Comparison of the available cross-sectional imaging techniques for the assessment of fibrosis in CD.

Cross Sectional Imaging	Features	Limitations	Future Perspectives
MRE	No radiation High contrast resolution Possibility of performing fluoro-magnetic resonance Can be combined with perianal imaging High accuracy for severe fibrosis identification	Time consuming Intravenous and oral contrast agents Longer scanning time than CTE Less robust than CTE Lower patient compliance than CTE Availability	Validation in more robust clinical trials Combination with radiomics
DWI-MR	Short-time Possible with standard MR scanners No intravenous contrast Qualitative and quantitative analysis High accuracy for inflammation and penetrating complications in IBD High accuracy for severe fibrosis identification	Lack of anatomic details Low reproducibility of ADC Availability	Promising results to be confirmed in more robust clinical trials
DKI-MR	More physiologic imaging No intravenous contrast High accuracy for inflammation Correlation with different fibrosis grades	Few data	Promising results to be confirmed in more robust clinical trials
MT-MR	No intravenous contrast agent Correlation with different fibrosis grades Higher accuracy for fibrosis than MRE with or without DWI	Few data	Promising results to be confirmed in more robust clinical trials
CTE	Accessible Fast Robust Better spatial resolution than MRE	Radiation	Combination with radiomics Reduction in the radiation dose with high-standard dual-source or ultra-high-pitch CT scanners and iterative reconstruction systems
PET/CTE PET/MRE	In combination with CTE or MRE adds functional data	Radiation (labeled marker; CTE) High cost Limited availability Lack of anatomic details	The disadvantages and lack of advantages when compared to CTE and MRE may hinder further developments
USE US-SWI	Real-time visualization of tissue stiffness	Operator dependent Not easy to interpret More difficult to compare current examination with previous studies Heterogeneous data	Promising results to be confirmed in more robust clinical trials
CEUS	Severe fibrosis identification when associated to elastography techniques	Operator dependent Not easy to interpret More difficult to compare current examination with previous studies Heterogeneous data	Promising results to be confirmed in more robust clinical trials

CTE: computed tomography enterography; CEUS: contrast-enhanced ultrasonography; DKI-MR: diffusion kurtosis imaging–magnetic resonance; DWI-MR: diffusion-weighted imaging–magnetic resonance; MRE: magnetic resonance enterography; MT-MR: magnetization transfer–magnetic resonance; PET/CTE: positron emission tomography/CTE; PET/MRE: positron emission tomography/MRE; USE: ultrasound strain elastography; US-SWI: ultrasound–shear wave imaging.