Ability of DWI to characterize bowel fibrosis depends on the degree of bowel inflammation
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Although diffusion-weighted imaging (DWI) is reported to be accurate in detecting bowel inflammation in Crohn’s disease (CD), its ability to assess bowel fibrosis remains unclear. This study assessed the role of DWI in the characterization of bowel fibrosis using surgical histopathology as the reference standard.
Abdominal DWI was performed before elective surgery in 30 consecutive patients with CD. The apparent diffusion coefficients (ADCs) in pathologic bowel walls were calculated. Region-by-region correlations between DWI and the surgical specimens were performed to determine the histologic degrees of bowel fibrosis and inflammation.
ADCs correlated negatively with bowel inflammation (r = − 0.499, p < 0.001) and fibrosis (r = − 0.464, p < 0.001) in 90 specimens; the ADCs in regions of nonfibrosis and mild fibrosis were significantly higher than those in regions of moderate–severe fibrosis (p = 0.008). However, there was a significant correlation between the ADCs and bowel fibrosis (r = − 0.641, p = 0.001) in mildly inflamed segments but not in moderately (r = − 0.274, p = 0.255) or severely (r = − 0.225, p = 0.120) inflamed segments. In the mildly inflamed segments, the ADCs had good accuracy with an area under the receiver-operating characteristic curve of 0.867 (p = 0.004) for distinguishing nonfibrosis and mild fibrosis from moderate–severe fibrosis.
ADC can be used to assess bowel inflammation in patients with CD. However, it only enables the accurate detection of the degree of bowel fibrosis in mildly inflamed bowel walls. Therefore, caution is advised when using ADC to predict the degree of intestinal fibrosis.
• Diffusion-weighted imaging was used to assess bowel inflammation in patients with Crohn’s disease.
• The ability of diffusion-weighted imaging to evaluate bowel fibrosis decreased with increasing bowel inflammation.
• Diffusion-weighted imaging enabled accurate detection of the degree of fibrosis only in mildly inflamed bowel walls.
KeywordsDiffusion magnetic resonance imaging Crohn’s disease Fibrosis
Apparent diffusion coefficient
Magnetic resonance imaging
The authors thank Zhongwei Zhang, a diagnostic medical physics doctor from the Radiology Department at the University of Florida, for reading and commenting on the paper. They are also grateful to Jian Zhang, a statistician from the Clinical Research Center at ZhongShan Ophthalmic Center, Sun Yat-Sen University, for valuable suggestion about statistical analysis.
The authors gratefully acknowledge the financial support by the National Natural Science Foundation of China (81600508, 81770654, 81500501, 81870451, 81771908, 81571750).
Compliance with ethical standards
The scientific guarantor of this publication is Shi-Ting Feng, Can-hui Sun.
Conflict of interest
The authors declare that they have no conflicts of interest.
Statistics and biometry
No complex statistical methods were necessary for this paper.
Written informed consent was obtained from all subjects (patients) in this study.
Institutional Review Board approval was obtained.
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