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Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 7, 2016; 22(5): 1756-1766
Published online Feb 7, 2016. doi: 10.3748/wjg.v22.i5.1756
Advances in endoscopic ultrasound imaging of colorectal diseases
Elena Tatiana Cârțână, Dan Ionuț Gheonea, Adrian Săftoiu
Elena Tatiana Cârțână, Dan Ionuț Gheonea, Adrian Săftoiu, Department of Gastroenterology, Research Center of Gastroenterology and Hepatology Craiova, University of Medicine and Pharmacy of Craiova, 200638 Craiova, Romania
Adrian Săftoiu, Department of Endoscopy, Gastrointestinal Unit, Copenhagen University Hospital Herlev, Herlev Ringvej, 2730 Herlev, Denmark
Author contributions: Cârțână ET and Gheonea DI analysed the literature and drafted the article; Săftoiu A designed and revised the content.
Supported by The frame of European Social Found, Human Resources Development Operational Programme 2007-2013, project No. POSDRU/159/1.5/S/133377.
Conflict-of-interest statement: The authors have no conflict of interest to declare.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Correspondence to: Adrian Săftoiu, MD, PhD, MSc, FASGE, Department of Gastroenterology, Research Center of Gastroenterology and Hepatology Craiova, University of Medicine and Pharmacy of Craiova, 1 Mai nr. 66, 200638 Craiova, Romania.
Telephone: +40-744-823355 Fax: +40-251-310287
Received: April 28, 2015
Peer-review started: May 6, 2015
First decision: September 29, 2015
Revised: October 21, 2015
Accepted: December 14, 2015
Article in press: December 14, 2015
Published online: February 7, 2016

The development of endoscopic ultrasound (EUS) has had a significant impact for patients with digestive diseases, enabling enhanced diagnostic and therapeutic procedures, with most of the available evidence focusing on upper gastrointestinal (GI) and pancreatico-biliary diseases. For the lower GI tract the main application of EUS has been in staging rectal cancer, as a complementary technique to other cross-sectional imaging methods. EUS can provide highly accurate in-depth assessments of tumour infiltration, performing best in the diagnosis of early rectal tumours. In the light of recent developments other EUS applications for colorectal diseases have been also envisaged and are currently under investigation, including beyond-rectum tumour staging by means of the newly developed forward-viewing radial array echoendoscope. Due to its high resolution, EUS might be also regarded as an ideal method for the evaluation of subepithelial lesions. Their differential diagnosis is possible by imaging the originating wall layer and the associated echostructure, and cytological and histological confirmation can be obtained through EUS-guided fine needle aspiration or trucut biopsy. However, reports on the use of EUS in colorectal subepithelial lesions are currently limited. EUS allows detailed examination of perirectal and perianal complications in Crohn’s disease and, as a safe and less expensive investigation, can be used to monitor therapeutic response of fistulae, which seems to improve outcomes and reduce the need for additional surgery. Furthermore, EUS image enhancement techniques, such as the use of contrast agents or elastography, have recently been evaluated for colorectal indications as well. Possible applications of contrast enhancement include the assessment of tumour angiogenesis in colorectal cancer, the monitoring of disease activity in inflammatory bowel disease based on quantification of bowel wall vascularization, and differentiating between benign and malignant subepithelial tumours. Recent reports suggest that EUS elastography enables highly accurate discrimination of colorectal adenocarcinomas from adenomas, while inflammatory bowel disease phenotypes can be distinguished based on the strain ratio calculation. Among EUS-guided therapies, the drainage of abdominal and pelvic collections has been regarded as a safe and effective procedure to be used as an alternative for the transcutaneous route, while the placing of fiducial markers under EUS guidance for targeted radiotherapy in rectal cancer or the use of contrast microbubbles as drug-delivery vehicles represent experimental therapeutic applications that could greatly impact the forthcoming management of patients with colorectal diseases, pending on further investigations.

Keywords: Endoscopic ultrasound, Contrast-enhanced endoscopic ultrasound, Elastography, Colorectal cancer, Inflammatory bowel disease, Colorectal submucosal tumours, Endoscopic ultrasound-guided therapy

Core tip: Beyond staging rectal cancer, an already established endoscopic ultrasound (EUS) indication, novel applications for colorectal diseases are under investigation, including the possibility of staging tumours throughout the entire colon with the recently developed forward-viewing radial echoendoscope. Contrast-enhanced EUS may be used for the characterization and the prognostic assessment in both colorectal tumours and inflammatory bowel disease, while EUS elastography could enhance the differential diagnosis of benign and malignant colorectal lesions, pending on further studies. EUS-guided therapeutic procedures include drainage of abdomino-pelvic collections and other experimental procedures, such as insertion of fiducial markers and targeted microbubble drug delivery, which will be also reviewed.