Advances in endoscopic visualization of colorectal polyps

Development and validation of a novel colonoscopy withdrawal time indicator based on YOLOv5

BACKGROUND AND AIM

The study aims to introduce a novel indicator, effective withdrawal time (WTS), which measures the time spent actively searching for suspicious lesions during colonoscopy and to compare WTS and the conventional withdrawal time (WT).

METHODS

Colonoscopy video data from 472 patients across two hospitals were retrospectively analyzed. WTS was computed through a combination of artificial intelligence (AI) and manual verification. The results obtained through WTS were compared with those generated by the AI system. Patients were categorized into four groups based on the presence of polyps and whether resections or biopsies were performed. Bland Altman plots were utilized to compare AI-computed WTS with manually verified WTS. Scatterplots were used to illustrate WTS within the four groups, among different hospitals, and across various physicians. A parallel box plot was employed to depict the proportions of WTS relative to WT within each of the four groups.

RESULTS

The study included 472 patients, with a median age of 55 years, and 57.8% were male. A significant correlation with manually verified WTS (r = 0.918) was observed in AI-computed WTS. Significant differences in WTS/WT among the four groups were revealed by the parallel box plot (P < 0.001). The group with no detected polyps had the highest WTS/WT, with a median of 0.69 (interquartile range: 0.40, 0.97). WTS patterns were found to be varied between the two hospitals and among senior and junior physicians.

CONCLUSIONS

A promising alternative to traditional WT for quality control and training assessment in colonoscopy is offered by AI-assisted computation of WTS.

Value of endoscopy with narrow-band imaging and probe-based confocal laser endomicroscopy in the diagnosis of preneoplastic lesions of gastrointestinal tract

INTRODUCTION

Amongst all malignant tumors, cancers of the digestive tract rank first in terms of yearly deaths. Patients above 60 years of age are the most affected, as the diagnosis is frequently made in advanced stages of the disease when therapy is less effective. Our study aimed to evaluate the efficiency of narrow-band imaging (NBI) endoscopy and probe-based confocal laser endomicroscopy (pCLE) in the correct diagnosis of preneoplastic lesions in the upper and lower digestive tract.

PATIENTS, MATERIALS AND METHODS

We included 46 patients with digestive preneoplastic lesions, who underwent either upper or lower digestive endoscopy, followed by NBI and pCLE. We recorded 5-10 frames per each lesion, from different angles and distances during white-light endoscopy and selected frames from full recordings of NBI and pCLE. Usual preparation was used for the endoscopic procedures; pCLE required in vivo administration of 10% Sodium Fluorescein as a contrast agent. Pathology was performed in case of solid tumors. Three medical professionals with different levels of training, blinded to the results, interpreted the data.

RESULTS

The experienced physician correlated very well the NBI findings with pathology (0.93, p=0.05), while the resident physician and the experienced nurse obtain lower, albeit still statistically significant, values (0.73 and 0.62, respectively). For pCLE, the experienced physician obtained near-perfect correlation with pathology (0.96), followed closely by the resident physician (0.93). The nurse obtained a modest correlation (0.42). All examiners obtained approximately equal performances in discerning between malignant and benign lesions.

CONCLUSIONS

Digestive endoscopy in NBI mode proved its effectiveness. Even less experienced endoscopists can achieve good results, while an experienced nurse can positively influence the diagnosis. In the case of pCLE, when available, it can greatly reduce diagnostic times, while requiring higher expertise and specialty training.

Does the Numerical Colour Value (NCV) correlate with preneoplastic and neoplastic colorectal lesions?

BACKGROUND

White light endoscopy (WLE) is the gold standard for detection of colorectal cancer. Autofluorescence endoscopy (AFE) is among the novel methods expected to increase the sensitivity and specificity of endoscopic diagnosis. The main objective of the study was to determine the diagnostic efficacy of AFE for the detection of preneoplastic and neoplastic colorectal lesions and to identify high-grade neoplasia using Numerical Colour Value (NCV).

METHODS

This retrospective study included 188 patients with colorectal mucosal lesions diagnosed on WLE and assessed using AFE; they were included in the study if a complete patient record was available (description of visualized colorectal lesions, NCV and histopathology report). The NCV was compared with the histological result.

