Adiabatic pulses

Tannús, Alberto; Garwood, Michael

doi:10.1002/(sici)1099-1492(199712)10:8<423::aid-nbm488>3.0.co;2-x

Cited by 366 publications

(407 citation statements)

References 54 publications

(61 reference statements)

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“…In our study, gradient offset independent adiabatic (GOIA) inversion pulses (23), similar to those recently proposed by Andronesi et al (24), were chosen for volume selection. GOIA pulses allow adiabatic inversion with excellent profile features while offering very high RF bandwidth.…”

Section: Pulse Designmentioning

confidence: 99%

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In vivo ³¹P spectroscopy by fully adiabatic extended image selected in vivo spectroscopy: A comparison between 3 T and 7 T

Bogner

Chmelík

Andronesi

et al. 2011

Magnetic Resonance in Med

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An improved image selected in vivo spectroscopy (ISIS) sequence for localized 31 P magnetic resonance spectroscopy at 7 T was developed. To reduce errors in localization accuracy, adiabatic excitation, gradient offset independent adiabatic inversion pulses, and a special extended ISIS ordering scheme were used. The localization accuracy of extended ISIS was investigated in phantoms. The possible spectral quality and reproducibility in vivo was explored in a volunteer (brain, muscle, and liver). A comparison between 3 T and 7 T was performed in five volunteers. Adiabatic extended ISIS provided high spectral quality and accurate localization. The contamination in phantom experiments was only~5%, even if a pulse repetition time~1.2ÁT 1 was chosen to maximize the signal-to-noise ratio per unit time. High reproducibility was found in the calf muscle for 2.5 cm isotropic voxels at 7 T. When compared with 3 T, localized 31 P magnetic resonance spectroscopy in the human calf muscle at 7 T provided 3.2 times higher signal-to-noise ratio (as judged from phosphocreatine peak amplitude in frequency domain after matched filtering). At 7 T, extended ISIS allowed the performance of high-quality localized 31 P magnetic resonance spectroscopy in a short measurement time (~3 to 4 min) and isotropic voxel sizes of~2.5 to 3 cm. With such short measurement times, localized 31 P magnetic resonance spectroscopy has the potential to be applied not only for clinical research but also for routine clinical practice. Magn Reson Med 66:923-930,

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Section: Pulse Designmentioning

confidence: 99%

“…GOIA pulses allow adiabatic inversion with excellent profile features while offering very high RF bandwidth. With GOIA, profiles similar to those available with frequency offset corrected inversion pulses can be realized with less RF power (15,23,24). For our ISIS sequence, a GOIA-W(16,4) pulse shape (24) was used.…”

Section: Pulse Designmentioning

confidence: 99%

In vivo ³¹P spectroscopy by fully adiabatic extended image selected in vivo spectroscopy: A comparison between 3 T and 7 T

Bogner

Chmelík

Andronesi

et al. 2011

Magnetic Resonance in Med

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“…For instance, the advantages of nominal adiabatic 90 hyperbolic secant pulses used for OVS [98] are (i) to be tailored to meet the specific needs of the in vivo geometry within the RF power limits, (ii) to provide a B 1 -insensitive slice selection profile and (iii) to minimize chemical shift displacement errors through broad bandwidth of the pulse. In the case of excitation and inversion, the adiabatic pulse, above a certain B 1 threshold, offers the same nutation independent of B 1 amplitude and is beneficial for a large VOI [96,98].…”

Section: Localized 13 C-mrs Detection Of Brain Glycogen In Practicementioning

confidence: 99%

Technical and experimental features of Magnetic Resonance Spectroscopy of brain glycogen metabolism

