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  1. Book ; Online ; Thesis: Bildgebung des Pankreaskarzinoms mittels Dual-Layer Spektral-CT

    Schilling, Clara Theresa Verfasser] / [Braren, Rickmer [Akademischer Betreuer] / Reichert, Maximilian Gutachter] / [Braren, Rickmer [Gutachter]

    2024  

    Author's details Clara Theresa Schilling ; Gutachter: Maximilian Reichert, Rickmer Braren ; Betreuer: Rickmer Braren
    Keywords Medizin, Gesundheit ; Medicine, Health
    Subject code sg610
    Language German
    Publisher Universitätsbibliothek der TU München
    Publishing place München
    Document type Book ; Online ; Thesis
    Database Digital theses on the web

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  2. Article ; Online: Comparison of Magnetic Resonance Imaging and Endoscopic Ultrasound in the Sizing of Intraductal Papillary Mucinous Neoplasia of the Pancreas.

    Hesse, Felix / Ritter, Jessica / Hapfelmeier, Alexander / Braren, Rickmer / Phillip, Veit

    Pancreas

    2023  Volume 52, Issue 6, Page(s) e315–e320

    Abstract: Objectives: Because IPMNs are potentially malignant, surveillance of IPMN is recommended by magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS). The aim of the study was the evaluation of the concordance between EUS and MRI regarding cyst ... ...

    Abstract Objectives: Because IPMNs are potentially malignant, surveillance of IPMN is recommended by magnetic resonance imaging (MRI) and endoscopic ultrasound (EUS). The aim of the study was the evaluation of the concordance between EUS and MRI regarding cyst size.
    Methods: Retrospective data analysis was done for patients with IPMN in whom EUS and MRI were performed simultaneously (≤60 days). The measured cyst size of both procedures was compared by Bland-Altman plots. Agreement of cyst localization and dilation of main pancreatic duct was assessed using kappa statistics.
    Results: Fifty-nine cases were evaluated (median age, 71 years; 65% female; median time interval between both investigations, 17 days). The mean difference of IPMN maximal diameter between EUS and MRI was 0.55 mm with a prediction interval of -9.20 to +10.29 mm for 95% of the expected differences. There was strong interobserver agreement regarding cyst localization ( κ = 0.669, P = 1.06e -13 ) and the width of main pancreatic duct (<5, 5-9, and ≥10 mm; κ = 0.676 caput, κ = 0.823 corpus).
    Conclusions: We found a clinically relevant difference in cyst size comparing EUS and MRI. Therefore, alternating EUS and MRI for follow-up of the "worrisome feature" size growth is not reasonable.
    MeSH term(s) Humans ; Female ; Aged ; Male ; Pancreatic Intraductal Neoplasms/diagnostic imaging ; Retrospective Studies ; Carcinoma, Pancreatic Ductal/diagnostic imaging ; Carcinoma, Pancreatic Ductal/pathology ; Pancreatic Neoplasms/diagnostic imaging ; Pancreatic Neoplasms/pathology ; Pancreas/pathology ; Magnetic Resonance Imaging ; Endosonography ; Cysts
    Language English
    Publishing date 2023-11-01
    Publishing country United States
    Document type Journal Article
    ZDB-ID 632831-3
    ISSN 1536-4828 ; 0885-3177
    ISSN (online) 1536-4828
    ISSN 0885-3177
    DOI 10.1097/MPA.0000000000002264
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Book ; Online ; Thesis: Prädiktion des histopathologischen Gradings hepatozellulärer Karzinome durch die Kombination von 18FDG-PET/CT und DCE-MRT in einem translationalen Rattenmodell

    Hörl, Marie Sophie Elisabeth Verfasser] / [Braren, Rickmer [Akademischer Betreuer] / Kaissis, Giorgios Gutachter] / [Braren, Rickmer [Gutachter]

    2023  

    Author's details Marie Sophie Elisabeth Hörl ; Gutachter: Giorgios Kaissis, Rickmer Braren ; Betreuer: Rickmer Braren
    Keywords Medizin, Gesundheit ; Medicine, Health
    Subject code sg610
    Language German
    Publisher Universitätsbibliothek der TU München
    Publishing place München
    Document type Book ; Online ; Thesis
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  4. Book ; Online ; Thesis: Validation der C13-Magnetresonanzspektroskopie-Bildgebung mittels Protonenspektroskopie und klinischer Chemie am DEN-induzierten HCC der Ratte

