EUS compared with endoscopy plus transabdominal US in the initial diagnostic evaluation of patients with upper abdominal pain.

BACKGROUND: Primary upper endoscopy (EGD) and transabdominal US (TUS) are often performed in patients with upper abdominal pain. OBJECTIVE: Primary: Determine whether the combination of EGD and EUS was equivalent to EGD plus TUS in the diagnostic evaluation of upper abdominal pain. Secondary: Compare EUS versus TUS in detecting abdominal lesions, and compare EGD by using an oblique-viewing echoendoscope versus the standard, forward-viewing endoscope in detecting mucosal lesions. DESIGN: Prospective, paired design. SETTING: Six academic endoscopy centers. PATIENTS: This study involved patients with upper abdominal pain referred for endoscopy. INTERVENTION: All patients had EGD, EUS, and TUS. The EGD was done using both an oblique-viewing echoendoscope and the standard, forward-viewing endoscope (randomized order) by two separate endoscopists in a blinded fashion, followed by EUS. TUS was performed within 4 weeks of EGD/EUS, also in a blinded fashion. FOLLOW-UP: telephone interviews and chart reviews. MAIN OUTCOME MEASUREMENTS: Diagnose possible etiology of upper abdominal pain and detect clinically significant lesions. RESULTS: A diagnosis of the etiology of upper abdominal pain was made in 66 of 172 patients (38%). The diagnostic rate was 42 of 66 patients (64%) for EGD plus EUS versus 41 of 66 patients (62%) for EGD plus TUS, which was statistically equivalent (McNemar test; P = .27). One hundred ninety-eight lesions were diagnosed with either EUS or TUS. EUS was superior to TUS for visualizing the pancreas (P < .0001) and for diagnosing chronic pancreatitis (P = .03). Two biliary stones were detected only by EUS. Two hundred fifty-one mucosal lesions were similarly diagnosed with EGD with either the standard, forward-viewing endoscope or the oblique-viewing echoendoscope (kappa = 0.48 [95% CI, .43-.54]). EGD with the standard, forward-viewing endoscope was preferred for biopsies. LIMITATIONS: No cost analysis. CONCLUSION: The combination of EGD with EUS is equivalent to EGD plus TUS for diagnosing a potential etiology of upper abdominal pain. EUS is superior to TUS for detecting chronic pancreatitis. EGD combined with EUS should be considered in the first-line diagnostic evaluation of patients with upper abdominal pain.

Image analysis for classification of dysplasia in Barrett's esophagus using endoscopic optical coherence tomography.

Barrett's esophagus (BE) and associated adenocarcinoma have emerged as a major health care problem. Endoscopic optical coherence tomography is a microscopic sub-surface imaging technology that has been shown to differentiate tissue layers of the gastrointestinal wall and identify dysplasia in the mucosa, and is proposed as a surveillance tool to aid in management of BE. In this work a computer-aided diagnosis (CAD) system has been demonstrated for classification of dysplasia in Barrett's esophagus using EOCT. The system is composed of four modules: region of interest segmentation, dysplasia-related image feature extraction, feature selection, and site classification and validation. Multiple feature extraction and classification methods were evaluated and the process of developing the CAD system is described in detail. Use of multiple EOCT images to classify a single site was also investigated. A total of 96 EOCT image-biopsy pairs (63 non-dysplastic, 26 low-grade and 7 high-grade dysplastic biopsy sites) from a previously described clinical study were analyzed using the CAD system, yielding an accuracy of 84% for classification of non-dysplastic vs. dysplastic BE tissue. The results motivate continued development of CAD to potentially enable EOCT surveillance of large surface areas of Barrett's mucosa to identify dysplasia.

In vivo characterization of pancreatic and lymph node tissue by using EUS spectrum analysis: a validation study.

