***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND In contrast to st and ard video endoscopy , magnifying endoscopy after local acetic acid application enables recognition of mucosal surface architecture . OBJECTIVE To investigate the diagnostic yield of magnifying endoscopy with acetic acid-targeted biopsies compared to r and om , 4-quadrant biopsies . DESIGN Prospect i ve r and omized trial ( ratio 1:1 ) with crossover design . SETTING Two referral hospitals in Germany . PATIENTS Thirty-one patients with Barrett 's esophagus or visible columnar-lined lower esophagus . INTERVENTIONS Patients were r and omized to undergo either st and ard video endoscopy with 4-quadrant biopsies or magnifying endoscopy in conjunction with acetic acid application . All patients were re-examined 14 days after the initial endoscopy with the corresponding procedure . MAIN OUTCOME MEASUREMENTS Primary outcome analysis ( per protocol and per biopsy ) was the histological proof of Barrett 's epithelium . Secondary outcome analysis was the correlation between the surface architecture and the presence of Barrett 's epithelium and the needed number of biopsies to confirm Barrett 's epithelium for the 2 different procedures . RESULTS Magnifying endoscopy enabled the prediction of Barrett 's epithelium with a sensitivity of 100 % and a specificity of 66 % , respectively ( accuracy 83.8 % ) . Acetic acid-guided biopsies obtained a significantly higher percentage of tissues containing SCE ( 78 % ; 188/241 ) compared to r and om biopsies ( 57 % ; 159/280 ) . LIMITATIONS No data on the diagnosis of Barrett 's dysplasia . CONCLUSION Magnifying endoscopy with acetic acid-guided biopsies is superior to st and ard video endoscopy with r and om biopsies , and the number of biopsies needed to confirm Barrett 's epithelium is half as much when compared to r and om biopsies BACKGROUND AND STUDY AIMS Validation of a simplified classification of mucosal morphology in prediction of histology in Barrett 's esophagus using narrow-b and imaging with magnification ( NBI-Z ) and assessing its reproducibility by endoscopists experienced in the use of NBI ( NBI-experts ) and by endoscopists who were new to NBI ( non-NBI-experts ) . PATIENTS AND METHODS In a prospect i ve cohort study of 109 patients with Barrett 's esophagus at a single tertiary referral center , mucosal patterns visualized in Barrett 's esophagus on NBI-Z were classified into four easily distinguishable types : A , round pits with regular microvasculature ; B , villous/ridge pits with regular microvasculature ; C , absent pits with regular microvasculature ; D , distorted pits with irregular microvasculature . The NBI-Z grading was compared with the final histopathological diagnosis , and positive ( PPV ) and negative predictive values ( NPV ) were calculated . The reproducibility of the grading was then assessed by NBI-expert and non-NBI-expert endoscopists , and interobserver and intraobserver agreement were calculated using kappa statistics . RESULTS Per-biopsy analysis : In 903 out of 1021 distinct areas ( 87.9 % ) the NBI-Z grading corresponded to the histological diagnosis . Per-patient analysis : The PPV and NPV for type A pattern ( columnar mucosa without intestinal metaplasia ) were 100 % and 97 % respectively ; for types B and C ( intestinal metaplasia ) they were 88 % and 91 % respectively , and for type D ( high- grade dysplasia ) 81 % and 99 % respectively . Inter- and intraobserver agreement : The mean kappa values in assessing the various patterns were 0.71 and 0.87 in the non-expert group ; 0.78 and 0.91 in the expert group . CONCLUSIONS This study has vali date d a simplified classification of the various morphologic patterns visualized in Barrett 's esophagus and confirmed its reproducibility when used by NBI-expert and non-NBI-expert endoscopists BACKGROUND & AIMS Endoscopic tri-modal imaging ( ETMI ) incorporates high-resolution endoscopy ( HRE ) , autofluorescence imaging ( AFI ) , and narrow b and imaging ( NBI ) . A recent uncontrolled study found that ETMI improved the detection of high- grade dysplasia ( HGD ) and early carcinoma ( Ca ) in Barrett 's esophagus ( BE ) . The aim was to compare