    Keim, Dominik Michael Verfasser] / [Braren, Rickmer [Akademischer Betreuer] / Schilling, Franz Gutachter] / [Braren, Rickmer [Gutachter]

    2023  

    Author's details Dominik Michael Keim ; Gutachter: Franz Schilling, Rickmer Braren ; Betreuer: Rickmer Braren
    Keywords Medizin, Gesundheit ; Medicine, Health
    Subject code sg610
    Language German
    Publisher Universitätsbibliothek der TU München
    Publishing place München
    Document type Book ; Online ; Thesis
    Database Digital theses on the web

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  5. Article: Pancreatic cancer detection and characterization-state of the art cross-sectional imaging and imaging data analysis.

    Kaissis, Georgios / Braren, Rickmer

    Translational gastroenterology and hepatology

    2019  Volume 4, Page(s) 35

    Abstract: Pancreatic ductal adenocarcinoma (PDAC) represents a deadly disease, prognosticated to become the 2nd most common cause of cancer related death in the western world by 2030. State of the art radiologic high-resolution cross-sectional imaging by computed ... ...

    Abstract Pancreatic ductal adenocarcinoma (PDAC) represents a deadly disease, prognosticated to become the 2nd most common cause of cancer related death in the western world by 2030. State of the art radiologic high-resolution cross-sectional imaging by computed tomography (CT) and magnetic resonance imaging (MRI) represent advanced techniques for early lesion detection, pre-therapeutic patient staging and therapy response monitoring. In light of molecular taxonomies currently under development, the implementation of advanced imaging data post-processing pipelines and the integration of imaging and clinical data for the development of risk assessment and clinical decision support tools are required. This review will present the current state of cross-sectional radiologic imaging and image post-processing related to PDAC.
    Language English
    Publishing date 2019-05-21
    Publishing country China
    Document type Journal Article ; Review
    ISSN 2415-1289
    ISSN 2415-1289
    DOI 10.21037/tgh.2019.05.04
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Motion-induced phase-corrected homodyne reconstruction for partial Fourier single-shot diffusion-weighted echo planar imaging of the liver.

    Van, Anh T / McTavish, Sean / Peeters, Johannes M / Weiss, Kilian / Makowski, Marcus R / Braren, Rickmer F / Karampinos, Dimitrios C

    NMR in biomedicine

    2024  , Page(s) e5147

    Abstract: Partial Fourier encoding is popular in single-shot (ss) diffusion-weighted (DW) echo planar imaging (EPI) because it enables a shorter echo time (TE) and, hence, improves the signal-to-noise-ratio. Motion during diffusion encoding causes k-space shifting ...

    Abstract Partial Fourier encoding is popular in single-shot (ss) diffusion-weighted (DW) echo planar imaging (EPI) because it enables a shorter echo time (TE) and, hence, improves the signal-to-noise-ratio. Motion during diffusion encoding causes k-space shifting and dispersion, which compromises the quality of the homodyne reconstruction. This work provides a comprehensive understanding of the artifacts in homodyne reconstruction of partial Fourier ss-DW-EPI data in the presence of motion-induced phase and proposes the motion-induced phase-corrected homodyne (mpc-hdyne) reconstruction method to ameliorate these artifacts. Simulations with different types of motion-induced phase were performed to provide an understanding of the potential artifacts that occur in the homodyne reconstruction of partial Fourier ss-DW-EPI data. To correct for the artifacts, the mpc-hdyne reconstruction is proposed. The algorithm recenters k-space, updates the partial Fourier factor according to detected global k-space shifts, and removes low-resolution nonlinear phase before the conventional homodyne reconstruction. The mpc-hdyne reconstruction is tested on both simulation and in vivo data. Motion-induced phase can cause signal overestimation, worm artifacts, and signal loss in partial Fourier ss-DW-EPI data with the conventional homodyne reconstruction. Simulation and in vivo data showed that the proposed mpc-hdyne reconstruction ameliorated artifacts, yielding higher quality DW images compared with conventional homodyne reconstruction. Based on the understanding of the artifacts in homodyne reconstruction of partial Fourier ss-DW-EPI data, the mpc-hdyne reconstruction was proposed and showed superior performance compared with the conventional homodyne reconstruction on both simulation and in vivo data.
    Language English
    Publishing date 2024-04-01
    Publishing country England
    Document type Journal Article
    ZDB-ID 1000976-0
    ISSN 1099-1492 ; 0952-3480
    ISSN (online) 1099-1492
    ISSN 0952-3480
    DOI 10.1002/nbm.5147
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    Zs.A 2869: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (2.OG)
    ab Jg. 2022: Lesesaal (EG)

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  7. Article ; Online: Preserving fairness and diagnostic accuracy in private large-scale AI models for medical imaging.

