Aydin Demircioglu

Aydin Demircioglu
University Hospital Essen | UK Essen · Institute of Diagnostic and Interventional Radiology and Neuroradiology

PhD

About

39
Publications
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300
Citations

Publications

Publications (39)
Article
Full-text available
Background Recently, radiomics has emerged as a non-invasive, imaging-based tissue characterization method in multiple cancer types. One limitation for robust and reproducible analysis lies in the inter-reader variability of the tumor annotations, which can potentially cause differences in the extracted feature sets and results. In this study, the...
Article
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Purpose: To develop and evaluate fully automatic scan range delimitation for chest CT by using deep learning. Materials and methods: For this retrospective study, scan ranges were annotated by two expert radiologists in consensus in 1149 (mean age, 65 years ± 16 [standard deviation]; 595 male patients) chest CT topograms acquired between March 2...
Article
Full-text available
Background Many studies in radiomics are using feature selection methods to identify the most predictive features. At the same time, they employ cross-validation to estimate the performance of the developed models. However, if the feature selection is performed before the cross-validation, data leakage can occur, and the results can be biased. To m...
Article
Objectives: A critical problem in radiomic studies is the high dimensionality of the datasets, which stems from small sample sizes and many generic features extracted from the volume of interest. Therefore, feature selection methods are used, which aim to remove redundant as well as irrelevant features. Because there are many feature selection alg...
Article
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Background In radiomic studies, several models are often trained with different combinations of feature selection methods and classifiers. The features of the best model are usually considered relevant to the problem, and they represent potential biomarkers. Features selected from statistically similarly performing models are generally not studied....
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An important quality criterion for radiographs is the correct anatomical side marking. A deep neural network is evaluated to predict the correct anatomical side in radiographs of the knee acquired in anterior–posterior direction. In this retrospective study, a ResNet-34 network was trained on 2892 radiographs from 2540 patients to predict the anato...
Article
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Purpose We aimed to investigate treatment effect of endovascular thrombectomy (EVT) on the change of National Institutes of Health Stroke Scale (NIHSS) scores in acute ischemic stroke (AIS) patients with anterior large vessel occlusion (LVO). Predictors of early neurological improvement (ENI) were assessed in those with successful reperfusion. Met...
Article
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Objectives Age estimation, especially in pediatric patients, is regularly used in different contexts ranging from forensic over medicolegal to clinical applications. A deep neural network has been developed to automatically estimate chronological age from knee radiographs in pediatric patients. Methods In this retrospective study, 3816 radiographs...
Article
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Short tau inversion recovery (STIR) sequences are frequently used in magnetic resonance imaging (MRI) of the spine. However, STIR sequences require a significant amount of scanning time. The purpose of the present study was to generate virtual STIR (vSTIR) images from non-contrast, non-fat-suppressed T1- and T2-weighted images using a conditional g...
Article
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Objectives: To improve organ protection with the frozen elephant trunk (FET) procedure, a so-called four-sites perfusion in combination with proximalization for the distal aortic anastomosis was performed. The impact of these techniques on patient outcome is reported. Methods: Between February 2005 and April 2020, a total of 357 patients underwe...
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Background: To evaluate the potential of simultaneously acquired 18F-FDG PET- and MR-derived quantitative imaging data sets of primary soft-tissue sarcomas for the prediction of neoadjuvant treatment response, the metastatic status and tumor grade. Methods: A total of 52 patients with a high-risk soft-tissue sarcoma underwent a 18F-FDG PET/MR ex...
Article
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For CT pulmonary angiograms, a scout view obtained in anterior–posterior projection is usually used for planning. For bolus tracking the radiographer manually locates a position in the CT scout view where the pulmonary trunk will be visible in an axial CT pre-scan. We automate the task of localizing the pulmonary trunk in CT scout views by deep lea...
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Background: To investigate and compare the diagnostic performance of 18F-Fluorodeoxyglucose (18F-FDG) PET/MR and MR alone in whole-body primary staging and restaging of patients with rectal cancer. Methods: A retrospective analysis was performed to evaluate diagnostic accuracies of combined reading of PET/MR and MR alone in T, N and M staging ag...
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Background: To investigate the diagnostic performance of simultaneous 18F-fluoro-deoxyglucose ([18F]-FDG) PET/MR enterography in assessing and grading endoscopically active inflammation in patients with ulcerative colitis. Methods: 50 patients underwent PET/MR 24 h before ileocolonoscopy. Inflammatory activities of bowel segments were evaluated wit...
Article
Purpose: To evaluate and compare the clinical utility of simultaneously obtained quantitative 18F-fluorodeoxyglucose positron-emission-tomography (18F-FDG PET) and diffusion-weighted imaging (DWI) datasets for the prediction of histopathological therapy response of soft tissue sarcomas (STS) under neoadjuvant isolated limb perfusion (ILP). Methods:...
Article
Objective To compare the diagnostic performance of fecal biomarkers and ¹⁸ F-fludeoxyglucose ( ¹⁸ F-FDG) positron emmision tomography-MR (PET-MR) in the assessment of disease activity in patients with ulcerative colitis. Methods This study was conducted under the framework of a single-center clinical trial (clinicaltrials.gov [NCT03781284]). N = 5...
