Publications by authors named "Alanna Ebigbo"

55 Publications

Modified endoscopic mucosal resection techniques for treating precancerous colorectal lesions.

Ann Gastroenterol 2021 Nov-Dec;34(6):757-769. Epub 2021 Jul 2.

Hepatogastroenterology Unit, Second Department of Internal Medicine-Propaedeutic, Medical School, National and Kapodistrian University of Athens, "Attikon" University General Hospital, Athens, Greece (Georgios Tziatzios, Ioannis S. Papanikolaou, Konstantinos Triantafyllou).

Endoscopic mucosal resection (EMR) is a technique allowing efficacious and minimally invasive resection of precancerous lesions across the entire gastrointestinal tract. However, conventional EMR, involving injection of fluid into the submucosal space, is imperfect, given the high rate of recurrence of post-endoscopic resection adenoma, especially after piecemeal resection. In light of these observations, modifications of the technique have been proposed to overcome the weakness of conventional EMR. Some of them were designed to maximize the chance of resection-cap-assisted EMR, underwater EMR, tip-in EMR, precutting, assisted by ligation device-while others were designed to minimize the complications (cold EMR). In this review, we present their modes of action and summarize the evidence regarding their efficacy and safety.
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http://dx.doi.org/10.20524/aog.2021.0647DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8596214PMC
July 2021

[Impact of Covid 19 on endoscopy in Germany].

Z Gastroenterol 2021 Oct 22. Epub 2021 Oct 22.

III. Medizinische Klinik - Gastroenterologie und Infektiologie, Universitätsklinikum Augsburg, Augsburg, Germany.

Background: Practices and hospitals are facing great challenges in coping with the COVID-19-pandemic. So far, data on the impact of the pandemic on gastroenterological facilities are lacking, especially on a temporal course. A database is lacking, especially for the outpatient care sector. University Hospital of Augsburg was commissioned to generate data on this as a part of the collaborative project B-FAST of the Network of University Medicine (NUM).

Methods: Gastroenterological institutions nationwide were surveyed by an online questionnaire. Recruitment was carried out via the German Society of Gastroenterology, Digestive and Metabolic Diseases (DGVS) and the Professional Association of Gastroenterologists in Private Practice (bng). This manuscript provides an overview of data on the use of protective equipment, pre-interventional testing of patients, staff screening and economic impact over the course of the pandemic.

Results: 429 facilities answered the questionnaire. Practices tested their patients pre-interventionally significantly less often than clinics (7.8% vs. 82.6%). In clinics, inpatients (93.1%) were tested significantly more often than outpatients (72.2%). The use of personal protective equipment (PPE) increased significantly during the pandemic. It was shown that over 70% of facilities screened their staff for SARS-CoV-2 without cause. Clinics cancelled elective procedures significantly more often than practices in quarter 4/2020. Procedures and turnover decreased in 2020 compared to the previous year. However, fewer facilities were affected by a loss of revenue than expected in previous studies.

Conclusion: Our data demonstrate the variable implementation of pre-interventional SARS-CoV-2 testing in outpatient and inpatient care. The use of adequate PPE and staff screening increased during the pandemic.
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http://dx.doi.org/10.1055/a-1649-8184DOI Listing
October 2021

Gastric cancer incidence and mortality trends between 2007-2016 in three European countries.

Endoscopy 2021 Oct 19. Epub 2021 Oct 19.

Faculty of Medicine, CIDES/CINTESIS, Faculty of Medicine, University of Porto, Portugal, Porto, Portugal.

Background/aims: Increased awareness of gastric cancer risk, easy access to upper endoscopy, high-definition endoscopes with virtual chromoendoscopy may have led to an increase in early gastric cancer diagnosis within the last years in Europe. Early diagnosis of gastric cancer may be associated with improved survival. Currently, no data exist on the impact of early diagnosis in gastric cancer patients' survival at a population level in Europe. Our aim was to assess incidence, early diagnosis rate and gastric cancer survival both in North-Western and Southern European countries with a low to moderate GC incidence.

Methods: Data on 41,138 gastric cancer cases between 2007 and 2016 were retrieved from national cancer registries of Belgium, the Netherlands and the Northern Region in Portugal (RORENO). Age standardized incidence and mortality rates (ASMR) were assessed and expressed by 100,000 persons. Early diagnosis was defined as T1 staged tumors (TNM staging). Net survival estimates for 2007-2011 vs 2012-2016 were determined and compared.

Results: Age-standardized incidence and mortality decreased over time in Belgium, Northern Portugal and the Netherlands. Early gastric cancer diagnosis increased over time for all the countries. Net 1- year survival improved significantly between the two time periods in all countries and at 5 years in Belgium and Portugal.

Conclusions: This is the first study comparing trends in gastric cancer incidence and mortality in some European countries. We found from 2007-2016 a trend towards a rising proportion of T1 gastric cancers and a decrease in ASMR over time, supporting the efforts in secondary prevention strategies.
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http://dx.doi.org/10.1055/a-1673-1118DOI Listing
October 2021

Gastrointestinal bleeding and endoscopic findings in critically and non-critically ill patients with corona virus disease 2019 (COVID-19): Results from Lean European Open Survey on SARS-CoV-2 (LEOSS) and COKA registries.

United European Gastroenterol J 2021 11 15;9(9):1081-1090. Epub 2021 Oct 15.

