Enteroscopy in small-bowel Crohn’s disease (CD): hypes and hopes

Crohn’s disease (CD) is a chronic inflammation of the intestines that follows a relapsing or remitting course. Endoscopic imaging and radiological imaging are essential for diagnosis and to assess disease severity, response to treatment, and complications. CD most commonly affects the terminal ileum, which is accessible with conventional ileocolonoscopy. Nevertheless, jejunal lesions are present in more than half of Crohn’s patients and are associatedwith an increased risk of clinical relapse [1]. The presence of proximal small-bowel lesions has an impact on prognosis and therapeutic management, with early introduction of immunomodulators and biologicals [2]. Several modalities are available for small-bowel imaging. However, a standardized algorithm is lacking and the choice of modality is largely dependent on local availability and expertise. A prospective, blinded study compared multiple small-bowel imaging modalities after ileocolonoscopy in 93 patients with suspected or established CD [3]. The sensitivity and specificity for terminal ileal CD were 100 and 91% for smallbowel capsule endoscopy (SBCE), 81 and 86% for magnetic resonance (MR) enterography, and 76 and 85% for computed tomography (CT) enterography, respectively. Additionally, SBCE significantly enhanced the detection of proximal small-bowel lesions [3]. According to a recent meta-analysis, no significant difference was found between the sensitivity and specificity of CT enterography and MR enterography to detect active small-bowel CD, and accuracy was largely similar for ultrasound (US) in an earlier systematic review [4]. SBCE is considered the most sensitive test to exclude early small-intestinal lesions, with a negative predictive value of 96% [5]. The risk of capsule retention is relatively low in patients with suspected CD in the absence of obstructive symptoms. On the contrary in patients with established CD, retention risk significantly increases. Small-bowel US is increasingly used for preliminary assessment and during the follow-up of patients with potential inflammatory bowel disease (IBD). The advantages of abdominal US include easy access, low cost, non-invasiveness, and lack of ionizing radiation, although the accuracy is highly dependent on the available expertise. The currently ongoing MREnterography or ulTRasound in Crohn disease (METRIC) study prospectively compares the diagnostic efficacy, therapeutic impact, and cost-effectiveness of MR enterography and small-bowel US in relapsing CD. In the present issue of the journal, Navaneethan et al. [6] aim to evaluate the role of balloon-assisted enteroscopy (BAE) in 65 patients with suspected and established small-bowel CD after a complete evaluation including CT or MR enterography. Interestingly, in the group of patients with suspected CD (n=22), enteroscopy increased the diagnostic specificity of SBCE and confirmed CD in 3 patients whose lesions seemed nonspecific upon SBCE. Additionally, in the group of patients with established CD (n=43), active inflammation was identified in 18 patients, which led to escalation of medical therapy. Endoscopic balloon dilation (EBD) of fibrotic stenosis was successfully carried out in 5 patients. Of note, the agreement between CT or MR enterography and BAE in suspected CD was only modest (36.4%), with normal BAE findings in the majority of the patients with increased wall thickness. In contrast, in established CD a large proportion of the lesions were detected already with conventional imaging (overall agreement with CT or MR enterography was 75.6%). Nonetheless, although this is one of the largest series evaluating the additive value of BAE in the management of CD patients, results should still be considered as preliminary; and BAE should be reserved for patients with unexplained symptoms and laboratory alterations suggestive of small-bowel CD or complications of