Chromoendoscopy with Water Infusion Colonoscopy in Detecting Colonic Lesions

Abstract

Background: Water infusion in lieu of air insufflation colonoscopy achieves high cecal intubation rate; the cleansing effect of water improves identification of mucosal pathologies. Aim: To determine the feasibility of combining chromoendoscopy with water infusion colonoscopy in detecting colonic lesions. Method: Water infusion colonoscopy was performed with warm water (37°C) containing 0.005% Methylene blue (MB). Air was turned off until the cecum was reached and appendix opening identified under water. Air was then insufflated and fluid suctioned on scope withdrawal to aid examination and removal of lesions. Bowel preparation was rated good (3), fair (2), poor (1) on scope insertion. Results: 50 unselected patients underwent screening colonoscopy using the MB water infusion technique. Cecal intubation rate was 100%. Bowel preparation quality was fair [mean score 2.1 (SD 0.4)]. Neoplastic polyps were identified in 23 patients (46%). A total of 50 adenomas were identified: cecum (3), ascending (19), transverse (8), descending (10), sigmoid (5) and rectum (5). One adenoma had high grade dysplasia. The size distribution of the adenomas was: <6 mm (18), 6-9 mm (15), ≥10 mm (17). A total of 72 non-neoplastic lesions were identified: hyperplastic polyps (56), no specific abnormalities (16). Total withdrawal time was 15.6 (SD 6.6) minutes. Total procedure time was 27.9 (SD 9.5) minutes. The blue color water did not impair examination although a green color change of the fluid indicated fair to poor prep from residual stool. There were no significant complications (1 patient had transient passage of green urine). Conclusions: Chromoendoscopy added to the water infusion technique is feasible. Compared to historical adenoma detection rate of air insufflation colonoscopy [38% (JAMA 2008;299: 1027) and 42% (NEJM 2000;343: 162)], the current report had a numerically higher neoplastic polyp pick up rate of 46%. The cleansing effect coupled with dye staining may have enhanced the detection of adenomas. Conventional targeted chromoendoscopy requires up to an average of 33 minutes in total procedure time (JAMA 2008;299: 1027). Withdrawal time for conventional pancolonic chromoendoscopy requires up to an average of 26 minutes (Clin Gastroenterol Hepatol 2006;4: 349). The current method offers shorter procedure time compared with the traditional method of spraying of the mucosa with the chromoendoscopy dye. Compatibility with conventional colonoscope also minimizes set up cost for this novel combination. Table 1 Withdrawal time (min.)/ Total procedure time (min.) 15.6 (SD 6.6)/ 27.9 (SD 9.5) Neoplastic polyps pick up rate 46% Number of lesions indentified/Neoplastic/Non-neoplastic 122/50/72 Open table in a new tab