Clinic for Internal Medicine III-Gastroenterology and Infectious Diseases, University Hospital Augsburg, Augsburg, Germany.

Background: Corona virus disease 2019 (COVID-19) patients are at increased risk for thromboembolic events. It is unclear whether the risk for gastrointestinal (GI) bleeding is also increased.

Methods: We considered 4128 COVID-19 patients enrolled in the Lean European Open Survey on SARS-CoV-2 (LEOSS) registry. The association between occurrence of GI bleeding and comorbidities as well as medication were examined. In addition, 1216 patients from COKA registry were analyzed focusing on endoscopy diagnostic findings.

Results: A cumulative number of 97 patients (1.8%) with GI bleeding were identified in the LEOSS registry and COKA registry. Of 4128 patients from the LEOSS registry, 66 patients (1.6%) had a GI bleeding. The rate of GI bleeding in patients with intensive care unit (ICU) admission was 4.5%. The use of therapeutic dose of anticoagulants showed a significant association with the increased incidence of bleeding in the critical phase of disease. The Charlson comorbidity index and the COVID-19 severity index were significantly higher in the group of patients with GI bleeding than in the group of patients without GI bleeding (5.83 (SD = 2.93) vs. 3.66 (SD = 3.06), p < 0.01 and 3.26 (SD = 1.69) vs. 2.33 (SD = 1.53), p < 0.01, respectively). In the COKA registry 31 patients (2.5%) developed a GI bleeding. Of these, the source of bleeding was identified in upper GI tract in 21 patients (67.7%) with ulcer as the most frequent bleeding source (25.8%, n = 8) followed by gastroesophageal reflux (16.1%, n = 5). In three patients (9.7%) GI bleeding source was located in lower GI tract caused mainly by diverticular bleeding (6.5%, n = 2). In seven patients (22.6%) the bleeding localization remained unknown.

Conclusion: Consistent with previous research, comorbidities and disease severity correlate with the incidence of GI bleeding. Also, therapeutic anticoagulation seems to be associated with a higher risk of GI bleeding. Overall, the risk of GI bleeding seems not to be increased in COVID-19 patients.
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http://dx.doi.org/10.1002/ueg2.12165DOI Listing
November 2021

Evaluation of the ESGE recommendations for COVID-19 pre-endoscopy risk-stratification in a high-volume center in Germany.

Endosc Int Open 2021 Oct 16;9(10):E1556-E1560. Epub 2021 Sep 16.

Department of Gastroenterology and Infectious Diseases, University Hospital of Augsburg, Augsburg, Germany.

The European Society of Gastrointestinal Endoscopy (ESGE) has defined COVID-19 infection prevention and control strategies within the endoscopy unit. These include pre-endoscopic questionnaire-based risk-stratification as well as pre-procedure viral testing. Real-life data on the effectiveness of these measures are presented here. Data from the outpatient endoscopic unit of the University Hospital Augsburg between July 1, 2020 and December 31, 2020 including the second pandemic wave were reviewed retrospectively. All patients were assessed with a pre-endoscopic risk-stratification questionnaire as well as viral testing using an antigen point-of-care test (Ag-POCT) in conjunction with a standard polymerase chain reaction (PCR) test. Highly elective procedures were postponed. The theoretically expected number of SARS-CoV-2-positive patients was simulated and compared with the actual number. In addition, endoscopy staff was evaluated with a rapid antibody test to determine the number of infections among the personnel. In total, 1029 procedures, 591 questionnaires, 591 Ag-POCTs, and 529 standard PCR tests were performed in 591 patients. 247 procedures in 142 patients were postponed. One Ag-POCT was positive but with a negative PCR test, while one PCR test was positive but with a negative Ag-POCT. This was lower than the theoretically expected number of COVID-19-positive patients (n = 15). One of 43 employees (2.3 %) in the outpatient endoscopy unit was seropositive. Pre-endoscopic risk management including questionnaire-based risk stratification and viral testing seems to be an effective tool in combination with personal protective equipment for SARS-CoV-2 infection prevention and control within the endoscopy unit even in a high-prevalence setting.
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http://dx.doi.org/10.1055/a-1526-1169DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8445688PMC
October 2021

Performance of antigen testing for diagnosis of COVID-19: a direct comparison of a lateral flow device to nucleic acid amplification based tests.

BMC Infect Dis 2021 Aug 10;21(1):798. Epub 2021 Aug 10.

III. Medical Clinic-Gastroenterology, Infectious Diseases, University Hospital of Augsburg, Stenglinstraße 2, 86156, Augsburg, Germany.

Objectives: The gold standard for diagnosing an infection with SARS-CoV-2 is detection of viral RNA by nucleic acid amplification techniques. Test capacities, however, are limited. Therefore, numerous easy-to-use rapid antigen tests based on lateral flow technology have been developed. Manufacturer-reported performance data seem convincing, but real-world data are missing.

Methods: We retrospectively analysed all prospectively collected antigen tests results performed between 23.06.2020 and 26.11.2020, generated by non-laboratory personnel at the point-of-care from oro- or nasopharyngeal swab samples at the University Hospital Augsburg and compared them to concomitantly (within 24 h.) generated results from molecular tests.