RESULTS

Histology revealed 38 hyperplastic colon polyps, 77 low-grade dysplastic lesions, 17 high-grade dysplastic lesions, 24 adenocarcinomas and 32 inflammatory lesions. The mean NCVs of high-grade dysplasia (HGD) and adenocarcinoma were 2.24 ± 0.22 and 2.73 ± 0.16, respectively, significantly higher than the NCV of hyperplastic colon polyps (0.95 ± 0.06), low-grade dysplasia (LGD) (1.27 ± 0.05) and inflammatory lesions (1.26 ± 0.17). The NCV cut-off value for HGD and adenocarcinoma was set at 1.7. The sensitivity, specificity, PPV (positive predictive value) and NPV (negative predictive value) were 95.2%, 87.9%, 97.5%, 84.8%, respectively.

CONCLUSION

Our study showed that AFE could provide useful diagnostic information regarding preneoplastic and neoplastic colorectal lesions. Additionally, the NCV significantly correlated with the histopathology results.

Comparison of diagnostic efficacy between AFI, NBI, and AFI combined with NBI for colonic cancers: A meta-analysis

BACKGROUND/AIMS

Advanced endoscopic imaging technologies have been used for the early detection and differentiation of colonic cancers recently. We aim to evaluate the diagnostic efficacy of autofluorescence imaging (AFI), narrow-band imaging (NBI), and AFI combined with NBI for colonic cancers.

MATERIALS AND METHODS

We searched Medline/PubMed, Embase, Web of Science, and Cochrane Library databases for relevant articles. A random-effects model was used to assess diagnostic efficacy. Heterogeneity was tested by the I2 statistic and Chi-square test. Meta-regression was used to analyze the sources of heterogeneity.

RESULTS

The pooled sensitivities for AFI, NBI, and AFI plus NBI were 0.84 (95% confidence interval (CI) 0.82-0.87), 0.84 (95% CI 0.81-0.86), and 0.93 (95% CI 0.90-0.95), respectively. The pooled specificities were 0.44 (95% CI 0.40-0.48), 0.69 (95% CI 0.65-0.72), and 0.69 (95% CI 0.64-0.74), respectively. The sensitivity estimate was significantly higher for AFI plus NBI than AFI or NBI alone (P = 0.041), and the specificity estimates were significantly higher for NBI and AFI plus NBI than AFI (P = 0.031).The pooled diagnostic odds ratio for AFI, NBI, and AFI plus NBI were 8.71 (95% CI 2.90-26.16), 16.02 (95% CI 7.05-36.39), and 57.55 (95% CI 9.82-337.33), respectively. Furthermore, the summary receiver operating characteristic curve area under the curve for AFI, NBI, and AFI plus NBI were 0.8125 with Q* =0.7469, 0.8696 with Q* =0.8001, and 0.9447 with Q* =0.8835, respectively. The Q* index for AFI plus NBI was significantly higher than AFI or NBI alone (P = 0.048).

CONCLUSION

The combination of AFI and NBI was associated with increased diagnostic value for colonic cancers compared with AFI and NBI alone.

Diagnostic performance of confocal laser endomicroscopy for optical diagnosis of gastric intestinal metaplasia: a meta-analysis

BACKGROUND

Gastric intestinal metaplasia (IM) is generally considered as a precancerous condition, a related risk factor for intestinal-type gastric cancer. However, an accurate endoscopic diagnosis of IM is a clinical challenge. Confocal Laser Endomicroscopy (CLE) is a newly technique that can provide real-time magnified images and visualize tissues at cellular or subcellular levels. The aim of this study is to clarify the diagnostic value of CLE in detection of IM in patients at high risk of gastric cancer.

METHODS

Systematic literature searches up to April 2015 in PubMed, Embase, Web of Science, Cochrane Library databases were conducted by two reviewers independently. The Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool was applied to assess study quality and to reduce potential bias. A meta-analysis using Meta-Disc (version 1.4) and STATA software (version 13) was performed.

