Endoscopic examination of the small bowel: from standard white light to confocal endomicroscopy

Development and validation of a classification and scoring system for the diagnosis of oral squamous cell carcinomas through confocal laser endomicroscopy

Background

Confocal laser endomicroscopy (CLE) is an optical biopsy method allowing in vivo microscopic imaging at 1000-fold magnification. It was the aim to evaluate CLE in the human oral cavity for the differentiation of physiological/carcinomatous mucosa and to establish and validate, for the first time, a scoring system to facilitate CLE assessment.

Methods

The study consisted of 4 phases: (1) CLE-imaging (in vivo) was performed after the intravenous injection of fluorescein in patients with histologically confirmed carcinomatous oral mucosa; (2) CLE-experts (n = 3) verified the applicability of CLE in the oral cavity for the differentiation between physiological and cancerous tissue compared to the gold standard of histopathological assessment; (3) based on specific patterns of tissue changes, CLE-experts (n = 3) developed a classification and scoring system (DOC-Score) to simplify the diagnosis of oral squamous cell carcinomas; (4) validation of the newly developed DOC-Score by non-CLE-experts (n = 3); final statistical evaluation of their classification performance (comparison to the results of CLE-experts and the histopathological analyses).

Results

Experts acquired and edited 45 sequences (260 s) of physiological and 50 sequences (518 s) of carcinomatous mucosa (total: 95 sequences/778 s). All sequences were evaluated independently by experts and non-experts (based on the newly proposed classification system). Sensitivity (0.953) and specificity (0.889) of the diagnoses by experts as well as sensitivity (0.973) and specificity (0.881) of the non-expert ratings correlated well with the results of the present gold standard of tissue histopathology. Experts had a positive predictive value (PPV) of 0.905 and a negative predictive value (NPV) of 0.945. Non-experts reached a PPV of 0.901 and a NPV of 0.967 with the help of the DOC-Score. Inter-rater reliability (Fleiss` kappa) was 0.73 for experts and 0.814 for non-experts. The intra-rater reliability (Cronbach’s alpha) of the experts was 0.989 and 0.884 for non-experts.

Conclusions

CLE is a suitable and valid method for experts to diagnose oral cancer. Using the DOC-Score system, an accurate chair-side diagnosis of oral cancer is feasible with comparable results to the gold standard of histopathology—even in daily clinical practice for non-experienced raters.

Assessment of Crohn's disease activity by confocal laser endomicroscopy

BACKGROUND

Confocal laser endomicroscopy (CLE) allows microscopic imaging within the mucosal layer of the gut during ongoing endoscopy. Different studies have addressed the potential of CLE for in vivo diagnosis of ulcerative colitis and microscopic colitis. However, there are no data on the utility of CLE for in vivo diagnosis of Crohn's disease (CD). The aim was to assess the clinical utility of CLE in patients with CD and to determine whether disease activity can be graded using CLE.

METHODS

Consecutive patients with and without CD were enrolled. The colonic mucosa was examined by standard white-light endoscopy followed by CLE. The features seen on CLE were compared between CD patients and controls.

RESULTS

In all, 76 patients with CD were screened, of whom 54 patients were included in the present study. Eighteen patients without inflammatory bowel disease (IBD) served as controls. A significantly higher proportion of patients with active CD had increased colonic crypt tortuosity, enlarged crypt lumen, microerosions, augmented vascularization, and increased cellular infiltrates within the lamina propria. In quiescent CD, a significant increase in crypt and goblet cell number was detected compared with controls. Based on our findings, we propose a Crohn's Disease Endomicroscopic Activity Score (CDEAS) for assessing CD activity in vivo.

CONCLUSIONS

CLE has the potential to significantly improve diagnosis of CD compared with standard endoscopy. These findings should be evaluated in future prospective trials to assess the value of this newly developed CLE score for prediction of disease course and therapeutic responses.

Enteroscopy: Advances in diagnostic imaging

Routine endoscopic imaging of the small bowel is performed with videoendoscopic white light technology. However, currently there are many new methods that improve our visual acuity when evaluating the small bowel mucosa. These methods are collectively called "advanced endoscopic imaging". These imaging methods include high-definition white light endoscopy, standard and dye-less or "virtual" chromoendoscopy, magnification endoscopy and confocal laser endomicroscopy. Regardless of the method used to image the small bowel the endosocopist needs to pay attention to detail and focus on three essential aspects: a) the shape of the lesion, b) the superficial mucosal detail (i.e. "pit pattern") and c) the submucosal vascular pattern. This review describes advances in the endoscopic imaging methods to study the small bowel.

In vivo characterisation of superficial colorectal neoplastic lesions with high-resolution probe-based confocal laser endomicroscopy in combination with video-mosaicing: a feasibility study to enhance routine endoscopy

BACKGROUND

Recent technological advances in miniaturisation have allowed for a confocal scanning microscope to be integrated into trans-endoscopic probes enabling endoscopists to collect in vivo virtual biopsies of the gastrointestinal mucosa during endoscopy.

AIMS

The aim of the present study was to assess prospectively the clinical applicability and predictive power of a probe-based confocal laser endomicroscopy for the in vivo diagnosis of colorectal neoplasia.

METHODS

Patients with evidence of colorectal superficial neoplasia at routine endoscopy, were included prospectively in this study. Lesions were identified using white-light endoscopy followed by pCLE imaging recorded by a Coloflex UHD-type probe. The images were interpreted as either neoplastic or not according to vascular and cellular changes. pCLE readings were then compared with histopathological results from endoscopically resected lesions and/or targeted biopsy specimens.

RESULTS

A total of 32 lesions were identified in 20 consecutive patients. Histopathology diagnosis was of adenomas in 19 cases, hyperplastic polyps in 11 cases and adenocarcinoma in 2 cases. For the detection of neoplastic tissue pCLE had a sensitivity of 100%, a specificity of 84.6%, an accuracy of 92.3, a PPV of 90.5% and a NPV of 100%.

CONCLUSIONS

pCLE permits high-quality imaging, enabling prediction of intraepithelial neoplasia with a high level of accuracy.

An advanced chromocolonoscopic picture is worth a thousand words, but is it worth the effort?

Chromocolonoscopy is a commonly used advanced or multimodal colon imaging method to interrogate the colon mucosa and colon polyps. The two main objectives of chromocolonosopy are to (a) detect a colon polyp and (b) define (differentiate) the lesion. Although data supporting the use of chromocolonoscopy for colon polyp detection are not strongly founded, this technique may be helpful in differentiating colon polyps and may aid in their endoscopic resection.

Novel applications of balloon endoscopy

Double-balloon endoscopy has been available for investigation of the small bowel since 2001, concomitantly with capsule endoscopy. Beyond established indications, endoscopic examination of the small bowel is currently performed in many clinical conditions involving the small bowel, which were under investigated in the past. Biopsies of lesions observed by capsule endoscopy or balloon enteroscopy can be taken and the lesions can sometimes be treated during a balloon Endoscopic procedure. Double-balloon endoscopy can be used in patients when conventional endoscopy was incomplete. The main applications of double-balloon endoscopy are the examination of patients with a surgically modified gastrointestinal tract and colonoscopy after a previously failed attempt to reach the cecum. In the latter indication, using a dedicated double-balloon colonoscope, the success rate of cecal intubation may be nearly 100%.