Cresyl violet as a new contrast agent in probe-based confocal laser endomicroscopy for in vivo diagnosis of gastric intestinal metaplasia

Use of Two Novel Dyes to Enhance Visualization of Cut Ends of the Vessel in Microvascular Anastomosis-An Experimental Study of 45 Rats

BACKGROUND

Good visualization is a prerequisite for performing microvascular anastomosis. The most commonly used dye, methylene blue, has several limitations: it is washed off quickly and stains all the vessel layers. The objective of our study is to use 2 new novel dyes for improving visualization.

METHODS

After ethical committee approval, 2 Dyes (2% cresyl violet, 1% eosin) were studied in 3 groups, 20 rats in each group and 5 rats in the combined group. End-to-side anastomosis was performed in the classic fashion in 45 rats. After venotomy, the dye was applied to the raw surface of the vessels and subsequently, anastomosis was performed. The improvement in visualization was judged by 3 blinded experts and nonexperts in 4 groups on a scale of 1-10. Scores were statistically analyzed. After 2 weeks, animals were re-explored to check the delayed patency, and segments were harvested for histopathologic analysis.

RESULTS

The immediate and delayed patency rates were 100% (45/45) and 97% (33/34), respectively. In statistical analysis, the combined group (P = 0.005)was judged statistically significant because of the contrast in color. All the layers were stained by both dyes, staining lasted until the end of the surgery. Visibility of the cut ends was better in cresyl violet. All histopathologic findings suggested normal changes at the anastomotic site.

CONCLUSIONS

This study showed that the use of these 2 dyes was not only feasible but highly efficacious. Even though all the layers were stained by both the dyes, the visibility of the cut ends was better. In both dyes, staining lasted until the end of surgery. To the best of our knowledge, this is the first study that has used these 2 novel dyes to improve visualization in microvascular anastomosis in an experimental setting.

Confocal Laser Endomicroscopy for Detection of Early Upper Gastrointestinal Cancer

Esophageal and gastric cancers are common diseases with high morbidity and mortality; thus, early detection and treatment are beneficial to improve prognosis. Confocal laser endomicroscopy (CLE) is a novel imaging technique that permits the histological analysis of tissues during endoscopy. CLE has been shown to uniquely affect the diagnosis of early upper gastrointestinal cancers. Relevant literature was searched using PubMed and Google Scholar databases. Despite inherent flaws, CLE can reduce tissue damage and improve diagnostic accuracy to a certain extent. CLE in combination with other imaging methods can help enhance the detection rate and avoid unnecessary biopsies in the management of esophageal or gastric cancer and precancerous lesions. CLE is of great significance in the diagnosis and surveillance of early cancers of the upper gastrointestinal tract. Further technical innovations and the standardisation of CLE will make it more responsive to the needs of routine clinical applications.

Visualization of the human enteric nervous system by probe confocal laser endomicroscopy: a first real-time observation of Hirschsprung's disease and allied disorders

Background

Our group previously proved that the human enteric nervous system can be visualized with confocal laser endomicroscopy after topical application of cresyl violet using surgically resected intestine specimens. The present report documents the first in vivo visualization of the human enteric nervous system with confocal laser endomicroscopy using local cresyl violet staining. The aim of this study was to evaluate the technical feasibility and clinical efficiency of confocal laser endomicroscopy in patients with Hirschsprung’s disease and allied disorders in vivo.

Methods

Confocal laser endomicroscopy was performed in vivo in two patients to confirm the presence of the enteric nervous system during surgery in patients with Hirschsprung’s disease and allied disorders. Cresyl violet was gently injected from the serosal side into the muscular layer of the intestine, and scanning was performed within 30 min. Then, the scanned intestines were resected, and the visualized area of the specimens was pathologically evaluated.

Results

The ganglion cell nuclei and the enteric nervous system network were clearly visualized intraoperatively in both cases. The morphological findings were similar to the pathological findings of the enteric nervous system in both cases although the period of visibility was brief.

Conclusion

This study demonstrated the first, real-time observation of the enteric nervous system in humans using confocal laser endomicroscopy and suggest the potential to identify the enteric nervous system intra-operatively during surgery for Hirschsprung’s disease and allied disorders.

Visualization of the human enteric nervous system by confocal laser endomicroscopy in Hirschsprung's disease: An alternative to intraoperative histopathological diagnosis?

BACKGROUND

Hirschsprung's disease is a congenital abnormality of the enteric nervous system (ENS) presenting severe constipation soon after birth due to the lack of ganglion cells in the distal gut. Surgery for Hirschsprung's disease requires an intraoperative histopathological diagnosis to assess the extent of aganglionosis. Confocal laser endomicroscopy (CLE) is a novel endoscopic technique allowing real-time, in vivo analysis of cellular details during ongoing endoscopy. In this study, we evaluated the possibility of a new application of CLE to provide real-time observations of the ENS in patients with Hirschsprung's disease. In this preclinical feasibility study, we assessed the visualization of the ENS by CLE using surgically resected intestines.

METHODS

The subjects were nine patients who underwent pull-through surgery for Hirschsprung's disease between September 2014 and March 2016. The colon specimens were stained with 0.1% cresyl violet and evaluated using CLE. We compared the CLE findings with those of the histopathological examination.

KEY RESULTS

The ENS was clearly visualized as a ladder-like structure in the ganglionic segment but was not observed in the aganglionic segment. Of the 69 samples, corresponding positive and negative results for both CLE and the histopathology were obtained in 61 (88%). In addition, CLE was able to visualize unique, wavy structures comprising thick nerve bundles characteristic of the aganglionic/transition zone in Hirschsprung's disease.

CONCLUSIONS AND INFERENCES

As a novel tool for visualizing the human ENS, CLE has the potential to revolutionize how pediatric surgeons identify the level of ganglionosis during surgery for Hirschsprung's disease and may be a superior alternative to intraoperative histopathological diagnosis.