15 results on '"Torsten Hopp"'
Search Results
2. Image-based registration between full x-ray and spot mammograms: analysis of registration accuracy in subgroups.
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Sarah Said, Paola Clauser, Nicole V. Ruiter, Pascal A. Baltzer, and Torsten Hopp
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- 2023
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3. Model-data-driven image reconstruction with neural networks for ultrasound computed tomography breast imaging.
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Yuling Fan, Hongjian Wang, Hartmut Gemmeke, Torsten Hopp, and Juergen Hesser
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- 2022
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4. Segmentation of the mouse skull for MRI guided transcranial focused ultrasound therapy planning.
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Torsten Hopp, Luca Springer, Carl Gross, Saskia Grudzenski-Theis, Franziska Mathis-Ullrich, and Nicole V. Ruiter
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- 2022
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5. Image based registration between full x-ray and spot mammograms for x-ray guided stereotactic breast biopsy.
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Sarah Said, Paola Clauser, Nicole V. Ruiter, Pascal A. Baltzer, and Torsten Hopp
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- 2022
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6. First imaging results with the new generation of the KIT 3D ultrasound tomography device
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Torsten Hopp, Michael Zapf, Laura Fernandez-Lago, Fridtjof Feldbusch, Hartmut E. Gemmeke, and Nicole V. Ruiter
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- 2023
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7. Model-data-driven image reconstruction with neural networks for ultrasound computed tomography breast imaging
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Juergen Hesser, Torsten Hopp, Yuling Fan, Hartmut Gemmeke, and Hongjian Wang
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Network architecture ,Ground truth ,Artificial neural network ,Mean squared error ,Breast imaging ,business.industry ,Computer science ,Cognitive Neuroscience ,Attenuation ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Iterative reconstruction ,Computer Science Applications ,Artificial Intelligence ,Computer vision ,Artificial intelligence ,business ,Test data - Abstract
With the goal of developing an accurate and fast image reconstruction algorithm for ultrasound computed tomography, we combine elements of model- and data-driven approaches and propose a learned method which addresses the disadvantages of both approaches. We design a deep neural network which accounts for a nonlinear forward operator and primal-dual algorithm by its inherent network architecture. The network is trained end-to-end, with ultrasound pressure field data as input to get directly an optimized reconstruction of speed of sound and attenuation images. The training and test data are based on a set of Optical and Acoustic Breast Phantom Database, where we use the image as ground truth and simulate pressure field data according to our forward model. Extensive experiments show that our method achieves significant improvements over state-of-the-art reconstruction methods in this field. Experiments show that the proposed algorithm improves the measures structural similarity measure (SSIM) from 0.74 to 0.95 and root mean squared error (RMSE) from 0.13 to 0.09 on average concerning the speed of sound reconstruction, while it improves the SSIM from 0.60 to 0.94 and RMSE from 0.24 to 0.10 on average in attenuation reconstruction.
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- 2022
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8. Simulation-to-real generalization for deep-learning-based refraction-corrected ultrasound tomography image reconstruction
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Wenzhao Zhao, Yuling Fan, Hongjian Wang, Hartmut Gemmeke, Koen W A van Dongen, Torsten Hopp, and Jürgen Hesser
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Radiological and Ultrasound Technology ,Radiology, Nuclear Medicine and imaging - Abstract
Objective. The image reconstruction of ultrasound computed tomography is computationally expensive with conventional iterative methods. The fully learned direct deep learning reconstruction is promising to speed up image reconstruction significantly. However, for direct reconstruction from measurement data, due to the lack of real labeled data, the neural network is usually trained on a simulation dataset and shows poor performance on real data because of the simulation-to-real gap. Approach. To improve the simulation-to-real generalization of neural networks, a series of strategies are developed including a Fourier-transform-integrated neural network, measurement-domain data augmentation methods, and a self-supervised-learning-based patch-wise preprocessing neural network. Our strategies are evaluated on both the simulation dataset and real measurement datasets from two different prototype machines. Main results. The experimental results show that our deep learning methods help to improve the neural networks’ robustness against noise and the generalizability to real measurement data. Significance. Our methods prove that it is possible for neural networks to achieve superior performance to traditional iterative reconstruction algorithms in imaging quality and allow for real-time 2D-image reconstruction. This study helps pave the path for the application of deep learning methods to practical ultrasound tomography image reconstruction based on simulation datasets.
