Charles D. Melville

Tethered Capsule Endoscopy, A Low-Cost and High-Performance Alternative Technology for the Screening of Esophageal Cancer and Barrett's Esophagus

Esophageal cancer is currently the fastest growing cancer in the United States. To help combat the recent rise in morbidity, our laboratory has developed a low-cost tethered capsule endoscope system (TCE) aimed at improving early detection of esophageal cancer. The TCE contains a resonant fiberoptic laser scanner (1.6 mm O.D.) which fits into 6.4-mm easy-to-swallow capsule at the distal tip. The tethered portion contains a single mode optical fiber multiplexed to three laser diodes at the proximal end. This design offers two main advantages over current endoscope technology. First, because of its small size, the TCE can be swallowed with minimal patient discomfort, thereby obviating sedation. Second, by imaging via directed laser light, the TCE is strategically positioned to employ several burgeoning laser-based diagnostic technologies, such as narrow-band, hyperspectral, and fluorescence imaging. It is believed that the combination of such imaging techniques with novel biomarkers of dysplasia will greatly assist in identifying precancerous conditions such as Barretts esophagus (BE). As the probe is swallowed, the fiber scanner captures high resolution, wide-field color images of the gastroesophageal junction (500 lines at 0.05-mm resolution) currently at 15-Hz frame rate. Video images are recorded as the capsule is slowly retracted by its tether. Accompanying software generates panoramic images from the video output by mosaicing individual frames to aid in pattern recognition. This initial report describes the rationale for the unique TCE system design, results from preliminary testing in vitro and in vivo, and discussion on the merits of this new platform technology as a basis for developing a low-cost screening program for esophageal cancer.

Su2005 Nanomolar Detection Sensitivity in Wide-Field Multispectral Fluorescence Endoscopy

G A A b st ra ct s histology. Methods: BE patients with and without early neoplasia underwent endoscopic resection (ER) of areas marked in-vivo with electrocoagulation markers (ECM). Subsequently ER specimens underwent additional ex-vivo marking with several different markers (ink, pin, ECM) followed by ex-vivo VLE scanning. Tissue blocks were carefully sectioned guided by the placed markers. After further histological processing a histopathology slide was sectioned from each block. When necessary, extensive sectioning of tissue blocks was performed in order to visualize all markers that were included in the tissue block on histology. All histopathology and VLE slides were evaluated by 2 researchers and considered a match if a) ≥ 2 markers were visible on both modalities and b) mucosal patterns aside from these markers matched on both histology and VLE. All slides were evaluated by an expert BE pathologist. Results: From 16 ER specimens (overall diagnosis: 7 non-dysplastic BE, 9 dysplastic BE (1 LGD, 4 HGD, 4 EAC)) 120 tissue blocks were sectioned of which 57 contained multiple markers and thus could potentially be matched with VLE. Based on several combinations of these markers in total 14 histology-VLE matches could ultimately be constructed. Markers that achieved the best yield of matches respectively were: invivo placed ECMs (8 matches with 12 markers), pins (7 with 11), and ink (4 with 5). Histopathological evaluation was not hindered by marker use. In this pilot study the last 6 ER specimens yielded 9/14 matches demonstrating a clear learning curve due to methodological improvements in marker placement and tissue block sectioning. Conclusion: One-to-one correlation of VLE and histology is complex but feasible. The groundwork laid in this study will provide high-quality histology-VLE correlations that will allow further research on VLE structures and VLE features of early neoplasia in BE.