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Nishioka, Norman

Spectrally encoded confocal microscopy and optical frequency domain imaging are two non-contact optical imaging technologies that provide images of tissue cellular and architectural morphology, which are both used for histopathological diagnosis. Although spectrally encoded confocal microscopy has better transverse resolution than optical frequency domain imaging, optical frequency domain imaging can penetrate deeper into tissues, which potentially enables the visualization of different morphologic features. We have developed a co-registered spectrally encoded confocal microscopy and optical frequency domain imaging system and have obtained preliminary images from human oesophageal biopsy samples to compare the capabilities of these imaging techniques for diagnosing oesophageal pathology.

Endoscopic mucosal resection (EMR) is being advocated as a diagnostic, staging, and therapeutic technique for the management of Barrett esophagus (BE)-related neoplasia. With the emergence of new endoluminal therapy including EMR for the treatment of BE-related superficial adenocarcinomas, accurate staging has become crucial to select patients for different treatment arms. Intramucosal adenocarcinomas can be successfully treated by endoluminal techniques, whereas submucosal invasive tumors with a greater risk of lymph node metastasis are likely candidates for esophagectomy. Endoscopic ultrasound (EUS) is used to stage superficial BE-related neoplasms, yet endoscopic staging can be incongruent to that obtained after pathologic examination. In this study, we sought to determine morphologic factors, which may influence EUS staging in 35 cases with intramucosal adenocarcinoma diagnosed by subsequent EMR, focusing on tumor characteristics and structural changes associated with BE. Among the latter duplication of the muscularis mucosae, either fragmented or well-organized, was seen in 64% of 11 cases that were overstaged as having submucosal invasion by EUS, compared with 38% of those accurately staged. A greater vertical thickness of the tumor was also associated with overstaging by EUS (1.61+/-0.75 mm in the discordant vs. 1.16+/-0.67 mm in the concordant groups, P=0.028). The results illustrate how morphologic factors may affect EUS staging of superficial esophageal adenocarcinomas. EUS alone is not sufficient for staging these neoplasms precisely, and to accurately stratify patients into different treatment arms, EMR should play a role as a complementary staging modality.

Here, we introduce “tethered capsule endomicroscopy,” that involves swallowing an optomechanically-engineered pill that captures cross-sectional, 30 μm (lateral) × 7 μm (axial) resolution, microscopic images of the gut wall as it travels through the digestive tract. Results in human subjects show that this technique rapidly provides three-dimensional, microstructural images of the upper gastrointestinal tract in a simple and painless procedure, opening up new opportunities for screening for internal diseases.

Cyclooxygenase-2 expression is upregulated in Barrett’s esophagus and esophageal adenocarcinoma. Photodynamic therapy using porfimer sodium can result in ablation of dysplasia and intramucosal carcinoma, eradication of Barrett’s esophagus, and restitution of squamous epithelium. The aim of this study was to determine the effect of photodynamic therapy on cyclooxygenase-2 expression in esophageal epithelium. Paired pre- and post-photodynamic therapy biopsy samples from the same anatomical levels of 20 individuals who had undergone photodynamic therapy for Barrett’s esophagus with high-grade dysplasia and/or intramucosal carcinoma were immunostained using a cyclooxygenase-2 monoclonal antibody. Cyclooxygenase-2 expression was graded in squamous epithelium, Barrett’s esophagus, and neoplasia (if present) as follows: grade 0 (no staining), grade 1 (staining in 1–10% of cells), grade 2 (staining in 11–90% of cells), and grade 3 (staining in >90% of cells). Pre-photodynamic therapy median cyclooxygenase-2 expression was grade 2 (range 1–3) in neoplastic foci and grade 1 (range 1–3) in nondysplastic Barrett’s esophagus (P = 0.0009 for pairwise comparison). With the exception of a few cells staining in the basal epithelial layers, median cyclooxygenase-2 expression was graded as 0 (similar to controls) in both pre-photodynamic therapy squamous epithelium and post-photodynamic therapy neosquamous epithelium. This was significantly lower when compared to either neoplastic foci (P < 0.0001) or nondysplastic Barrett’s esophagus (P < 0.0001) pre-photodynamic therapy. Notably, in four patients with post-photodynamic therapy recurrent neoplasia, cyclooxygenase-2 expression returned to elevated levels. Cyclooxygenase-2 expression is elevated in Barrett’s esophagus with high-grade dysplasia or intramucosal carcinoma prior to photodynamic therapy. Following successful photodynamic therapy, cyclooxygenase-2 expression in neosquamous epithelium returns to a low baseline level similar to that observed in native esophageal squamous epithelium. Post-photodynamic therapy neoplastic recurrence is associated with elevated cyclooxygenase-2 expression. Prospective studies should determine whether cyclooxygenase inhibitors have a role as adjuvant therapy to prevent recurrence of Barrett’s esophagus following endoscopic therapy.