Results: For a total of 3630 antigen tests, 3110 NAAT results were available. Overall, sensitivity, specificity, NPV and PPV of antigen testing were 59.4%, 99.0%, 98.7% and 64.8%, respectively. Sensitivity and PPV were lower in asymptomatic patients (47.6% and 44.4%, respectively) and only slightly higher in patients with clinical symptoms (66.7% and 85.0%, respectively). Some samples with very low Ct-values (minimum Ct 13) were not detected by antigen testing. 31 false positive results occurred. ROC curve analysis showed that reducing the COI cut-off from 1, as suggested by the manufacturer, to 0.9 is optimal, albeit with an AUC of only 0.66.

Conclusion: In real life, performance of lateral-flow-based antigen tests are well below the manufacturer's specifications, irrespective of patient's symptoms. Their use for detection of individual patients infected with SARS-CoV2 should be discouraged. This does not preclude their usefulness in large-scale screening programs to reduce transmission events on a population-wide scale.
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http://dx.doi.org/10.1186/s12879-021-06524-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8354301PMC
August 2021

Underwater vs Conventional Endoscopic Mucosal Resection of Large Sessile or Flat Colorectal Polyps: A Prospective Randomized Controlled Trial.

Gastroenterology 2021 Nov 8;161(5):1460-1474.e1. Epub 2021 Aug 8.

Department of Gastroenterology, University Hospital Augsburg, Augsburg, Germany.

Background & Aims: Conventional endoscopic mucosal resection (CEMR) with submucosal injection is the current standard for the resection of large, nonmalignant colorectal polyps. We investigated whether underwater endoscopic mucosal resection (UEMR) is superior to CEMR for large (20-40mm) sessile or flat colorectal polyps.

Methods: In this prospective randomized controlled study, patients with sessile or flat colorectal polyps between 20 and 40 mm in size were randomly assigned to UEMR or CEMR. The primary outcome was the recurrence rate after 6 months. Secondary outcomes included en bloc and R0 resection rates, number of resected pieces, procedure time, and adverse events.

Results: En bloc resection rates were 33.3% in the UEMR group and 18.4% in the CEMR group (P = .045); R0 resection rates were 32.1% and 15.8% for UEMR vs CEMR, respectively (P = .025). UEMR was performed with significantly fewer pieces compared to CEMR (2 pieces: 45.5% UEMR vs 17.7% CEMR; P = .001). The overall recurrence rate did not differ between both groups (P = .253); however, subgroup analysis showed a significant difference in favor of UEMR for lesions of >30 mm to ≤40 mm in size (P = .031). The resection time was significantly shorter in the UEMR group (8 vs 14 minutes; P < .001). Adverse events did not differ between both groups (P = .611).

Conclusions: UEMR is superior to CEMR regarding en bloc resection, R0 resection, and procedure time for large colorectal lesions and shows significantly lower recurrence rates for lesions >30 mm to ≤40 mm in size. UEMR should be considered for the endoscopic resection of large colorectal polyps.
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http://dx.doi.org/10.1053/j.gastro.2021.07.044DOI Listing
November 2021

Endoscopic Submucosal Dissection in Europe: Results of 1000 Neoplastic Lesions From the German Endoscopic Submucosal Dissection Registry.

Gastroenterology 2021 Oct 26;161(4):1168-1178. Epub 2021 Jun 26.

Department of Gastroenterology, University Hospital Augsburg, Augsburg, Germany. Electronic address:

Background And Aims: Endoscopic submucosal dissection (ESD) enables the curative resection of early malignant lesions and is associated with reduced recurrence risk. Due to the lack of comprehensive ESD data in the West, the German ESD registry was set up to evaluate relevant outcomes of ESD.

Methods: The German ESD registry is a prospective uncontrolled multicenter study. During a 35-month period, 20 centers included 1000 ESDs of neoplastic lesions. The results were evaluated in terms of en bloc, R0, curative resection rates, and recurrence rate after a 3-month and 12-month follow-up. Additionally, participating centers were grouped into low-volume (≤20 ESDs/y), middle-volume (20-50/y), and high-volume centers (>50/y). A multivariate analysis investigating risk factors for noncurative resection was performed.

Results: Overall, en bloc, R0, and curative resection rates of 92.4% (95% confidence interval [CI], 0.90-0.94), 78.8% (95% CI, 0.76-0.81), and 72.3% (95% CI, 0.69-0.75) were achieved, respectively. The overall complication rate was 8.3% (95% CI, 0.067-0.102), whereas the recurrence rate after 12 months was 2.1%. High-volume centers had significantly higher en bloc, R0, curative resection rates, and recurrence rates and lower complication rates than middle- or low-volume centers. The lesion size, hybrid ESD, age, stage T1b carcinoma, and treatment outside high-volume centers were identified as risk factors for noncurative ESD.

Conclusion: In Germany, ESD achieves excellent en bloc resection rates but only modest curative resection rates. ESD requires a high level of expertise, and results vary significantly depending on the center's yearly case volume.
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http://dx.doi.org/10.1053/j.gastro.2021.06.049DOI Listing
October 2021

Barrett esophagus: What to expect from Artificial Intelligence?

Best Pract Res Clin Gastroenterol 2021 Jun-Aug;52-53:101726. Epub 2021 Feb 8.

Department of Gastroenterology, University Hospital of Augsburg, Germany.

The evaluation and assessment of Barrett's esophagus is challenging for both expert and nonexpert endoscopists. However, the early diagnosis of cancer in Barrett's esophagus is crucial for its prognosis, and could save costs. Pre-clinical and clinical studies on the application of Artificial Intelligence (AI) in Barrett's esophagus have shown promising results. In this review, we focus on the current challenges and future perspectives of implementing AI systems in the management of patients with Barrett's esophagus.
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http://dx.doi.org/10.1016/j.bpg.2021.101726DOI Listing
July 2021

Convolutional Neural Networks for the evaluation of cancer in Barrett's esophagus: Explainable AI to lighten up the black-box.