BACKGROUND: Quantitative spectral analysis of the radiofrequency (RF) signals that underlie grayscale EUS images can be used to provide additional, objective information about tissue state. OBJECTIVE: Our purpose was to validate RF spectral analysis as a method to distinguish between (1) benign and malignant lymph nodes and (2) normal pancreas, chronic pancreatitis, and pancreatic cancer. DESIGN AND SETTING: A prospective validation study of eligible patients was conducted to compare with pilot study RF data. PATIENTS: Forty-three patients underwent EUS of the esophagus, stomach, pancreas, and surrounding intra-abdominal and mediastinal lymph nodes (19 from a previous pilot study and 24 additional patients). MAIN OUTCOME MEASUREMENTS: Midband fit, slope, intercept, and correlation coefficient from a linear regression of the calibrated RF power spectra were determined. RESULTS: Discriminant analysis of mean pilot-study parameters was then performed to classify validation-study parameters. For benign versus malignant lymph nodes, midband fit and intercept (both with t test P < .058) provided classification with 67% accuracy and area under the receiver operating curve (AUC) of 0.86. For diseased versus normal pancreas, midband fit and correlation coefficient (both with analysis of variance P < .001) provided 93% accuracy and an AUC of 0.98. For pancreatic cancer versus chronic pancreatitis, the same parameters provided 77% accuracy and an AUC of 0.89. Results improved further when classification was performed with all data. LIMITATIONS: Moderate sample size and spatial averaging inherent to the technique. CONCLUSIONS: This study confirms that mean spectral parameters provide a noninvasive method to quantitatively discriminate benign and malignant lymph nodes as well as normal and diseased pancreas.

Characterization of pancreatic cancer and intra-abdominal lymph node malignancy using spectrum analysis of endoscopic ultrasound imaging.

This study assessed the ability of spectral analysis of endoscopic ultrasound (EUS) RF signals acquired in humans in vivo to distinguish between (1) benign and malignant intraabdominal and mediastinal lymph nodes and (2) pancreatic cancer, chronic pancreatitis, and normal pancreas. Mean midband fit, slope, intercept, and correlation coefficient from a linear regression of the calibrated RF power spectra were computed over regions of interest defined by the endoscopist. Linear discriminant analysis was then performed to develop a classification of the resulting spectral parameters. For lymph nodes, classification based on the midband fit and intercept provided 67% sensitivity, 82% specificity, and 73% accuracy for malignant vs. benign nodes. For pancreas, classification based on midband fit and correlation coefficient provided 95% sensitivity, 93% specificity, and 93% accuracy for diseased vs. normal pancreas and 85% sensitivity, 71% specificity, and 85% accuracy for pancreatic cancer vs. chronic pancreatitis. These promising results suggest that mean spectral parameters can provide a non-invasive method to quantitatively characterize pancreatic cancer and lymph malignancy in vivo.

Squamous overgrowth is not a safety concern for photodynamic therapy for Barrett's esophagus with high-grade dysplasia.

BACKGROUND & AIMS: Photodynamic therapy with porfimer sodium combined with acid suppression (PHOPDT) is used to treat patients with Barrett's esophagus (BE) with high-grade dysplasia (HGD). A 5-year phase 3 trial was conducted to determine the extent of squamous overgrowth of BE with HGD after PHOPDT. METHODS: Squamous overgrowth was compared in patients with BE with HGD randomly assigned (2:1) to receive PHOPDT (n=138) or 20 mg omeprazole twice daily (n=70). Patients underwent 4-quadrant jumbo esophageal biopsies every 2 cm throughout the pretreatment length of BE until 4 consecutive quarterly follow-up results were negative for HGD and then biannually up to 5 years or treatment failure. Endoscopies were reviewed by blinded gastroenterology pathologists. RESULTS: Histologic assessment of 33,658 biopsies showed no significant difference (P> .05) in squamous overgrowth between groups when compared per patient (30% vs 33%) or per biopsy (0.5% vs 1.3%), or when the average number of biopsies with squamous overgrowth were compared per patient (0.48 vs 0.66). The highest grade of neoplasia per endoscopy was not found exclusively beneath squamous mucosa in any patient. CONCLUSIONS: No difference was observed in squamous overgrowth between patients given PHOPDT plus omeprazole compared with only omeprazole. Squamous overgrowth did not obscure the most advanced neoplasia in any patient. Treatment of HGD with PHOPDT in patients with BE does not present a long-term risk of failure to detect subsquamous dysplasia or carcinoma.

