crusher gradient followed

Optimal control of the signal-to-noise ratio per unit time of …

The U.S. Department of Energy''s Office of Scientific and Technical Information OSTI.GOV Journal Article: Optimal control of the signal-to-noise ratio per unit time of a spin 1/2 particle: The crusher gradient and the radiation damping cases

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Pulse Sequence Diagram | Radiology Key

Crusher gradients are applied at each side of the slice-selective gradient (applied during the 180 pulse) to achieve more accurate refocusing at time TE. So we apply a gradient in the negative direction that has an area equal to ½ of that of the readout gradient ( Fig. 14-5 ).

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Optimal control of the signal-to-noise ratio per unit time of …

We show to which extent the signal to noise ratio per unit time of a spin 1/2 particle can be maximized. We consider a cyclic repetition of experiments made of a measurement followed by a radio-frequency magnetic field excitation of the system, in the case of unbounded amplitude. In the periodic regime, the objective of the control problem is to design the initial state of the system and the ...

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reeder body MR water fat imaging

The RF pulse is followed immediately by a crusher gradient, after which the standard imaging sequence is played. Such pulses are highly effective in regions where both the main magnetic field (B o) and the RF field from the coil (B 1) are homogeneous. ...

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Fast computation of full density matrix of multispin …

The strengths of the crusher gradients were determined by: gradient strength × frequency interval of digitized RF bandwidth × crusher gradient duration = π. As a result, the phase was shifted 180 degrees for each spatial point, namely, the transverse magnetizations can be canceled for every two spatial points after the application of the crusher gradients.

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Quantitative T2 in the occipital lobe: The role of the CPMG …

Original Research Quantitative T 2 in the Occipital Lobe: The Role of the CPMG Refocusing Rate Bojana Stefanovic, BS,* John G. Sled, PhD, and G. Bruce Pike, PhD Purpose: To investigate the dependence of occipital gray and white matter T 2 on the Carr-Purcell-Meiboom-Gill

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Pulse Sequences

Here, the right crusher gradient destroys the free induction decay (FID) caused by imperfect $ 180^circ $ pulse. The left one is required to balance the right crusher gradient. The last thing shown on the $ G_z $ line is the killer gradient which helps to destroy the residual transverse magnetization prior to next TR.

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Quantitative Perfusion Imaging with Pulsed Arterial Spin Labeling: …

ration pulses on imaging plane followed by the sech inversion labeling pulse on labeling plane were applied. Periodic saturation pulses applied from TI1 to TI1S consist of a train of 909excitation pulses, each followed by a crusher gradient. Five imaging slices of ...

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Optimal control of the signal-to-noise ratio per unit time of a spin 1/2 particle: The crusher gradient …

crusher gradient and the radiation damping cases M. Lapert, E. Assémat, S. J. Glaser, and D ... We consider a cyclic repetition of experiments made of a measurement followed by a radio-frequency

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532 Optimizing crusher gradients when using multiple …

Crusher area in mT/m*ms. Presat crusher is the presaturation crusher placed before the 180o tagging pulse, while postsat is the presaturation crusher placed after the 180o pulse. The imaging parameters for the phantom experiments were: TE=20ms, TI 0.5mm

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Optimal control of the signal-to-noise ratio per unit time of a spin …

crusher gradient and the radiation damping cases M. Lapert, E. Assémat, S. J. Glaser, and D ... We consider a cyclic repetition of experiments made of a measurement followed by a radio-frequency

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Crusher Gradient Reversal to Eliminate Stimulated Echo Artifacts in …

Crusher Gradient Reversal to Eliminate Stimulated Echo Artifacts in Dual Spin Echo Diffusion MRI G. Wu1, S. Lee1, X. Zhao1, and Z. Li1 1GE Healthcare, Waukesha, WI, United States Introduction The dual spin echo (DSE) technique is to reduce eddy-curre nt ...

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(PDF) Combining T 2 measurements and crusher gradients …

light red, control), followed by the T 2-relaxation-under-spin-tagging (TRUST) T 2-preparation (T 2-prep) module, then the bipolar gradient, and finally the image acquisition scheme.

