Stefan Foertsch

Chromoendoscopy in magnetically guided capsule endoscopy

BackgroundDiagnosis of intestinal metaplasia and dysplasia via conventional endoscopy is characterized by low interobserver agreement and poor correlation with histopathologic findings. Chromoendoscopy significantly enhances the visibility of mucosa irregularities, like metaplasia and dysplasia mucosa. Magnetically guided capsule endoscopy (MGCE) offers an alternative technology for upper GI examination. We expect the difficulties of diagnosis of neoplasm in conventional endoscopy to transfer to MGCE. Thus, we aim to chart a path for the application of chromoendoscopy on MGCE via an ex-vivo animal study.MethodsWe propose a modified preparation protocol which adds a staining step to the existing MGCE preparation protocol. An optimal staining concentration is quantitatively determined for different stain types and pathologies. To that end 190 pig stomach tissue samples with and without lesion imitations were stained with different dye concentrations. Quantitative visual criteria are introduced to measure the quality of the staining with respect to mucosa and lesion visibility. Thusly determined optimal concentrations are tested in an ex-vivo pig stomach experiment under magnetic guidance of an endoscopic capsule with the modified protocol.ResultsWe found that the proposed protocol modification does not impact the visibility in the stomach or steerability of the endoscopy capsule. An average optimal staining concentration for the proposed protocol was found at 0.4% for Methylene blue and Indigo carmine. The lesion visibility is improved using the previously obtained optimal dye concentration.ConclusionsWe conclude that chromoendoscopy may be applied in MGCE and improves mucosa and lesion visibility. Systematic evaluation provides important information on appropriate staining concentration. However, further animal and human in-vivo studies are necessary.

Chromoendoscopy With Automatic Lesion Enhancement in Magnetically Guided Capsule Endoscopy: A Feasibility Study

G A A b st ra ct s for ability to detect and quantify DSS-induced acute colonic inflammation or chronic colitis in 129SvEv IL-10 null mice. We hypothesized that probes would differ in specificity or sensitivity for detection of inflammation. Methods: DSS-treated mice, IL-10 null mice with chronic colitis, and H2O controls were fed a liquid diet (Nutren 1.0 Fiber:dH2O, 1:1) for 4 days to clear GI tract of solid feces. WT mice were given 3% DSS for 5 days and studied 4 days later, a time of known severe colonic inflammation. Probes were given by retroorbital injection. In Vivo imaging was performed with an FMT 2500 LX imaging system. Intestinal tissues were dissected immediately after In Vivo imaging, imaged fresh or after fixation to test if NIRF signal is preserved in fixed tissues. Inflammation detected by probe activation was verified by H&E staining and confocal microscopy. NIRF signal intensity was quantified using 3D region of interest (ROI) analysis In Vivo or 2D ROI ex vivo. Results: (1) All 7 probes were tested In Vivo and ex vivo in DSS model. Several probes yielded significantly increased fluorescence signal (p<0.05) in colon of diseased mice versus H2O controls. Most sensitive probes were used and confirmed in IL-10 null mice. (2) In Vivo Cat K 680 FAST (152±14 vs. 82±5 pmol in fluorochromes, p<0.05) and MMPSense 680 (134±23 vs. 72±14 pmol in fluorochromes, p=0.06) probes yielded significantly higher NIRF signal in inflammation/colitis models vs. controls. Signal was localized to colon by coregistration with MRI. (2) Ex vivo, all 7 probes yielded significant increases in NIRF signal which was highest with MMPSense 680 (193.3% increase vs. controls) and cathepsin based probes (>100% increase vs. controls). (3) Ex vivo fluorescence signal was preserved by appropriate fixation. H&E staining and confocal microscopy confirmed inflammation detected by NIRF probes. NIRF signal intensity and colitis score were strongly correlated (r = 0.87). Conclusions: We developed a new In Vivo method for valid detection and quantification of GI inflammation using activatable NIRF probes in living animals. Cat K 680 FAST andMMPSense 680 probes were the most sensitive for detection and quantification of acute inflammation In Vivo and ex vivo. This approach is useful for In Vivo or ex vivo monitoring and quantification of murine inflammatory bowel diseases. 1 Zhang, Gastrointest Endosc 2008 68 520, 2 Marten, Gastroenterology 2002 122 406.

First Study With a MGCE Simulator: Is There a Benefit of Chromoendoscopy in Magnetically Guided Capsule Endoscopy?

gastroscopy in 6/10 patients (60% p=1), whereas no patient had ascites (p=0.21). VCE still showed small bowel lesions in 7/10 patients (p=0.21), . CONCLUSION: In our study VCE allowed the identification of small bowel lesions in all patients with portal hypertension. TIPS effectively reduces presence and severity of oesophageal varices, but the reduction of small bowel lesions, congestive gastropathy.and ascites was not significant, possibly due to the small patient series. The role of differing post-TIPS intervals should also be evaluated.