NMR with excitation modulated by Frank sequences

Blümich, Bernhard; Gong, Qingxia; Byrne, Eimear; Greferath, Marcus

doi:10.1016/j.jmr.2009.03.009

Cited by 28 publications

(31 citation statements)

References 37 publications

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“…The excitation of more than one strip per b w is also possible during one readout, as shown in Fig. 5, by stepped shifting of the excitation frequency (similarly to that done in a Frank pulse [33]), followed by correlation and forward FT using the first N = N SR N OS data points, with N SR = 2 in this case equal to the number of frequency steps. The basic idea of using the sequences presented in Figs.…”

Section: Theorymentioning

confidence: 99%

Multi-Band-SWIFT

Idiyatullin

Corum

2015

Journal of Magnetic Resonance

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A useful extension to SWIFT (SWeep Imaging with Fourier Transformation) utilizing sidebands of the excitation pulse is introduced. This MRI method, called Multi-Band-SWIFT, achieves much higher bandwidth than standard SWIFT by using multiple segmented excitations (bands) of the field of view. A description of the general idea and variants of the pulse sequence are presented. From simulations and semi-phenomenological theory, estimations of power deposition and signal-to-noise ratio are made. MB-SWIFT and ZTE (zero-TE) sequences are compared based on images of a phantom and human mandible. Multi-Band-SWIFT provides a bridge between SWIFT and ZTE sequences and allows greatly increased excitation and acquisition bandwidths relative to standard SWIFT for the same hardware switching parameters and requires less peak amplitude of the radiofrequency field (or greater flip angle at same peak amplitude) as compared to ZTE. Multi-Band-SWIFT appears to be an attractive extension of SWIFT for certain musculoskeletal and other medical imaging applications, as well as for imaging materials.

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Section: Theorymentioning

confidence: 99%

Multi-Band-SWIFT

Idiyatullin

Corum

2015

Journal of Magnetic Resonance

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“…This is known as sweep imaging with Fourier transformation (SWIFT) or simultaneous excitation and acquisition (SEA). The acquired data need to be deconvolved with the excitation pulse, but the end result is a much more time-efficient acquisition than with typical 3D acquisitions [34][35][36][37]. Other techniques that have only been used in the pre-clinical phase include methods in which radiofrequency (rf) absorption is assessed rather than signal detection [38].…”

Section: Tissue Fluid and Materials Propertiesmentioning

confidence: 99%

“…Radial from centre out, FID acquisition Gradient echo 2D, 3D Radial rephasing gradients Cones [165] 3D Spiral, from centre out, FID data collection Spiral [166] Stack of spirals [33] Echo planar imaging [167] Twisted radial projection [168] bSSFP [116,169] bUTE [170] VIPR-ATR [171] bUTE VIPR-ATR SWIFT, SEA [34][35][36][37] 3D radiofrequency sub-pulses Radial, centre out 3D, three-dimensional; 2D, two-dimensional; UTE, ultrashort TE; BLAST, back projection low angle shot; PETRA, pointwise encoding time reduction with radial acquisition; ZTE, zero TE; WASPI, water-and fat-suppressed proton projection imaging; FID, free induction decay; bSSFP, balanced steady-state free precession; bUTE, balanced UTE; VIPR-ATR, vastly undersampled isotropic projection reconstruction-alternating length repetition times; SWIFT, sweep imaging with Fourier transformation; SEA, simultaneous excitation and acquisition.…”

Section: Imaging In the Presence Of Metalmentioning

confidence: 99%

The Agfa Mayneord lecture: MRI of short and ultrashortT₂andT₂* components of tissues, fluids and materials using clinical systems

Bydder¹

2011

BJR

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ABSTRACT. A variety of techniques are now available to directly or indirectly detect signal from tissues, fluids and materials that have short, ultrashort or supershort T 2 or T 2 * components. There are also methods of developing image contrast between tissues and fluids in the short T 2 or T 2 * range that can provide visualisation of anatomy, which has not been previously seen with MRI. Magnetisation transfer methods can now be applied to previously invisible tissues, providing indirect access to supershort T 2 components. Particular methods have been developed to target susceptibility effects and quantify them after correcting for anatomical distortion. Specific methods have also been developed to image the effects of magnetic iron oxide particles with positive contrast. Major advances have been made in techniques designed to correct for loss of signal and gross image distortion near metal. These methods are likely to substantially increase the range of application for MRI.

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“…Some candidates are sequences based upon rows or columns of Hadamard matrices [24] and Frank [27,28] (or Chu [29,30] ) sequences which were recently introduced to NMR by Blümich et al [31] For the elimination of radiation damping, neither of these choices are likely to perform well unless applied very carefully. Hadamard sequences often contain repetitive structures and so are unlikely to be as effective as the MLBSs in attenuating radiation damping due to periodic partial refocusing of the magnetization in different excitation slices.…”

Section: Other Noise Sequencesmentioning

confidence: 99%

Defeating Radiation Damping and Magnetic Field Inhomogeneity with Spatially Encoded Noise

Michal

2010

ChemPhysChem

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A simple NMR experiment capable of providing well resolved spectra under conditions where either radiation damping or static magnetic field inhomogeneity would broaden otherwise high-resolution NMR spectra is introduced. The approach involves using a strong pulsed magnetic field gradient and a selective radio-frequency pulse to encode a predetermined noise pattern into the spatial distribution of magnetization. Following readout in a much smaller field gradient, the noise sequence may be deconvolved from the acquired data and a high-resolution spectrum is obtained, eliminating the effects of either radiation damping or the static field inhomogeneity. In the presence of field inhomogeneity a field map is also obtained from the same single transient. A quasi-two-dimensional version of the experiment eliminates the need for deconvolution and produces improved results with simplified processing, but without requiring a full two-dimensional experiment. Example spectra are shown for both radiation damping and one-dimensional field inhomogeneity with improvement in linewidths of more than a factor of 40.

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NMR with excitation modulated by Frank sequences

Cited by 28 publications

References 37 publications

Multi-Band-SWIFT

Multi-Band-SWIFT

The Agfa Mayneord lecture: MRI of short and ultrashortT₂andT₂* components of tissues, fluids and materials using clinical systems

Defeating Radiation Damping and Magnetic Field Inhomogeneity with Spatially Encoded Noise

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NMR with excitation modulated by Frank sequences

Cited by 28 publications

References 37 publications

Multi-Band-SWIFT

Multi-Band-SWIFT

The Agfa Mayneord lecture: MRI of short and ultrashortT2andT2* components of tissues, fluids and materials using clinical systems

Defeating Radiation Damping and Magnetic Field Inhomogeneity with Spatially Encoded Noise

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Product

Resources

About

The Agfa Mayneord lecture: MRI of short and ultrashortT₂andT₂* components of tissues, fluids and materials using clinical systems