ETMI with st and ard video endoscopy ( SVE ) for the detection of HGD/Ca with the use of a r and omized cross-over design . METHODS Patients referred for work-up of inconspicuous HGD/Ca were eligible and underwent both SVE and ETMI in r and omized order within an interval of 6 - 12 weeks . During ETMI , inspection with HRE was followed by AFI . Detected lesions were inspected in detail with NBI and biopsied , followed by r and om biopsies . During SVE , any visible lesion was biopsied followed by r and om biopsies . RESULTS Eighty-seven patients with BE underwent ETMI and SVE . No significant difference was observed in overall histologic yield between ETMI and SVE . ETMI had a significantly higher targeted yield compared with SVE because of AFI . However , the yield of targeted biopsies of ETMI was significantly inferior to the overall yield of SVE . Detailed inspection with NBI reduced the false-positive rate of HRE + AFI from 71 % to 48 % but misclassified 17 % of HGD/Ca lesions as not suspicious . CONCLUSIONS ETMI statistically significant improves the targeted detection of HGD/Ca compared with SVE . Subsequent characterization of lesions with NBI appears to be of limited value . At this stage , ETMI can not replace r and om biopsies for detection of lesions or targeted biopsies for characterization of lesions in a high-risk population BACKGROUND The optimal management of high- grade dysplasia in patients with Barrett 's esophagus is controversial . The aim of this study was to assess the prevalence of unsuspected carcinoma at esophagectomy in patients with Barrett 's esophagus with high- grade dysplasia after endoscopic surveillance with jumbo biopsy forceps compared with st and ard biopsy forceps . METHODS Twelve patients with high- grade dysplasia in Barrett 's esophagus without gross or microscopic evidence of carcinoma underwent esophagectomy after preoperative endoscopy with 4-quadrant jumbo biopsies at 2-cm intervals .  The findings in this group were compared with those in a group of patients with Barrett 's esophagus who underwent esophagectomy for high- grade dysplasia after biopsies obtained at 2-cm intervals with st and ard biopsy forceps . RESULTS Unsuspected cancer was found in 4 of 12 ( 33 % ) patients in the jumbo biopsy group compared with 6 of 16 ( 38 % ) in the st and ard biopsy group ( p = NS ) . All 6 cancers in the st and ard biopsy group were intramucosal , whereas 2 were intramucosal and 2 were submucosal in the jumbo biopsy group . No patients in either group had lymph node metastases . CONCLUSIONS Unsuspected cancer is found frequently in patients with Barrett 's esophagus who are undergoing esophagectomy for high- grade dysplasia despite the use of a rigorous jumbo biopsy protocol . Esophageal resection is still indicated in appropriately selected patients with high- grade dysplasia until better markers of cancer risk are available OBJECTIVE : The optimal management of Barrett 's esophagus ( BE ) is controversial . Little is known about current practice patterns or associated direct medical costs . METHODS : In a national cross-sectional survey , we asked a r and om sample of gastroenterologists how they would manage patients with BE and various degrees of dysplasia . We used logistic regression to identify factors associated with so-called “ frequent ” ( at least every 12 months ) surveillance . We calculated direct medical costs using Medicare payments and population -based estimates of the number of BE patients under surveillance . RESULTS : Approximately 50 % of 555 gastroenterologists responded . More than 96 % of respondents recommended endoscopic surveillance for BE . For BE without dysplasia , 30 % would perform frequent surveillance ; this was the case particularly gastroenterologists older than age 45 yr ( odds ratio = 1.91 , p= 0.038 ) or those receiving primarily fee-for-service reimbursement ( odds ratio = 2.57 , p= 0.004 ) . For BE with low- grade dysplasia , the frequency of endoscopy was highly variable ( range , 1–24 months ) . For BE with high- grade dysplasia , 73 % of gastroenterologists recommended esophagectomy and the remainder recommended endoscopic surveillance . Approximately 95 % of the