meta-DENSE complex acquisition for reduced intravoxel

Software Simulation of Magnetic Resonance Imaging - Ca Da Alt N

compensated (M =M =0) gradient waveforms to null the intravoxel phase This results in signal loss in the vicinity of the device due to intravoxel dephasing, and leads to a disturbance of the phase image. The local fields are established May 28, 2016 This was due to high velocity of CSF and subsequent turbulent flow resulting in intravoxel dephasing. Patient had normal pressure hydrocephalus reducing intravoxel dephasing signal loss. This RF phase cycling scheme, when combined with existing meta-DENSE suppression of the T1 recovering signal tively referred to as susceptibility artifact.

of intravoxel dephasing among flowing spins that have large intravoxel veloc-ity variability. The arterial images with suppressed background and venous signals were obtained by means of sub-traction of a dark artery measurement (Fig 1, A) and a bright artery measure-ment (Fig 1, B), both of which were in one single image. The bright artery and Displacement encoding with stimulated echoes (DENSE) with a meta-DENSE readout and RF phase cycling to suppress the STEAM anti-echo is described for reducing intravoxel dephasing signal loss. This RF phase cycling scheme, when combined with existing meta-DENSE suppression of the T1 recovering signal, yields higher quality DENSE myocardial strain maps. Phantom and human images are provided to mechanism is intravoxel dephasing: Luminal blood contains spins travelingatvaryingvelocities(eg,duetolaminarflow).Betweenthe time of excitation and readout, these spins move through the mag-netic field gradients at different rates, resulting in intravoxel phase dispersion with signal loss.8 One may further exploit the intravoxel This paper addresses one of the major problems in interventional magnetic resonance imaging (MRI): the visualization of interventional devices. For visualization locally induced magnetic fields are used, which disturb the homogeneity of the main magnetic field of the MR scanner.

meta-DENSE complex acquisition for reduced intravoxel

At low spatial resolution in particular, the respective field gradients lead to an apparent increase in intravoxel dephasing, and subsequently, to signal loss or inaccurate R2* estimates. Moreover, the difference in magnetic susceptibility ([chi]) of tumors and normal tissues accelerates intravoxel dephasing of transverse magnetization in tumor and creates off-resonance effects or [T.sup.*sub.2] contrast, a combination of spin-spin relaxation ([T.sub.2]) and [B.sub.0] magnetic field inhomogeneity.

meta-DENSE complex acquisition for reduced intravoxel

Todd Constable. PDF. Download Free PDF. Free PDF. Download with Google Download with Facebook. or.

Spin dephasing under nonlinear gradients: Implications for imaging and field mapping. Magnetic Resonance in Medicine, 2012. Todd Constable. PDF. Download Free PDF. Free PDF. Download with Google Download with Facebook. or. Create a free account to download. PDF. PDF. 2004-08-01 2012-04-01 INTRAVOXEL DEPHASING.
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Forskningsoutput: Tidskriftsbidrag › Artikel i vetenskaplig tidskrift.

Fourier transformation results voxel dephasing originates from an increase in broadness of The refocusing mechanism fails if intravoxel dephasing exceeds over ±180º manifest by band-like artifacts.
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Journal of Magnetic Resonance - Research Outputs - Lund

The application of gradients causes protons to accelerate or decelerate, based on the direction of flow, with a gain or loss in phase respectively. Within each voxel, a mixture of stationary and flowing protons may exist causing a difference of phase between the protons 2015-04-06 2012-04-23 2013-08-01 The cause of intravoxel dephasing is not yet well understood. This phenomenon is due to the spin dephasing when the voxel size is comparable to the residual lumen at level of stenosis ( 7 ). In addition to, previous studies were explained that turbulent flow in the axilla area of a small vessel may cause an intravoxel dephasing, especially at a broad bifurcation angle ( 8 , 9 ).

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Individuell kartläggning av hjärnan, ett fmri-datasæt med hög

This article assumes prior knowledge of Wave-CAIPI[1]. In particular, this article attempts to describe the methodology used to generate Figure 9 of [1]. For simplicity, assume a two-dimensional problem. ‘‘intravoxel dephasing,’’ but also from incomplete refocus-phase-encoding direction shift the gradient echo along corre-ing of the slice-selection gradient. Moreover, while intra-sponding directions in k space. Fourier transformation results voxel dephasing originates from an increase in broadness of The refocusing mechanism fails if intravoxel dephasing exceeds over ±180º manifest by band-like artifacts.