Simple methods to improve the standardised endoscopic evaluation of the digestive tract

Simple methods to improve the standardised endoscopic evaluation of the digestive tract

Digestive endoscopy is widely used nowadays for diagnostic as well as for therapeutic purposes. However, the results are often limited because of an inadequate preparation or an incomplete examination. Therefore, we propose a list of simple gestures that can help improve the endoscopic evaluation of the digestive tract.

Preprocedure preparation

Upper GI endoscopy

  1. Fasting for solids for at least 6 hours prior to the procedure;
  2. No liquid intake within 2 hours before the procedure;
  3. Studies showed that a solution containing simethicone and a mucolytic agent as acetyl cysteine helps eliminate the foam and improves visibility (100 mL water+ 200mg simethicone+ 1000 mg N acetyl cysteine 20-30 minutes before the procedure; intraprocedural administration was associated with damage of the working channel because of the crystallization of simethicone). [1,2]

Lower digestive endoscopy

  1. Low fiber diet one day prior to the procedure;
  2. Recent randomized clinical trials have shown that 400-1200 mg of oral simethicone during bowel preparation improve the quality and the adenoma detection rate; [3]
  3. Split-dose administration of the laxatives is recommended for elective colonoscopy compared to the single dose, because it ensures a better bowel preparation and a higher compliance rate; the last dose of bowel preparation must be taken within 5 hours before colonoscopy and completed at least 2 hours before the beginning of the procedure. [4]

 

During the procedure

  • Adequate photodocumentation of each segment and any abnormal finding;
  • For correct staging we recommend the use of appropriate terminology and classifications: the Los Angeles classification for errosive esophagitis; the Prague classification for Barrett’s esophagus; the Paris, JNET and NICE (NBI) classifications for neoplastic lesions; the Forrest classification for peptic ulcers; Zagar – caustic esophagitis; the Baveno classification for  esophageal varices; the Spigelman classification for duodenal polyps in FAP (familial adenomatous polyposis); the Siewert classification  for adenocarcinomas of the eso-gastric junction and the Sarin classification for gastric varices. [1, 4]
  • For a correct evaluation of neoplastic lesions and their extension we recommend using a high definition endoscope and virtual or standard chromoendoscopy to increase diagnostic accuracy.
    1. Virtual chromoendoscopy:
      • Narrow band imaging – NBI (Olympus)- uses green and blue wavelenghts and enhances the vascular and glandular pattern therefore helping to predict the histology of the lesion (Figures 1, 2, 3, 4, 5); [5,6]
      • Linked color imaging (LCI) and blue laser imaging (BLI) (Fujifilm) – BLI uses blue and green colors and enhances the surface and the superficial vascular structures (similar to NBI), while LCI uses all three colors (green, blue and red) resulting in an image similar to the one in WLE but with more vivid colors. Studies show that LCI could allow easy recognition and early detection of gastric cancer even for inexperienced endoscopists. [7]
    2. Standard chromoendoscopy is a cheap and readily accessible method used to characterise the neoplastic lesions consisting of intravital dyes ( absorptive dyes like methylene blue, Lugol or contrast-based dyes like indigo carmine):
  • Methylene blue (most frequently used dye) –it is absorbed by epithelial cells of the small bowel or colon, determining a blue coloration of the mucosa compared to dysplastic/malignant lesions who stain in an uneven manner allowing the inspection of the glandular pattern (Kudo classification) and the separation of non-neoplastic from neoplastic lesions  (Figures 1, 4, 5, 6,7,8); like any other stain, it can be applied on certain areas or on the whole examined surface. [8]
  • Acetic acid (2.5%) – a reactive dye, in contact with the mucosa determines the acetylation of cytoplasmic proteins who are found in a small amount in neoplastic cells, determining a discoloration of normal mucosa while delimiting the areas of dysplasia in Barrett’s esophagus; [9]
    • Lugol (10-20 mL 2% Lugol through a spray catheter or directly through the working channel) reacts with the cells containing glycogen and therefore the mucosa appears dark brown while the areas of dysplasia and carcinoma within the squamos epithilium do not stain (ESGE recommends the use of Lugol chromoendoscopy for detection of dysplasia/ carcinoma in patients with previous lung or ENT cancer). [10]

