Comparative acceptability of transnasal esophagoscopy and esophageal capsule esophagoscopy: a randomized, controlled trial in veterans.

BACKGROUND: EGD screening for Barrett's esophagus (BE) is costly, with insufficient evidence to support its effectiveness. OBJECTIVE: To compare acceptance and tolerability of 2 novel, office-based, endoscopic screening techniques done on nonsedated patients. DESIGN: Randomized block study design with allocation concealment. SETTING: Outpatient clinic setting at a Veterans Affairs medical center. PATIENTS: A total of 184 veterans with or without GERD symptoms. INTERVENTIONS: Transnasal esophagoscopy (TNE) or esophageal capsule esophagoscopy (ECE). MAIN OUTCOME MEASUREMENTS: Acceptance and tolerability of TNE and ECE and effectiveness of BE screening. RESULTS: Esophageal screening was accepted by 184 of 1210 (15.2%) veterans. The majority were men (96%) and African American (58%), with a mean (± standard deviation) age of 58.9 (± 8.1) years. Five TNE participants (5%) and 2 ECE participants (2%) refused the assigned procedure after randomization (P = .25). Eleven patients (12.6%) randomized to TNE crossed the minimal clinically important threshold for overall procedure tolerability, as opposed to no patients randomized to ECE (P = .001). Effectiveness of BE screening was not significantly different in both procedures (TNE vs ECE = 3.2% vs 5.4%; P = .47). Overall, BE was present in 8 of 75 white participants (10.6%) and in 0 of 107 African American participants (P < .001). LIMITATIONS: The general veteran population may not reflect the screening population for BE. CONCLUSION: Despite a small proportion of veterans expressing interest in esophageal screening, both TNE and ECE were feasible in the outpatient clinic setting and were accepted by >95% of participants who did express an interest. Screening was effective only in white participants. Moderate differences in tolerability between TNE and ECE notwithstanding, cost considerations along with availability of equipment and trained personnel should guide the modality to be used for BE screening.

Development of a program to train physician extenders to perform transnasal esophagoscopy and screen for Barrett's esophagus.

BACKGROUND & AIMS: Screening for Barrett's esophagus (BE) and esophageal adenocarcinoma is not recommended because it was not found to be cost effective. However, physician extenders (PEs) are able to perform unsedated procedures; their involvement might reduce the costs of BE screening. We examined the feasibility of training PEs to independently perform transnasal esophagoscopy (TNE) and screen patients for BE and measured their learning curve. METHODS: Two PEs at a Veterans Affairs (VA) medical center underwent a structured didactic training program and observed nasopharyngoscopies before performing TNE under the supervision of attending endoscopists. Individual technical and cognitive components of TNE were rated on a 9-point structured scale. Learning curves were constructed using cumulative summation. Once the PEs were judged to be technically competent, each PE performed 10 independent videotaped TNEs, which were graded. RESULTS: Both PEs identified anatomic landmarks after 18 consecutive procedures. PE1 and PE2 performed satisfactory nasal intubations after 20 and 25 procedures and esophageal intubations after 29 and 35 procedures, respectively. They acquired overall competence after supervised training on 43 and 47 procedures, respectively. CONCLUSIONS: We developed a program at a VA medical center to train PEs to perform TNE to screen for BE. The PEs were able to perform TNE and recognize esophageal landmarks independently after a modest number of supervised procedures.

Immediate unprepared hydroflush colonoscopy for severe lower GI bleeding: a feasibility study.

