Volumetric Laser Endomicroscopy Scans Research Articles

Institutional Experience in Diagnostic Usability of Volumetric Laser Endo-Microscopy in Barrettʼs Esophagus

Introduction: Barrett's Esophagus (BE) is a well-known precursor lesion to Esophageal Adenocarcinoma. Random four-quadrant biopsies every 1-2 cm (the Seattle Biopsy Protocol) in addition to aggressive sampling of any mucosal abnormality has been recommended; however, there is controversy about the intense biopsy sampling protocol in detecting the incidental Barrett's dysplasia and cancer. Volumetric laser endomicroscopy (VLE) is a novel second-generation optical coherence tomography imaging procedure that elicits volumetric cross-sectional and longitudinal images over six cm of the esophagus with resolution less than ten microns Methods: A prospective enrollment of patients with known BE at our institution was conducted from September 2014-Febuary 2015. Patients were undergoing surveillance and/or therapeutic endoscopic procedures along with VLE. Patients of age 18 and above with history of BE were included. Based on VLE findings; lesions with high-risk features were identified and targeted biopsies were taken. Seattle protocol biopsies, which is the standard of care, were also taken in four quadrants every 1 cm for surveillance. Biopsies were evaluated by two-blinded pathologists. Results: Fifty-two patients with known BE were included in the analysis. There were no adverse events associated with the use of VLE. Mean age was 66 +/- 10 years with 71% males (n=37). Out of 52 patients, 41(79 %) underwent prior radio frequency ablations and/or endoscopic mucosal resections. Seattle protocol biopsies were performed in all 52 cases and additional targeted biopsies were performed in 46 cases as prompted by findings seen on VLE. Out of 52 cases, 21 were found to have BE on histopathology. VLE scans were abnormal in 19 out of 21 patients giving the sensitivity of 91% and NPV of 75%. One patient with BE had normal HD-WLE but abnormal features were detected on VLE scan. The two patients missed on VLE scanning had small foci of non-dysplastic BE at the gastro-esophageal junction and these were appreciated as small islands on HD-WLE. All the cases of BE were detected with combination HD-WLE and VLE. Conclusion: VLE is a reliable clinical modality which can be used for detection of BE. When used in conjunction with HD-WLE, the diagnostic yield is favorable and can decrease the miss rate of BE. Our study demonstrated excellent sensitivity and NPV. We believe there is a learning curve and further experience will only improve the diagnostic yield.

Detection of buried Barrett’s glands after radiofrequency ablation with volumetric laser endomicroscopy

The prevalence and clinical relevance of buried Barrett's glands (BB) after radiofrequency ablation (RFA) in Barrett's esophagus (BE) are debated. Recent optical coherence tomography studies demonstrated a high prevalence of BBs. Direct histological correlation, however, has been lacking. Volumetric laser endomicroscopy (VLE) is a second-generation optical coherence tomography system capable of scanning a large surface of the esophageal wall layers with low-power microscopy resolution. The aim was to evaluate whether post-RFA subsquamous glandular structures (SGSs), detected with VLE, actually correspond to BBs by pursuing direct histological correlation with VLE images. In vivo VLE was performed to detect SGSs in patients with endoscopic regression of BE post-RFA. A second in vivo VLE scan was performed to confirm correct delineation of the SGSs. After endoscopic resection, the specimens were imaged ex vivo with VLE. Extensive histological sectioning of SGS areas was performed, and all histology slides were evaluated by an expert BE pathologist. Seventeen patients underwent successful in vivo VLE (histological diagnosis before endoscopic treatment: early adenocarcinoma in 8 patients and high-grade dysplasia in 9). In 4 of 17 patients, no SGSs were identified during VLE, and a random resection was performed. In the remaining 13 patients (76%), VLE detected SGS areas, which were all confirmed on a second in vivo VLE scan and subsequently resected. Most SGSs identified by VLE corresponded to normal histological structures (eg, dilated glands and blood vessels). However, 1 area containing BBs was found on histology. No specific VLE features to distinguish between BBs and normal SGSs were identified. VLE is able to detect subsquamous esophageal structures. One area showed BBs beneath endoscopically normal-appearing neosquamous epithelium; however, most post-RFA SGSs identified by VLE correspond to normal histological structures. ( NTR4056.).

Mo1501 Attending Endoscopists and Gastroenterology (GI) Trainees Have Similar Performance When Characterizing Diminutive Colorectal Polyps With Narrow Band Imaging (NBI)

Mo1501 Attending Endoscopists and Gastroenterology (GI) Trainees Have Similar Performance When Characterizing Diminutive Colorectal Polyps With Narrow Band Imaging (NBI)

Endoscopy and gastrointestinal neoplasia: Diagnosis and management

Volumetric laser endomicroscopy (VLE) is an advanced imaging system that provides a near-microscopic resolution scan of the esophageal wall layers up to 3-mm deep. VLE has the potential to improve detection of early neoplasia in Barrett’s esophagus (BE). However, interpretation of VLE images is complex because of the large amount of data that need to be interpreted in real time. The aim of this study was to investigate the feasibility of a computer algorithm to identify early BE neoplasia on ex vivo VLE images.We used 60 VLE images from a database of high-quality ex vivo VLE-histology correlations, obtained from BE patients ± neoplasia (30 nondysplastic BE [NDBE] and 30 high-grade dysplasia/early adenocarcinoma images). VLE features from a recently developed clinical VLE prediction score for BE neoplasia served as input for the algorithm: (1) higher VLE surface than subsurface signal and (2) lack of layering. With this input, novel clinically inspired algorithm features were developed, based on signal intensity statistics and grayscale correlations. For comparison, generic image analysis methods were examined for their performance to detect neoplasia. For classification of the images in the NDBE or neoplastic group, several machine learning methods were evaluated. Leave-1-out cross-validation was used for algorithm validation.Three novel clinically inspired algorithm features were developed. The feature “layering and signal decay statistics” showed the optimal performance compared with the other clinically features (“layering” and “signal intensity distribution”) and generic image analyses methods, with an area under the receiver operating characteristic curve (AUC) of .95. Corresponding sensitivity and specificity were 90% and 93%, respectively. In addition, the algorithm showed a better performance than the clinical VLE prediction score (AUC .81).This is the first study in which a computer algorithm for BE neoplasia was developed based on VLE images with direct histologic correlates. The algorithm showed good performance to detect BE neoplasia in ex vivo VLE images compared with the performance of a recently developed clinical VLE prediction score. This study suggests that an automatic detection algorithm has the potential to assist endoscopists in detecting early neoplasia on VLE. Future studies on in vivo VLE scans are needed to further validate the algorithm.