Effects of infliximab therapy on transmural lesions as assessed by magnetic resonance enteroclysis in patients with ileal Crohn's disease

Up to 50% of patients with Crohn's disease (CD) experience secondary loss of response (SLR) to infliximab. Patients with SLR may show clinical signs of iron deficiency as a result of inflammation despite being iron-replete. The magnetic resonance imaging (MRI)-based radiomic index, R2*, can detect changes in iron metabolism. Therefore, the R2* parameter has considerable potential for detection of SLR to infliximab. The aims of this study were to explore the correlation between R2* and inflammation and to develop a non-invasive nomogram based on R2* to identify SLR to infliximab in patients with CD. Three hundred and twenty-two infliximab-treated patients with CD who underwent magnetic resonance enterography within 2 weeks before or after 54 weeks of infliximab therapy were divided into training and validation datasets at a ratio of 8:2. Point-biserial analysis was conducted to confirm the relationship between R2* and inflammation. A multivariate logistic regression model was created using R2*, CRP and hemoglobin (OR, 1.10, 1.04 and 0.98; P < 0.05). Receiver-operating characteristic curves and the Hosmer-Lemeshow test were used to assess the performance of the model. A correlation between R2* and inflammation was identified. Different trends in R2* and iron status indices were observed between patients with responsive and non-responsive CD, which is worthy of further study. The model was converted to a visualized nomogram that had a good ability to discriminate the outcomes of infliximab therapy with an area under the curve of 0.723 (95% CI, 0.661–0.785) in the training dataset and 0.715 (95% CI, 0.587–0.843) in the validation dataset. We confirmed a correlation between R2* and inflammation in patients with CD. Based on the MRI-based radiomic signature, a novel nomogram was established and validated to facilitate individualized identification of SLR to infliximab in patients with CD.

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Crohn's disease evaluated with magnetic resonance enteroclysis: diagnostic performance of experienced and inexperienced readers before and after training

Acta Radiologica ◽

10.1080/02841850802409539 ◽

2008 ◽

Vol 49 (9) ◽

pp. 967-974 ◽

Cited By ~ 6

Author(s):

A. Negaard ◽

A. Mulahasanovic ◽

L. A. Reisaeter ◽

K. Aasekjaer ◽

L. Sandvik ◽

...

Keyword(s):

Crohn’S Disease ◽

Magnetic Resonance ◽

Small Bowel ◽

Crohn's Disease ◽

Terminal Ileum ◽

Diagnostic Performance ◽

Interobserver Agreement ◽

Training Evaluation ◽

Before And After ◽

Magnetic Resonance Enteroclysis

Background: Magnetic resonance enteroclysis (MRE) is suggested to become the preferred radiological method in small-bowel Crohn's disease (CD). However, the performance of inexperienced readers may influence the diagnostic value of the method and has not been previously investigated. Purpose: To compare readings of MRE in small-bowel CD performed by experienced and inexperienced readers before and after training. Material and Methods: One experienced radiologist (observer 1) and two trainees (observers 2 and 3) reviewed 60 MRE examinations. A second reading was performed after training. Bowel wall thickness (BWT), ulcers (BWU), stenosis (BWS), fistulas (FIS), and abscesses (ABS) were evaluated. A reference standard based on clinical records was established. Results: BWT in the terminal ileum was evaluated with high diagnostic performance (sensitivity: observer 1, 83%; observer 2, 72%; observer 3, 78%). Only BWU was diagnosed with a higher sensitivity by observer 1 (78% vs. 33% and 39%, respectively; P=0.02). False-positive findings for BWT in the jejunum (observer 2: 7; observer 3: 4) and fistulas and abscesses (observer 2: 11/5; observer 3: 5/4) were made by the trainees. Interobserver agreement in the jejunum was poor (observer 1/observer 2: κ=0.23; observer 1/observer 3: κ=−0.03) and in the ileum good (observer 1/observer 2: κ=0.78; observer 1/observer 3: κ=0.73). After training, evaluation of BWU (observer 2: 56%, P=0.22; observer 3: 44%, P=0.03), BWT (observer 2: 2; observer 3: 2), and interobserver agreement in the jejunum improved (observer 1/observer 2: κ=0.66; observer 1/observer 3: κ=0.66). However, the number of diagnosed fistulas and abscesses remained high. Conclusion: Before training, most findings of Crohn's disease in the terminal ileum were evaluated with high diagnostic performance by all readers. However, the inexperienced readers evaluated BWU with a low sensitivity and overestimated the number of FIS, number of ABS, and increased BWT in the jejunum. After training, evaluation by inexperienced readers of BWU and increased BWT in the jejunum improved.

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