BACKGROUND: Urgent colonoscopy is not always the preferred initial intervention in severe lower GI bleeding because of the need for a large volume of oral bowel preparation, the time required for administering the preparation, and concern regarding adequate visualization. OBJECTIVE: To evaluate the feasibility, safety, and outcomes of immediate unprepared hydroflush colonoscopy for severe lower GI bleeding. DESIGN: Prospective feasibility study of immediate colonoscopy after tap-water enema without oral bowel preparation, aided by water-jet pumps and mechanical suction devices in patients admitted to the intensive care unit with a primary diagnosis of severe lower GI bleeding. SETTING: Tertiary referral center. MAIN OUTCOME MEASUREMENTS: Primary outcome measurement was the percentage of colonoscopies in which the preparation permitted satisfactory evaluation of the entire length of the colon suspected to contain the source of bleeding. Secondary outcome measurements were visualization of a definite source of bleeding, length of hospital and intensive care unit (ICU) stays, rebleeding rates, and transfusion requirements. RESULTS: Thirteen procedures were performed in 12 patients. Complete colonoscopy to the cecum was performed in 9 of 13 patients (69.2%). However, endoscopic visualization was thought to be adequate for definitive or presumptive identification of the source of bleeding in all procedures, with no colonoscopy repeated because of inadequate preparation. A definite source of bleeding was identified in 5 of 13 procedures (38.5%). The median length of ICU stay was 1.5 days; of hospital stay, 4.3 days. Recurrent bleeding during the same hospitalization, requiring repeated endoscopy, surgery, or angiotherapy, was seen in 3 of 12 patients (25%). LIMITATIONS: Uncontrolled feasibility study of selected patients. CONCLUSION: Immediate unprepared hydroflush colonoscopy in patients with severe lower GI bleeding is feasible with the hydroflush technique.

Characterization of the pancreas in vivo using EUS spectrum analysis with electronic array echoendoscopes.

BACKGROUND: Spectral analysis of the radiofrequency (RF) signals that underlie grayscale EUS images has been used to provide quantitative, objective information about tissue histology. OBJECTIVE: Our purpose was to validate RF spectral analysis as a method to distinguish between chronic pancreatitis (CP) and pancreatic cancer (PC). DESIGN AND SETTING: A prospective study of eligible patients was conducted to analyze the RF data obtained by using electronic array echoendoscopes. PATIENTS: Pancreatic images were obtained by using electronic array echoendoscopes from 41 patients in a prospective study, including 15 patients with PC, 15 with CP, and 11 with a normal pancreas. MAIN OUTCOME MEASUREMENTS: Midband fit, slope, intercept, correlation coefficient, and root mean square deviation from a linear regression of the calibrated power spectra were determined and compared among the groups. RESULTS: Statistical analysis showed that significant differences were observable between groups for mean midband fit, intercept, and root mean square deviation (t test, P < .05). Discriminant analysis of these parameters was then performed to classify the data. For CP (n = 15) versus PC (n = 15), the same parameters provided 83% accuracy and an area under the curve of 0.83. LIMITATIONS: Moderate sample size and spatial averaging inherent in the technique. CONCLUSIONS: This study shows that mean spectral parameters of the backscattered signals obtained by using electronic array echoendoscopes can provide a noninvasive method to quantitatively discriminate between CP and PC.

Small bowel capsule endoscopy in patients with cardiac pacemakers and implantable cardioverter defibrillators: Outcome analysis using telemetry review.

AIM: To determine if there were any interactions between cardiac devices and small bowel capsules secondary to electromagnetic interference (EMI) in patients who have undergone small bowel capsule endoscopy (SBCE). METHODS: Authors conducted a chart review of 20 patients with a cardiac pacemaker (CP) or implantable cardioverter defibrillator (ICD) who underwent continuous electrocardiographic monitoring during their SBCE from 2003-2008. authors searched for unexplained electrocardiogram (ECG) findings, changes in CP and ICD set parameters, any abnormality in transmitted capsule data, and adverse clinical events. RESULTS: There were no adverse events or hemodynamically significant arrhythmias reported. CP and ICD set parameters were preserved. The majority of ECG abnormalities were also found in pre- or post- SBCE ECG tracings and the CP behavior during arrhythmias appeared appropriate. Two patients seemed to have episodes of undersensing by the CP. However, similar findings were documented in ECGs taken outside the time frame of the SBCE. One patient was observed to have a low signal encountered from the capsule resulting in lack of localization, but no images were lost. CONCLUSION: Capsule-induced EMI remains a possibility but is unlikely to be clinically important. CP-induced interference of SBCE is also possible, but is infrequent and does not result in loss of images transmitted by the capsule.

