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A phantom that can be used for mapping geometric distortion in magnetic resonance imaging (MRI) is described. This phantom provides an array of densely distributed control points in three-dimensional (3D) space. These points form the basis of a comprehensive measurement method to correct for geometric distortion in MR images arising principally from(More)
Spatial encoding in MR techniques is achieved by sampling the signal as a function of time in the presence of a magnetic field gradient. The gradients are assumed to generate a linear magnetic field gradient, and typical image reconstruction relies upon this approximation. However, high-speed gradients in the current generation of MRI scanners often(More)
Determining the information content of vocal signals and understanding morphological modifications of vocal anatomy are key steps towards revealing the selection pressures acting on a given species' vocal communication system. Here, we used a combination of acoustic and anatomical data to investigate whether male koala bellows provide reliable information(More)
Magnetic resonance histology (MRH) has become a widespread tool to examine brain morphology in situ or ex vivo. Samples are routinely fixed and stained to allow for longer scan times with increased contrast and resolution. Although the zebrafish is an important model for neuroscience, to date most MRH studies have focused almost exclusively on mice. In this(More)
Recently, a 3D phantom that can provide a comprehensive and accurate measurement of the geometric distortion in MRI has been developed. Using this phantom, a full assessment of the geometric distortion in a number of clinical MRI systems (GE and Siemens) has been carried out and detailed results are presented in this paper. As expected, the main source of(More)
In this paper, we present the correction of the geometric distortion measured in the clinical magnetic resonance imaging (MRI) systems reported in the preceding paper (Part I) using a 3D method based on the phantom-mapped geometric distortion data. This method allows the correction to be made on phantom images acquired without or with the vendor correction(More)
The main aim of this study was to employ high-resolution MRI to investigate the spatiotemporal development of pathological features associated with contusive spinal cord injury (SCI) in mice. Experimental mice were subjected to either sham surgery or moderate contusive SCI. A 16.4-T small-animal MR system was employed for nondestructive imaging of(More)
OBJECTIVE To determine whether liver fat percent (LFP) is associated with the metabolic syndrome independently of visceral fat area (VFA). METHODS 43 High-risk vascular patients not on lipid-lowering therapy were evaluated for the Adult Treatment Panel III (ATPIII) metabolic syndrome criteria and underwent magnetic resonance imaging (MRI) to quantify VFA(More)
Intrauterine growth restriction (IUGR) can increase susceptibility to perinatal hypoxic brain injury for reasons that are unknown. Previous studies of the neonatal IUGR brain have suggested that the cerebral mitochondrial capacity is reduced but the glycolytic capacity increased relative to normal weight (NW) neonates. In view of these two factors, we(More)
UNLABELLED The measurement of ventilation distribution is currently performed using inhaled tracer gases for multiple breath inhalation studies or imaging techniques to quantify spatial gas distribution. Most tracer gases used for these studies have properties different from that of air. The effect of gas density on regional ventilation distribution has not(More)