Soares

Gruetter

Lei

2017

Analytical Biochemistry

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a b s t r a c tIn the brain, glycogen is a source of glucose not only in emergency situations but also during normal brain activity. Altered brain glycogen metabolism is associated with energetic dysregulation in pathological conditions, such as diabetes or epilepsy. Both in humans and animals, brain glycogen levels have been assessed non-invasively by Carbon-13 Magnetic Resonance Spectroscopy ( 13 C-MRS) in vivo. With this approach, glycogen synthesis and degradation may be followed in real time, thereby providing valuable insights into brain glycogen dynamics. However, compared to the liver and muscle, where glycogen is abundant, the sensitivity for detection of brain glycogen by 13 C-MRS is inherently low. In this review we focus on strategies used to optimize the sensitivity for 13 C-MRS detection of glycogen. Namely, we explore several technical perspectives, such as magnetic field strength, field homogeneity, coil design, decoupling, and localization methods. Furthermore, we also address basic principles underlying the use of 13 C-labeled precursors to enhance the detectable glycogen signal, emphasizing specific experimental aspects relevant for obtaining kinetic information on brain glycogen.

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“…Pulses were designed using the principle of gradient modulated offset-independent adiabaticity (GOIA), as described by Tannus and Garwood (14). The GOIA method ensures constant adiabaticity throughout the duration of the pulse and smoothly varying RF amplitude, frequency, and gradient waveforms.…”

Section: Theorymentioning

confidence: 99%

High‐field MRSI of the prostate using a transmit/receive endorectal coil and gradient modulated adiabatic localization

Near

Romagnoli

Curtis

et al. 2009

Magnetic Resonance Imaging

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Purpose: To demonstrate in vivo magnetic resonance spectroscopic imaging (MRSI) of the human prostate at 4.0T using a transmit/receive endorectal coil and a pulse sequence designed specifically for this application. Materials and Methods:A solid, reusable endorectal probe was designed for both radiofrequency transmission and reception. Finite difference time domain (FDTD) simulations were performed to characterize the coil's electric field distribution, and temperature measurements were performed in a beef tissue phantom to determine the coil's safe operating limit. The localization by selective adiabatic refocusing (LASER) pulse sequence was implemented using six gradient modulated offset independent adiabatic (GOIA) pulses for very sharp, B 1 -insensitive voxel localization.Results: Based on the simulations and temperature measurements, the coil's safe operating limit was conservatively estimated to be 1.0W for 15 minutes. The transition width of the GOIA pulse selection profiles was only 6% of the bandwidth, compared with 22% for a specific absorption rate (SAR)-matched conventional adiabatic pulse. Using the coil and pulse sequence described here, MRSI data were successfully acquired from a patient with biopsyproven prostate cancer, with a nominal voxel size of 0.34 cc in a scan time of 15 minutes. Conclusion:This work demonstrates the safe and effective use of a transmit/receive endorectal coil for in vivo MRSI of the prostate.

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Adiabatic pulses

Cited by 366 publications

References 54 publications

In vivo ³¹P spectroscopy by fully adiabatic extended image selected in vivo spectroscopy: A comparison between 3 T and 7 T

In vivo ³¹P spectroscopy by fully adiabatic extended image selected in vivo spectroscopy: A comparison between 3 T and 7 T

Technical and experimental features of Magnetic Resonance Spectroscopy of brain glycogen metabolism

High‐field MRSI of the prostate using a transmit/receive endorectal coil and gradient modulated adiabatic localization

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Adiabatic pulses

Cited by 366 publications

References 54 publications

In vivo 31P spectroscopy by fully adiabatic extended image selected in vivo spectroscopy: A comparison between 3 T and 7 T

In vivo 31P spectroscopy by fully adiabatic extended image selected in vivo spectroscopy: A comparison between 3 T and 7 T

Technical and experimental features of Magnetic Resonance Spectroscopy of brain glycogen metabolism

High‐field MRSI of the prostate using a transmit/receive endorectal coil and gradient modulated adiabatic localization

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Resources

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In vivo ³¹P spectroscopy by fully adiabatic extended image selected in vivo spectroscopy: A comparison between 3 T and 7 T

In vivo ³¹P spectroscopy by fully adiabatic extended image selected in vivo spectroscopy: A comparison between 3 T and 7 T