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- 2022
9. Wave-based ultrasound transmission tomography using the paraxial approximation in 2D
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Olga Molchanova, Hartmut Gemmeke, Michael Zapf, Torsten Hopp, Hongjian Wang, and Nicole Ruiter
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- 2022
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10. Realization of an pseudo-randomly sampled 3D USCT
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Michael Zapf, Torsten Hopp, Hartmut Gemmeke, Martin Angerer, Zewei Lu, Olga Molchanova, Nima Rashvand, Roberto Blanco, Petra Steck, Benjamin Leyrer, Denis Tcherniakhovski, Dietmar Bormann, Klaus Schlote-Holubek, and Nicole V. Ruiter
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- 2022
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11. Model-Based Dose Identification of Dalbavancin for Long-Term Suppressive Outpatient Treatment of Ventricular Assist Device Infections
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Ute Chiriac, Uwe Liebchen, Otto Roman Frey, Heike Lanzinger, Sabrina Klein, Torsten Hoppe-Tichy, Matthias Karck, Anna Meyer, and Benedict Morath
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dalbavancin ,ventricular assist device ,population pharmacokinetics ,therapeutic drug monitoring ,long-term treatment ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Increasing evidence suggests that dalbavancin is an effective long-term treatment for ventricular assist device (VAD) infections, with various prolonged dosing regimens currently in use. This retrospective study aimed to assess dalbavancin pharmacokinetics in VAD patients and identify optimal, feasible dosing regimens for long-term suppressive outpatient therapy. Data from Heidelberg University Hospital’s VAD register were analyzed using non-linear mixed-effects modeling for pharmacokinetic analysis and dosing simulations (Lixoft®). The probability of target attainment (PTA) and cumulative fraction of response (CFR) were calculated for different protein-binding scenarios considering the minimum inhibitory concentration (MIC) distribution of Staphylococcus aureus. Using data from 13 patients with 38 blood samples, a two-compartment model best described the dalbavancin pharmacokinetics, with a typical value for clearance of 0.050 L/h, central volume of distribution of 6.5 L, and peripheral volume of 15.4 L. No covariates significantly improved the model fit. The observed protein binding varied between 96 and 98%. Dosing simulations demonstrated that 1500 mg every 3 weeks ensured the target attainment for stasis at MIC values of 0.125 mg/L (PTA ≥ 90%) up to a protein binding of 99%. Considering the CRF, longer dosing intervals up to 5 weeks might be possible. Depending on individual MICs and protein binding, a dalbavancin regimen of 1500 mg every 3 to 5 weeks therefore appears to be a valuable option for outpatient therapy of VAD infections. Therapeutic drug monitoring should be considered to manage inter-individual variability and to support clinicians in long-term treatments of subacute and chronic infections.
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- 2024
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12. Burden of intracerebral haemorrhage in Europe: forecasting incidence and mortality between 2019 and 2050Research in context
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Hatem A. Wafa, Iain Marshall, Charles D.A. Wolfe, Wanqing Xie, Catherine O. Johnson, Roland Veltkamp, Yanzhong Wang, Kirsten H. Harvey, Eleni Korompoki, Lucio D’Anna, Omid Halse, Emily R. Harvey, Klemens Hügen, Uwe Malzahn, Sabine Ullmann, Carolin Schuhmann, Gabriele Putz Todd, Hannes Brinz, Cornelia Fiessler, Peter U. Heuschmann, Kirsten Haas, Viktoria Rücker, Christian Enzinger, Stefan Ropele, Daniela Pinter, Melanie Haidegger, Thomas Gattringer, Simon Fandler-Höfler, Joan Montaner, Elena Palà, Anna Penalba, Marcel Lamana Vallverdu, Daisy Guaman Pilco, Stéphanie Debette, Igor Sibon, Pauline Renou, Morgane Lachaize, Léa Milan, Nathalie Heyvang, Sylvain Ledure, Pascale Michel, Johanna Conhoc, Léa Donnadieu, Kelly Hyves, Valeria Caso, Maria Giulia Mosconi, Mara Graziani, Virginia Cancelloni, Laura Marchini, Bianca Emanuela Koehler, Peter Brønnum Nielsen, Torben Bjerregaard Larsen, Gregory Y.H. Lip, Solveigh Horstmann, Jan Purrucker, Peter Ringleb, Mariam Haffa, Sabrina Klein, Lenka Taylor, Torsten Hoppe-Tichy, Walter E. Haefeli, Hanna M. Seidling, Jürgen Burhenne, Kathrin I. Foerster, Viktoria Wurmbach, Claudia Marquart, Deirdre A. Lane, Elena Ivany, and Robyn Lotto
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Future ,Stroke ,Intracerebral haemorrhage ,Epidemiology ,Europe ,Public aspects of medicine ,RA1-1270 - Abstract
