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Endoscopy 2023; 55(12): 1081-1082
DOI: 10.1055/a-2189-4890
Editorial

Next generation of virtual chromoendoscopy improves adenoma detection during colonoscopy

Referring to Antonelli G et al. doi: 10.1055/a-2129-7254
Ralf Kiesslich
1   Innere Medizin II, HELIOS Dr Horst Schmidt Kliniken Wiesbaden, Wiesbaden, Germany (Ringgold ID: RIN38696)
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It is well known that standard chromoendoscopy is helpful for adenoma detection, especially in patients with inflammatory bowel disease [11]. However, standard chromoendoscopy requires dye application and a spraying catheter, which adds to the time and costs of colonoscopy. The acceptance of chromoendoscopy during daily routine is low.

The development of virtual chromoendoscopy has overcome these limitations. Different mucosal details can be highlighted simply by pressing a button on the endoscope. All endoscope companies have developed their own brands of virtual chromoendoscopy (e.g. narrow-band imaging [NBI], i-SCAN digital contrast, flexible spectral imaging color enhancement, optical endoscopy). Virtual chromoendoscopy is of advantage for lesion characterization, especially NBI, which is used to characterize superficial vessels. However, a recent meta-analysis showed no benefit of virtual chromoendoscopy in adenoma detection [22].

The study by Antonelli et al. [33] in this issue of Endoscopy describes a new technology of virtual chromoendoscopy. Texture and color enhancement imaging (TXI; Olympus, Tokyo, Japan) is a new technology that enhances texture and brightness separately. Both enhanced images are then merged and displayed to the endoscopist. The advantage of TXI compared with NBI is a much brighter image providing more visible mucosal detail.

The authors conducted a randomized trial where they compared adenoma detection rates (ADRs) during colonoscopy with and without the use of TXI. The results are significant. ADR was increased from 42.7% to 58.9%. However, significance was only reached for smaller lesions (<10mm). More small adenomas were found all over the colon, irrespective of morphology. Interestingly, serrated adenoma detection was not significantly higher in the TXI group.

“All described techniques are comparable because they significantly increase the adenoma detection rate for small adenomas, without increasing the detection of advanced adenomas.”

ADR reached almost 60% by using TXI. In the USA, ADRs have increased from 33.93% in 2014 to 38.12% in 2018 based on 2646833 colonoscopies [44], but are still much lower than 60%.

The current study included symptomatic patients and those attending for screening. Symptomatic patients have a higher prevalence of adenomas and colon cancer. The study also involved different types of endoscopes and it remained unclear how many patients were included at each participating center. Thus, it is difficult to conclude what clinical effect TXI provides for screening and whether the findings can be generalized. Furthermore, the question of whether the additional small adenomas detected are of any clinical meaning remains to be answered.

The old term “advanced adenoma” summarizes adenomas with a size ≥10mm, high grade dysplasia, or dominant villous architecture. TXI could not identify more advanced adenomas. The European Society of Gastrointestinal Endoscopy has recently defined high risk lesions as those that lead to a follow-up colonoscopy after 3 years compared with 10 years for low risk situations [55]. Antonelli et al. showed that a significantly greater number of high risk patients were identified when using TXI. It will be of interest to analyze other techniques aimed at improving adenoma detection to determine whether they also have an effect of identifying more high risk lesions.

High quality colonoscopy in general is dependent on an experienced endoscopist, excellent bowel preparation, adequate withdrawal time, and complete removal of premalignant lesions. Every endoscopist who participates in colon cancer screening programs should know their individual ADR. There are many ways to increase the ADR in colonoscopy; so, what are the alternatives to TXI?

Artificial intelligence is a disruptive technology, which is also available for colonoscopy. The technique assists the endoscopist and highlights possible polyps based on deep learning algorithms. The results are comparable to TXI: more small adenomas are detected [66] and ADRs can reach up to 60%. However, additional costs are incurred and regular software updates are mandatory.

Endocuff (Arc Medical Design, Leeds, UK) can be used to flatten the colonic folds during withdrawal. There is a significant effect, resulting in higher ADRs [77]. However, Endocuff has to be mounted onto the distal end of the endoscope and can only be removed when the endoscope is outside the patient. Endocuff can lead to difficulties intubating the terminal ileum and may interfere with adenoma resection. Endocuff can also be combined with TXI [88]. In one recent study, TXI alone led to an ADR of 52.1%, whereas TXI combined with Endocuff resulted in an ADR of 65.6% [88].

Standard chromoendoscopy can also be achieved with an orally administered methylene blue formation [99]. Chromoendoscopy is already in place when colonoscopy starts because the patient swallows the methylene blue capsule during bowel preparation. This approach also leads to high ADRs (56.3%) [99].

All described techniques are comparable because they significantly increase the ADR for small adenomas, without increasing the detection of advanced adenomas.

The beauty of the current study by Antonelli et al. [33] is the simplicity of the technique. The new-generation virtual chromoendoscopy is already integrated into the new video processor and the technique is available by simply pressing a button.

Although this is the first study evaluating this new technology, and we need to see more data from randomized trials, the novel TXI filter seems to be very promising for daily routine and overall acceptance by endoscopists.



Publication History

Article published online:
06 November 2023

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Refers to:

Texture and color enhancement imaging versus high definition white-light endoscopy for detection of colorectal neoplasia: a randomized trialEndoscopy 2023; 55(12): 1072-1080
DOI: 10.1055/a-2129-7254