Published online Jul 28, 2019. doi: 10.3748/wjg.v25.i28.3808
Peer-review started: March 22, 2019
First decision: April 16, 2019
Revised: May 4, 2019
Accepted: July 5, 2019
Article in press: July 5, 2019
Published online: July 28, 2019
Magnetic resonance enterography (MRE) and wireless capsule endoscopy (WCE) are equally accepted modalities for noninvasive screening of small bowel involvement (SBI) in children with Crohn’s disease (CD) and indeterminate colitis (IC) and there is a paucity of data comparing the two in children. Thereby guiding the clinician in selecting the ideal diagnostic approach. Many prospective adult studies and few in pediatrics comparing MRE to WCE in identifying small bowel (SB) CD showed no significant difference in the diagnostic yield and accuracy of MRE and WCE in established non-stricturing CD or suspected and established CD together. The current study is the first prospective study in children with established IBD in the United States assessing the roles of MRE and WCE in identifying SB disease involvement in IBD. This study provides evidence for capsule endoscopy role whether it is superior or complementary in the evaluation of established disease exacerbation in patients with IBD in relation to MRE thereby guiding the clinician in selecting the ideal diagnostic approach.
Therefore, the goal of this study is to provide additional evidence and guidance for capsule endoscopy role in the evaluation of established CD exacerbation compared to MRE into relation Pediatric Crohn's Disease Activity Index (PCDAI), and histological indices.
The primary goals of this study are to prospectively compare the diagnostic yield, concordance rate, sensitivity and specificity between MRE and WCE findings and their agreement with the PCDAI or with histological small bowel involvement in children with known IBD; CD or IC. Secondary goals are to assess the performance of each of the modalities (MRE, WCE and PCDAI) in relation to each other in order to predict the results of the compared tests and to assess the correlation between Lewis capsule endoscopy score and PCDAI.
Consecutive patients diagnosed with CD and IC were screened for inclusion. After informed consent patient’s demographic and clinical data was abstracted. The current pediatric disease activity index (PCDAI) and endoscopic findings were included. Patients underwent MRE and WCE including preprocedural patency capsule within a maximum of 7 d of each other. Pathological presence of active small bowel disease in ileal and duodenal biopsies were collected if the endoscopy was performed within 2 mo of the WCE study. Patients who failed to pass the PC were excluded from the study. WCE was read by two different experienced gastroenterologists (Attard TM and Colombo JM) blinded to each other's findings and to the findings on MRE (Mardis NJ). Agreement between WCE reviewers, WCE and MRE findings and concordance between positive PCDAI and SBI based on MRE compared with WCE was computed.
In CD patients, when both MRE and WCE were compared using PCDAI > 10 as the standard reference reflecting active small intestinal CD, the sensitivity of MRE is higher than WCE but specificity of MRE were lower than WCE. If the histology in ileum or/and duodenum was used as the reference for active small bowel involvement which is usually the most reliable reported standard, WCE had a higher specificity as compared to MRE (83.3% vs 50%). Concordance between WCE and MRE was poor (69%) whether both agreed positively or negatively. While WCE was more specific than MRE in detecting SB disease, the two modalities were comparable in test accuracy. Specificities of both WCE and MRE in the current study were lower than that reported in pediatric patients with suspected or established CD populations. An active disease defined with higher PCDAI score > 10, will increase the predictive ability of WCE to be positive and it supports the use of PCDAI routinely in the assessment of SBI along with radiologic or endoscopic modalities. The argument remains to be elucidated on what is the gold standard that best identify the SBI in patients with IBD.
Our study supports the use of the radiation free, less invasive and generally tolerated imaging modalities of WCE and MRE with each having a favorable role in the assessment of SBI in children with established CD. Although the unique ability of the capsule to detect mucosal changes and similar unique ability of MRE to detect mural changes, there is still need for a standardized scoring system to describe the specificity of these findings. WCE more accurately detected small bowel disease with a much higher specificity while MRE had a higher sensitivity in pediatric IBD. Patients with active CD (PCDAI > 10) were more likely to have a positive WCE as compared to those with a negative PCDAI. Despite the disagreement between the two modalities, accuracy was comparable between MRE and WCE suggesting that they may have a complementary role in the assessment of small bowel disease.
Future studies should continue to integrate the use of WCE, low risk imaging modalities and clinical parameters in defining the best standard to identify SBI in children with CD. It will be useful to integrate a composite of these modalities in a practical validated scoring measure that identify SBI in the least invasive approach.