Publications by authors named "Thomas Schlegl"

Objective: To investigate the localization, distribution, and type of central microaneurysms (MAs) and their relationship with retinal vascular alterations in patients with retinal vein occlusion (RVO).

Methods: In this cross-sectional study, ultra-widefield color fundus photography (UWF-CF), standard and single-capture 65° widefield (WF) optical coherence tomography angiography (OCTA) were performed in consecutive patients with RVO treated at the Department of Ophthalmology and Optometry, Medical University of Vienna. UWF-CF, en face and B-Scans in 6 mm × 6 mm OCTA were examined for detection of MAs.

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Background And Objective: Due to the high prevalence of dental caries, fixed dental restorations are regularly required to restore compromised teeth or replace missing teeth while retaining function and aesthetic appearance. The fabrication of dental restorations, however, remains challenging due to the complexity of the human masticatory system as well as the unique morphology of each individual dentition. Adaptation and reworking are frequently required during the insertion of fixed dental prostheses (FDPs), which increase cost and treatment time.

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Article Synopsis
  • Researchers wanted to see which method (MHz-OCTA, FA, or CF) is best at finding tiny issues called microaneurysms in people with a vision problem called diabetic retinopathy.
  • They looked at 47 people's eyes and found that MHz-OCTA found more microaneurysms (56%) compared to CF (36%).
  • Using both MHz-OCTA and CF together helped find even more microaneurysms (70%), showing that combining these methods can be really helpful for better detection.
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Purpose: To evaluate the association of microvascular lesions on ultrawidefield (UWF) color fundus (CF) images with retinal nonperfusion (RNP) up to the midperiphery on single-capture widefield (WF) OCT angiography (OCTA) in patients with diabetic retinopathy (DR).

Design: Cross-sectional study.

Subjects: Seventy-five eyes of 50 patients with mild to severe nonproliferative DR (NPDR) and proliferative DR (PDR) were included in this analysis.

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Article Synopsis
  • * Traditional deep learning methods for DR detection require detailed expert labeling of images, which is time-consuming and expensive.
  • * The new MIL-ResNet network detects retinal biomarkers with high accuracy using minimal annotations, outperforming earlier networks and offering a strong tool for clinical ophthalmic screening.
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By providing three-dimensional visualization of tissues and instruments at high resolution, live volumetric optical coherence tomography (4D-OCT) has the potential to revolutionize ophthalmic surgery. However, the necessary imaging speed is accompanied by increased noise levels. A high data rate and the requirement for minimal latency impose major limitations for real-time noise reduction.

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Article Synopsis
  • - The study aims to compare the effectiveness of widefield optical coherence tomography angiography (WF-OCTA) and ultrawidefield fluorescein angiography (UWF-FA) in detecting retinal neovascularisation (NV) in patients with proliferative diabetic retinopathy (PDR).
  • - Results show that WF-OCTA has a higher sensitivity (95%) for detecting PDR compared to ultrawidefield color fundus photography (78%), with strong agreement in certain quadrants but weaker in others.
  • - The findings suggest that WF-OCTA could serve as a reliable, non-invasive alternative to traditional FA in diagnosing PDR, potentially enhancing clinical assessments.
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Article Synopsis
  • * The study focused on creating a predictive model for dysphagia risk in hospitalized patients using machine learning techniques applied to data from over 33,000 electronic health records.
  • * The top-performing models, Random Forest and Adaboost classifiers, demonstrated high accuracy with an area under the curve of 0.94, surpassing existing dysphagia prediction models, and future integration into clinical practice is suggested for evaluating benefits.
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Background: Automatically detecting and quantifying pneumothorax on chest computed tomography (CT) may impact clinical decision-making. Machine learning methods published so far struggle with the heterogeneity of technical parameters and the presence of additional pathologies, highlighting the importance of stable algorithms.

Methods: A deep residual UNet was developed and evaluated for automated, volume-level pneumothorax grading (i.

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Article Synopsis
  • The authors acknowledge an error in the published figure of their paper regarding the anatomical segmentation in retinal OCT.
  • They intend to provide an updated version of Fig. 3 to correct the mistake.
  • The correct output of the last convolutional layers should indicate "11" channels instead of "2," accounting for 10 retinal layers plus the background.
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Diagnosis and treatment guidance are aided by detecting relevant biomarkers in medical images. Although supervised deep learning can perform accurate segmentation of pathological areas, it is limited by requiring a priori definitions of these regions, large-scale annotations, and a representative patient cohort in the training set. In contrast, anomaly detection is not limited to specific definitions of pathologies and allows for training on healthy samples without annotation.

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Obtaining expert labels in clinical imaging is difficult since exhaustive annotation is time-consuming. Furthermore, not all possibly relevant markers may be known and sufficiently well described a priori to even guide annotation. While supervised learning yields good results if expert labeled training data is available, the visual variability, and thus the vocabulary of findings, we can detect and exploit, is limited to the annotated lesions.

