Dye used in chromoendoscopy for detection of cancer:
Ans is d i.e. Methylene blue > Toluidine blue "Chromoendoscopy, the intravital staining of gastrointestinal epithelia, provides additional diagnostic information with respect to the epithelial morphology and pathophysiology. Based on experience gathered mainly in Japan, chromoendoscopy is now in more widespread use, in paicular to identify preneoplastic and neoplastic lesions. The most promising techniques are the depiction of squamous epithelium neoplasia of the esophagus with Lugol's solution, staining of Barrett's mucosa by methylene blue, including the potential to identify neoplasia, and the demarcation of neoplasia with indigo carmine in stomach and colon for local endoscopic resection."- aicle: Chromoendoscopy: From a Research Tool to Clinical Progress U. Peitz, P. Malfeheiner at website: ikelNr=67480 "Chromoendoscopy involves the use of agents that enhance the distinction between diseased and normal mucosa, either by filling surface cervices or by differential uptake by diseased epithelium. Many chromoendoscopy agents have been studied in the detection of esophageal carcinoma, of which Lugol's iodine and methylene blue have been most widely studied."- Carcinoma of the Esophagus By Sheila C. Rankin p.31 Chromoendoscopy involves the use of stains or dyes during endoscopy to improve the visualization and characterization of the gastrointestinal mucosa. The stains are mainly Vital dyes- Lugol's solution, methylene blue, and toluidine blue or Contrast agents- indigo carmine and dilute acetic acid solution Lugol's solution Is absorbed by glycogen containing, nonketatinized squamous epithelium. Lugol's stained tissue will characteristically turn green-brown. Any condition that depletes glycogen, including inflammation, dysplasia, and early-stage cancer, will result in an absence of uptake of the dye. Lugol's iodine is used to determine the extent of BE, and to screen for squamous esophageal cancer in high-risk populations. Methylene blue dye is taken up by the cytoplasm or absorptive cells such as the normal epithelial cells of the colon and small intestine, and goblet cells, which are present in Barrett's epithelium. It will not stain nonabsorptive normal epithelium of the stomach as is found in the cardia and fundus, or normal squamous mucosa of the esophagus. Chromoendoscopy with methylene blue has been used to screen for colonic neoplasia , to diagnose BE and to screen for areas of precursor lesions and carcinoma in the stomach. Methylene blue stains barrett's epithelium as it is taken up by the cytoplasm of goblet cells. Dysplastic change is associated with a reduction in goblet cell numbers and an increasing nuclear to cytoplasmic ratio propoional to the degree of dysplasia, and such tissues absorb methylene blue to a lesser extent than surrounding cells. Increasing grades of dysplasia may appear as heterogeneous or unstained areas, allowing targeted rather than random biopsies to be taken and have been repoed to improve the detection of high-grade intraepithelial neoplasia in Barrett's esophagus. Indigo carmine Unlike Lugol's iodine or methylene blue, indigo carmine is not taken up by tissues but instead pools in crevices between epithelial cells, thereby highlighting small lesions or irregularities in the mucosal architecture. Chromodendoscopy with indigo carmine has been used to diagnose BE, and to investigate polypoid and nonpolypoid lesion in the colon.Toluidine Blue Toluidine blue stains cellular nuclei. When applied topically it preferentially identifies malignant and inflammatory tissues, in pa because of their greater nuclear/cytoplasmic ratio. It has most commonly been used for the identification of early squamous esophageal cancer.
Gentian violet
Toluidine blue
Hemotoxiline and eosine
Methylene blue