Comput Biol Med 2021 08 17;135:104578. Epub 2021 Jun 17.

Regensburg Medical Image Computing (ReMIC), Ostbayerische Technische Hochschule Regensburg (OTH Regensburg), Germany; Regensburg Center of Health Sciences and Technology (RCHST), OTH Regensburg, Germany.

Even though artificial intelligence and machine learning have demonstrated remarkable performances in medical image computing, their level of accountability and transparency must be provided in such evaluations. The reliability related to machine learning predictions must be explained and interpreted, especially if diagnosis support is addressed. For this task, the black-box nature of deep learning techniques must be lightened up to transfer its promising results into clinical practice. Hence, we aim to investigate the use of explainable artificial intelligence techniques to quantitatively highlight discriminative regions during the classification of early-cancerous tissues in Barrett's esophagus-diagnosed patients. Four Convolutional Neural Network models (AlexNet, SqueezeNet, ResNet50, and VGG16) were analyzed using five different interpretation techniques (saliency, guided backpropagation, integrated gradients, input × gradients, and DeepLIFT) to compare their agreement with experts' previous annotations of cancerous tissue. We could show that saliency attributes match best with the manual experts' delineations. Moreover, there is moderate to high correlation between the sensitivity of a model and the human-and-computer agreement. The results also lightened that the higher the model's sensitivity, the stronger the correlation of human and computational segmentation agreement. We observed a relevant relation between computational learning and experts' insights, demonstrating how human knowledge may influence the correct computational learning.
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http://dx.doi.org/10.1016/j.compbiomed.2021.104578DOI Listing
August 2021

Higher rate of en bloc resection with underwater than conventional endoscopic mucosal resection: A meta-analysis.

Dig Liver Dis 2021 Aug 29;53(8):958-964. Epub 2021 May 29.

Department of Gastroenterology, University Hospital Augsburg, Augsburg, Germany.

Objectives: Previous meta-analysis including nonrandomized studies showed marginal benefit of underwater endoscopic mucosal resection(U-EMR) compared to conventional EMR(C-EMR) in terms of polypectomy outcomes. We evaluated U-EMR compared to C-EMR in the treatment of colorectal polyps with respect to effectiveness and safety by analyzing only randomized controlled trials(RCTs).

Material And Methods: PubMed and Cochrane Library databases were searched for RCTs published until 11/2020, evaluating U-EMR vs. C-EMR regarding en bloc resection, post-endoscopic resection adenoma recurrence, complete resection, adverse events rates and difference in resection time. Abstracts from Digestive Disease Week, United European Gastroenterology Week and ESGE Days meetings were also searched. Effect size on outcomes is presented as risk ratio(RR; 95% confidence interval[CI]) or mean difference(MD; 95%CI). The I test was used for quantifying heterogeneity, while Grading of Recommendations Assessment, Development and Evaluation(GRADE) was used to assess strength of evidence.

Results: Six RCTs analyzing outcomes from 1157 colorectal polypectomies(U-EMR589;C-EMR,568) were included. U-EMR associated with significant higher rate of en bloc resection compared to C-EMR [RR(95%CI):1.26(1.01-1.58); Chi² for heterogeneity=30.43, P<0.0001; I²=84%, GRADE: Very low]. This effect was more prominent regarding resection of polyps sized ≥20 mm compared to polyps <20 mm [RR(95%CI):1.64(1.22-2.20) vs. 1.10(0.98-1.23)]. Post-resection recurrence [RR(95%CI):0.52(0.28-0.94);GRADE:Low] was lower significantly in U-EMR group. In contrast, no significant difference was detected between U-EMR and C-EMR regarding complete resection [RR(95%CI): 1.06(0.91-1.24) GRADE:Very low] and adverse events occurrence[RR(95%CI):1.00 (0.72-1.39); GRADE:Low].

Conclusion: Meta-analysis of RCTs supports that U-EMR resection achieves higher rate of en bloc resection compared to conventional EMR. This effect is driven when resecting large(≥20 mm) polyps.
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http://dx.doi.org/10.1016/j.dld.2021.05.001DOI Listing
August 2021

Endoscopic Treatment of Zenker's Diverticulum: Comparable Treatment Outcomes in Treatment-Naïve and Pretreated Patients.

Gastroenterol Res Pract 2021 16;2021:9237617. Epub 2021 Mar 16.

Department of Internal Medicine III at the University Hospital Augsburg, Germany.

Background And Aims: Flexible endoscopic treatment plays an important role in the treatment of Zenker's diverticulum (ZD). This study analyzes long-term symptom control and the rate of adverse events in treatment-naïve patients and patients with recurrence, using the stag beetle knife junior (sb knife jr).

Methods: From August 2013 to May 2019, 100 patients with symptomatic ZD were treated with flexible endoscopy using the sb knife jr. Before treatment, as well as 1 and 6 months afterwards, symptoms were obtained by a nine-point questionnaire, with symptoms weighted from 0 to 4.