gastroenterologists who recommended surveillance for high- grade dysplasia , however , were not in agreement with recommended protocol s. We estimated the national annual expenditure for  surveillance endoscopy every 24 months for BE without dysplasia to be at least $ 22 million . Increase in surveillance intensity from low frequency ( every 36 months ) to high frequency ( every 12 months ) strategies would escalate costs by $ 29 million annually . CONCLUSIONS : Physician age and reimbursement influence BE surveillance practice , suggesting the influence of non clinical factors on clinical decisionmaking . The majority of clinicians who would recommend surveillance for high- grade dysplasia may not be using an appropriately aggressive strategy . Variations in surveillance strategies can have large cost implication BACKGROUND Confocal laser endomicroscopy ( CLE ) enables in vivo microscopic imaging of the GI tract mucosa . However , there are limited data on endoscope-based CLE ( eCLE ) for imaging Barrett 's esophagus ( BE ) . OBJECTIVE To compare high-definition white-light endoscopy ( HDWLE ) alone with r and om biopsy ( RB ) and HDWLE + eCLE and targeted biopsy ( TB ) for diagnosis of BE neoplasia . DESIGN Multicenter , r and omized , controlled trial . SETTING Academic medical centers . PATIENTS Adult patients with BE undergoing routine surveillance or referred for early neoplasia . INTERVENTION Patients were r and omized to HDWLE + RB ( group 1 ) or HDWLE + eCLE + TB ( group 2 ) . Real-time diagnoses and management plans were recorded after HDWLE in both groups and after eCLE in group 2 . Blinded expert pathology diagnosis was the reference st and ard . MAIN OUTCOME MEASUREMENTS Diagnostic yield , performance characteristics , clinical impact . RESULTS A total of 192 patients with BE were studied . HDWLE + eCLE + TB led to a lower number of mucosal biopsies and higher diagnostic yield for neoplasia ( 34 % vs 7 % ; P < .0001 ) , compared with HDWLE + RB but with comparable accuracy . HDWLE + eCLE + TB tripled the diagnostic yield for neoplasia ( 22 % vs 6 % ; P = .002 ) and would have obviated the need for any biopsy in 65 % of patients . The addition of eCLE to HDWLE increased the sensitivity for neoplasia detection to 96 % from 40 % ( P < .0001 ) without significant reduction in specificity . In vivo CLE changed the treatment plan in 36 % of patients . LIMITATIONS Tertiary-care referral centers and expert endoscopists limit generalizability . CONCLUSION Real-time eCLE and TB after HDWLE can improve the diagnostic yield and accuracy for neoplasia and significantly impact in vivo decision making by altering the diagnosis and guiding therapy . ( CLINICAL TRIAL REGISTRATION NUMBER NCT01124214 . ) BACKGROUND A narrow b and imaging ( NBI ) endoscopy system has been developed that allows superficial surface imaging of esophageal tissue in vivo . OBJECTIVE The objective was to assess the potential of NBI for prediction of histology during screening and surveillance endoscopy in patients with Barrett 's esophagus ( BE ) . DESIGN A prospect i ve cohort study . SETTING Veterans Affairs Medical Center . PATIENTS Fifty-one patients with known or suspected BE . METHODS NBI images were grade d according to mucosal pattern ( ridge/villous , circular and irregular/distorted ) and vascular pattern ( normal and abnormal ) , and correlated with histology in a prospect i ve , blinded manner . MAIN OUTCOME MEASUREMENTS Biopsy-confirmed intestinal metaplasia ( IM ) and dysplasia were used as the outcome measures . RESULTS Of 51 patients ( mean BE length 3.5 cm ) , 28 had IM without dysplasia , 8 had low- grade dysplasia ( LGD ) , 7 had high- grade dysplasia ( HGD ) , and 8 had cardiac-type mucosa . The sensitivity , specificity , and positive predictive value of ridge/villous pattern for diagnosis of IM without HGD were 93.5 % , 86.7 % , and 94 
    Output:
    
Our meta- analysis indicates that targeted biopsies with acetic acid chromoendoscopy , electronic chromoendoscopy by using narrow-b and imaging , and endoscope-based CLE meet the thresholds set by the ASGE PIVI , at least when performed by endoscopists with expertise in advanced imaging techniques .