Motion artifacts associated with in vivo endoscopic OCT images of the esophagus.

3-D optical coherence tomography (OCT) has been extensively investigated as a potential screening and/or surveillance tool for Barrett's esophagus (BE). Understanding and correcting motion artifact may improve image interpretation. In this work, the motion trace was analyzed to show the physiological origin (respiration and heart beat) of the artifacts. Results showed that increasing balloon pressure did not sufficiently suppress the physiological motion artifact. An automated registration algorithm was designed to correct such artifacts. The performance of the algorithm was evaluated in images of normal porcine esophagus and demonstrated in images of BE in human patients.

Endoscopically guided spectral-domain OCT with double-balloon catheters.

Fourier-domain optical coherence tomography (OCT) and balloon-based catheters have furthered the potential of OCT as a real-time surveillance tool for Barrett's esophagus (BE). However, a balloon catheter, which expands the esophagus and centers the catheter, applies direct pressure on the esophagus. This may affect the tissue appearance and the ability to detect dysplasia in BE. To study this effect, we propose a double-balloon catheter to allow imaging with and without balloon-tissue contact. A system design based on a spectral-domain OCT platform is reported and validated by acquisition of high quality, volumetric images of swine esophagus in vivo.

Initial evaluation of a novel, prototype, forward-viewing echoendoscope in a porcine arterial bleeding model (with video).

BACKGROUND: Real-time visualization of submucosal arterial flow at the base of an ulcer might improve endoscopic hemostasis by permitting more accurate assessment of the artery, precise targeting of therapy, and confirmation of vessel ablation. OBJECTIVE: To evaluate the utility of a novel, forward-viewing echoendoscope in identifying bleeding submucosal arteries, guiding hemostatic therapy, and confirming cessation of flow through treated vessels. DESIGN: In 7 pigs, a previously described porcine model for peptic ulcer hemorrhage was created by isolating the gastroepiploic and/or short gastric artery and tunneling it into the subserosal space at laparotomy. SETTING: Animal research facility. INTERVENTION: The prototype endoscope was used to image submucosal arterial flow. EUS guidance was then used to deliver endoscopic hemostatic therapy and assess treatment adequacy. MAIN OUTCOME MEASUREMENTS: Identification of the target submucosal artery and successful delivery of EUS-guided endoscopic therapy, evidenced by cessation of Doppler flow through the target vessel. RESULTS: Tunneled arteries were visualized endosonographically in all 7 cases. EUS-guided submucosal injection of epinephrine was successful in 2 of 2 cases. EUS-guided delivery of thermal hemostatic therapy was successful in 2 of 4 cases. Absence of flow through treated vessels was confirmed in cases in which EUS-guided therapy was successfully delivered. LIMITATIONS: Acute animal model. CONCLUSION: Proof of principle experiments in a porcine peptic ulcer hemorrhage model suggest that real-time sonographic imaging of submucosal arteries is feasible with a forward-viewing echoendoscope, and guided hemostatic therapy can be delivered.

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.

Variability in measurements of pancreatic cyst size among EUS, CT, and magnetic resonance imaging modalities.

BACKGROUND: Cyst size is an important factor in the management of pancreatic cysts, both in predicting the need for surgery and the frequency of follow-up. OBJECTIVE: To determine agreement and precision of EUS, CT, and magnetic resonance imaging (MRI) modalities in the evaluation of pancreatic cyst diameter. DESIGN: Retrospective chart review. SETTING: Tertiary-care center, January 2000 to June 2009. PATIENTS: This study involved 175 patients presenting for EUS evaluation of pancreatic cysts, with size measured by at least two of the aforementioned imaging studies within a 90-day period. MAIN OUTCOME MEASUREMENTS: Largest cyst diameter from EUS, CT, MRI/MRCP, and surgical pathology. RESULTS: A total of 175 patients underwent EUS. Seventy-three had CT plus EUS, 33 had MRI/MRCP plus EUS, 23 had MRI/MRCP plus CT, and 15 had all imaging studies, occurring within 90 days of each other. Median size differences between studies: EUS and CT (ie, absolute value of size determined by EUS minus size determined by CT) = 4 mm (range 0-25 mm), EUS and MRI = 4 mm (range 0-17 mm), CT and MRI = 3 mm (range 2-20 mm). Median size differences for surgical pathology specimens compared with results of 12 EUS, 13 CT, and 8 MRI/MRCP studies were as follows: EUS and pathology = 9.5 mm (range 0-20 mm), CT and pathology = 5 mm (range 0-21 mm), MRI and pathology = 5.5 mm (range 2-44 mm). LIMITATIONS: Interobserver variability and small sample of surgical pathology cysts. CONCLUSION: There is considerable variation in size estimates of pancreatic cysts by different imaging modalities, which practitioners should take into account when making management decisions. Use of a single imaging modality is recommended during follow-up. The precision of imaging studies for measuring pancreatic cysts must be prospectively defined if change in size is to be reliably used for clinical management.