Results: Overall, 126 interventions were performed. The median follow-up period was 41 months (range 7-74). For the three most frequent symptoms, regurgitation, dysphagia, and dry cough, a significant reduction of the mean score could be achieved, from 2.85/3.45/2.85 before the initial treatment to 0.56/1.09/0.98 6 months later. 17 patients were retreated because of recurrence. Out of these, 12 patients underwent a 2, 4 patients a 3, and 1 patient a 4 session, respectively. The mean dysphagia score for successfully treated patients could be reduced from initially 2.34 to 0.49/0.33/0.67 after the 1/2/3 session, the frequency of dysphagia from 3.45 to 0.92/1.00/1.33, and the score for regurgitations from 2.85 to 0.35/1.00/0.67. In first-line treatment, as well as in retreatment, no severe adverse event occurred.

Conclusion: Patients with ZD can be treated safely and effectively with the sb knife jr. Retreatment leads to equal symptom relief as compared to a successful first-line treatment and is not associated with a higher rate of adverse events.
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http://dx.doi.org/10.1155/2021/9237617DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8080870PMC
March 2021

Gastric cancer- endoscopic treatment of early lesions, the West learns from the East.

Best Pract Res Clin Gastroenterol 2021 Mar-Apr;50-51:101739. Epub 2021 Feb 22.

University Hospital Augsburg, Department of Gastroenterology, Germany.

Gastric cancer still has one of the highest incidence rates worldwide. Screening programs have been established in high incidence regions, especially in Asia, but in the West, screening for gastric cancer is not generally recommended. Gastroscopy is the gold standard for diagnosing gastric cancer. For the treatment of early gastric cancer, endoscopic resection is the method of choice. With the ESD technique, larger lesions can be resected en-bloc. Guideline and extended guideline criteria for the choice of lesions for ESD have been evaluated extensively, initially in Asia and later in the West as well. For lesions which are out of indication, a surgical approach must be recommended. To detect early recurrence or metachronous lesions, follow-up should be performed after ER.
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http://dx.doi.org/10.1016/j.bpg.2021.101739DOI Listing
May 2021

Endoscopists' diagnostic accuracy in detecting upper gastrointestinal neoplasia in the framework of artificial intelligence studies.

Endoscopy 2021 May 5. Epub 2021 May 5.

Gastroenterology Department, Portuguese Oncology Institute of Porto, Porto, Portugal.

Background:  Estimates on miss rates for upper gastrointestinal neoplasia (UGIN) rely on registry data or old studies. Quality assurance programs for upper GI endoscopy are not fully established owing to the lack of infrastructure to measure endoscopists' competence. We aimed to assess endoscopists' accuracy for the recognition of UGIN exploiting the framework of artificial intelligence (AI) validation studies.

Methods:  Literature searches of databases (PubMed/MEDLINE, EMBASE, Scopus) up to August 2020 were performed to identify articles evaluating the accuracy of individual endoscopists for the recognition of UGIN within studies validating AI against a histologically verified expert-annotated ground-truth. The main outcomes were endoscopists' pooled sensitivity, specificity, positive and negative predictive value (PPV/NPV), and area under the curve (AUC) for all UGIN, for esophageal squamous cell neoplasia (ESCN), Barrett esophagus-related neoplasia (BERN), and gastric adenocarcinoma (GAC).

Results:  Seven studies (2 ESCN, 3 BERN, 1 GAC, 1 UGIN overall) with 122 endoscopists were included. The pooled endoscopists' sensitivity and specificity for UGIN were 82 % (95 % confidence interval [CI] 80 %-84 %) and 79 % (95 %CI 76 %-81 %), respectively. Endoscopists' accuracy was higher for GAC detection (AUC 0.95 [95 %CI 0.93-0.98]) than for ESCN (AUC 0.90 [95 %CI 0.88-0.92]) and BERN detection (AUC 0.86 [95 %CI 0.84-0.88]). Sensitivity was higher for Eastern vs. Western endoscopists (87 % [95 %CI 84 %-89 %] vs. 75 % [95 %CI 72 %-78 %]), and for expert vs. non-expert endoscopists (85 % [95 %CI 83 %-87 %] vs. 71 % [95 %CI 67 %-75 %]).

Conclusion:  We show suboptimal accuracy of endoscopists for the recognition of UGIN even within a framework that included a higher prevalence and disease awareness. Future AI validation studies represent a framework to assess endoscopist competence.
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http://dx.doi.org/10.1055/a-1500-3730DOI Listing
May 2021

Artificial intelligence in the upper GI tract: the future is fast approaching.

Gastrointest Endosc 2021 06 11;93(6):1342-1343. Epub 2021 Mar 11.

Department of Gastroenterology, University Hospital of Augsburg, Augsburg, Germany.

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http://dx.doi.org/10.1016/j.gie.2021.01.012DOI Listing
June 2021

Typical Imaging Patterns in COVID-19 Infections of the Lung on Plain Chest Radiographs to Aid Early Triage.

Rofo 2021 Oct 10;193(10):1189-1196. Epub 2021 Mar 10.

Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Augsburg, Germany.

Purpose:  To evaluate imaging patterns of a COVID-19 infection of the lungs on chest radiographs and their value in discriminating this infection from other viral pneumonias.

Materials And Methods:  All 321 patients who presented with respiratory impairment suspicious for COVID-19 infection between February 3 and May 8, 2020 and who received a chest radiograph were included in this analysis. Imaging findings were classified as typical for COVID-19 (bilateral, peripheral opacifications/consolidations), non-typical (findings consistent with lobar pneumonia), indeterminate (all other distribution patterns of opacifications/consolidations), or none (no opacifications/consolidations). The sensitivity, specificity, as well as positive and negative predictive value for the diagnostic value of the category "typical" were determined. Chi² test was used to compare the pattern distribution between the different types of pneumonia.

