Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 41 for “"Motion correction"”.
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Motion correction of PET/CT images
… or more, it is impossible for patients to remain motionless throughout the scanning process. This movements create motion-related artifacts which alter the quantitative and qualitative results produced by the scanning process. The patient's motion results in image blurring, reduction in the image …
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Assessment of New Innovations In Pet/Ct For Respiratory Motion Correction
… due to the long acquisition times, respiratory motion blur is unavoidable in PET images especially in the lower lung and upper abdomen. This leads to reductions in measured radiotracer concentration and lesion detectability all of which can potentially result in incorrect management of patients. …
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Implementation of anatomical navigators for real time motion correction in diffusion tensor imaging
Prospective motion correction methods using an optical system, diffusion-weighted prospective acquisition correction, or a free induction decay navigator have recently been applied to correct for motion in diffusion tensor imaging. These methods have some limitations and drawbacks. This article …
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A control system approach to subject specific prospective respiratory motion correction in cardiac MRI
Respiratory motion of the heart is a problem for high-resolution cardiac MRI. Diaphragmatic navigator gating with a 5mm acceptance window is most commonly used to address this but has an inherently low respiratory efficiency that is further compromised by respiratory drift. A novel method is …
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Self-navigated prospective motion correction of repeated 3D-EPI acquisitions for functional MRI applications
… over threedimensional (3D)-EPI as it is more motion robust. However, 3D-EPI offers various advantages over 2D-EPI for functional MRI (fMRI), including the absence of spin-history artifacts, potential for faster acceleration, and better signal quality at higher spatial resolution. As such, …
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Implementation,Validation and Application of an Automated Motion Correction Algorithm in Hepatic Perfusion CT for Image-Guided Radiotherapy
… a registration algorithm to reduce breathing motion artifacts in hepatic perfusion CT, and 2) to evaluate the potential of perfusion CT to improve radiotherapy of liver cancer. An automated one-dimensional correlation-based registration algorithm was developed and validated in phantom and pig …
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A Multi-DOF Soft Robot Mechanism for Patient Motion Correction and Beam Orientation Selection in Cancer Radiation Therapy
… to harness soft robot mechanisms for real-time motion correction in cancer radiation therapy scenarios. Additionally, in most inverse treatment planning schemes today, the “right” beam angles among the myriad possibilities in beam space are usually determined through intuition and experience by …
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Development and optimization of high resolution multi-shot magnetic resonance acquisitions for diffusion weighted imaging
… challenges being low signal to noise ratio and motion induced phase errors. The work in this thesis aims at creating an acquisition that is able to image with a high SNR efficiency in order to achieve higher resolutions. This is accomplished through the use 3D excitations in order to optimize …
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HEAD MOTION EVALUATION AND CORRECTION IN MAGNETOENCEPHALOGRAPHY
Head motions during magnetoencephalography (MEG) data acquisition lead to inaccuracy in MEG signal localization and statistical sensitivity. Multiple head motion correction methods have been developed and validated to insure the head motion effects are removed, with the aim of improving …
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Physics-Inspired Deep Learning for Inverse Problems in MRI
… a deep learning framework for rigid-body motion correction in MRI, where the forward imaging model informs both the network architecture and the inference procedure. Our method incorporates potentially unknown motion parameters as inputs to the network and then optimizes them for each test …
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Test-retest Reliability of Intrinsic Human Brain Default-Mode fMRI Connectivity: Slice Acquisition and Physiological Noise Correction Effects
… strategies for physiological noise and head motion correction in resting state brain FC-fMRI. In particular, as a general marker of noise correction performance we use the test-retest reproducibility of the DMN. The guiding hypothesis is that methods that improve reproducibility should …
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A Robust and Efficient Framework for Slice-to-Volume Reconstruction: Application to Fetal MRI
Volumetric reconstruction in presence of motion is a challenging problem in medical imaging. When imaging moving targets, many modalities are limited to fast 2D imaging techniques that provide cross-sectional snapshots (2D images) of the subject with an attempt to "freeze'' in-plane motion. …
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Deep Learning Domain Adaptation in Brain MRI: Investigating Motion Mitigation in Adult and Neonatal Scans
… results in patient movement leading to motion artifacts, particularly among non-compliant patients like newborns. While Deep Learning (DL) models have emerged as powerful retrospective solutions for motion mitigation, their performance is expected to degrade when applied to data from …
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Say cheese! Brain imaging of texture perception
… implemented for fMRI; while for fNIRS, multiple motion-correction techniques were implemented and assessed on their ability to reduce masticatory-related noise. Multi-echo fMRI revealed neural selectivity to food texture within the right oral somatosensory and left orbitofrontal cortex using …
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Advances In Computer Aided Protein Structure Determination From Sparse Cryo Electron Microscopy Data
… recent advances in direct electron detectors and motion correction algorithms it can frequently deliver electron density maps in the range of 3-5Å resolution. To obtain as much atomic level detail of the structure as possible from this data an accurate atomic model must be built. This can be done …
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Computational methods for medical image registration
… atlas construction from healthy porcine hearts, motion correction in contrast-enhanced image sequences, and the development of novel computational techniques that improve the performance of existing medical image registration methods. We provide an overview of each of the problems that we …
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Comparison between different techniques of preprocessing for resting state fMRI analysis
… state fMRI study, different algorithms of motion correction showed no significant difference in the results. Temporal filtering by rectangular filter for particular bands of frequency showed no significant difference in the data analysis. Gaussian and Hamming windows however, work well for …
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Characterization of the Intrinsic Neural Timescale Indices as a Reliable Fingerprint of Brain Dynamics
… age trends, sex interactions, and widespread motion sensitivity, particularly in sensory and salience networks. These findings support the existence of a developmentally structured gradient of cortical temporal dynamics and underscore the need for careful metric selection and motion correction …
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Online, low-latency decision making for Fetal Magnetic Resonance Imaging with machine learning
… of HASTE images routinely suffer from fetal motion which leads to image artifacts, incomplete brain coverage as well as longer scan times. To address this problem, interleaved 3D Echo-planar Imaging (EPI) navigators are acquired along with HASTE images, which can provide pose information for …
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