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Objectives The introduction of the 2016 WHO classification of CNS tumors has made the combined molecular and histopathological characterization of tumors a pivotal part of glioma patient management. Recent publications on radiogenomics-based prediction of the mutational status have demonstrated the predictive potential of imaging-based, non-invasiv...
Article
Zielsetzung Ziel dieser Studie war die Evaluierung des prädiktiven Potenzials der Radiomics-Analyse zur Bestimmung des N- und M-Stadiums des primären Zervixkarzinoms anhand multiparametrischer 18F-FDG-PET/MRT-Bildgebung. Material und Methoden 30 Patientinnen mit einem histologisch gesicherten, primären und therapienaiven Zervixkarzinom unterzogen s...
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Purpose To evaluate the diagnostic performance of PET-MR enterography in detecting histological active inflammation in patients with ulcerative colitis and the impact of bowel purgation on diagnostic accuracies of PET-MR parameters. Methods Fifty patients were enrolled in this randomized controlled trial (clinicaltrials.gov [NCT03781284]). Forty p...
Article
Objectives The aim of this study was to compare PET/MR enterography with ileocolonoscopy regarding patients' acceptance and their future preference. Methods Between October 2014 and February 2018 one-hundred-eleven patients underwent PET/MR enterography and ileocolonoscopy within 2 weeks. Overall acceptance of each modality was rated using a 10-po...
Article
Purpose: To investigate differences between positron emission tomography/magnetic resonance imaging (PET/MRI) and PET/computed tomography (PET/CT) in lesion detection and classification in oncological whole-body examinations and to investigate radiation exposure differences between both modalities. Material and Methods: In this prospective, single-...
Article
Radiomics beschäftigt sich mit der statistischen Analyse von radiologischen Bilddaten. Dieser Beitrag führt in Radiomics ein und zeigt einige ihrer Anwendungsbeispiele auf. Insbesondere wurde an einem Beispiel demonstriert, dass Pathologie und Radiologie in Zusammenarbeit zu besseren Diagnosen kommen können. Es ist nicht zu bestreiten, dass die kün...
Article
Despite the great media attention for artificial intelligence (AI), for many health care professionals the term and the functioning of AI remain a "black box," leading to exaggerated expectations on the one hand and unfounded fears on the other. In this review, we provide a conceptual classification and a brief summary of the technical fundamentals...
Article
Zusammenfassung Radiomics ist eine Methode der medizinischen Bildanalyse, bei der quantitative Merkmale aus Bilddaten extrahiert und mittels Machine Learning zu prädiktiven Modellen weiterverarbeitet werden. Ziel dieser Arbeit ist es, die technischen Grundlagen von Radiomics und mögliche klinische Anwendungen unter besonderer Berücksichtigung nukle...
Article
Our purpose was to assess the diagnostic potential of simultaneously acquired 18F-FDG PET and MRI data sets for therapy response assessment of isolated limb perfusion (ILP) in patients with soft-tissue sarcomas (STS). Methods: In total, 45 patients with histopathologically verified STS were prospectively enrolled for an integrated 18F-FDG PET/MRI e...
Article
Objectives: We aimed to compare the in vitro flow dynamics of the Perimount Magna Ease™ (PME) and the Trifecta™ (TF) bioprostheses. Material and methods: A new flow chamber was designed to compare the flow patterns of the PME (Edwards Lifesciences, Irvine, CA, USA) and the TF (SJM, St. Paul, MN, USA) aortic valve prostheses. This new channel offere...
Article
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Background: Detection of ossification areas of hand bones in X-ray images is an important task, e.g. as a preprocessing step in automated bone age estimation. Deep neural networks have emerged recently as de facto standard detection methods, but their drawback is the need of large annotated datasets. Finetuning pre-trained networks is a viable alt...
Article
Rationale: To define an [18F]-FDG PET/MR enterography index as a hybrid surrogate marker for active ileocolonic inflammation in Crohn's disease (CD) and assess its diagnostic performance in comparison to validated MR indices (MaRIA, Clermont score). Methods: 52 CD patients with recurrent symptoms underwent ileocolonoscopy and [18F]-FDG PET/MR enter...
Article
Background: Transit-time flow measurement (TTFM) should be routinely used in CABG surgery to verify graft function. Most recently, a 2D high-frequency-ultrasound (HF-US) epi-cardiac imaging probe has been released (MiraQTM, Medistim, Oslo, Norway), which allows to evaluate the cannulation/clamping site of the aorta morphologically and to evaluate...
Article
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The aim of the present in vitro study was the evaluation of the fluid dynamical performance of the Carpentier-Edwards PERIMOUNT Magna Ease depending on the prosthetic size (21, 23, and 25 mm) and the cardiac output (3.6-6.4 L/min). A self-constructed flow channel in combination with particle image velocimetry (PIV) enabled precise results with high...
Article
Kernelized support vector machines (SVMs) belong to the most widely used classification methods. However, in contrast to linear SVMs, the computation time required to train such a machine becomes a bottleneck when facing large data sets. In order to mitigate this shortcoming of kernel SVMs, many approximate training algorithms were developed. While...
Article
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Kernelized Support Vector Machines (SVMs) are among the best performing supervised learning methods. But for optimal predictive performance, time-consuming parameter tuning is crucial, which impedes application. To tackle this problem, the classic model selection procedure based on grid-search and cross-validation was refined, e.g. by data subsampl...
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Obesity in adults and children is increasing worldwide at alarming rates. Obese children and adolescents are likely to become obese adults with increased risk of a number of comorbidities. In addition to preventing the development of obesity at young age, it is necessary to individualize the therapy of already obese children and adolescents in orde...
Thesis
In der vorliegenden Arbeit verallgemeinern wir im Wesentlichen zwei Theoreme von Mackaay-Picken und Picken (2002, 2004). Im ihrem Artikel zeigen Mackaay und Picken,dass es eine bijektive Korrespodenz zwischen Deligne 2-Klassen $\xi \in \check{H}^2(M, \mathcal{D}^2)$ und Holonomie Abbildungen von der zweiten dünnen Homotopiegruppe $\pi_2^2(M)$ in di...

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