Results:  Imaging patterns defined as typical for COVID-19 infections were documented in 35/111 (31.5 %) patients with confirmed COVID-19 infection but only in 4/210 (2 %) patients with any other kind of pneumonia, resulting in a sensitivity of 31.5 %, a specificity of 98.1 %, and a positive and negative predictive value of 89.7 % or 73 %, respectively. The sensitivity could be increased to 45.9 % when defining also unilateral, peripheral opacifications/consolidations with no relevant pathology contralaterally as consistent with a COVID-19 infection, while the specificity decreases slightly to 93.3 %. The pattern distribution between COVID-19 patients and those with other types of pneumonia differed significantly (p < 0.0001).

Conclusion:  Although the moderate sensitivity does not allow the meaningful use of chest radiographs as part of primary screening, the specific pattern of findings in a relevant proportion of those affected should be communicated quickly as additional information and trigger appropriate protective measures.

Key Points:   · COVID-19 infections show specific X-ray image patterns in 1/3 of patients.. · Bilateral, peripheral opacities and/or consolidations are typical imaging patterns.. · Unilateral, peripheral opacities and/or consolidations should also raise suspicion of COVID-19 infection..

Citation Format: · Kasper J, Decker J, Wiesenreiter K et al. Typical Imaging Patterns in COVID-19 Infections of the Lung on Plain Chest Radiographs to Aid Early Triage. Fortschr Röntgenstr 2021; 193: 1189 - 1196.
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http://dx.doi.org/10.1055/a-1388-8147DOI Listing
October 2021

Sustained cellular immunity in adults recovered from mild COVID-19.

Cytometry A 2021 05 31;99(5):429-434. Epub 2021 Jan 31.

Hematology and Oncology, Medical Faculty, University of Augsburg, Augsburg, Germany.

Transient lymphocytopenia is frequently observed in acute phase of coronavirus disease 2019 (COVID-19). It remains a concern whether impairment of cellular immunity may be retained after COVID-19. Here, we demonstrate by extensive lymphocyte profiling in 44 adults after mild COVID-19 that cellular immunity is not fundamentally altered in convalescent patients. Except for increased activated CD8+ lymphocytes, total counts of B, T, and NK cells and their subsets did not differ significantly between patients after COVID-19 and healthy controls after a median of 27 days (range 13-45) suggesting no residual cellular immune deficiency after recovery from mild COVID-19.
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http://dx.doi.org/10.1002/cyto.a.24309DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8014675PMC
May 2021

Endoscopic prediction of submucosal invasion in Barrett's cancer with the use of artificial intelligence: a pilot study.

Endoscopy 2021 09 16;53(9):878-883. Epub 2020 Nov 16.

III Medizinische Klinik, Universitätsklinikum Augsburg, Augsburg Germany.

Background: The accurate differentiation between T1a and T1b Barrett's-related cancer has both therapeutic and prognostic implications but is challenging even for experienced physicians. We trained an artificial intelligence (AI) system on the basis of deep artificial neural networks (deep learning) to differentiate between T1a and T1b Barrett's cancer on white-light images.

Methods: Endoscopic images from three tertiary care centers in Germany were collected retrospectively. A deep learning system was trained and tested using the principles of cross validation. A total of 230 white-light endoscopic images (108 T1a and 122 T1b) were evaluated using the AI system. For comparison, the images were also classified by experts specialized in endoscopic diagnosis and treatment of Barrett's cancer.

Results: The sensitivity, specificity, F1 score, and accuracy of the AI system in the differentiation between T1a and T1b cancer lesions was 0.77, 0.64, 0.74, and 0.71, respectively. There was no statistically significant difference between the performance of the AI system and that of experts, who showed sensitivity, specificity, F1, and accuracy of 0.63, 0.78, 0.67, and 0.70, respectively.

Conclusion: This pilot study demonstrates the first multicenter application of an AI-based system in the prediction of submucosal invasion in endoscopic images of Barrett's cancer. AI scored equally to international experts in the field, but more work is necessary to improve the system and apply it to video sequences and real-life settings. Nevertheless, the correct prediction of submucosal invasion in Barrett's cancer remains challenging for both experts and AI.
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http://dx.doi.org/10.1055/a-1311-8570DOI Listing
September 2021

Standalone performance of artificial intelligence for upper GI neoplasia: a meta-analysis.

Gut 2020 Oct 30. Epub 2020 Oct 30.

CIDES/CINTESIS, Faculty of Medicine, University of Porto, Porto, Portugal

Objective: Artificial intelligence (AI) may reduce underdiagnosed or overlooked upper GI (UGI) neoplastic and preneoplastic conditions, due to subtle appearance and low disease prevalence. Only disease-specific AI performances have been reported, generating uncertainty on its clinical value.

Design: We searched PubMed, Embase and Scopus until July 2020, for studies on the diagnostic performance of AI in detection and characterisation of UGI lesions. Primary outcomes were pooled diagnostic accuracy, sensitivity and specificity of AI. Secondary outcomes were pooled positive (PPV) and negative (NPV) predictive values. We calculated pooled proportion rates (%), designed summary receiving operating characteristic curves with respective area under the curves (AUCs) and performed metaregression and sensitivity analysis.