Automated quantification of colonic crypt morphology using integrated microscopy and optical coherence tomography.

Colonic crypt morphological patterns have shown a close correlation with histopathological diagnosis. Imaging technologies such as high-magnification chromoendoscopy and endoscopic optical coherence tomography (OCT) are capable of visualizing crypt morphology in vivo. We have imaged colonic tissue in vitro to simulate high-magnification chromoendoscopy and endoscopic OCT and demonstrate quantification of morphological features of colonic crypts using automated image analysis. 2-D microscopic images with methylene blue staining and correlated 3-D OCT volumes were segmented using marker-based watershed segmentation. 2-D and 3-D crypt morphological features were quantified. The accuracy of segmentation was validated, and measured features are in agreement with known crypt morphology. This work can enable studies to determine the clinical utility of high-magnification chromoendoscopy and endoscopic OCT, as well as studies to evaluate crypt morphology as a biomarker for colonic disease progression.

Artificial neural network as a predictive instrument in patients with acute nonvariceal upper gastrointestinal hemorrhage.

BACKGROUND & AIMS: Triage of patients with acute upper gastrointestinal hemorrhage (UGIH) has traditionally required urgent upper endoscopy. The aim of this study is to evaluate the use of artificial neural network for nonendoscopic triage. METHODS: A cohort of 387 patients was used to train (n = 194) and internally validate (n = 193) the neural network, which was then externally validated in 200 patients and compared with the clinical and complete Rockall score. Two outcome variables were assessed: major stigmata of recent hemorrhage and need for endoscopic therapy. Patient cohort data from 2 independent tertiary-care medical centers were prospectively collected. Adult patients hospitalized at both sites during the same time period with a primary diagnosis of acute nonvariceal UGIH. RESULTS: In predicting the 2 measured outcomes, sensitivity of neural network was >80%, with high negative predictive values (92-96%) in both cohorts but with lower specificity in the external cohort. Both Rockall scores had adequate sensitivity (>80%) but poor specificity (<40%) at outcome prediction. Comparing areas under receiver operating characteristic curves, the clinical Rockall score was significantly inferior to neural network in both cohorts (/= 0.78), while in the external cohort, neural network performed similarly to the complete Rockall score (>/= 0.78). CONCLUSIONS: In acute nonvariceal UGIH, artificial neural network (nonendoscopic triage) performed as well as the complete Rockall score (endoscopic triage) at predicting stigmata of recent hemorrhage and need for endoscopic therapy, even when tested in an external patient population.

EUS spectrum analysis for in vivo characterization of pancreatic and lymph node tissue: a pilot study.

BACKGROUND: EUS is limited by variability in the examiner's subjective interpretation of B-scan images to differentiate among normal, inflammatory, and malignant tissue. By using information otherwise discarded by conventional EUS systems, quantitative spectral analysis of the raw radiofrequency (RF) signals underlying EUS images enables tissue to be characterized more objectively. OBJECTIVE: Our purpose was to determine the feasibility of using spectral analysis of EUS data for characterization of pancreatic tissue and lymph nodes. DESIGN AND SETTING: A pilot study of eligible patients was conducted to analyze the RF data obtained during EUS by using spectral parameters. PATIENTS: Twenty-one subjects who underwent EUS of the esophagus, stomach, pancreas, and surrounding intra-abdominal and mediastinal lymph nodes. MAIN OUTCOME MEASUREMENTS: Linear regression parameters of calibrated power spectra of the RF signals were tested to differentiate normal pancreas from chronic pancreatitis and from pancreatic cancer as well as benign from malignant-appearing lymph nodes. RESULTS: The mean intercept, slope, and midband fit of the spectra differed significantly among normal pancreas, adenocarcinoma, and chronic pancreatitis when all were compared with each other (P < .01). On direct comparison, mean midband fit for adenocarcinoma differed significantly from that for chronic pancreatitis (P < .05). For lymph nodes, mean midband fit and intercept differed significantly between benign- and malignant-appearing lymph nodes (P < .01 and P < .05, respectively). LIMITATIONS: Small sample population and spatial averaging inherent to this technique. CONCLUSIONS: Mean spectral parameters in EUS imaging can provide a noninvasive method to discriminate normal from diseased pancreas and lymph nodes.