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.

Creation of an effective and reproducible nonsurvival porcine model that simulates actively bleeding peptic ulcers.

BACKGROUND: Efforts to develop improved endoscopic therapeutic methods for upper GI bleeding require an effective animal model. OBJECTIVE: To develop a nonsurvival porcine model that simulates acute peptic ulcer bleeding. DESIGN: Prospective animal (porcine) study. SETTING: Animal laboratory. INTERVENTIONS: A surgical seromyotomy was created along the external surface of the greater curvature of the stomach in anesthesized pigs. A submucosal plane was developed and the gastroepiploic bundle, in continuity, was placed adjacent to the mucosa, and the seromuscular tissues were re-approximated over the vascular bundle. By using EGD, a needle-knife with electrocautery was then used to incise the mucosal tissue overlying the vascular bundle. Standard endoscopic methods for bleeding control were then tested in this animal model. MAIN OUTCOME MEASUREMENTS: To evaluate whether successful bleeding that simulates submucosal arterial bleeding from peptic ulcer disease could be achieved in a porcine animal model. RESULTS: Successful simulation of active peptic ulcer bleeding was achieved with this nonsurvival porcine model in a total of 5 sequential pigs. Other porcine models for bleeding were tested and found to be unsatisfactory. Hemoclips and combination injection-thermal therapy were used to stop bleeding over Doppler-positive areas, with subsequent endoscopic nonimaging Doppler US probe examination of the ulcer bed revealing a negative Doppler signal. LIMITATIONS: This was an animal laboratory study. Further human studies would be ideal once any future endoscopic interventions are proven to be safe in animals. CONCLUSIONS: This active bleeding ulcer model can be used to develop future endoscopic therapies and for training purposes.

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.

Long-term follow-up of patients with clinically indeterminate suspicion of pancreatic cancer and normal EUS.

BACKGROUND: EUS often is performed because of a clinical suspicion of pancreatic cancer when the results of other noninvasive diagnostic tests are indeterminate. The aim of this study was to determine the true negative predictive value of a normal EUS in a cohort of patients with an indeterminate suspicion of pancreatic cancer by obtaining long-term follow-up information. METHODS: Patients referred for EUS of the pancreas for the following indications were identified: elevated carbohydrate-associated antigen (CA 19-9) without other definitive evidence of pancreatic cancer, subtle abnormalities on CT of the pancreas, and unexplained abdominal pain and/or weight loss. Endoscopy procedure reports, as well as inpatient and outpatient records were obtained. In addition, referring physicians, as well as patients, were contacted to acquire adequate follow-up information. RESULTS: A total of 80 patients were included in the study. Follow-up of at least 6 months was obtained for 76 (95%) patients (mean follow-up 23.9 months). No patient with a normal EUS of the pancreas developed pancreatic cancer or required pancreatic surgery during the follow-up period. One patient in whom a diagnosis of chronic pancreatitis was made by EUS subsequently was found to have pancreatic cancer at surgery. CONCLUSIONS: A normal EUS of the pancreas in the setting of subtle radiologic findings, serologic abnormalities, and/or nonspecific symptoms definitively rules out the presence of pancreatic cancer.