The Diagnostic Role of Magnetic Resonance Enterography as a Complementary Test to Colonoscopy in Active Crohn's Disease

The Spectrum of Magnetic Resonance Enterography Findings and the Role of Diffusion-Weighted Imaging in Patients with Active Crohn's Disease

Background

The goal of this study was to evaluate magnetic resonance enterography (MRE) findings and assess the role of diffusion-weighted imaging (DWI) in patients suffering from active Crohn's disease.

Methods

This retrospective study included a total number of 76 patients diagnosed with active Crohn's disease, as established by the Crohn's Disease Activity Index (CDAI). The study consisted of 30 women and 46 men, ranging in age from 13 to 72 years. All participants underwent MRE with DWI sequences. The study was conducted at Imam Khomeini hospital in Tehran between 2013 and 2018. The imaging modality utilized for the study included a 3-T SIGNA Excite MRE machine and a Siemens Magnetom 3-T magnetic resonance imaging (MRI) machine.

Results

Bowel wall restriction was observed in less than half of the patients, and no significant correlation was found with extramural findings such as mesenteric edema. The study did not reveal any meaningful association between diffusion restriction and specific mural enhancement patterns, mesenteric lymphadenopathy with or without enhancement, or the length of the affected segments (P>0.05). The most common findings observed in MRI were ileum thickness in 72.4% of patients, mesenteric lymphadenopathy without enhancement in 46.1%, ileocecal thickness in 42.1%, DWI findings in 42.1%, the presence of a comb sign in 36.8%, and jejunum thickness in 30.3% of patients.

Conclusion

MRE findings are useful in the evaluation of Crohn's disease activity.

Diagnostic Accuracy of Magnetic Resonance Enterography in the Evaluation of Colonic Abnormalities in Crohn's Disease: A Systematic Review and Meta-Analysis

OBJECTIVES

To Evaluate the diagnostic performance of magnetic resonance enterography (MRE) for detecting colonic involvement of Crohn's disease (CD).

MATERIALS AND METHODS

A systematic search of the electronic bibliographic databases was conducted. The inclusion criteria of published original articles were: (1) Utilized MRE to evaluate colon; (2) Patients with documented CD by colonoscopy; (3) Provided crude data of diagnostic performance in the large bowel; (4) Performed segmental evaluation. The colorectal segments were defined as the right colon, transverse colon, left colon, and rectum. A hierarchical bivariate method was used for analysis.

RESULTS

Eleven articles (12 populations and 987 patients) were included. The pooled sensitivity and specificity of the studies were 69% (95% CI: 0.52-0.82) and 95% (95% CI:0.92-0.97), respectively (AUC = 0.95). The pooled positive and negative likelihood ratios were 14 (95% CI:7.5-26.3) and 0.31 (95% CI:0.19-0.51), respectively. Regarding segments, the left colon had the highest sensitivity (60%) and lowest specificity (92%), while the transverse colon showed lowest sensitivity (49%) and highest specificity (95%). Comparing the age groups, MRE sensitivity and specificity was 80% and 95%, versus 62% and 94%, in pediatrics and adults respectively.

CONCLUSION

MRE has a high specificity to detect colon pathologies in CD, while the sensitivity is low. Therefore, the test has a high value to rule in CD, while negative results are not sufficient to rule it out. Meanwhile, considering the higher sensitivity rate of the test in pediatrics, it has the potential to be used as a first-line investigation.

Assessment of the usefulness of imaging studies and biomarkers in the activity of Crohn's disease

Aim

The aim of the study was to determine the suitability of available diagnostic methods, by means of comparison, for predicting disease activity, based on cost efficiency and sensitivity criteria.

Material and methods

In this study, we conducted analyses of 37 patients with Crohn’s disease (CD). CD was graded as “active” or “inactive” by adopting certain cut-off values for every marker. The main assumption was that methods used to grade CD severity do not give false positive results. The authors decided to measure the agreement between the methods by applying Cohen’s κ coefficient.

Results

Endoscopy shows the highest sensitivity, negative predictive value, and accuracy in detecting CD. In the case of both intestines, the sensitivity of endoscopy reached 93.9% and the accuracy 94.6%, while the sensitivity and accuracy of enterography and calprotectin were 51.5% vs. 71,9% and 56.8% vs. 72.2%, respectively. For the large intestine, the sensitivity and accuracy of endoscopy reached 100%. For the small intestine, endoscopy had 55% sensitivity and 75% accuracy, while enterography showed only 66.7% and 81.1%, respectively. The best agreement (77.1%, p = 0.005) was seen between endoscopy and calprotectin for full intestines. However, the value of Cohen’s κ suggests that this agreement is moderate. The optimal cut-off value for calprotectin was 43 µg/g, and the ROC curve (AUC = 0.871) was large enough to conclude that calprotectin is a statistically significant (p < 0.001) indicator of CD activity.

Conclusions

Statistically significant compliance was shown only between colonoscopy and faecal calprotectin.