Summary: Background: Anticipating the burden of intracerebral haemorrhage is crucial for proactive management and building resilience against future health challenges. Prior forecasts are based on population demography and to a lesser extent epidemiological trends. This study aims to utilise selected modifiable risk factors and socio-demographic indicators to forecast the incidence and mortality of intracerebral haemorrhage in Europe between 2019 and 2050. Methods: Three intracerebral haemorrhage risk factors identified in the Global Burden of Diseases, Injuries, and Risk Factors study (GBD 2019)—high systolic blood pressure, high fasting plasma glucose, and high body mass index—were utilised to predict the risk-attributable fractions between 2019 and 2050. Disease burden not attributable to these risk factors was then forecasted using time series models (autoregressive integrated moving average [ARIMA]), incorporating the Socio-demographic Index (SDI) as an external predictor. The optimal parameters of ARIMA models were selected for each age-sex-country group based on the Akaike Information Criterion (AIC). Different health scenarios were constructed by extending the past 85th and 15th percentiles of annualised rates of change in risk factors and SDI across all location-years, stratified by age and sex groups. A decomposition analysis was performed to assess the relative contributions of population size, age composition, and intracerebral haemorrhage risk on the projected changes. Findings: Compared with observed figures in 2019, our analysis predicts an increase in the burden of intracerebral haemorrhage in Europe in 2050, with a marginal rise of 0.6% (95% uncertainty interval [UI], −7.4% to 9.6%) in incident cases and an 8.9% (−2.8% to 23.6%) increase in mortality, reaching 141.2 (120.6–166.5) thousand and 144.2 (122.9–172.2) thousand respectively. These projections may fluctuate depending on trajectories of the risk factors and SDI; worsened trends could result in increases of 16.7% (8.7%–25.3%) in incidence and 31.2% (17.7%–48%) in mortality, while better trajectories may lead to a 10% (16.4%–2.3%) decrease in intracerebral haemorrhage cases with stabilised mortality. Individuals aged ≥80 years are expected to contribute significantly to the burden, comprising 62.7% of the cases in 2050, up from 40% in 2019, and 72.5% of deaths, up from 50.5%. Country-wide variations were noted in the projected changes, with decreases in the standardised rates across all nations but varying crude rates. The largest relative reductions in counts for both incidence and mortality are expected in Latvia, Bulgaria, and Hungary—ranging from −38.2% to −32.4% and −37.3% to −30.2% respectively. In contrast, the greatest increases for both measures were forecasted in Ireland (45.7% and 74.4%), Luxembourg (45% and 70.7%), and Cyprus (44.5% and 74.2%). The modelled increase in the burden of intracerebral haemorrhage could largely be attributed to population ageing. Interpretation: This study provides a comprehensive forecast of intracerebral haemorrhage in Europe until 2050, presenting different trajectories. The potential increase in the number of people experiencing and dying from intracerebral haemorrhage could have profound implications for both caregiving responsibilities and associated costs. However, forecasts were divergent between different scenarios and among EU countries, signalling the pivotal role of public health initiatives in steering the trajectories. Funding: The European Union’s Horizon 2020 Research and Innovation Programme under grant agreement No. 754517. The National Institute for Health and Care Research (NIHR) under its Programme Grants for Applied Research (NIHR202339).
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- 2024
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13. Effectiveness, barriers and facilitating factors of strategies for active delabelling of patients with penicillin allergy labels: a systematic review protocol
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Torsten Hoppe-Tichy, Benedict Morath, Claudia Denkinger, Elham Khatamzas, Hannah Nürnberg, Tabea Krause, Lars Oetken, Sophie Rauer, and Amelie Rapp
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Medicine - Abstract
Introduction Up to 15% of adult patients in the clinical setting report to be allergic to penicillin. However, in most cases, penicillin allergy is not confirmed. Due to the negative aspects associated with erroneous penicillin allergy, the implementation of active delabelling processes for penicillin allergy is an important part of antibiotic stewardship programmes. Depending on the clinical setting, different factors need to be considered during implementation. This review examines the effectiveness of different delabelling interventions and summarises components and structures that facilitate, support or constrain structured penicillin allergy delabelling.Methods and analysis This review will adhere to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The databases MEDLINE (via PubMed), EMBASE and Cochrane Library were searched for studies reporting on any intervention to identify, assess or rule out uncertain penicillin allergy. To improve completeness, two further databases are also searched for grey literature. Study design, intervention type, professional groups involved, effectiveness, limitations, barriers, facilitating factors, clinical setting and associated regulatory factors will be extracted and analysed. In addition, exclusion criteria for participation in the delabelling intervention and criteria for not delabelling penicillin allergy will be summarised. In case of failed protocols, these are highlighted and quantitatively analysed if possible. Two independent reviewers will perform the screening process and data extraction. Discordant decisions will be resolved through review by a third reviewer. Bias assessment of the individual studies will be performed using the Newcastle Ottawa Scale.Ethics and dissemination Because individual patient-related data are not analysed, an ethical approval is not required. The review will be published in a peer-reviewed scientific journal.