Five-year efficacy and safety of photodynamic therapy with Photofrin in Barrett's high-grade dysplasia.

BACKGROUND: Barrett's esophagus (BE) with high-grade dysplasia (HGD) is a risk factor for development of esophageal carcinoma. Photodynamic therapy (PDT) with Photofrin (PHO) has been used to eliminate HGD in BE. OBJECTIVE: Our purpose was to compare PHOPDT plus omeprazole with omeprazole only (OM). DESIGN: Five-year follow-up of a randomized, multicenter, multinational, pathology-blinded HGD trial. SETTING: 30 sites in 4 countries. PATIENTS: 208. INTERVENTIONS: Patients with BE and HGD were randomized (2:1) to PHOPDT (n=138) or OM (n=70) into a 2-year trial followed up for 3 more years. PHOPDT patients received 2 mg/kg PHO intravenously followed by endoscopic laser light exposure of Barrett's mucosa at a wavelength of 630 nm within 40 to 50 hours to a maximum of 3 courses at least 90 days apart. Both groups received 20 mg of OM twice daily. Pathologists at one center assessed biopsy specimens in a blinded fashion. MAIN OUTCOME MEASUREMENT: HGD ablation status over 5 years of follow-up. RESULTS: At 5 years PHOPDT was significantly more effective than OM in eliminating HGD (77% [106/138] vs 39% [27/70], P<.0001). A secondary outcome measure preventing progression to cancer showed a significant difference (P=.027) with about half the likelihood of cancer occurring in PHOPDT (21/138 [15%]) compared with OM (20/70 [29%]), with a significantly (P=.004) longer time to progression to cancer favoring PHOPDT. LIMITATIONS: Not all patients were available for follow-up. CONCLUSIONS: This 5-year randomized trial of BE patients with HGD demonstrates that PHOPDT is a clinically and statistically effective therapy in producing long-term ablation of HGD and reducing the potential impact of cancer compared with OM.

Postprocedure radiologist's interpretation of ERCP x-ray films: a prospective outcomes study.

OBJECTIVE: To prospectively determine if the current practice of radiologists' interpretation of post-ERCP spot images sent by endoscopists resulted in discrepancies in interpretation, affected subsequent management of patients, and resulted in additional costs. METHODS: A prospective analysis of 145 consecutive patients who underwent ERCP over the course of 4 months was performed. A separate endoscopist, not involved in the patient's care, reviewed the radiologist's report of the ERCP x-ray films to determine whether there was either concordance or discordance with the procedural findings. All patients' clinical courses were prospectively followed for a minimum of 6 months to determine whether clinical decision-making was affected by the radiologists' interpretation of the x-ray films. Secondarily, the cost of the current practice of postprocedure interpretation of ECRP radiographs was measured. SETTING: This study took place at University Hospitals of Cleveland, which is a tertiary care facility. RESULTS: In total, there were 61 (47%) discordant interpretations of 130 cholangiograms and 27 (38%) discordant interpretations of 72 pancreatograms, with an overall discordance between an endoscopist and a radiologist in 80 (55%) of the 145 cases. Clinical management was subsequently affected in 3 (2.1%) cases, all of which involved a discordant reading. In each of the 3 cases, further testing validated the gastroenterologist's initial findings at the time of the procedure. Radiologists were reimbursed $5395 for interpretation of ERCP x-ray films. Extrapolated over the course of a year, the reimbursement at this single tertiary care hospital would be greater than $16,000. Additional testing based on discordant reports resulted in $2510 of reimbursement for 3 patients. LIMITATION: The limitation of this study is that it reflects data from only one academic institution. CONCLUSIONS: Radiologists' interpretation of postprocedure ERCP films were inadequate, with a 47% discordance rate among cholangiograms and a 38% discordance rate among pancreatograms. The routine practice of postprocedure ERCP x-ray film interpretation by radiologists altered clinical practice in 2.1% of cases; subsequent care did not confirm radiologists' findings and imparted increased risk to the patients. This practice proved to be a misallocation of resources and should not be continued.