Background: Diagnosis of eosinophilic esophagitis (EoE) currently requires endoscopic biopsy and histopathologic analysis of the biopsy specimens to count intraepithelial eosinophils. Reflectance confocal microscopy (RCM) is an endomicroscopy technology that is capable of obtaining high-resolution, optically sectioned images of esophageal mucosa without the administration of exogenous contrast. Objective: In this study, we investigated the capability of a high-speed form of RCM, termed spectrally encoded confocal microscopy (SECM), to count intraepithelial esophageal eosinophils and characterize other microscopic findings of EoE. Design: A total of 43 biopsy samples from 35 pediatric patients and 8 biopsy samples from 8 adult patients undergoing EGD for EoE were imaged by SECM immediately after their removal and then processed for routine histopathology. Two SECM readers, trained on adult cases, prospectively counted intraepithelial eosinophils and detected the presence of abscess, degranulation, and basal cell hyperplasia on SECM images from the pediatric patients. A pathologist blinded to the SECM data analyzed the same from corresponding slides. Setting: The Gastrointestinal Unit, Massachusetts General Hospital. Results: Eosinophils by SECM demonstrated a higher reflectance than the surrounding cells and other inflammatory cells. There was good correlation between SECM and histology maximum eosinophil counts/high-power field (R = 0.76, P < .0001). Intra- and interobserver correlations for SECM counts were very good (R = 0.93 and R = 0.92, respectively; P < .0001). For the commonly used eosinophil count cutoff of 15 per high-power field, the sensitivity and specificity of SECM for EoE were 100%. The sensitivity and specificity for abscess, degranulation, and basal cell hyperplasia were 100% and 82%, 91% and 60%, and 94% and 80%, respectively. Intra- and interobserver agreements for these microscopic features of EoE were very good (κ = 0.9/0.9, 0.84/1.0, 0.91/0.81, respectively). Limitation: Ex vivo study. Conclusions: This study demonstrates that RCM can be used to accurately count intraepithelial eosinophils and identify other microscopic abnormalities associated with EoE on freshly excised biopsy samples. These findings suggest that RCM may be developed into a tool for assessing eosinophilic infiltration in the esophagus in vivo.

Background: Optical coherence tomography (OCT) is an optical imaging method that produces high-resolution cross-sectional images of the esophagus. The accuracy of OCT for differentiating tissue types at the squamocolumnar junction (SCJ) has not been established. Objective: The purpose of this study was to identify and validate OCT image criteria for distinguishing metaplastic from nonmetaplastic tissue at the SCJ. Design: A total of 196 biopsy-correlated OCT images of the SCJ were acquired from 113 patients undergoing upper endoscopy. A pathologist blinded to the OCT results reviewed each pathology specimen and determined the presence of the following histopathology: gastric cardia, squamous mucosa, pancreatic metaplasia, and intestinal metaplasia. An algorithm for diagnosing specialized intestinal metaplasia (SIM) was created by reviewing a training set of 40 biopsy-correlated OCT images. Two blinded investigators prospectively tested the algorithm on a validation set of 123 images. Results: OCT images of squamous mucosa were characterized by a layered appearance without epithelial glands; gastric cardia, by vertical pit and gland structure, a well-defined epithelial surface reflectivity, and relatively poor image penetration; and SIM by an irregular architecture and good image penetration. The OCT criteria were 85% sensitive and 95% specific for SIM when applied retrospectively to the training set. When applied to the validation set, the algorithm was 81% sensitive for both OCT readers and 66% and 57% specific for diagnosing SIM. The interobserver agreement was good (κ = 0.53). Conclusions: OCT imaging can identify SIM at the SCJ with an accuracy similar to that of endoscopy.

Background: Random biopsy esophageal surveillance can be subject to sampling errors, resulting in diagnostic uncertainty. Optical frequency domain imaging (OFDI) is a high-speed, 3-dimensional endoscopic microscopy technique. When deployed through a balloon-centering catheter, OFDI can automatically image the entire distal esophagus (6.0 cm length) in approximately 2 minutes. Objective: To test a new platform for guided biopsy that allows the operator to select target regions of interest on an OFDI dataset, and then use a laser to mark the esophagus at corresponding locations. The specific goals include determining the optimal laser parameters, testing the accuracy of the laser marking process, evaluating the endoscopic visibility of the laser marks, and assessing the amount of mucosal damage produced by the laser. Design: Experimental study conducted in 5 swine in vivo. Setting: Massachusetts General Hospital. Main Outcome Measurements: Success rate, including endoscopic visibility of laser marks and accuracy of the laser marking process for selected target sites, and extent of the thermal damage caused by the laser marks. Results: All of the laser-induced marks were visible by endoscopy. Target locations were correctly marked with a success rate of 97.07% (95% confidence interval, 89.8%-99.7%). Thermal damage was limited to the superficial layers of the mucosa and was observed to partially heal within 2 days. Limitations: An animal study with artificially placed targets to simulate pathology. Conclusions: The study demonstrates that laser marking of esophageal sites identified in comprehensive OFDI datasets is feasible and can be performed with sufficient accuracy, precision, and visibility to guide biopsy in vivo.

