Ralf Gutjahr
Technische Universität München
Imaging phantomOpticsPhysicsBiomedical engineeringArtificial intelligenceBilateral filterPixelNoise reductionPattern recognitionEnergy (signal processing)Materials scienceImage resolutionScannerPhoton countingNuclear medicineComputer scienceComputed tomographyImage qualityMedicineDetector
31Publications
7H-index
344Citations
Publications 24
Newest
#1André Euler (TUM: Technische Universität München)
Last. Hatem AlkadhiH-Index: 85
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OBJECTIVES The aim of this study was to compare the image quality of low-kV protocols with optimized automatic tube voltage selection (ATVS) settings to reduce either radiation dose or contrast medium (CM) with that of a reference protocol for computed tomography angiography (CTA) of the thoracoabdominal aorta. MATERIALS AND METHODS In this institutional review board-approved, single-center, prospective randomized controlled trial, 126 patients receiving CTA of the aorta were allocated to one of...
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#1Thomas Sartoretti (UZH: University of Zurich)H-Index: 1
#2Matthias EberhardH-Index: 10
Last. André Euler (UZH: University of Zurich)H-Index: 8
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PURPOSE The aim of this study was to systematically evaluate the potential to combine investigational contrast media with spectrally optimized energy-thresholding of photon-counting detector computed tomography (PCCT) for subtraction of calcified plaques in a coronary artery stenosis phantom. METHODS A small vessel phantom containing 3 fillable tubes (diameter, 3 mm each) with calcified plaques was placed into an anthropomorphic chest phantom. The plaques had incremental thicknesses ranging from...
1 CitationsSource
#1Ralf Gutjahr (TUM: Technische Universität München)H-Index: 7
#2Robbert C. Bakker (UU: Utrecht University)H-Index: 3
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The purpose of this study was to assess the feasibility of dual-energy CT-based material decomposition using dual-X-ray spectra information to determine local concentrations of holmium microspheres in phantoms and in an animal model. A spectral calibration phantom with a solution containing 10 mg/mL holmium and various tube settings was scanned using a third-generation dual-energy CT scanner to depict an energy-dependent and material-dependent enhancement vectors. A serial dilution of holmium (m...
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#1Mayank PatwariH-Index: 1
#2Ralf GutjahrH-Index: 7
Last. Andreas MaierH-Index: 36
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#1Mayank Patwari (Siemens)H-Index: 1
#2Ralf Gutjahr (Siemens)H-Index: 7
Last. Rainer Raupach (Siemens)H-Index: 30
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Deep neural networks have shown great success in low dose CT denoising. However, most of these deep neural networks have several hundred thousand trainable parameters. This, combined with the inherent non-linearity of the neural network, makes the deep neural network diffcult to understand with low accountability. In this study we introduce JBFnet, a neural network for low dose CT denoising. The architecture of JBFnet implements iterative bilateral filtering. The filter functions of the Joint Bi...
2 CitationsSource
#1Mayank Patwari (FAU: University of Erlangen-Nuremberg)H-Index: 1
#2Ralf GutjahrH-Index: 7
Last. Andreas MaierH-Index: 36
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Denoising of clinical CT images is an active area for deep learning research. Current clinically approved methods use iterative reconstruction methods to reduce the noise in CT images. Iterative reconstruction techniques require multiple forward and backward projections, which are time-consuming and computationally expensive. Recently, deep learning methods have been successfully used to denoise CT images. However, conventional deep learning methods suffer from the 'black box' problem. They have...
#1Mayank PatwariH-Index: 1
#2Ralf GutjahrH-Index: 7
Last. Andreas MaierH-Index: 36
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Poster: "ECR 2020 / C-03463 / Low dose CT denoising with residual convolutional networks and deep learned perceptual loss " by: " M. Patwari 1, R. Gutjahr2, R. Raupach3, A. Maier1; 1Erlangen/DE, 2Nurnberg, Deutschland/DE, 3Forchheim/DE"
#1Mayank Patwari (FAU: University of Erlangen-Nuremberg)H-Index: 1
#2Ralf Gutjahr (Siemens)H-Index: 7
Last. Andreas Maier (FAU: University of Erlangen-Nuremberg)H-Index: 36
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With the increasing use of CT in diagnostic imaging, reducing the clinical radiation dose is necessary for ensuring patient safety. Reduced radiation dose results in quantum noise which adversely affects image quality and diagnostic value. Moreover, obtaining high quality images to act as reference images for image quality assessment is difficult. Therefore, automatic no-reference quality assessment of reconstructed images is necessary to preserve diagnostic image quality, while controlling radi...
3 CitationsSource
OBJECTIVE: The aim of this study was to determine if computed tomography (CT) angiography using an individualized transition delay (CTA-ID) would facilitate reductions in injection rate and iodine dose. METHODS: The CTA-ID was performed in 20 patients with routine injection rate and iodine dose; 20 patients with injection rate lowered by 1 mL/s; and 40 patients with injection rate lowered by 1 mL/s with 29% less iodine. Routine CTAs in the same or size-matched patients served as controls. Diagno...
2 CitationsSource
#1Ricarda HinzpeterH-Index: 9
#2Matthias EberhardH-Index: 10
Last. Hatem AlkadhiH-Index: 85
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An individualized trigger delay improves contrast opacification in CT angiography of the aorta, yielding a higher and more constant attenuation as well as an improved subjective image quality.
6 CitationsSource