Light and sound - emerging imaging techniques for inflammatory bowel disease

Table 1 Recommendations and state-of-the-art in inflammatory bowel disease imaging according to international guidelines[15-18]

Initial diagnosis and follow-up	Colonoscopy with ileoscopy is recommended for the initial evaluation of inflammatory bowel disease (IBD) and for the differentiation IBD subtypes
	Sampling of mucosal biopsy specimens from multiple sites during the initial endoscopic evaluation of IBD is recommended
	Flexible sigmoidoscopy should be performed in patients with IBD when colonoscopy is contraindicated
	Radiological imaging techniques are complementary to endoscopic assessment. Cross-sectional imaging offers the opportunity to detect and stage inflammatory, obstructive and fistulizing Crohn's disease (CD) and is fundamental at first diagnosis to stage disease and to monitor follow-up
	Ultrasound (US) is a well-tolerated and radiation-free imaging technique, particularly for the terminal ileum and the colon. Examinations are impaired by gas-filled bowel and by large body habitus
	US is able to detect signs of Crohn's disease and has high and comparable diagnostic accuracy at the initial presentation of terminal ileal CD
	US can be used to assess disease activity in Crohn's disease of the terminal ileum
	US imaging is an adjunct to endoscopy for diagnosis of colonic IBD
	Transabdominal US has a high accuracy for assessing the activity and severity of Crohn’s colitis; the performance in UC is less clear; the accuracy of monitoring therapy in colonic Crohn's disease is not well defined
Surveillance and management of dysplasia	It is recommended that all patients with UC or CD colitis undergo a screening colonoscopy 8 yr after disease onset to re-evaluate extent of disease and initiate surveillance for colorectal neoplasia
	It is recommended to perform surveillance colonoscopy every 1 to 3 yr beginning after 8 yr of disease in patients with UC with macroscopic or histologic evidence of inflammation proximal to and including the sigmoid colon and for patients with Crohn’s colitis with greater than one-third of colon involvement
	If white-light colonoscopy is performed in case of surveillance, high definition (HD) is recommended rather than standard definition (SD)
	If surveillance is performed with SD colonoscopy, chromoendoscopy is recommended rather than white-light
	If performing surveillance with HD colonoscopy, chromoendoscopy is suggested rather than white-light colonoscopy
	If performing surveillance with SD colonoscopy, narrow-band imaging (NBI) is not suggested in place of white-light
	If performing surveillance with high-definition colonoscopy, NBI is not suggested in place of white-light
	If performing surveillance with image-enhanced HD colonoscopy, NBI is not suggested in place of chromoendoscopy
Management of dysplasia discovered on surveillance colonoscopy	After complete removal of endoscopically resectable polypoid dysplastic lesions, surveillance colonoscopy is recommended rather than colectomy
	After complete removal of endoscopically resectable nonpolypoid dysplastic lesions, surveillance colonoscopy is suggested rather than colectomy
	For patients with endoscopically invisible dysplasia (confirmed by a gastrointestinal pathologist), referral is suggested to an endoscopist with expertise in IBD surveillance using chromoendoscopy with high-definition colonoscopy

Table 2 Assessment of disease activity with advanced endoscopic imaging in the context of clinical trials

Ref.	Technique	No. of patients	Findings
Kiesslich et al[84], 2003	CE	165	Agreement with histology: 84.5% (72 of 84) vs 60% (49 of 81)
Kudo et al[85], 2009	NBI	30	Obscure mucosal vascular pattern is associated with inflammatory cell infiltrates (26% vs 0%), goblet cell depletion (32% vs 5%), and basal plasmacytosis (2% vs 21%)
Danese et al[87], 2010	NBI	14	Positive appearance on NBI correlated with increase in angiogenesis or vessel density
Neumann et al[88], 2013	Virtual CE (i-Scan)	78	Inflammatory extent and activity accordance with the histological results: 48.71% and 53.85% (white-light) and 92.31% and 89.74% (i-Scan)
Watanabe et al[89], 2008	CLE	17	Distinct alterations in active and non-active UC patients compared to histology
Li et al[90], 2010	CLE	73	Crypt architecture and fluorescein leakage with CLE correlate with histological results
Neumann et al[92], 2012	CLE	54	CDEAS consisting of six parameters: crypt number, crypt distortion, micro erosions, cellular infiltrate, vascularity, and number of goblet cells
			Strong correlation of CDEAS and CRP

CE: Chromoendoscopy; NBI: Narrow-band imaging; CLE: Confocal laser endomicroscopy.