RESULTS

A total of four studies enrolled 218 patients and 579 lesions were included in this meta-analysis. On per-lesion basis, the pooled sensitivity and specificity of CLE were 0.97(95 % confidence interval (CI) = 0.94-0.98) and 0.94 (95 % CI = 0.91-0.97) respectively. The pooled positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were 15.20 (95 % CI = 9.46-24.41) and 0.04 (95 % CI = 0.02-0.07) respectively. The pooled diagnostic odds ratio (DOR) was 479.59 (95 % CI = 205.64-1118.51) and summary receiver operating curve (SROC) area under the curve was 0.9884. There was no statistical significance of publication bias.

CONCLUSION

CLE is a promising endoscopic tool in the detection of IM with the relatively high diagnostic value in patients at high risk of gastric cancer.

Emerging new trends in neurosurgical technologies

There has been tremendous progress in the modern day technologies causing a rapid evolution in the field of neurosurgery. The neurosurgeons have been equipped with the latest advancements such as the use of robotics in surgery, the image-guided neurosurgical procedures, and the stereotactic neurosurgery. In addition, the preoperative screening techniques have drastically improved the success of the surgical procedure. Neuronavigation has allowed the precise localization of the deep-seated brain structures thereby helping in the accurate operation of the affected regions without stirring the normal brain tissues. Such preciseness has helped in the improvement of the patient outcome. All these aspects have been discussed in detail in this review with a focus on their developmental background.

New concepts in vocal fold imaging: a review

OBJECTIVE

To review new imaging technology potentially useful in the clinical practice of laryngology.

HYPOTHESIS

Narrow band imaging, iScan (Pentax Medical Company, Montvale, NJ), optical computed tomography, and confocal microscopy have potential value for enhancing diagnosis of laryngeal pathology.

DESIGN

Literature review.

METHODS

Literature search of computer databases including MEDLINE and PubMed.

RESULTS

A review of 50 articles suggests that new imaging technologies may enhance clinical diagnostic capabilities.

CONCLUSION

The probable value of new imaging technologies suggests that further research is needed to refine these technologies and define their clinical efficacy.

Confocal laser endomicroscopy in neurosurgery: a new technique with much potential

Technical innovations in brain tumour diagnostic and therapy have led to significant improvements of patient outcome and recurrence free interval. The use of technical devices such as surgical microscopes as well as neuronavigational systems have helped localising tumours as much as fluorescent agents, such as 5-aminolaevulinic acid, have helped visualizing pathologically altered tissue. Nonetheless, intraoperative instantaneous frozen sections and histological diagnosis remain the only method of gaining certainty of the nature of the resected tissue. This technique is time consuming and does not provide close-to-real-time information. In gastroenterology, confocal endoscopy closed the gap between tissue resection and histological examination, providing an almost real-time histological diagnosis. The potential of this technique using a confocal laser endoscope EndoMAG1 by Karl Storz Company was evaluated by our group on pig brains, tumour tissue cell cultures, and fresh human tumour specimen. Here, the authors report for the first time on the results of applying this new technique and provide first confocal endoscopic images of various brain and tumour structures. In all, the technique harbours a very promising potential to provide almost real-time intraoperative diagnosis, but further studies are needed to provide evidence for the technique's potential.

Autofluorescent imaging in patients with peritoneal carcinomatosis

BACKGROUND AND OBJECTIVES

Autofluorescence imaging (AFI) is mainly used to detect (pre)cancerous colorectal and pulmonal lesions. This is the first report establishing the feasibility of AFI in patients with peritoneal carcinomatosis (PC).

METHODS

This is a prospective analysis of 10 patients undergoing conventional white-light laparoscopy (WL) and AFI for PC of different gastrointestinal tumors and 1 ovarian cancer. Before taking biopsies, suspicious peritoneal lesions were first detected by WL and then investigated by AFI. The intraoperative findings were photographed and then correlated with histological results.

RESULTS

Conventional WL and AFI evaluation was successful in all patients. A total of 38 biopsies were taken. The neoplasm detection rate under WL was 66% and increased to 86% when using AFI. The positive tumor detection rate was slightly higher in low AF lesions (83 vs 88%) and higher in tumor nodules (94%) than in flat peritoneal lesions (75%). For tumor nodules, the sensitivity was 94%, and the specificity was 100%. For flat lesions, the sensitivity was 75% and specificity 50%.

CONCLUSIONS

We demonstrate the feasibility and effectiveness of AFI in patients with PC.

