Introduction

Crohn’s disease (CD) is a chronic inflammatory bowel disease (IBD) characterized by transmural bowel wall inflammation which lasts throughout the patient’s life with childhood onset in 10% to 25% among all the CD patients[1]. The assessment of disease extension and activity is crucial in juvenile with CD to determine optimal treatment strategies and thereafter monitor response to treatment. This assessment usually relies on endoscopy. However, endoscopy cannot always be performed completely, and there are several drawbacks related to the invasiveness, procedure related discomfort, risk of bowel perforation and relatively poor patient acceptance. Especially for children, enteroscopy is a more painful and terrible experience. Magnetic resonance imaging (MRI) is characterized by a very high soft tissue contrast, lack of ionizing radiation and lower incidence of adverse events related to the intravenous contrast employed compared with CT. Recently, some study compared between MRE and colonoscopy in assessing CD inflammatory lesions and related complications for adult patients . Only a few studieshave tested the accuracy of MR enterography in localizing and evaluating CD intestinal lesions in children, with preliminary satisfactory results. However, there are no reports of its use in adolescents. The aim of this study is to evaluate the accuracy of MRE in the diagnosis of active lesions and ulcers in juvenile CD against endoscopic and histopathology reference standard.

Method

Data were collected on two different 3T MRI scanners (MAGNETOM Skyra /Verio, Siemens Healthcare, Erlangen ,Germany) with a 16-channel body coil. For this retrospective study, fifty-two adolescent CD patients (28 women, 24 men; mean age, 12 years old; range, 6-17 years) were included, who underwent ileocolonoscopy and MR enterography within 7days and the terminal ileum biopsy was available. T2-weighted and pre- and postcontrast enhanced T1-weighted and DWI sequence were acquired. The Simplified Endoscopic Activity Score for Crohn’s Disease ( SES-CD) , histopathologic endoscopic acute inflammation score[eAIS]) and Magnetic resonance enterography global score (MEGS) [2] were scored in the terminal ileum; sensitivity and specificity of MEGS for disease activity and ulceration against SES-CD and eAIS were compared by using the McNemar test. The correlation between MEGS and the reference standard (SES-CD and eAIS) was assessed by Spearman rank estimation. The diagnostic accuracy of MER for active disease and ulceration defined by endoscopic or histopathologic were calculated. Receiver operating characteristic curves (ROC) were constructed.

Results

An example of MR alterations associated with the presence of active inflammation is shown in Fig 1. There was no significant difference in the detection of terminal ileum active lesions and ulcerative lesions among MRE and colonoscopy and histopathology. MEGS showed strong correlation to SES-CD (r =0.698) and weak correlation to eAIS(r= 0.21) (Fig 2). With endoscopy as the reference standard, receiver operating characteristic curves of detected lesions, active lesions (SES-CD ≥2) and ulcer lesions are shown in figure 3A. With histopathologic as the reference standard, receiver operating characteristic curves of detected active lesions (eAIS ≥2) and ulcer lesions are shown in figure 3B. Against SES-CD, the AUC obtained by magnetic resonance score of inflammatory and active diseases and ulcer lesions were 0.87, 0.87 and 0.85, respectively. Against eAIS, for evaluation of active disease and ulcer lesions MEGS score generated AUC are 0.60 and 0.60, respectively. The corresponding receiver operating characteristic curves were not significantly different.

Discussion and Conclusion

In this study, we retrospectively examined the accuracy of MEGS in diagnosing terminal ileum inflammation in juvenile crohn's disease with both SES-CD and eAIS as the reference standard. We found that for both endoscopically defined and histologically defined active inflammation and ulcerative lesions MEGS have high diagnostic accuracy (85–87% and 60%, respectively), these results are consistent with other studies of MRE versus colonoscopy and histopathology in adult crohn patients.[3,4,5]. Results of this study suggest that MEGS score is also suitable for Crohn patients in children, and has considerable diagnostic accuracy compared with other MRI scores in judging the activity of lesions and the presence or absence of ulcers. Overall, the results of this study suggest that MR may be considered as an alternative to endoscopy in cases with an established diagnosis of juvenile CD in which biopsy samples are not necessary.

Acknowledgements

No acknowledgement found.

References

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