<> "The repository administrator has not yet configured an RDF license."^^ . <> . . "Automatic interventional Imaging for the Parametrisation of Vascular Structures"^^ . "Improvements for Medical Imaging\r\nRobotic computer tomography systems offer a wide range possibilities for non-circular and patient specific trajectories. These could reduce metal artifacts,\r\nimprove the image quality or increase the available space for the practitioners.\r\nBut every trajectory needs to be calibrated to reconstruct the CT image. There\r\nare two main approaches, an offline calibration uses a special phantom that has\r\nto be imaged before the patient and the online calibration where the trajectory\r\nis calibrated with the images acquired from using a prior CT image.\r\nIn chapter 5, a method for calibrating arbitrary Cone-Beam Computed\r\nTomography (CBCT) trajectories (FORCASTER) is developed. It detects\r\nand matches feature points in simulated projections and acquired projections.\r\nThese paired feature points are then used to correct the projection parameters\r\nby directly calculating the correction factor or with a minimization algorithm,\r\nwhich is also presented in this part. To simulate projections a prior image of\r\nthe object is needed, but it is also shown that this calibration functions if the\r\nprior image has some differences compared to the object that is currently imaged. The FORCASTER algorithm achieves similar calibration results when\r\ncompared to state-of-the-art algorithms.\r\nThe following chapter 6 introduces FORCAST-EST, an extension for the\r\nFORCASTER algorithm, which estimates the starting parameters for the calibration. This allows the calibration of trajectories that come without positional\r\nand rotational data for the individual projections. It simulates projections in a\r\ngrid and then compares every acquired projection to the grid, first in a coarse\r\nsearch and then in the surrounding of the best matches. The estimates are\r\nsufficient to calibrate the trajectory with a similar accuracy as FORCASTER\r\nusing the regular starting parameters recorded by the CBCT system.\r\nIn chapter 3 of this thesis, an algorithm for detecting arteries in dynamic\r\ncontrast enhanced MRI images is presented. Through thresholding, flood fill\r\nand morphological operations, a mask for the artery at the time point where\r\nthe initial wave of contrast agent arrives is created. The process is deterministic\r\nand independent of the user experience. Since the annotation of the artery has\r\na strong impact on the calculated perfusion values, helps this algorithm with\r\nreproducibility and comparability of perfusion imaging.\r\nThe chapter 4 presents a web-based MRI image generator for teaching students. It allows the students to choose different sequences and set the relevant\r\nparameters, and they can then see how it changes the resulting MRI image.\r\nThe software runs completely inside the browser and is open source1\r\n.\r\nThe presented work show algorithms that help in the imaging process by\r\nimproving reproducability and comparability or in reconstructing CBCT volumes."^^ . "2024" . . . . . . . "Christian"^^ . "Tönnes"^^ . "Christian Tönnes"^^ . . . . . . "Automatic interventional Imaging for the Parametrisation of Vascular Structures (PDF)"^^ . . . "PhD_Tönnes.pdf"^^ . . . "Automatic interventional Imaging for the Parametrisation of Vascular Structures (Anderes)"^^ . . . . . . "indexcodes.txt"^^ . . . "Automatic interventional Imaging for the Parametrisation of Vascular Structures (Anderes)"^^ . . . . . . "lightbox.jpg"^^ . . . "Automatic interventional Imaging for the Parametrisation of Vascular Structures (Anderes)"^^ . . . . . . "preview.jpg"^^ . . . "Automatic interventional Imaging for the Parametrisation of Vascular Structures (Anderes)"^^ . . . . . . "medium.jpg"^^ . . . "Automatic interventional Imaging for the Parametrisation of Vascular Structures (Anderes)"^^ . . . . . . "small.jpg"^^ . . "HTML Summary of #34473 \n\nAutomatic interventional Imaging for the Parametrisation of Vascular Structures\n\n" . "text/html" . . . "004 Informatik"@de . "004 Data processing Computer science"@en . . . "570 Biowissenschaften, Biologie"@de . "570 Life sciences"@en . . . "610 Medizin"@de . "610 Medical sciences Medicine"@en . .