Transparent cap colonoscopy versus standard colonoscopy to improve caecal intubation

BACKGROUND

Colonoscopy is considered the gold-standard investigation for screening and diagnosis of colorectal cancer. It is also becoming increasingly desirable for assessment, management, diagnosis and follow-up of other colorectal diseases, such as inflammatory bowel diseases and acute diverticulitis. Hence, due to the increasing demand for colonoscopy, devices to advance examination techniques are highly sought-after and the colonoscope with the transparent cap could be one of these.

OBJECTIVES

To identify and review all relevant data in order to determine whether colonoscopy with a transparent cap is a more effective diagnostic tool than colonoscopy.

SEARCH METHODS

We searched the MEDLINE, EMBASE and CINAHL databases, and the Cochrane Central Register of Controlled Trials for all randomised controlled trials (RCTs) comparing the use of colonoscopy with a transparent cap with standard colonoscopy.

SELECTION CRITERIA

Studies were included if they were randomised controlled trials which compared the use of colonoscopy with a transparent cap with standard colonoscopy.

DATA COLLECTION AND ANALYSIS

Data on study methods, participants, interventions used and outcomes measured was extracted from each study. Data was entered into the Cochrane Review Manager software (RevMan 5.0, 2008) and analysed using Cochrane MetaView.

MAIN RESULTS

In the present meta-analysis, we considered 14 randomised controlled trials so far published. The findings of our work indicate that colonoscopy with transparent cap has a faster caecal intubation time when compared with standard colonoscopy. Reviewing studies individually would also seem to favour colonoscopy with transparent cap for polyp detection rate and pain during procedure but due to lack of comparable data meta-analysis was not feasible.

AUTHORS' CONCLUSIONS

This review suggests that a transparent cap on the end of the colonoscope may give a marginally faster caecal intubation time compared with standard colonoscopy. It also suggests that there is a better polyp detection rate and less pain with the cap. However, the authors feel that further randomised controlled trials in this area would provide more clinically significant information on this adjunct to colonoscopy.

Probe-based confocal laser endomicroscopy evaluation of colon preneoplastic lesions, with particular attention to the aberrant crypt foci, and comparative assessment with histological features obtained by conventional endoscopy

The colorectal carcinoma represents one of the most common and aggressive malignancies, still characterized by an unacceptable mortality rate, mainly due to the high metastatic potential and to a late diagnosis. In the last years, the research community focused on the chance of improving the endoscopic screening to detect neoplastic lesions in a very early stage. Several studies proposed aberrant colonic crypt foci as the earliest recognizable step of transformation in colonic multiphase carcinogenesis. We previously demonstrated the clinical applicability and predictive power of probe-based confocal laser endoscopy (pCLE) in superficial colorectal neoplastic lesions and also characterized in vivo a case of dysplasia-associated lesional mass (DALM) in ulcerative colitis. Now, we aim to evaluate the accuracy of pCLE in the detection of ACF comparing in double-blind manner the microendoscopic and histopathological features resulting from colonic biopsy. By pCLE, we identified specific crypt architecture modifications associated with changes in cellular infiltration and vessels architecture, highlighting a good correspondence between pCLE features and histology.

Meta-analysis of narrow-band imaging versus conventional colonoscopy for adenoma detection

BACKGROUND

At colonoscopy, missed adenomas have been well documented at approximately 22%. The challenge is in reducing this miss rate. Narrow-band imaging (NBI) has been extensively evaluated in prospective, randomized, controlled studies for polyp detection. Sample-size calculations show us that these studies may be underpowered, and hence a meta-analysis is required.

OBJECTIVE

Our aim was to determine whether use of NBI enhances the detection of adenomas.

DESIGN

Meta-analyses were conducted of 7 studies using NBI for adenoma detection rate. MEDLINE, Embase, PubMed, and Cochrane databases were searched by using a combination of the following terms: "colonoscopy," "NBI," and "electronic chromoendoscopy."

PATIENTS

There was a total of 2936 patients in the NBI studies.

INTERVENTIONS

Prospective, randomized trials of NBI versus standard white-light colonoscopy (WLC) were conducted. We excluded spray chromoendoscopy studies and studies of inflammatory bowel disease and polyposis syndromes.