Pancreatic-stent placement for prevention of post-ERCP pancreatitis: a cost-effectiveness analysis.

BACKGROUND: Controlled trials support pancreatic-stent placement as an effective intervention for the prevention of post-ERCP acute pancreatitis in high-risk patients. OBJECTIVE: To perform a decision analysis to evaluate the most cost-effective strategy for preventing post-ERCP pancreatitis. DESIGN: Cost-effectiveness analysis. SETTING: Patients undergoing ERCP. INTERVENTIONS: Three competing strategies were evaluated in a decision analysis model from a third-party-payer perspective in hypothetical patients undergoing ERCP. In strategy I, none of the patients had pancreatic-stent placement. Strategy II had only those patients identified to be at high risk for post-ERCP, and, in strategy III, all patients underwent prophylactic stent placement. Probabilities of developing post-ERCP pancreatitis and the risk reduction by placement of a pancreatic stent were obtained from published information. Cost estimates were obtained from Medicare reimbursement rates. MAIN OUTCOME MEASUREMENTS: Incremental cost-effectiveness ratio (ICER) of different strategies. RESULTS: Strategy I was the least-expensive strategy but yielded the least number of life years. Strategy II yielded the highest number of years of life, with an ICER of $11,766 per year of life saved, and strategy III was dominated by strategy II. LIMITATIONS: Indirect costs and pharmacologic prophylaxis were not considered in this analysis. CONCLUSIONS: Pancreatic-stent placement for the prevention of post-ERCP pancreatitis in high-risk patients is a cost-effective strategy.

Gastroesophageal reflux disease-associated esophagitis induces endogenous cytokine production leading to motor abnormalities.

BACKGROUND & AIMS: Gastroesophageal reflux disease is a condition frequently associated with esophagitis and motor abnormalities. Recent evidence suggests that proinflammatory cytokines, such as interleukin (IL)-1beta and IL-6, may be implicated because they reduce esophageal muscle contractility, but these results derive from in vitro or animal models of esophagitis. This study used human esophageal cells and tissues to identify the cellular source of cytokines in human esophagitis investigate whether cytokines can be induced by gastric refluxate, and examine whether esophageal tissue- or cell-derived mediators affect muscle contractility. METHODS: Endoscopic mucosal biopsy specimens were obtained from patients with and without esophagitis, organ-cultured, and undernatants were assessed for cytokine content. The cytokine profile of esophageal epithelial, fibroblast, and muscle cells was analyzed, and esophageal mucosa and cell products were tested in an esophageal circular muscle contraction assay. RESULTS: The mucosa of esophagitis patients produced significantly greater amounts of IL-1beta and IL-6 compared with those of control patients. Cultured esophageal epithelial cells produced IL-6, as did fibroblasts and muscle cells. Epithelial cells exposed to buffered, but not denatured, gastric juice produced IL-6. Undernatants of mucosal biopsy cultures from esophagitis patients reduced esophageal muscle contraction, as did supernatants from esophageal epithelial cell cultures. CONCLUSIONS: The human esophagus produces cytokines capable of reducing contractility of esophageal muscle cells. Exposure to gastric juice is sufficient to stimulate esophageal epithelial cells to produce IL-6, a cytokine able to alter esophageal contractility. These results indicate that classic cytokines are important mediators of the motor disturbances associated with human esophageal inflammation.

Computer-aided diagnosis of dysplasia in Barrett's esophagus using endoscopic optical coherence tomography.

Barrett's esophagus (BE) and associated adenocarcinoma have emerged as a major health care problem over the last two decades. Because of the widespread use of endoscopy, BE is being recognized increasingly in all Western countries. In clinical trials of endoscopic optical coherence tomography (EOCT), we defined certain image features that appear to be characteristic of precancerous (dysplastic) mucosa: decreased scattering and disorganization in the microscopic morphology. The objective of the present work is to develop computer-aided diagnosis (CAD) algorithms that aid the detection of dysplasia in BE. The image dataset used in the present study was derived from a total of 405 EOCT images (13 patients) that were paired with highly correlated histologic sections of corresponding biopsies. Of these, 106 images were included in the study. The CAD algorithm used was based on a standard texture analysis method (center-symmetric auto-correlation). Using histology as the reference standard, this CAD algorithm had a sensitivity of 82%, specificity of 74%, and accuracy of 83%. CAD has the potential to quantify and standardize the diagnosis of dysplasia and allows high throughput image evaluation for EOCT screening applications. With further refinements, CAD could also improve the accuracy of EOCT identification of dysplasia in BE.