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Improved Quantitative Myocardial T Mapping: Impact of the …

FULL PAPER Improved Quantitative Myocardial T 2 Mapping: Impact of the Fitting Model Mehmet Akc¸akaya,1y Tamer A. Basha,1y Sebastian Weing€artner, 1,2 Sebastien Roujol,1 Sophie Berg,1 and Reza Nezafat1* Purpose: To develop an improved T 2 prepared (T ...

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Fast computation of full density matrix of multispin …

The strengths of the crusher gradients were determined by: gradient strength × frequency interval of digitized RF bandwidth × crusher gradient duration = π. As a result, the phase was shifted 180 degrees for each spatial point, namely, the transverse magnetizations can be canceled for every two spatial points after the application of the crusher gradients.

2021 prices

Joint Myocardial T1 and T2 Mapping Using a Combination of …

NOTE Joint Myocardial T 1 and T 2 Mapping Using a Combination of Saturation Recovery and T 2-preparation Mehmet Akc¸akaya,1,2,3* Sebastian Weing€artner, 3,4 Tamer A. Basha,3 Sebastien Roujol,3 Steven Bellm,3 and Reza Nezafat3 Purpose: To develop a

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Assessment of glycosaminoglycan concentration in vivo by …

Three 90 -crusher gradient pairs were used before the readout 90 pulse to remove transverse bulk magnetization. The three crusher gradients of 1-ms duration …

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Determination of the rate of the glutamate/glutamine …

A spatially selective five-lobe sinc pulse was used to excite a 2-cm y slice followed by a crusher gradient (90%, 10 ms) to enhance surface lipid suppression. For adiabatic polarization transfer, 1 H magnetization first was excited and polarized with a segmented BIR4 90° pulse ( 32 ) on 1 H and a simultaneous adiabatic full-passage pulse on 13 C to allow the formation of 1 H- 13 C one-bond ...

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Magnetism

A crusher gradient (G) is typically applied immediately after the pulse to destroy transverse coherences. After being tipped into the transverse plane tissues begin to recover longitudinal magnetization as a function of their T1 values.

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Crusher

A crusher is a machine designed to reduce large rocks into smaller rocks, gravel, sand or rock dust.Crushers may be used to reduce the size, or change the form, of waste materials so they can be more easily disposed of or recycled, or to reduce the size of a solid mix of raw materials (as in rock ore), so that pieces of different composition can be differentiated.

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reeder body MR water fat imaging

The RF pulse is followed immediately by a crusher gradient, after which the standard imaging sequence is played. Such pulses are highly effective in regions where both the main magnetic field (B o) and the RF field from the coil (B 1) are homogeneous. ...

2021 prices

Breath-hold black blood quantitative T1rho imaging of liver …

The crusher gradient used at the end of T1rho-prep can result in short-term eddy current effect in FSE acquisition. A 2-ms delay was added after T1rho-prep to address the short-term eddy current from these crusher gradients ( 33 ).

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Resurrection of Crushed

Consider the simplest pulse/gradient combi-nation [(p/2) x –(GT) z]: an RF pulse along the x axis with a flip angle of p/2 followed by a "crusher" B 0 gradient in the z direction with strength G and duration time T. Such a scheme appears in a wide range of

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Combining T 2 measurements and crusher gradients into …

Of the implemented techniques, TRUST allowed us to follow intravascular signal deeper into the vascular tree than the approach with (relatively weak) crusher gradients when quantifying the transport time of water across the blood-brain barrier.

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Proc. Intl. Soc. Mag. Reson. Med 9 (2001) 897

pulse is followed by a non-selective 180 pulse and a crusher gradient. A time delay τ between the 90 and the 180 pulse ensures sufficient longitudinal relaxation before the inversion. The inverted magnetisation is then "probed" by the application of a slicelow flip

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Magnetism

A crusher gradient (G) is typically applied immediately after the pulse to destroy transverse coherences. After being tipped into the transverse plane tissues begin to recover longitudinal magnetization as a function of their T1 values.

2021 prices

Optimal control of the signal-to-noise ratio per unit time of …

We show to which extent the signal to noise ratio per unit time of a spin 1/2 particle can be maximized. We consider a cyclic repetition of experiments made of a measurement followed by a radio-frequency magnetic field excitation of the system, in the case of unbounded amplitude. ...