MAIN OUTCOME MEASUREMENTS

Adenoma and polyp detection rates and the number of polyps and adenomas detected per person.

RESULTS

There was no statistically significant difference in the overall adenoma detection rate with the use of NBI or WLC (36% vs 34%; P = .413 [relative risk 1.06; 95% CI, 0.97-1.16]), and there was no statistically significant difference in polyp detection rate by using NBI or WLC (37% vs 35%; P = .289 [relative risk 1.22; 95% CI, 0.85-1.76]). When the number of adenomas and polyps per patient was analyzed, no significant difference was found between NBI and WLC (0.645 vs 0.59; P = .105 and 0.373 vs 0.348; P = .139 [weighted mean difference 0.19; 95% CI, ∞0.06 to 0.44], respectively).

LIMITATION

Variability in NBI studies can reduce the accuracy of this analysis.

CONCLUSIONS

NBI did not increase adenoma or polyp detection rates.

Optical spectroscopy combined with high-resolution magnetic resonance imaging for digestive wall assessment: endoluminal bimodal probe conception and characterization in vitro, on organic sample and in vivo on a rabbit

Colorectal cancer is a major health issue worldwide. Conventional white light endoscopy (WLE) coupled to histology is considered as the gold standard today and is the most widespread technique used for colorectal cancer diagnosis. However, during the early stages, colorectal cancer is very often characterized by flat adenomas which develop just underneath the mucosal surface. The use of WLE, which is heavily based on the detection of morphological changes, becomes quite delicate due to subtle or quasi-invisible morphological changes of the colonic lining. Several techniques are currently being investigated in the scope of providing new tools that would allow such a diagnostic or assist actual techniques in so doing. We hereby present a novel technique where high spatial resolution MRI is combined with autofluorescence and reflectance spectroscopy in a bimodal endoluminal probe to extract morphological data and biochemical information, respectively. The design and conception of the endoluminal probe are detailed and the promising preliminary results obtained in vitro (home-built phantom containing eosin and rhodamine B), on an organic sample (the kiwi fruit) and in vivo on a rabbit are presented and discussed.

Near-infrared (NIR) laparoscopy for intraoperative lymphatic road-mapping and sentinel node identification during definitive surgical resection of early-stage colorectal neoplasia

BACKGROUND

Appropriate lymphatic assessment is a cornerstone of definitive surgical resection for colorectal cancer. Near-infrared (NIR) laparoscopy may allow real-time intraoperative identification of territorial lymphatic drainage and sentinel nodes in patients with early-stage disease prior to radical basin resection.

METHODS

With IRB approval and individual consent, consecutive patients with radiologically localized neoplasia underwent peritumoral submucosal injection of indocyanine green (ICG, a fluorophore capable of injection site tattooing and efferent lymphatic migration) prior to standard laparoscopic oncological resection. Intraoperatively, a prototype NIR laparoscope provided both white light and, by switch activation, NIR irradiation with or without discrete spectral back-filtration. Fluorescence identification of sentinel nodes prior to formal specimen dissection allowed their identification for separate histopathological analysis by in situ clipping when found within the specimen or selective lymphadenectomy by "berry-picking" when such nodes lay outside of the standard resection field. Concordance with nonsentinel nodes was then analysed.

RESULTS

Eighteen patients (mean age = 66.4 years [range = 47.9-80.1], mean BMI = 29.1 [range = 20.0-39.9]) were studied. Fourteen had biopsy-proven carcinoma and four had endoscopically unresectable dysplasia. Mesocolic sentinel nodes (mean = 4.1/patient) were rendered obvious by fluorescence either solely within the standard resection field (n = 14) or both within and without the planned field (n = 4) within minutes of dye injection in every case. Laparoscopic ultrasound (n = 5) as well as histopathological analysis demonstrated oncologic correlation of mesocolic sentinel with corresponding territory nonsentinel nodes, correctly confirming the presence of mesocolic disease in 3 patients and the absence of such lymphatic spread in the remaining 15 patients.

CONCLUSIONS

In this study, NIR laparoscopy with ICG mapping allowed ready and rapid confirmation of mesocolic lymphatic drainage patterns and sentinel node identification. With further validation, this technology and technique promises precise, tailored resection surgery by indicating basin pattern and status in advance of radical lymphadenectomy.