    Tayebi Arasteh, Soroosh / Ziller, Alexander / Kuhl, Christiane / Makowski, Marcus / Nebelung, Sven / Braren, Rickmer / Rueckert, Daniel / Truhn, Daniel / Kaissis, Georgios

    Communications medicine

    2024  Volume 4, Issue 1, Page(s) 46

    Abstract: Background: Artificial intelligence (AI) models are increasingly used in the medical domain. However, as medical data is highly sensitive, special precautions to ensure its protection are required. The gold standard for privacy preservation is the ... ...

    Abstract Background: Artificial intelligence (AI) models are increasingly used in the medical domain. However, as medical data is highly sensitive, special precautions to ensure its protection are required. The gold standard for privacy preservation is the introduction of differential privacy (DP) to model training. Prior work indicates that DP has negative implications on model accuracy and fairness, which are unacceptable in medicine and represent a main barrier to the widespread use of privacy-preserving techniques. In this work, we evaluated the effect of privacy-preserving training of AI models regarding accuracy and fairness compared to non-private training.
    Methods: We used two datasets: (1) A large dataset (N = 193,311) of high quality clinical chest radiographs, and (2) a dataset (N = 1625) of 3D abdominal computed tomography (CT) images, with the task of classifying the presence of pancreatic ductal adenocarcinoma (PDAC). Both were retrospectively collected and manually labeled by experienced radiologists. We then compared non-private deep convolutional neural networks (CNNs) and privacy-preserving (DP) models with respect to privacy-utility trade-offs measured as area under the receiver operating characteristic curve (AUROC), and privacy-fairness trade-offs, measured as Pearson's r or Statistical Parity Difference.
    Results: We find that, while the privacy-preserving training yields lower accuracy, it largely does not amplify discrimination against age, sex or co-morbidity. However, we find an indication that difficult diagnoses and subgroups suffer stronger performance hits in private training.
    Conclusions: Our study shows that - under the challenging realistic circumstances of a real-life clinical dataset - the privacy-preserving training of diagnostic deep learning models is possible with excellent diagnostic accuracy and fairness.
    Language English
    Publishing date 2024-03-14
    Publishing country England
    Document type Journal Article
    ISSN 2730-664X
    ISSN (online) 2730-664X
    DOI 10.1038/s43856-024-00462-6
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Comparison of Virtual Non-Contrast and True Non-Contrast CT Images Obtained by Dual-Layer Spectral CT in COPD Patients.

    Steinhardt, Manuel / Marka, Alexander W / Ziegelmayer, Sebastian / Makowski, Marcus / Braren, Rickmer / Graf, Markus / Gawlitza, Joshua

    Bioengineering (Basel, Switzerland)

    2024  Volume 11, Issue 4

    Abstract: Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death. Recent studies have underlined the importance of non-contrast-enhanced chest CT scans not only for emphysema progression quantification, but for correlation with clinical ...

    Abstract Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death. Recent studies have underlined the importance of non-contrast-enhanced chest CT scans not only for emphysema progression quantification, but for correlation with clinical outcomes as well. As about 40 percent of the 300 million CT scans per year are contrast-enhanced, no proper emphysema quantification is available in a one-stop-shop approach for patients with known or newly diagnosed COPD. Since the introduction of spectral imaging (e.g., dual-energy CT scanners), it has been possible to create virtual non-contrast-enhanced images (VNC) from contrast-enhanced images, making it theoretically possible to offer proper COPD imaging despite contrast enhancing. This study is aimed towards investigating whether these VNC images are comparable to true non-contrast-enhanced images (TNC), thereby reducing the radiation exposure of patients and usage of resources in hospitals. In total, 100 COPD patients with two scans, one with (VNC) and one without contrast media (TNC), within 8 weeks or less obtained by a spectral CT using dual-layer technology, were included in this retrospective study. TNC and VNC were compared according to their voxel-density histograms. While the comparison showed significant differences in the low attenuated volumes (LAVs) of TNC and VNC regarding the emphysema threshold of -950 Houndsfield Units (HU), the 15th and 10th percentiles of the LAVs used as a proxy for pre-emphysema were comparable. Upon further investigation, the threshold-based LAVs (-950 HU) of TNC and VNC were comparable in patients with a water equivalent diameter (DW) below 270 mm. The study concludes that VNC imaging may be a viable option for assessing emphysema progression in COPD patients, particularly those with a normal body mass index (BMI). Further, pre-emphysema was generally comparable between TNC and VNC. This approach could potentially reduce radiation exposure and hospital resources by making additional TNC scans obsolete.
    Language English
    Publishing date 2024-03-22
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2746191-9
    ISSN 2306-5354
    ISSN 2306-5354
    DOI 10.3390/bioengineering11040301
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Repeatability and reproducibility of apparent exchange rate measurements in yeast cell phantoms using filter-exchange imaging.

