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Background and study aims: The clinical utility of narrow-band imaging (NBI) for Barrett's esophagus is limited by the multiplicity of classification schemes. We evaluated the interobserver agreement and accuracy of a new consensus-driven simplified binary classification of NBI surface patterns. Patients and methods: NBI images from macroscopically normal areas in patients with Barrett's esophagus were retrieved from endoscopy databases and were randomized for review by seven endoscopists (three experts, four nonexperts). A simplified binary classification of NBI mucosal and vascular patterns was used: (1) regular pattern (nondysplastic Barrett's esophagus); (2) irregular pattern (dysplastic Barrett's esophagus). Agreement in relation to surface patterns and predicted histology (dysplasia vs. no dysplasia) was calculated using κ statistics. Results: A total of 252 NBI images from 75 patients with Barrett's esophagus were assessed: 93 showed intestinal metaplasia, 91 low-grade dysplasia, and 68 high-grade dysplasia/esophageal adenocarcinoma. The median score for image quality was 4 (very good). Interobserver agreement for mucosal and vascular patterns and dysplasia prediction was fair: κ = 0.40 (95%CI: 0.37-0.42), 0.36 (95%CI: 0.33-0.38), and 0.39 (95%CI: 0.36-0.41) respectively, with comparable results for experts and nonexperts. Intraobserver agreement was substantially better among experts than among nonexperts, with mucosal κ = 0.63 vs. 0.49, vascular κ = 0.58 vs. 0.43, and predicted histology κ = 0.68 vs. 0.54 (all P < 0.005). Mean sensitivity and specificity of NBI surface patterns for predicting dysplasia were 47% (95%CI: 44%-55%) and 72% (95%CI: 69%-76%) respectively. Conclusions: Using a consensus-driven simplified classification of NBI surface patterns for Barrett's esophagus, the interobserver agreement was fair with suboptimal sensitivity and specificity. Significant improvements in NBI interpretation are needed prior to the routine use of NBI surface patterns for the assessment of Barrett's esophagus. [ABSTRACT FROM AUTHOR]

This review deals with the current, well-established indications for two-( 18 F)-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) scanning in patients with gastrointestinal cancers. FDG-PET is a non-invasive, functional imaging technique. FDG exploits the native glucose transporter to enter the cell. Since many tumours have enhanced glucose uptake, FDG is readily accumulated in malignant cells and can be detected by a PET camera. FDG-PET has been established as an important diagnostic tool in clinical oncology. This review deals with the current, well-established indications for FDG-PET scanning in patients with gastrointestinal cancers. In the current practice, FDG-PET is most commonly used to stage oesophageal carcinoma, to detect and stage recurrence of colorectal carcinoma and to differentiate between benign and malignant pancreatic lesions. The benefit of FDG-PET scanning in patients with oesophagus carcinoma is best established in stage IV disease, as the diagnostic accuracy to detect metastatic disease is higher compared to the combination of computed tomography (CT) and endoscopic ultrasound (EUS). In patients with a history of colorectal carcinoma, FDG-PET scanning is particularly effective in diagnosing recurrent disease, especially in those with a rising carcinoembryonic antigen without a suspect lesion on conventional imaging. Large series have indicated that the sensitivity and specificity for detecting recurrent colorectal carcinoma are in the range of 87%-100% and 66%-100%, respectively. Equally, FDG-PET has a high sensitivity (68%-96%) and specificity (78%-100%) in detecting pancreatic carcinoma in patients with a suspicious-looking pancreatic mass on CT scan. Lastly, we focus on the use of FDG-PET as a modality for early monitoring of treatment response in patients with gastrointestinal stromal cell tumours. Without doubt, future developments will further establish the diagnostic role of the FDG-PET scan in the care of patients with gastrointestinal cancers. [ABSTRACT FROM AUTHOR]