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The identification and quantification of markers in medical images is critical for diagnosis, prognosis, and disease management. Supervised machine learning enables the detection and exploitation of findings that are known a priori after annotation of training examples by experts. However, supervision does not scale well, due to the amount of necessary training examples, and the limitation of the marker vocabulary to known entities.

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Purpose: To evaluate the potential of machine learning to predict best-corrected visual acuity (BCVA) outcomes from structural and functional assessments during the initiation phase in patients receiving standardized ranibizumab therapy for neovascular age-related macular degeneration (AMD).

Design: Post hoc analysis of a randomized, prospective clinical trial.

Participants: Data of 614 evaluable patients receiving intravitreal ranibizumab monthly or pro re nata according to protocol-specified criteria in the HARBOR trial.

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Purpose: Development and validation of a fully automated method to detect and quantify macular fluid in conventional OCT images.

Design: Development of a diagnostic modality.

Participants: The clinical dataset for fluid detection consisted of 1200 OCT volumes of patients with neovascular age-related macular degeneration (AMD, n = 400), diabetic macular edema (DME, n = 400), or retinal vein occlusion (RVO, n = 400) acquired with Zeiss Cirrus (Carl Zeiss Meditec, Dublin, CA) (n = 600) or Heidelberg Spectralis (Heidelberg Engineering, Heidelberg, Germany) (n = 600) OCT devices.

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Purpose: We develop a longitudinal statistical model describing best-corrected visual acuity (BCVA) changes in anti-VEGF therapy in relation to imaging data, and predict the future BCVA outcome for individual patients by combining population-wide trends and initial subject-specific time points.

Methods: Automatic segmentation algorithms were used to measure intraretinal (IRF) and subretinal (SRF) fluid volume on monthly spectral-domain optical coherence tomography scans of eyes with central retinal vein occlusion (CRVO) receiving standardized anti-VEGF treatment. The trajectory of BCVA over time was modeled as a multivariable repeated-measure mixed-effects regression model including fluid volumes as covariates.

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Article Synopsis
  • The study aims to map the spatial distribution of various fluid-related features in neovascular age-related macular degeneration (nAMD) by analyzing intraretinal cystoid fluid (IRC), subretinal fluid (SRF), and pigment-epithelial detachment (PED).
  • Automated segmentation was applied to optical coherence tomography scans from 1341 treatment-naïve patients to identify the presence and correlation of these features.
  • Results show that while there was low spatial correlation between SRF and the other components, there was a higher association between IRC and PED, suggesting new insights into the functional impacts of nAMD.
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Purpose: The purpose of this study was to predict low and high anti-VEGF injection requirements during a pro re nata (PRN) treatment, based on sets of optical coherence tomography (OCT) images acquired during the initiation phase in neovascular AMD.

Methods: Two-year clinical trial data of subjects receiving PRN ranibizumab according to protocol specified criteria in the HARBOR study after three initial monthly injections were included. OCT images were analyzed at baseline, month 1, and month 2.

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In this pilot study, we evaluated the potential of computational image analysis of optical coherence tomography (OCT) data to determine the prognosis of patients with diabetic macular edema (DME). Spectral-domain OCT scans with fully automated retinal layer segmentation and segmentation of intraretinal cystoid fluid (IRC) and subretinal fluid of 629 patients receiving anti-vascular endothelial growth factor therapy for DME in a randomized prospective clinical trial were analyzed. The results were used to define 312 potentially predictive features at three timepoints (baseline, weeks 12 and 24) for best-corrected visual acuity (BCVA) at baseline and after one year used in a random forest prediction path.

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The aim is to review the modalities in musculoskeletal imaging with view on the prognostic impact for the patient's and for social outcome and with view on three major fields of preventive medicine: nutrition and metabolism, sports, and patient education. The added value provided by preventive imaging is (1) to monitor bone health and body composition with a broad spectrum of biomarkers, (2) to detect and quantify variants or abnormalities of nerves, muscles, tendons, bones, and joints with a risk of overuse, rupture, or fracture, and (3) to develop radiology reports from the widely used narrative format to structured text and multimedia datasets. The awareness problem is a term for describing the underreporting and the underdiagnosis of fragility fractures in osteoporosis.

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Learning representative computational models from medical imaging data requires large training data sets. Often, voxel-level annotation is unfeasible for sufficient amounts of data. An alternative to manual annotation, is to use the enormous amount of knowledge encoded in imaging data and corresponding reports generated during clinical routine.

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While the visuomotor system is known to develop rapidly after birth, studies have observed spontaneous activity in vertebrates in visually excitable cortical areas already before extrinsic stimuli are present. Resting state networks and fetal eye movements were observed independently in utero, but no functional brain activity coupled with visual stimuli could be detected using fetal fMRI. This study closes this gap and links in utero eye movement with corresponding functional networks.

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