Endoscopic ultrasonography and prognosis of esophageal cancer.

BACKGROUND & AIMS: Endoscopic ultrasonography (EUS) staging is used for management of esophageal cancer, but its effect on the outcome of patients is unknown. Our aim was to study the association of receipt of EUS and overall survival in a cohort of patients with esophageal cancer. METHODS: All persons 65 years or older who were diagnosed with esophageal cancer between January 1994 and December 1999 in the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database were identified. Relevant demographic, cancer-specific information and EUS procedural information were extracted. RESULTS: Two thousand eight hundred thirty patients with esophageal cancer (48% squamous cell cancer) were eligible for analysis. Only 303 (10.7%) patients underwent a EUS examination. Patients who had EUS evaluation were more likely to undergo esophageal resection (21.1% vs 14.7%, P = .01) and more likely to have received adjuvant therapy (11.2% vs 6.7%, P = .008). When adjusted for age at diagnosis, race, gender, comorbidity, histology, and tumor stage, receipt of EUS was associated with a reduced risk of death (relative hazard, 0.594; 95% confidence interval, 0.52-0.68; P = .001). CONCLUSIONS: Undergoing EUS in patients with esophageal cancer is independently associated with improved survival, possibly because of improved stage-appropriate management such as use of adjuvant therapy and surgical resection.

Primary care physician attitudes toward endoscopic screening for GERD symptoms and unsedated esophagoscopy.

BACKGROUND: Current guidelines recommend consideration of screening patients with chronic GERD for Barrett's esophagus (BE). Unsedated esophagoscopy (UE) is a less costly alternative to standard EGD for identifying BE. The aim of this study was to determine the indications for EGD referral, the barriers to screening, and the interest in performing UE. METHODS: A one-page survey was mailed to a random sample of 500 family practitioners and 500 internists. This sample was obtained from the American Academy of Family Physicians and American Society of Internal Medicine (500 from each organization). RESULTS: The overall response rate was 54%. The majority (78%) refer more than 50% of their GERD patients for EGD; however, 34% also refer more than 10% of their patients for barium studies. Primary care physicians cited alarm symptoms, refractory symptoms, and chronicity and severity of symptoms as the major indications for referral for EGD. Gender, age, obesity, and tobacco use were cited less frequently. Cost of endoscopy, poor patient acceptance, and lack of evidence were the most common reasons cited for not referring for EGD. A majority of respondents (62%) indicated that the availability of UE would increase referral for the procedure, and 52% would be willing to perform UE in their office. CONCLUSIONS: Severe, refractory, and chronic symptoms are the primary reasons for endoscopic referral from primary care physicians who manage patients with GERD. Other risk factors for BE, such as gender and age, do not appear to be important determinants for endoscopic referral. Further evaluation of UE as a mechanism to increase screening for BE in primary care patients is merited.

Accuracy of endoscopic optical coherence tomography in the detection of dysplasia in Barrett's esophagus: a prospective, double-blinded study.