    Schillmaier, Mathias / Kaika, Athanasia / Topping, Geoffrey J / Braren, Rickmer / Schilling, Franz

    Magma (New York, N.Y.)

    2023  Volume 36, Issue 6, Page(s) 957–974

    Abstract: Objectives: Development of a protocol for validation and quality assurance of filter-exchange imaging (FEXI) pulse sequences with well-defined and reproducible phantoms.: Materials and methods: A FEXI pulse sequence was implemented on a 7 T ... ...

    Abstract Objectives: Development of a protocol for validation and quality assurance of filter-exchange imaging (FEXI) pulse sequences with well-defined and reproducible phantoms.
    Materials and methods: A FEXI pulse sequence was implemented on a 7 T preclinical MRI scanner. Six experiments in three different test categories were established for sequence validation, demonstration of the reproducibility of phantoms and the measurement of induced changes in the apparent exchange rate (AXR). First, an ice-water phantom was used to investigate the consistency of apparent diffusion coefficient (ADC) measurements with different diffusion filters. Second, yeast cell phantoms were utilized to validate the determination of the AXR in terms of repeatability (same phantom and session), reproducibility (separate but comparable phantoms in different sessions) and directionality of diffusion encodings. Third, the yeast cell phantoms were, furthermore, used to assess potential AXR bias because of altered cell density and temperature. In addition, a treatment experiment with aquaporin inhibitors was performed to evaluate the influence of these compounds on the cell membrane permeability in yeast cells.
    Results: FEXI-based ADC measurements of an ice-water phantom were performed for three different filter strengths, showed good agreement with the literature value of 1.099 × 10
    Conclusions: Using ice-water and yeast cell-based phantoms, a protocol for the validation of FEXI pulse sequences was established for the assessment of stability, repeatability, reproducibility and directionality. In addition, a strong dependence of AXR on cell density and temperature was shown. As AXR is an emerging novel imaging biomarker, the suggested protocol will be useful for quality assurance of AXR measurements within a study and potentially across multiple sites.
    MeSH term(s) Saccharomyces cerevisiae ; Ice ; Reproducibility of Results ; Diffusion Magnetic Resonance Imaging/methods ; Water ; Phantoms, Imaging
    Chemical Substances Ice ; Water (059QF0KO0R)
    Language English
    Publishing date 2023-07-12
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 1160826-2
    ISSN 1352-8661 ; 0968-5243
    ISSN (online) 1352-8661
    ISSN 0968-5243
    DOI 10.1007/s10334-023-01107-w
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    Zs.A 3788: Show issues Location:
    Je nach Verfügbarkeit (siehe Angabe bei Bestand)
    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (2.OG)
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  10. Article: Anwendungen der künstlichen Intelligenz in der Abdominalbildgebung

    Ziegelmayer, Sebastian / Braren, Rickmer

    Gastroenterologie up2date

    2021  Volume 17, Issue 04, Page(s) 353–365

    Keywords künstliche Intelligenz ; maschinelles Lernen ; Abdominalbildgebung ; Faltungsnetzwerke ; Radiomics
    Language German
    Publishing date 2021-12-01
    Publisher Georg Thieme Verlag KG
    Publishing place Stuttgart ; New York
    Document type Article
    ZDB-ID 2203033-5
    ISSN 1616-9727 ; 1616-9670
    ISSN (online) 1616-9727
    ISSN 1616-9670
    DOI 10.1055/a-1355-0636
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    Zs.A 6474: Show issues Location:
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