Sven Stephan Walter

Dr. Sven Stephan Walter

orcid

Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
1 September 2020 in The Spine Journal
Verified
Journal Article
Closed access
EMElke Maurer
Elke Maurer
CKChristian Klinger
Christian Klinger
RLRoberto Lorbeer
Roberto Lorbeer
WRWolfgang Rathmann
Wolfgang Rathmann
APAnnette Peters
Annette Peters
SWSven Stephan Walter
Sven Stephan Walter

1 January 2025 in Radiology
Verified
Journal Article
Closed access
SWSven Stephan Walter
Sven Stephan Walter
JVJan Vosshenrich
Jan Vosshenrich
TRTatiane Cantarelli Rodrigues
Tatiane Cantarelli Rodrigues
DDDanoob Dalili
Danoob Dalili
BFBenjamin Fritz
Benjamin Fritz
JFJan Fritz
Jan Fritz
Deep learning superresolution simultaneous multislice parallel imaging–accelerated knee MRI provided excellent image quality and improved diagnostic performance for articular cartilage defects while maintaining performance for meniscus and ligament tears.

1 May 2022 in Diagnostic and Interventional Radiology
Verified
Journal Article
Closed access
MWMoritz Winkelmann
Moritz Winkelmann
Sebastian GassenmaierSebastian Gassenmaier
Sebastian Gassenmaier
SWSven Stephan Walter
Sven Stephan Walter
CAChristoph Artzner
Christoph Artzner
FLFelix Lades
Felix Lades
MBMalte Niklas Bongers
Malte Niklas Bongers
PURPOSE Differentiation of incidental adrenal lesions remains a challenge in diagnostic imaging, especially on single-phase portal venous computed tomography (CT) in the oncological setting. The aim of the study was to explore the ability of dual-energy CT (DECT)-based iodine quantification and virtual non-contrast (VNC) imaging and advanced radiomic analysis of DECT for differentiation of adrenal adenomas from metastases.

23 July 2022 in Diagnostics
Verified
Journal Article
Open access
PDF file
CAChristoph Artzner
Christoph Artzner
MBMalte Niklas Bongers
Malte Niklas Bongers
Rainer KärgelRainer Kärgel
Rainer Kärgel
SFSebastian Faby
Sebastian Faby
GHGerald Hefferman
Gerald Hefferman
SWSven Stephan Walter
Sven Stephan Walter
The aim was to evaluate the accuracy of a prototypical artificial intelligence-based algorithm for automated segmentation and diameter measurement of the thoracic aorta (TA) using CT. One hundred twenty-two patients who underwent dual-source CT were retrospectively included. Ninety-three of these patients had been administered intravenous iodinated contrast. Images were evaluated using the prototypical algorithm, which segments the TA and determines the corresponding diameters at predefined anatomical locations based on the American Heart Association guidelines. The reference standard was established by two radiologists individually in a blinded, randomized fashion. Equivalency was tested and inter-reader agreement was assessed using intra-class correlation (ICC). In total, 99.2% of the parameters measured by the prototype were assessable. In nine patients, the prototype failed to determine one diameter along the vessel. Measurements along the TA did not differ between the algorithm and readers (p > 0.05), establishing equivalence. Inter-reader agreement between the algorithm and readers (ICC ≥ 0.961; 95% CI: 0.940–0.974), and between the readers was excellent (ICC ≥ 0.879; 95% CI: 0.818–0.92). The evaluated prototypical AI-based algorithm accurately measured TA diameters at each region of interest independent of the use of either contrast utilization or pathology. This indicates that the prototypical algorithm has substantial potential as a valuable tool in the rapid clinical evaluation of aortic pathology.

28 September 2018 in IEEE Journal of Biomedical and Health Informatics
Verified
Journal Article
Closed access
FFFaezeh Fallah
Faezeh Fallah
SWSven Stephan Walter
Sven Stephan Walter
FBFabian Bamberg
Fabian Bamberg
BYBin Yang
Bin Yang
Fat-water magnetic resonance (MR) images allow automated noninvasive analysis of morphological properties and fat fractions of vertebral bodies (VBs) and intervertebral discs (IVDs) that constitute an important part of human biomechanical systems. In this paper, we propose a fully automated approach for simultaneously segmenting multiple VBs and IVDs on fat-water MR images without prior localization or geometry estimation. This method involved a hierarchical random forest (HRF) classifier and a hierarchical conditional random field (HCRF) that encoded amulti-resolution image pyramid based on a set of multiscale local and contextual features. The HRF classifier employed penalized multivariate linear discriminants and SMOTEBagging to handle limited and imbalanced training data with large feature dimension. The HCRF estimated optimum labels according to their spatial and hierarchical consistencies by using the layer-wise significant features determined over the trained HRF classifier. To handle variable sample numbers at different resolutions, resolutionspecific hyperparameters were used. This method was trained and evaluated for segmenting 15 thoracic and lumbar VBs and their IVDs on fat-water MR images of a subset of a large cohort data set. It was further evaluated for segmenting 7 IVDs of the lower spine on fat-water images of a public grand challenge. These evaluations revealed the comparable accuracy of this method with the state-ofthe-art while requiring less computational burden due to a simultaneous localization and segmentation.

1 October 2017 in Magnetic Resonance Imaging
Verified
Journal Article
Closed access
SWSven Stephan Walter
Sven Stephan Walter
WLWei Liu
Wei Liu
ASAlto Stemmer
Alto Stemmer
PMPetros Martirosian
Petros Martirosian
KNKonstantin Nikolaou
Konstantin Nikolaou
SGSergios Gatidis
Sergios Gatidis