 

Biography

  1. Bisschops R, Areia M, Coron E, Dobru D. Performance measures for upper gastrointestinal endoscopy: a European Society of Gastrointestinal Endoscopy (ESGE) Quality Improvement Initiative. Endoscopy. 2016.
  2. Monrroy H, Vargas JI, Glasinovic E, Candia R. Use of N-acetylcysteine plus simethicone to improve mucosal visibility during upper GI endoscopy: a double-blind, randomized controlled trial. Gastrointest Endosc. 2018 Apr.
  3. Hassan C, East J, Radaelli F, Spada C. Bowel preparation for colonoscopy: European Society of Gastrointestinal Endoscopy (ESGE) Guideline – Update 2019. Endoscopy. 2019.
  4. Bisschops R, East JE, Hassan C, Hazewinkel Y. Advanced imaging for detection and differentiation of colorectal neoplasia: European Society of Gastrointestinal Endoscopy (ESGE) Guideline – Update 2019. Endoscopy. 2019.
  5. ASGE Technology Committee. High-definition and high-magnification endoscopes. Gastrointest Endosc. 2014
  6. Subramanian V, Ragunath K. Advanced endoscopic imaging: a review of commercially available technologies. Clin Gastroenterol Hepatol. 2014 Mar.
  7. Kanzaki H, Takenaka R, Kawahara Y, et al. Linked color imaging (LCI), a novel image-enhanced endoscopy technology, emphasizes the color of early gastric cancer. Endosc Int Open. 2017 Oct;
  8. Buchner AM. The Role of Chromoendoscopy in Evaluating Colorectal Dysplasia. Gastroenterol Hepatol (N Y). 2017 Jun;
  9. Longcroft-Wheaton G, Duku M, Mead R.. Acetic acid spray is an effective tool for the endoscopic detection of neoplasia in patients with Barrett’s esophagus. Clin Gastroenterol Hepatol. 2010.
  10. Trivedi PJ, Braden B. Indications, stains and techniques in chromoendoscopy. QJM. 2013 Feb;106(2).

 

Figure 1 Gastric lesion – irregular margins, central depression (Paris IIb); NBI view (left) and methylene blue (right) – central atrophic area, with blurred glandular pattern and elevated areas suggestive for intestinal metaplasia. Biopsies confirmed the diagnosis of adenocarcinoma.

Figure 2 Post-resection scar of the figure 2 lesion (pathology report: intramucosal adenocarcinoma) – white light (left), NBI (middle), NBI near focus (right) examination.

Figure 3 Laterally spreading tumor (LST) situated in the transverse colon in a patient with long standing colitis, in remission at present. The lesion can be observed in white light endoscopy (left), as well as in NBI (right) –it measures approximately 2/2 cm, it has slightly elevated margins (Paris Ib) and it is non-granular. The tumor was marked with ink in the 4 quadrants (some ink stains can be observed proximally).

Figure 4 Post-resection scar with minimal remnant adenomatous tissue as seen in NBI (middle) and methylene blue chromoendoscopy (right) treated by soft coagulation.

Figure 5 Paris IIa+Is polyp of approximately 25 mm situated 7 cm above the anal verge, observed in NBI (left) and methylene blue chromoendoscopy (right) – Kudo IIIL/NICE 2.

Figure 6 Piecemeal resection (left) of the polyp in figure 5 and soft coagulation of resection margins (right).

Figure 7 Rectal lesion situated right above the anal verge (recurrent adenoma after a previous resection) – evaluation with  distal attachment gastroscope for better visibility.

Figure 8 Examination after EMR resection of the figure 6 lesion – post-resection scar is examined by methylene blue chromoendoscopy for better evaluation of the adenomatous remnant tissue (arrows).

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