Image-enhanced endoscopy with I-scan technology for the evaluation of duodenal villous patterns.

BACKGROUND: I-scan technology is the newly developed endoscopic tool that works in real time and utilizes a digital contrast method to enhance endoscopic image. AIMS: We performed a feasibility study aimed to determine the diagnostic accuracy of i-scan technology for the evaluation of duodenal villous patterns, having histology as the reference standard. METHODS: In this prospective, single center, open study, patients undergoing upper endoscopy for an histological evaluation of duodenal mucosa were enrolled. All patients underwent upper endoscopy using high resolution view in association with i-scan technology. During endoscopy, duodenal villous patterns were evaluated and classified as normal, partial villous atrophy, or marked villous atrophy. Results were then compared with histology. RESULTS: One hundred fifteen subjects were recruited in this study. The endoscopist was able to find marked villous atrophy of the duodenum in 12 subjects, partial villous atrophy in 25, and normal villi in the remaining 78 individuals. The i-scan system was demonstrated to have great accuracy (100 %) in the detection of marked villous atrophy patterns. I-scan technology showed quite lower accuracy in determining partial villous atrophy or normal villous patterns (respectively, 90 % for both items). CONCLUSIONS: Image-enhancing endoscopic technology allows a clear visualization of villous patterns in the duodenum. By switching from the standard to the i-scan view, it is possible to optimize the accuracy of endoscopy in recognizing villous alteration in subjects undergoing endoscopic evaluation.

Quick test: a new test for the diagnosis of duodenal hypolactasia.

The hydrogen (H2) lactose breath test (BT) is a test commonly used for the diagnosis of hypolactasia. However, its sensitivity is not always good. In the last few years, the new Quick Lactase Test (QLT) has been developed for endoscopic diagnosis of adult-type hypolactasia. The aim of this study was to compare the efficacy of the new QLT with the traditional H2 lactose BT for the diagnosis of hypolactasia. Fifty dyspeptic patients (19 male, 31 female, mean age 38 +/- 6) were enrolled in the study. All the patients were subjected to the H2 lactose BT and to upper gastrointestinal endoscopy. Two postbulbar duodenal biopsies were used for the QLT (Biohit, Helsinki, Finland). The duodenum biopsies were incubated with lactose on a test plate: in patients with normolactasia a colour reaction develops as a result of hydrolysed lactose (positive result), whereas no reaction develops in patients with mild or severe hypolactasia (negative results). Twenty-two out of 50 patients (44%) had a positive H2 lactose BT. Among them, 21 showed a mild or severe hypolactasia with the QLT. When we considered patients with a negative H2 lactose BT (28 out of 50), 24 patients showed normal lactase activity in duodenal biopsies with the QLT, whereas in 4 patients there was discordance between the two tests. These patients were re-evaluated with a methane (CH4) and an H2 lactose BT and 3 of them were H2 non-producers with a high level of CH4 production. Only 1 patient with a negative result in the QLT remains negative to lactose BT. Our study showed a good correlation between the H2 lactose BT and the new QLT in the diagnosis of adult-type hypolactasia for the majority of patients. However, the QLT seems to be more sensitive than the H2 lactose BT, helping to identify a subgroup of patients with adult-type hypolactasia with a negative result in the H2 lactose BT. Based on these results we suggest performing the less expensive and more rapid QLT during the upper gastrointestinal endoscopy to evaluate the presence of lactase activity in duodenal biopsies.

Role of the "immersion technique" in diagnosing celiac disease with villous atrophy limited to the duodenal bulb.

GOALS: To investigate if the so-called immersion technique during upper endoscopy may be helpful to predict patterns of villous atrophy restricted to the duodenal bulb. BACKGROUND: Patients with celiac disease may have a patchy distribution of duodenal villous atrophy. In some cases, mucosa of duodenal bulb may be the only intestinal area involved. The immersion technique is a novel procedure that allows visualizing duodenal villi directly during endoscopy. STUDY: With this prospective study, the immersion duodenoscopy was performed in 67 celiac subjects to investigate their duodenal villous pattern. Villi were evaluated both in the first and in the second duodenal segment and judged as present or absent (flat mucosa). Results were compared with histology as reference. RESULTS: Among celiac subjects, 49 were newly diagnosed and 18 previously diagnosed celiac patients. Four (8%) newly diagnosed and 7 (39%) previously diagnosed celiac subjects had an extension of the villous atrophy (flat mucosa) limited to the duodenal bulb. The sensitivity, specificity, and positive and negative predictive values of the immersion-based duodenal investigation in predicting areas of duodenal villous atrophy was always 100%. CONCLUSIONS: Immersion technique may be useful for directing duodenal biopsies in celiac subjects with a patchy distribution of villous atrophy. This procedure can avoid blinded sampling of the duodenal mucosa and enhance the diagnostic yield.