Deep learning classification of ex vivo human colon tissues using spectroscopic optical coherence tomography.

Screening for colorectal cancer (CRC) with colonoscopy has improved patient outcomes; however, it remains the third leading cause of cancer-related mortality, novel strategies to improve screening are needed. Here, we propose an optical biopsy technique based on spectroscopic optical coherence tomography (OCT). Depth resolved OCT images are analyzed as a function of wavelength to measure optical tissue properties and used as input to machine learning algorithms. Previously, we used this approach to analyze mouse colon polyps. Here, we extend the approach to examine human biopsied colonic epithelial tissue samples ex vivo. Optical properties are used as input to a novel deep learning architecture, producing accuracy of up to 97.9% in discriminating tissue type. SOCT parameters are used to create false colored en face OCT images and deep learning classifications are used to enable visual classification by tissue type. This study advances SOCT toward clinical utility for analysis of colonic epithelium.

Deep learning classification of ex vivo human colon tissues using spectroscopic OCT.

Screening programs for colorectal cancer (CRC) have had a profound impact on the morbidity and mortality of this disease by detecting and removing early cancers and precancerous adenomas with colonoscopy. However, CRC continues to be the third leading cause of cancer-related mortality in both men and woman, partly because of limitations in colonoscopy-based screening. Thus, novel strategies to improve the efficiency and effectiveness of screening colonoscopy are urgently needed. Here, we propose to address this need using an optical biopsy technique based on spectroscopic optical coherence tomography (OCT). The depth resolved images obtained with OCT are analyzed as a function of wavelength to measure optical tissue properties. The optical properties can be used as input to machine learning algorithms as a means to classify adenomatous tissue in the colon. In this study, biopsied tissue samples from the colonic epithelium are analyzed ex vivo using spectroscopic OCT and tissue classifications are generated using a novel deep learning architecture, informed by machine learning methods including LSTM and KNN. The overall classification accuracy obtained was 88.9%, 76.0% and 97.9% in discriminating tissue type for these methods. Further, we apply an approach using false coloring of en face OCT images based on SOCT parameters and deep learning predictions to enable visual identification of tissue type. This study advances the spectroscopic OCT towards clinical utility for analyzing colonic epithelium for signs of adenoma.

No Microscope Needed: A Macroscopic Presentation of Collagenous Colitis.

Microscopic colitis (MC) is a common cause of chronic secretory diarrhea with variable etiologies, including nonsteroidal anti-inflammatory drugs. As its name implies, the diagnosis requires consistent histopathologic findings that typically accompany normal-appearing mucosa. However, accumulating evidence suggests that the presence of distinct endoscopic features is associated with MC. We present a case of MC that highlights the importance of recognizing these macroscopic findings because they can aid in diagnosis and have significant management implications.

Adverse Events and Reinterventions Following Pancreatic Endoscopic Sphincterotomy.

OBJECTIVES: Pancreatic endoscopic sphincterotomy (PES) is an independent risk factor for short- and long-term adverse events (AEs) of endoscopic retrograde cholangiopancreatography. We sought to measure PES-specific AEs and trends in the use of PES. METHODS: This was a retrospective cohort of consecutive patients who underwent first-time PES between June 2008 and June 2015. Indications for PES were dichotomized: (1) structural pathology (chronic pancreatitis and local complications of acute pancreatitis) and (2) suspected sphincter pathology (idiopathic recurrent acute pancreatitis and sphincter of Oddi dysfunction). Rates of AEs and pancreatic orifice reinterventions were measured, with reintervention rates limited to those having a minimum of 12-month follow-up. RESULTS: Of 567 patients, 198 (34.9%) underwent PES for structural and 369 (65.1%) for suspected sphincter pathology. Rates of post-endoscopic retrograde cholangiopancreatography pancreatitis and unplanned hospitalization were high when PES was originally performed for suspected sphincter pathology (12.6% and 14.6%, respectively). The overall reintervention rate was 28.9% and significantly greater for sphincter (41.7%) compared with structural pathology (13.5%, P = 0.005). CONCLUSIONS: The likelihood of reintervention after PES is high, particularly when the primary indication is suspected sphincter pathology such as idiopathic recurrent acute pancreatitis. Further prospective studies are needed to clarify if and when this maneuver confers significant benefit to patients.

A survey of credentialing for ERCP in the United States.

BACKGROUND AND AIMS: There are limited data measuring the variability in standards used by hospitals for credentialing physicians to ERCP in the United States. METHODS: We performed an electronic survey of U.S. gastroenterologists. RESULTS: Among 1126 respondents, 21% reported that their hospitals had no written guidelines for initial credentialing, and 59% reported that their hospitals had no written guidelines for repeat credentialing. Among those with guidelines, less than half had any of the criteria recommended by the American Society for Gastrointestinal Endoscopy. CONCLUSIONS: There is an urgent need to improve the credentialing process to enhance practice and to protect patients. An easy-to-use national system for recording and reporting ERCP quality data, like that of the GI Quality Improvement Consortium, is needed.