Results: Overall, 19 studies on detection of oesophageal squamous cell neoplasia (ESCN) or Barrett's esophagus-related neoplasia (BERN) or gastric adenocarcinoma (GCA) were included with 218, 445, 453 patients and 7976, 2340, 13 562 images, respectively. AI-sensitivity/specificity/PPV/NPV/positive likelihood ratio/negative likelihood ratio for UGI neoplasia detection were 90% (CI 85% to 94%)/89% (CI 85% to 92%)/87% (CI 83% to 91%)/91% (CI 87% to 94%)/8.2 (CI 5.7 to 11.7)/0.111 (CI 0.071 to 0.175), respectively, with an overall AUC of 0.95 (CI 0.93 to 0.97). No difference in AI performance across ESCN, BERN and GCA was found, AUC being 0.94 (CI 0.52 to 0.99), 0.96 (CI 0.95 to 0.98), 0.93 (CI 0.83 to 0.99), respectively. Overall, study quality was low, with high risk of selection bias. No significant publication bias was found.

Conclusion: We found a high overall AI accuracy for the diagnosis of any neoplastic lesion of the UGI tract that was independent of the underlying condition. This may be expected to substantially reduce the miss rate of precancerous lesions and early cancer when implemented in clinical practice.
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http://dx.doi.org/10.1136/gutjnl-2020-321922DOI Listing
October 2020

Impact of the COVID-19 outbreak on endoscopy training in a tertiary care centre in Germany.

Frontline Gastroenterol 2020 Oct 10;11(6):454-457. Epub 2020 Jun 10.

Department of Gastroenterology, Universitätsklinikum Augsburg, Augsburg, Bayern, Germany.

Objective: The COVID-19 crisis has impacted on all aspects of health care including medical education and training. We describe the disruption of endoscopy training in a tertiary care center in Germany.

Design/method: The reorganization of a high-volume endoscopy unit during the German COVID-19 outbreak is described with special focus on endoscopy trainees. Changes in case volume of gastroenterology fellows were evaluated and compared to a year prior to the outbreak.

Results: Reallocation of resources led to the transfer of gastroenterology fellows to intensive care and infectious disease units. Case volume of fellows declined between January and April 2020 by up to 63%. When compared with data from the year prior to the outbreak, endoscopy performed by fellows reduced by up to 56%. Educational meetings and skill evaluation were cancelled indefinitely.

Conclusion: The COVID-19 outbreak has had a negative impact on endoscopy training of gastroenterology fellows in a high-volume center in Germany. This must be taken into consideration when planning "return-strategies" after the pandemic.
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http://dx.doi.org/10.1136/flgastro-2020-101504DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7569514PMC
October 2020

Cost-effectiveness analysis of SARS-CoV-2 infection prevention strategies including pre-endoscopic virus testing and use of high risk personal protective equipment.

Endoscopy 2021 02 20;53(2):156-161. Epub 2020 Oct 20.

Department of Gastroenterology, Universitätsklinikum Augsburg, Augsburg, Germany.

Background: Infection prevention strategies to protect healthcare workers in endoscopy units during the post-peak phase of the COVID-19 pandemic are currently under intense discussion. In this paper, the cost-effectiveness of routine pre-endoscopy testing and high risk personal protective equipment (PPE) is addressed.

Method: A model based on theoretical assumptions of 10 000 asymptomatic patients presenting to a high volume center was created. Incremental cost-effectiveness ratios (ICERs) and absolute costs per endoscopy were calculated using a Monte Carlo simulation.

Results: ICER values for universal testing decreased with increasing prevalence rates. For higher prevalence rates (≥ 1 %), ICER values were lowest for routine pre-endoscopy testing coupled with use of high risk PPE, while cost per endoscopy was lowest for routine use of high risk PPE without universal testing.

Conclusion: In general, routine pre-endoscopy testing combined with high risk PPE becomes more cost-effective with rising prevalence rates of COVID-19.
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http://dx.doi.org/10.1055/a-1294-0427DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7869042PMC
February 2021

Assisting Barrett's esophagus identification using endoscopic data augmentation based on Generative Adversarial Networks.

Comput Biol Med 2020 11 10;126:104029. Epub 2020 Oct 10.

Department of Computing, São Paulo State University, UNESP, Brazil. Electronic address:

Barrett's esophagus figured a swift rise in the number of cases in the past years. Although traditional diagnosis methods offered a vital role in early-stage treatment, they are generally time- and resource-consuming. In this context, computer-aided approaches for automatic diagnosis emerged in the literature since early detection is intrinsically related to remission probabilities. However, they still suffer from drawbacks because of the lack of available data for machine learning purposes, thus implying reduced recognition rates. This work introduces Generative Adversarial Networks to generate high-quality endoscopic images, thereby identifying Barrett's esophagus and adenocarcinoma more precisely. Further, Convolution Neural Networks are used for feature extraction and classification purposes. The proposed approach is validated over two datasets of endoscopic images, with the experiments conducted over the full and patch-split images. The application of Deep Convolutional Generative Adversarial Networks for the data augmentation step and LeNet-5 and AlexNet for the classification step allowed us to validate the proposed methodology over an extensive set of datasets (based on original and augmented sets), reaching results of 90% of accuracy for the patch-based approach and 85% for the image-based approach. Both results are based on augmented datasets and are statistically different from the ones obtained in the original datasets of the same kind. Moreover, the impact of data augmentation was evaluated in the context of image description and classification, and the results obtained using synthetic images outperformed the ones over the original datasets, as well as other recent approaches from the literature. Such results suggest promising insights related to the importance of proper data for the accurate classification concerning computer-assisted Barrett's esophagus and adenocarcinoma detection.
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http://dx.doi.org/10.1016/j.compbiomed.2020.104029DOI Listing
November 2020

Advanced endoscopic imaging of colonic schistosomiasis.