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- 2024
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14. Glucocorticoid-induced microRNA-378 signaling mediates the progression of pancreatic cancer by enhancing autophagy
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Li Liu, Shanshan Han, Xi Xiao, Xuefeng An, Jury Gladkich, Ulf Hinz, Stefan Hillmer, Torsten Hoppe-Tichy, Yi Xu, Michael Schaefer, Oliver Strobel, and Ingrid Herr
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Cytology ,QH573-671 - Abstract
Abstract Glucocorticoids (GCs) are widely used in tumor therapy to reduce tumor growth, inflammation, edema, and other side effects. Controversially, GCs may also cause the progression of highly aggressive pancreatic ductal adenocarcinoma (PDAC). Because microRNA (miR) and autophagy signaling support the invasive growth of PDAC, we asked whether these mechanisms may be targeted by GCs. Six established human PDAC cell lines, tissue from patients who received GC medication (n = 35) prior to surgery, or not (n = 35), and tumor xenografts were examined by RT‒qPCR, transmission electron microscopy (TEM), monodansylcadaverine (MDC) staining, immunohistochemistry, in situ hybridization, gene array and Kaplan‒Meier analysis with bioinformatics, and MTT, western blot, colony, spheroid, migration, and invasion assays. We found that various GCs, including dexamethasone (DEX), induced typical features of macroautophagy with the appearance of autolysosomes, enhanced LC3-II, decreased SQSTM1/p62 expression and induced epithelial-mesenchymal transition (EMT) and gemcitabine resistance. The GC receptor (GR) antagonist mifepristone (RU486) counteracted DEX-induced autophagy features, suggesting that the GC-GR complex is involved in the induction of autophagy. The autophagy-related miR-378i and miR-378a-3p were selected as the top upregulated candidates, and their high expression in PDAC patient tissue correlated with low survival. siRNA-mediated downregulation of miR-378 inhibited DEX-induced autophagy, and tumor progression. Bioinformatics confirmed the contribution of miR-378 to the regulation of signaling networks involved in GC-induced autophagy and tumor progression. The construction of a molecular docking model revealed stable binding of miR-378 to the DEX-GR complex, suggesting direct regulation. These substantial, novel, in-depth data reveal that GCs favor autophagy-mediated cancer progression by inducing miR-378 and GR binding and implicate GR and miR-378 as new therapeutic targets.
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- 2022
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15. Cefiderocol Protects against Cytokine- and Endotoxin-Induced Disruption of Vascular Endothelial Cell Integrity in an In Vitro Experimental Model
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Dagmar Hildebrand, Jana Böhringer, Eva Körner, Ute Chiriac, Sandra Förmer, Aline Sähr, Torsten Hoppe-Tichy, Klaus Heeg, and Dennis Nurjadi
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cefiderocol ,beta-lactam antibiotic ,endothelial barrier ,vascular leakage ,Therapeutics. Pharmacology ,RM1-950 - Abstract
The severe course of bloodstream infections with Gram-negative bacilli can lead to organ dysfunctions and compromise the integrity of the vascular barrier, which are the hallmarks of sepsis. This study aimed to investigate the potential effect of cefiderocol on the barrier function of vascular endothelial cells (vECs) in an in vitro experimental set-up. Human umbilical vein cells (HUVECs), co-cultured with erythrocyte-depleted whole blood for up to 48 h, were activated with tumor necrosis factor-alpha (TNF-α) or lipopolysaccharide (LPS) to induce endothelial damage in the absence or presence of cefiderocol (concentrations of 10, 40 and 70 mg/L). The endothelial integrity was quantified using transendothelial electrical resistance (TEER) measurement, performed at 0, 3, 24 and 48 h after stimulation. Stimulation with TNF-α and LPS increased the endothelial permeability assessed by TEER at 24 and 48 h of co-culture. Furthermore, cefiderocol reduces interleukin-6 (IL-6), interleukin-1β (IL-1β) and TNF-α release in peripheral blood mononuclear cells (PBMCs) following LPS stimulation in a dose-dependent manner. Collectively, the data suggest that cefiderocol may have an influence on the cellular immune response and might support the maintenance of vEC integrity during inflammation associated with infection with Gram-negative bacteria, which warrants further investigations.
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- 2022
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