Cap-assisted retrograde single-balloon enteroscopy results in high terminal ileal intubation rate.

BACKGROUND AND STUDY AIMS: Retrograde single-balloon enteroscopy (RSBE) facilitates evaluation of the distal small bowel and provision of appropriate therapy when necessary. Intubation of the terminal ileum (TI) is a major rate-limiting step, with failure rates as high as 30 %. Cap-assisted endoscopy has proven beneficial in other aspects of endoscopy. We have noticed that it similarly aids in TI intubation during RSBE by facilitating opening of the ileocecal valve (ICV). The primary aim of this study was to measure the TI intubation rate using cap-assisted RSBE. Other procedural details and outcomes were also measured. PATIENTS AND METHODS: A total of 36 consecutive RSBEs performed between July 2011 and May 2014 at the Medical University of South Carolina were retrospectively reviewed. All procedures were performed or supervised by our center's small bowel endoscopist (ASB). Outcomes measured included TI intubation rate, procedure time, depth of maximal insertion (DMI), diagnostic yield (DY), therapeutic yield (TY), and complications. RESULTS: The TI intubation rate was 97 % (35 /36). The one failure was due to stool completely obscuring the cecum. Median procedure time was 54 minutes, with a mean DMI of 68 cm beyond the ICV. The technical success rate was 86 %, whereas DY and TY were 61 % and 25 %, respectively. There were no complications. The study was limited in that it involved a single endoscopist at a single center. CONCLUSIONS: Cap-assisted RSBE results in a high TI intubation rate, without compromise to safety or procedural yield.

Elevated gray and white matter densities in cocaine abstainers compared to current users.

RATIONALE: Numerous neuroimaging studies have demonstrated lower neural tissue density in chronic cocaine users, which may be linked to cognitive dysfunction. OBJECTIVES: The goal of this study was to determine whether neural tissue density was also impaired in individuals abstinent from cocaine and whether any observed changes were associated with cognitive performance. METHODS: A total of 73 participants were included: 24 active cocaine users, 24 abstainers (abstinent for at least 1 month), and 25 nondrug-abusing controls rigorously matched for age, gender, and IQ. All participants performed a cognitive assessment battery and received an MRI which was analyzed using voxel-based morphometry. RESULTS: The abstainers had significantly higher gray matter density than the current cocaine users in neocortical areas including the frontal and temporal cortex. In contrast to the users, there was no difference in white matter density in the abstainers relative to the controls. The abstainers performed better than current users on several behavioral tasks. Within users and abstainers, cortical density was correlated with performance on memory and reaction time tasks. Subcortical gray matter density was lower in both the users and abstainers relative to the controls. Within abstainers, subcortical tissue density was correlated with the ability to set-shift. CONCLUSIONS: These data suggest that individuals able to remain abstinent from cocaine for at least 1 month have elevated neocortical tissue density and perform better on multiple cognitive tests, relative to current cocaine users. Larger, longitudinal studies are needed to address this interaction between abstinence, cognition, and cortical tissue density directly.

Glut1 and Glut3 expression in lymphoma and their association with tumor intensity on 18F-fluorodeoxyglucose positron emission tomography.

OBJECTIVE: To evaluate the expression of glucose transporters (Gluts) 1 and 3 in Hodgkin and nonHodgkin lymphoma and to assess the association between their expression and the tumor intensity on 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET). METHODS: All 31 lymphoma patients in whom the histologic diagnosis was made and who had also undergone a prechemotherapy PET scan at our institution between June 2001 and December 2005 were included in this retrospective study. The percentage of tumor cells in the various lymphoma subtypes was estimated by comparison of hematoxylin and eosin stain with a lineage-associated immunohistochemical stain on the same block of tissue. Tissue specimens were stained with Glut1 and Glut3 antibodies. The percentages of Glut1+ and Glut3+ cells in the entire cell population (lymphoma cells and nonlymphomatous cells) and among the lymphoma cells were estimated. FDG PET images were reviewed and the tumor intensity was assessed by calculating the maximum standard uptake value (SUVmax). Correlation coefficients between SUVmax and the percentage of Glut1+ and Glut3+ cells in the entire cell population were calculated. RESULTS: In all 31 cases, tumors were visible on FDG PET and positive for Glut1 and Glut3. The correlation between the percentage of Glut1+ cells and SUVmax was statistically significant across all 31 cases (r = 0.73, P<0.0001, 95% confidence interval: 0.50-0.86) and across the 25 cases of nonHodgkin lymphoma (r = 0.71, P<0.0001, 95% confidence interval: 0.44-0.87). There was no statistically significant correlation between the percentage of Glut3+ cells and SUVmax. More importantly, in 16 of 31 cases (52%), only nonlymphomatous, benign cells expressed Glut1 or Glut3. CONCLUSION: Intensity of lymphoma on FDG PET is likely associated with Glut1 expression. The nonlymphomatous, benign cells may play an important role in visualization of lymphoma on FDG PET.