BACKGROUND: Endoscopic optical coherence tomography (EOCT) is a high-resolution, cross-sectional tissue-imaging technique that provides microscopic morphologic information. EOCT should detect dysplasia in Barrett's epithelium, but this has not been established in a prospective blinded study. This study evaluated the accuracy of EOCT for the diagnosis and the exclusion of dysplasia in patients with Barrett's esophagus. METHODS: A 2.4-mm diameter EOCT probe was modified for use with a cap-fitted, two-channel endoscope. Pairs of EOCT image streams and jumbo biopsy specimens were obtained. Endoscopy/EOCT procedures were performed by 4 endoscopists who separately reviewed the EOCT digital images for the absence or the presence of dysplasia (low grade, high grade, or cancer) for each biopsy specimen obtained. The endoscopists were blinded to the interpretation of the pathology. An experienced pathologist blinded to the endoscopic/EOCT findings evaluated each biopsy for the absence or the presence of dysplasia. The setting of the study was a major academic medical center. Adult patients with documented Barrett's esophagus greater than 2 cm were included in the study. The main outcome measurement was the accuracy of EOCT in the detection of dysplasia in patients with Barrett's esophagus. RESULTS: A total of 314 usable EOCT image stream/biopsy pairs were obtained in 33 patients. By using histology as the standard, the performance of EOCT was sensitivity, 68%; specificity, 82%; positive predictive value, 53%; negative predictive value, 89%; and diagnostic accuracy, 78%. Diagnostic accuracy for the 4 endoscopists ranged from 56% to 98%. Limitations of the study were the variability in endoscopists' accuracy rates, difficulty in real-time interpretation, and the need for refined criteria of dysplasia by EOCT imaging. CONCLUSIONS: The current EOCT system has an accuracy of 78% for the detection of dysplasia in patients with Barrett's esophagus. EOCT could be used to target biopsies to areas of Barrett's epithelium with a higher probability for the presence of dysplasia. However, further modifications, including increased resolution and identification of further potential OCT characteristics of dysplasia, are needed before EOCT can be used clinically.

In vivo optical coherence tomography imaging of the pancreatic and biliary ductal system.

BACKGROUND: In vivo optical coherence tomography (OCT) imaging has not yet been applied to the pancreatic ductal system. The aim of this study was to obtain in vivo OCT images of dog pancreatic and biliary ducts, and to correlate the images with histology. METHODS: Images of dog pancreatic and biliary ducts were obtained by using an in vivo OCT probe introduced through the respective papillary orifices. Each duct was imaged in multiple locations, and the site of imaging was marked with injected India ink. After imaging, the dogs were euthanized, and the pancreaticobiliary system was harvested. Histologic cross sections were correlated with in vivo OCT images by measuring the structures seen on in vivo OCT images and correlating them with structures seen on corresponding histology slides that contained India ink. OBSERVATIONS: Eighteen pairs of in vivo OCT images and histology slides from the bile duct and the pancreatic duct were obtained from 5 dogs. The entire duct wall could be visualized. A low reflective in vivo OCT layer corresponding to the epithelium could be discerned on many images. The bile duct showed a more complex architecture and had greater variations within the reflective OCT layers, possibly because of greater cellularity within the lamina propria. Nuclei within cells could not be identified, and structures adjacent to the ducts could not be imaged. CONCLUSIONS: In vivo OCT is capable of imaging the pancreaticobiliary ductal system and of identifying the epithelial layer. Because of limited depth of imaging (320-845 micron), OCT is unlikely to serve the purpose of tumor staging.

The changing landscape of practice patterns regarding unsedated endoscopy and propofol use: a national Web survey.

BACKGROUND: Lower reimbursements for endoscopic procedures and increasing demand for screening endoscopy over the past decade have spurred efforts to increase efficiency in the performance of endoscopic procedures. Two dichotomous approaches have emerged: (1) unsedated endoscopy and (2) propofol sedation. The aim was to determine national practice patterns of unsedated endoscopy and propofol sedation, and to assess endoscopists' attitudes toward unsedated screening with an electronic survey. METHODS: A short survey was developed and then was converted to a Web-based format. All national members of the American Society for Gastrointestinal Endoscopy (ASGE) were invited via electronic mail (e-mail) to participate. Survey data were collected electronically. RESULTS: Two e-mails elicited responses to the Web survey from 18% (724) of national ASGE members contacted, within 2 weeks. Of the respondents, 45% do not routinely offer unsedated EGD and colonoscopy, and only 15% of those respondents plan to incorporate unsedated endoscopy into their practice in the next year. Of the 55% who currently perform unsedated endoscopy, 85% do no more than 25 unsedated procedures per year. Lack of patient acceptance was the most common reason cited for not offering unsedated endoscopy. Most endoscopists felt that the availability of unsedated esophagoscopy or colonoscopy would not significantly increase screening for Barrett's esophagus or colonic polyps/colorectal cancer, respectively. Routine use of propofol sedation for EGD, colonoscopy, and ERCP/EUS was reported by 19%, 22%, and 19%, respectively. Community practitioners were more likely to use propofol than those at academic centers (p < 0.0002 for all). Of those not currently using propofol, 43% plan to incorporate it into their practice within the next year. Over 70% of respondents would themselves choose to be sedated for routine endoscopic procedures. CONCLUSIONS: Electronic surveys allow for rapid distribution and data collection but suffer from a limited response rate. The survey suggests that unsedated endoscopy has limited acceptance in the United States, and, without a major intervention that affects endoscopists' attitudes, its use is not likely to increase significantly. Unsedated endoscopy will not have a great impact on endoscopic screening. In contrast, propofol sedation has already gained acceptance in the community, and the routine use of propofol in endoscopy units will likely increase in the future.