2021 prices

Proc. Intl. Soc. Mag. Reson. Med 9 (2001) 897

pulse is followed by a non-selective 180 pulse and a crusher gradient. A time delay τ between the 90 and the 180 pulse ensures sufficient longitudinal relaxation before the inversion. The inverted magnetisation is then "probed" by the application of a slicelow flip

2021 prices

Improved Quantitative Myocardial T Mapping: Impact of the …

FULL PAPER Improved Quantitative Myocardial T 2 Mapping: Impact of the Fitting Model Mehmet Akc¸akaya,1y Tamer A. Basha,1y Sebastian Weing€artner, 1,2 Sebastien Roujol,1 Sophie Berg,1 and Reza Nezafat1* Purpose: To develop an improved T 2 prepared (T ...

2021 prices

Optimal control of the signal-to-noise ratio per unit time of …

We show to which extent the signal to noise ratio per unit time of a spin 1/2 particle can be maximized. We consider a cyclic repetition of experiments made of a measurement followed by a radio-frequency magnetic field excitation of the system, in the case of unbounded amplitude. In the periodic regime, the objective of the control problem is to design the initial state of the system and the ...

2021 prices

Combining T 2 measurements and crusher gradients into a …

In this protocol, the same Hadamard preparation and background suppression pulses were performed, followed by a T 2 ‐prep module with eTE = 0, 40, 80 or 160 ms, and finally a 3D gradient and spin‐echo readout (three shots, two averages per eTE, 3.75 × 3 3 2

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Gradient ROtating Outer Volume Excitation (GROOVE): A …

The pulse was combined with paired shaped gradients, and followed by either a 4-ms or 8-ms dephasing gradient (G z (t)) with an amplitude of 2 G/cm. To reduce artifacts, the G x gradient was turned on 500 μs before the execution of the RF pulse so the gradient strength could ramp up gradually.

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Fat-Water Imaging: An Overview

followed immediately by a crusher gradient, after which the standard imaging sequence is played. Fat-sat pulses are highly effective in regions where both the main magnetic field (B Bo) and the RF field from the coil (B1B) are relatively homogeneous. Typical ...

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Perfusion Imaging of Meningioma by Using Continuous …

PURPOSE: The goal of the present study was to determine the utility of continuous arterial spin labeling (CASL) for characterization of meningioma by MR perfusion imaging and to compare these results with those obtained from the T2 dynamic susceptibility contrast (T2DSC) method and from histopathologic examination. METHODS: Twenty-one cases of meningiomas were examined at 1.5T. …

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Bloch Equations & Relaxation

• Typically followed by a crusher gradient 180 Inversion Pulse UCLA Radiology Refocusing Pulses • Typically, 180 RF Pulse – Provides optimally refocused MXY – Largest spin echo signal • Refocus spin dephasing due to – imaging gradients – local magnetic ...

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Combining T 2 measurements and crusher gradients into …

Of the implemented techniques, TRUST allowed us to follow intravascular signal deeper into the vascular tree than the approach with (relatively weak) crusher gradients when quantifying the transport time of water across the blood-brain barrier.

2021 prices

Breath-hold black blood quantitative T1rho imaging of liver …

The crusher gradient used at the end of T1rho-prep can result in short-term eddy current effect in FSE acquisition. A 2-ms delay was added after T1rho-prep to address the short-term eddy current from these crusher gradients ( 33 ).

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Correction Gradients

Crusher Gradients • Crusher Gradients: is a correction gradient that preserves the desired signal pathways while eliminating unwanted ones by manipulating the phase of the signals. • Consists of two lobes with the same polarity immediately before and after the

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Combining T2 measurements and crusher gradients into a single …

crusher gradients that target fast flowing spins [b-values below 20 s/mm2] as well as stronger, higher b-value gra-dients that target diffusing spins have been used), which remove signal from the vasculature based on the velocity of blood along the gradient

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Figure 1.6 from Rapid magnetic resonance tissue …

Figure 1.6: A standard single-echo RF spin-echo (SE) pulse sequence consists of a 90 excitation pulse followed by a 180 refocusing pulse. Commonly, a crusher gradient pair played along slice-selection direction accompanies the refocusing pulse in order to remove unwanted signal pathways (black-colored gradient area) and a spoiler gradient played at the end of the slice-selection waveform ...

2021 prices

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