Role of narrow band imaging in Barrett's esophagus.

The present recommended strategy for detection of dysplasia and cancer in Barrett's esophagus is by randomly carrying out four quadrant biopsies every 2 cm. This approach is however prone to sampling error. Narrow band imaging has been routinely available for clinical use for more than half a decade now. This review will focus on the available data to date on the role of narrow band imaging in the detection and characterization of specialized intestinal metaplasia, high grade dysplasia and intramucosal cancer in Barrett's esophagus.

West meets East: preliminary results of narrow band imaging with optical magnification in the diagnosis of colorectal lesions: a multicenter Australian study using the modified Sano's classification.

INTRODUCTION: Narrow band imaging with optical magnification (NBI-Z) enables mucosal morphology to be assessed in real time by using light with narrowed band width and magnification of up to 115×. METHODS: Colorectal lesions detected were assessed with NBI-Z. Histology was predicted using the modified Sano's classification based on capillary network patterns (cn); type I: absent cn (hyperplastic polyp), type II: cn present, surrounding mucosal glands (adenoma), type IIIa: high density cn with tortuosity and lack of uniformity (intramucosal cancer) and type IIIb: nearly avascular cn (invasive cancer). Each lesion was also graded with a confidence level (low/high). High-definition videos (mean 28.2 s; range 12-55) of each lesion assessed with NBI-Z were then taken. This was followed by polypectomy, endoscopic or surgical resection. NBI-Z diagnosis was compared with the final histopathology. To test for interobserver agreement, an endoscopist blinded to the video acquisition process/histology was invited to grade the videos. RESULTS: A total of 50 lesions (2 assessors: 100 studies), with an average size of 8.4 mm (range 3-30), in 32 patients were assessed. Twenty were hyperplastic, 25 adenomas, 2 intramucosal and 3 invasive cancers of which 19 were located in the right and 31 in the left colon. The overall accuracy of NBI-Z in predicting histology was 90%, which increased to 95% (88/93) when lesions were predicted with high confidence. The sensitivity (Sn), specificity (Sp), positive (PPV) and negative predictive values (NPV) in differentiating neoplastic from non-neoplastic lesions with high confidence were 98%, 89%, 93% and 97%, respectively, while the Sn, Sp, PPV and NPV in predicting endoscopic resectability (type II, IIIa vs type I, IIIb) was 100%, 90%, 93% and 100%, respectively. The interobserver agreement between both assessors (κ value) was substantial at 0.89. CONCLUSIONS: Using confidence levels, NBI-Z permits prediction of colorectal neoplasia with high accuracies and might allow prompt decisions to be made if a lesion should be left in situ, resected and discarded or biopsied. This approach might lead to substantial time and cost savings and could potentially reduce complications associated with polypectomy and endoscopic resections.

Carbon dioxide insufflation during colonoscopy in deeply sedated patients.

AIM: To compare the impact of carbon dioxide (CO2) and air insufflation on patient tolerance/safety in deeply sedated patients undergoing colonoscopy. METHODS: Patients referred for colonoscopy were randomized to receive either CO2 or air insufflation during the procedure. Both the colonoscopist and patient were blinded to the type of gas used. During the procedure, insertion and withdrawal times, caecal intubation rates, total sedation given and capnography readings were recorded. The level of sedation and magnitude of patient discomfort during the procedure was assessed by a nurse using a visual analogue scale (VAS) (0-3). Patients then graded their level of discomfort and abdominal bloating using a similar VAS. Complications during and after the procedure were recorded. RESULTS: A total of 142 patients were randomized with 72 in the air arm and 70 in the CO2 arm. Mean age between the two study groups were similar. Insertion time to the caecum was quicker in the CO2 group at 7.3 min vs 9.9 min with air (P = 0.0083). The average withdrawal times were not significantly different between the two groups. Caecal intubation rates were 94.4% and 100% in the air and CO2 groups respectively (P = 0.012). The level of discomfort assessed by the nurse was 0.69 (air) and 0.39 (CO2) (P = 0.0155) and by the patient 0.82 (air) and 0.46 (CO2) (P = 0.0228). The level of abdominal bloating was 0.97 (air) and 0.36 (CO2) (P = 0.001). Capnography readings trended to be higher in the CO2 group at the commencement, caecal intubation, and conclusion of the procedure, even though this was not significantly different when compared to readings obtained during air insufflation. There were no complications in both arms. CONCLUSION: CO2 insufflation during colonoscopy is more efficacious than air, allowing quicker and better cecal intubation rates. Abdominal discomfort and bloating were significantly less with CO2 insufflation.