Background: Although aspirin is recommended for the prevention of colorectal cancer, the specific individuals for whom the benefits outweigh the risks are not clearly defined. Moreover, the precise mechanisms by which aspirin reduces the risk of cancer are unclear. We recently launched the ASPirin Intervention for the REDuction of colorectal cancer risk (ASPIRED) trial to address these uncertainties. Methods/design ASPIRED is a prospective, double-blind, multidose, placebo-controlled, biomarker clinical trial of aspirin use in individuals previously diagnosed with colorectal adenoma. Individuals (n = 180) will be randomized in a 1:1:1 ratio to low-dose (81 mg/day) or standard-dose (325 mg/day) aspirin or placebo. At two study visits, participants will provide lifestyle, dietary and biometric data in addition to urine, saliva and blood specimens. Stool, grossly normal colorectal mucosal biopsies and cytology brushings will be collected during a flexible sigmoidoscopy without bowel preparation. The study will examine the effect of aspirin on urinary prostaglandin metabolites (PGE-M; primary endpoint), plasma inflammatory markers (macrophage inhibitory cytokine-1 (MIC-1)), colonic expression of transcription factor binding (transcription factor 7-like 2 (TCF7L2)), colonocyte gene expression, including hydroxyprostaglandin dehydrogenase 15-(NAD) (HPGD) and those that encode Wnt signaling proteins, colonic cellular nanocytology and oral and gut microbial composition and function. Discussion Aspirin may prevent colorectal cancer through multiple, interrelated mechanisms. The ASPIRED trial will scrutinize these pathways and investigate putative mechanistically based risk-stratification biomarkers. Trial registration This protocol is registered with the U.S. National Institutes of Health trial registry, ClinicalTrials.gov, under the identifier NCT02394769. Registered on 16 March 2015. Electronic supplementary material The online version of this article (doi:10.1186/s13063-016-1744-z) contains supplementary material, which is available to authorized users.

Abstract. While color video endoscopy has enabled wide-field examination of the gastrointestinal tract, it often misses or incorrectly classifies lesions. Many of these missed lesions exhibit characteristic three-dimensional surface topographies. An endoscopic system that adds topographical measurements to conventional color imagery could therefore increase lesion detection and improve classification accuracy. We introduce photometric stereo endoscopy (PSE), a technique which allows high spatial frequency components of surface topography to be acquired simultaneously with conventional two-dimensional color imagery. We implement this technique in an endoscopic form factor and demonstrate that it can acquire the topography of small features with complex geometries and heterogeneous optical properties. PSE imaging of ex vivo human gastrointestinal tissue shows that surface topography measurements enable differentiation of abnormal shapes from surrounding normal tissue. Together, these results confirm that the topographical measurements can be obtained with relatively simple hardware in an endoscopic form factor, and suggest the potential of PSE to improve lesion detection and classification in gastrointestinal imaging.

Background: Spectrally encoded confocal microscopy (SECM) is a high-speed reflectance confocal microscopy technique that has the potential to be used for acquiring comprehensive images of the entire distal esophagus endoscopically with subcellular resolution. Objective: The goal of this study was to demonstrate large-area SECM in upper GI tissues and to determine whether the images contain microstructural information that is useful for pathologic diagnosis. Design: A feasibility study. Setting: Gastrointestinal Unit, Massachusetts General Hospital. Patients: Fifty biopsy samples from 36 patients undergoing routine EGD were imaged by SECM, in their entirety, immediately after their removal. Results: The microstructure seen in the SECM images was similar to that seen by histopathology. Gastric cardia mucosa was clearly differentiated from squamous mucosa. Gastric fundic/body type mucosa showed more tightly packed glands than gastric cardia mucosa. Fundic gland polyps showed cystically dilated glands lined with cuboidal epithelium. The presence of intraepithelial eosinophils was detected with the cells demonstrating a characteristic bilobed nucleus. Specialized intestinal metaplasia was identified by columnar epithelium and the presence of goblet cells. Barrett's esophagus (BE) with dysplasia was differentiated from specialized intestinal metaplasia by the loss of nuclear polarity and disorganized glandular architecture. Limitations: Ex vivo, descriptive study. Conclusions: Large-area SECM images of gastroesophageal biopsy samples enabled the visualization of both subcellular and architectural features of various upper GI mucosal types and were similar to the corresponding histopathologic slides. These results suggest that the development of an endoscopic SECM probe is merited.