نتایج جستجو برای: keywords motion correction
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Introduction: Recently, multiple approaches have been proposed to perform motion correction for diffusion imaging using optical tracking with cameras [1,2] or using MR-based methods which perform real-time registration between volumes [3-5]. In this study, we demonstrate the application of and compare both optical and MR-based motion correction to high-resolution diffusion-weighted imaging usin...
INTRODUCTION: Involuntary patient motion causes pixel misregistration and changes the effective diffusion-encoding, which, in turn, results in erroneous estimation of diffusion tensors or higher-order variants (1-3). The most common method of motion correction for DTI is retrospective coregistration of diffusionweighted volumes to a reference volume. However, retrospective correction methods ca...
Quantitative imaging aims to provide in vivo neuroimaging biomarkers with high research and diagnostic value that are sensitive to underlying tissue microstructure. In order to use these data to examine intra-cortical differences or to define boundaries between different myelo-architectural areas, high resolution data are required. The quality of such measurements is degraded in the presence of...
Physiological fluctuations resulting from the heart beat and respiration are a dominant source of noise in fMRI, particularly at high field strengths. Commonly used physiological noise correction techniques, such as RETROspective Image CORrection (RETROICOR), rely critically on the timing of the image acquisition relative to the heart beat, but do not account for the effects of subject motion. ...
We propose a method to compensate for six degree-of-freedom rigid motion in helical CT of the head. The method is demonstrated in simulations and in helical scans performed on a 16-slice CT scanner. Scans of a Hoffman brain phantom were acquired while an optical motion tracking system recorded the motion of the bed and the phantom. Motion correction was performed by restoring projection consist...
Measurement and Correction of Microscopic Head Motion during Magnetic Resonance Imaging of the Brain
Magnetic resonance imaging (MRI) is a widely used method for non-invasive study of the structure and function of the human brain. Increasing magnetic field strengths enable higher resolution imaging; however, long scan times and high motion sensitivity mean that image quality is often limited by the involuntary motion of the subject. Prospective motion correction is a technique that addresses t...
Introduction Breathing motion during multi-shot acquisitions causes artifacts which appear as ghosts in the reconstructed images. Various techniques for motion correction using parallel imaging have been proposed [1-5]. They reconstruct images from subdivisions of motion corrupted k-space data and average them subsequently for artifact reduction [2], replace motion corrupted k-space lines [3] o...
LaTIM, INSERM, UMR 1101, Brest, France Respiratory and cardiac motion in PET/MR imaging leads to reduced quantitative and qualitative image accuracy. Correction methodologies involve the use of double gated acquisitions which lead to low signal-to-noise ratio (SNR) and to issues concerning the combination of cardiac and respiratory frames. The objective of this work is to use a generalized reco...
Introduction The image quality of brain MRI scans can be compromised by head motion. Prospective motion correction based on external tracking systems has been proposed to ameliorate this issue. Stereo optical tracking systems have been shown to give good real-time motion correction with reasonable accuracy [1,2]. However, the accurate calibration for the stereo system as well as the calibration...
Resting-state functional magnetic resonance imaging (RS-fMRI) is used to investigate brain functional connectivity at rest. However, noise from human physiological motion is an unresolved problem associated with this technique. Following the unexpected previous result that group differences in head motion between control and patient groups caused group differences in the resting-state network w...
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