Endoscopy 2021 07 23;53(7):E251-E252. Epub 2020 Sep 23.

Department of Gastroenterology and Infectious Diseases, University Hospital, Augsburg, Germany.

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http://dx.doi.org/10.1055/a-1252-2637DOI Listing
July 2021

Impact of the COVID-19 pandemic on gastrointestinal endoscopy in Africa.

Endosc Int Open 2020 Aug 7;8(8):E1097-E1101. Epub 2020 Aug 7.

Endoscopy Unit, Nuovo Regina Margherita Hospital, Rome, Italy.

As with all other fields of medical practice, gastrointestinal endoscopy has been impacted by the COVID-19 pandemic. However, data on the impact of the pandemic in Africa, especially sub-Saharan Africa are lacking. A web-based survey was conducted by the International Working Group of the European Society for Gastrointestinal Endoscopy and the World Endoscopy Organization to determine the impact and effects the COVID-19 pandemic has had on endoscopists in African countries. Thirty-one gastroenterologists from 14 countries in north, central, and sub-Saharan Africa responded to the survey. The majority of respondents reduced their endoscopy volume considerably. Personal protective equipment including FFP-2 masks were available in almost all participating centers. Pre-endoscopy screening was performed as well. The COVID-19 pandemic has had a substantial impact on gastrointestinal endoscopy in most African countries; however, the impact may not have been as devastating as expected.
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http://dx.doi.org/10.1055/a-1210-4274DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7413826PMC
August 2020

Regular arrangement of collecting venules and the Kimura-Takemoto classification for the endoscopic diagnosis of Helicobacter pylori infection: Evaluation in a Western setting.

Dig Endosc 2021 May 28;33(4):587-591. Epub 2020 Oct 28.

Department of Gastroenterology, University Hospital Augsburg, Augsburg, Germany.

Background: The regular arrangement of collecting venules (RAC) and the Kimura-Takemoto classification of atrophic change (KTC) are simple and easy-to-use criteria which have been shown to reliably predict or rule out a Helicobacter pylori infection of the stomach. Although these features have been investigated extensively in Asia, their significance in the West has not been evaluated.

Methods: In a series of 200 consecutive gastroscopic examinations (single examiner, single center), the presence or absence of RAC and the KTC grade (open type vs closed type) were recorded prospectively. Helicobacter pylori infection was defined as a positive histology or a positive rapid urease test. Furthermore, multivariate analysis of endoscopic predictors of H. pylori infection based on the Kyoto classification of gastritis was performed.

Results: Two hundred patients were examined of which 57 had a H. pylori infection (28%). Both RAC and KTC had excellent negative predictive values of about 90% and sensitivity values of up to 85%. In multivariate analysis, atrophic change and diffuse redness without RAC were significantly associated with H. pylori infection.

Conclusion: Regular arrangement of collecting venules and KTC are simple endoscopic features which should be given attention by Western endoscopists and can be easily used to rule out a H. pylori infection of the stomach.
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http://dx.doi.org/10.1111/den.13808DOI Listing
May 2021

Psychosocial burden of healthcare professionals in times of COVID-19 - a survey conducted at the University Hospital Augsburg.

Ger Med Sci 2020 22;18:Doc05. Epub 2020 Jun 22.

Medical Clinic III, University Hospital Augsburg, Germany.

The outbreak of COVID-19 was declared a pandemic by the WHO in March 2020. Studies from China, where the virus first spread, have reported increased psychological strain in healthcare professionals. The aim of this study was to investigate the psychosocial burden of physicians and nurses depending on their degree of contact with COVID-19 patients. In addition, we explored which supportive resources they used and which supportive needs they experienced during the crisis. Data were collected between March and April 2020 at the University Hospital Augsburg. A total of 75 nurses and 35 physicians, working either in a special COVID-19 ward or in a regular ward, took part in the survey. The participants filled in two standardized questionnaires (the Patient Health Questionnaire, PHQ; and the Maslach Burnout Inventory, MBI), and reported their fear of a COVID-19 infection and stress at work on a 10-point Likert scale. Finally, they answered three open-ended questions about causes of burden, supportive resources and needs during the crisis. Nurses working in the COVID-19 wards reported higher levels of stress, exhaustion, and depressive mood, as well as lower levels of work-related fulfilment compared to their colleagues in the regular wards. Physicians reported similar scores independent of their contact with COVID-19 patients. The most common causes for burden were job strain and uncertainty about the future. Psychosocial support as well as leisure time were listed as important resources, and a better infrastructure adjustment to COVID-19 at the hospital (e.g. sufficient staff, keeping teams and working schedules stable) as suggestion for improvement. Our findings indicate that especially nurses working in COVID-19 wards are affected psychologically by the consequences of the pandemic. This might be due to a higher workload and longer time in direct contact with COVID-19 patients, compared to physicians.
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http://dx.doi.org/10.3205/000281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7314868PMC
July 2020
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