Correlation of endoscopic optical coherence tomography with histology in the lower-GI tract.

BACKGROUND: Optical coherence tomography (OCT), a noninvasive optical imaging technique, provides high-resolution cross-sectional images of tissue microstructure. We developed a system for real-time endoscopic OCT (EOCT) of the human GI tract. During clinical trials, the structure of mucosa and submucosa, glands, blood vessels, pits, villi, and crypts was observed in a range of GI organs. Although EOCT images are thought to accurately depict actual histologic features, there are few data to support this assumption. Therefore, the present study correlated images acquired with an EOCT imaging system in vitro to corresponding histologic sections. METHODS: EOCT images were obtained of fresh specimens of ileum, colon, and rectum that then were fixed in formalin and were processed for microscopic evaluation by using standard methods. The thickness of mucosa and of submucosa was determined for both EOCT images and histologic slides. RESULTS: The first hyper-reflective layer in the EOCT images was identified as mucosa. A close correlation (R 2=0.84) was observed between EOCT and histology. Furthermore, the submucosa and the muscularis propria could be identified as the next deepest hyporeflective band and a hyper-reflective layer, respectively, in EOCT images. The submucosa was found to be more compressible than mucosa, and its EOCT appearance was dependent on its content of adipose tissue. CONCLUSIONS: EOCT provides images that precisely correlate with the histologic structure of the mucosa and the submucosa of the GI tract.

The yield of bleeding scans in acute lower gastrointestinal hemorrhage.

GOALS/BACKGROUND: Previous studies have demonstrated low yield and conflicting results as to the ability of technetium-99m labeled red blood cell (TRBC) scintigraphy to accurately localize the site of bleeding in acute lower gastrointestinal hemorrhage. Our objective was to evaluate the accuracy of TRBC scintigraphy in clinical day-to-day practice at our institution and to determine predictors of a positive test. METHODS: A retrospective medical records review of all patients who underwent TRBC scintigraphy over a 5-year period was conducted at a single academic medical center. The site of bleeding found on TRBC scintigraphy was correlated with the endoscopic, angiographic, surgical, and pathologic findings in each patient. RESULTS: A total of 127 scans were performed in 115 patients. Forty-nine scans were positive (39%) and 78 were negative (61%). Forty-two patients had further evaluation after a positive scan, and the bleeding site was confirmed to be accurate in 20 of 42 patients (48%). A contradictory bleeding site was found in 5 of 49 positive scans (10%). Patients transfused greater than 2 units of packed red blood cells within 24 hours preceding the TRBC scan were twice as likely to have a positive scan (64%) than those transfused 2 units or less (32%) (P = 0.002). Multivariate analysis demonstrated that the number of units of blood transfused within 24 hours prior to the TRBC scan and the lowest recorded hematocrit were significantly different between patients with positive and negative scans. There was no difference in the rate of endoscopy between patients with a positive or negative scan result. CONCLUSIONS: TRBC scintigraphy has a relatively low yield in the evaluation of acute lower gastrointestinal bleeding. Objective selection criteria such as number of units of packed red blood cells transfused prior to obtaining the scan may increase the overall yield.