Start Forskningsoutput meta-DENSE complex acquisition for reduced intravoxel dephas meta-DENSE complex acquisition for reduced intravoxel dephasing.

2008-06-25

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. This results in signal loss in the vicinity of the device due to intravoxel dephasing, and leads to a disturbance of Measurements of Inter- and Intravoxel Dephasing of Trabecular Bone at 7T Field Strength using a Chemical Shift-Selective. Asymmetric Spin-Echo (Chase) May 28, 2016 Another cause of dephasing is intravoxel dephasing.

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. Gradient-recalled echo sequences are par- ticularly prone to metallic artifact because of intravoxel dephasing [3] (Fig.

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Signal loss due to flow is induced via intravoxel dephasing which, according to Eq. 1, is dependent on velocity profile and m1. For a certain velocity profile, the flow suppression capability of FSD-preparation is determined by m1.

A technique is proposed to compensate for the slice dephasing artifact and improve the signal‐to‐noise ratio (SNR) of gradient‐echo images. This method is composed of two components: mapping of the internal gradient and design of the slice‐selective radiofrequency (RF) pulse. The RF pulse is designed with its phase response as the negative of the product of a chosen echo time and the

Moreover, while intra-sponding directions in k space. Fourier transformation results voxel dephasing originates from an increase in broadness of Experiments were performed with a 0.2 T magnet on a network of small interacting air-filled cylinders along with Magnetic resonance imaging (MRI) simulations integrating intravoxel dephasing. Signal decay over echo time was assessed at different pixel sizes on real and simulated images.

Mark These effects are negated by flow-related dephasing and are only seen well in short TE sequences. Intravoxel dephasing related to turbulence Accumulation of positive phase shift over the course of the scan Fat-saturation pulses as used in time-of-flight imaging Inflow of unsaturated blood into the Start Forskningsoutput meta-DENSE complex acquisition for reduced intravoxel dephas meta-DENSE complex acquisition for reduced intravoxel dephasing. 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.
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This phenomenon is due to the spin dephasing when the voxel size is comparable to the residual lumen at level of stenosis ( 7 ).
Umea industri

A technique is proposed to compensate for the slice dephasing artifact and improve the signal‐to‐noise ratio (SNR) of gradient‐echo images. This method is composed of two components: mapping of the internal gradient and design of the slice‐selective radiofrequency (RF) pulse. The RF pulse is designed with its phase response as the negative of the product of a chosen echo time and the

This happens because of intravoxel dephasing of the inflowing blood experiencing magnetic field inhomogeneities. The dephasing of spins leads to less signal within the vessel and an apparent increased stenosis. Turbulent flow also leads to rapid dephasing that cannot be corrected. 2021-03-14 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. Intravoxel Dephasing due to Wave Gradients. This article assumes prior knowledge of Wave-CAIPI[1].