Heteronuclear Cross Polarization for Enhanced Sensitivity ofin Vivo13C MR Spectroscopy on a Clinical 1.5 T MR System

Bergh, A.J. (Bert) van den; Boogert, H.J. van den; Heerschap, Arend

doi:10.1006/jmre.1998.1533

Cited by 8 publications

(7 citation statements)

References 31 publications

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“…The most attractive features of both sequences are selectivity, efficient transfer at very low RF field amplitudes, very low RF duty cycle, and considerable tolerance to Hartmann-Hahn mismatch. In contrast, most of the previously reported methods (17,(22)(23)(24) were semi-selective in nature and the average RF amplitude used for cross polarization was in the range 700-1200 Hz, whereas it is only $200 Hz or even less in the present studies. The mixing sequence PRAWN exhibits useful tolerance to Hartmann-Hahn mismatch.…”

Section: Discussioncontrasting

confidence: 78%

“…One technique involves ''forward'' and ''reverse'' PT under spin lock conditions, which typically result in reduced motion artifacts. The pulse sequence (CYCLCROP-LOSY) for direct 13 C detection comprises PT in three slice selection steps from 1 H to 13 C, back to 1 H and finally once again to 13 C. A few studies have been made using J cross-polarization for the enhancement of 13 C signals in in vivo experiments (22)(23)(24). These studies are based on J cross-polarization using ''narrowband'' ($900 Hz) isotropic mixing, such as with WALTZ-4 pulse trains, implemented on a clinical MRI system.…”

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confidence: 99%

“…These studies are based on J cross-polarization using ''narrowband'' ($900 Hz) isotropic mixing, such as with WALTZ-4 pulse trains, implemented on a clinical MRI system. Very often, however, in in vivo studies (23,24), interest is focused on a specific metabolite or two. We have, therefore, decided to address this requirement by designing volume localized, chemical shift selective 13 C spectroscopy protocols in the rotating frame.…”

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confidence: 99%

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Volume localized shift selective ¹³C spectroscopy using pulsed rotating frame transfer sequences with windows (PRAWN)

Banerjee

Chandrakumar

2011

Magnetic Resonance in Med

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Some novel techniques for volume localized, chemical shift selective 13 C spectroscopy are described in this work. These techniques are based on rotating frame J cross polarization and are reported for both direct and indirect modes of 13 C detection. The performance of two selective mixing sequences, viz., pulsed rotating frame transfer sequences with windows (PRAWN) and PRAWN-p has been studied systematically with different liquid and gel phantoms. Two different front-end modules are used for volume localization, viz., point resolved spectroscopy (PRESS) and localized distortionless enhancement by polarization transfer (LODEPT). It is shown experimentally that both the selective J cross polarization sequences can operate efficiently with very low radiofrequency duty cycle; further, they have considerable tolerance to Hartmann-Hahn mismatch. A simple theoretical analysis is also presented to understand J cross-polarization dynamics at low RF field amplitudes. Key words: rotating frame coherence transfer; shift selective volume localized 13 C magnetic resonance spectroscopy; PRAWN; PRAWN-p; low RF duty cycle; Hartmann-Hahn mismatch tolerance; direct detection; indirect detection; PRESS; LODEPT 13 C nuclear magnetic resonance spectroscopy is a powerful tool to study metabolic events in living organisms (1-3). The advantage of this technique is that one can get very high spectral resolution (less crowding of peaks compared to proton nuclear magnetic resonance); however, this is countered by low natural abundance and poor sensitivity, which makes 13 C nuclear magnetic resonance (or magnetic resonance spectroscopy) methodology much more challenging than 1 H and 31 P magnetic resonance spectroscopy. Heteronuclear polarization transfer (PT) (4,5) from abundant spins such as 1 H provides a way to enhance the sensitivity of 13 C detection. The sensitivity of 13 C spectroscopy can be further improved by indirect detection, i.e., selective detection of 1 H spins that are coupled to 13 C. Some PT studies have been reported in the literature, based primarily on laboratory frame PT protocols (6-12). Among them, the most frequently used sequences are based on distortionless enhancement by polarization transfer (DEPT) (13) and insensitive nuclei enhanced by polarization transfer (INEPT) (14), e.g., localized DEPT (LODEPT) and localized INEPT (LINEPT) (15), and their semi-adiabatic versions (11). Heteronuclear J cross polarization (JCP) using spin-locking radiofrequency (RF) fields (4) is an important technique for many solid state and liquid state nuclear magnetic resonance experiments to enhance the sensitivity of detection of rare nuclei; however, this technique is not widely used for in vivo experiments. The application of rotating frame PT for 13 C localized spectroscopy and for 13 C editing has been reported in a series of papers by , using the MOIST mixing sequence (19,20) or adiabatic RF fields (21). One technique involves ''forward'' and ''reverse'' PT under spin lock conditions, which typically result in reduced motio...

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Section: Discussioncontrasting

confidence: 78%

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confidence: 99%

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confidence: 99%

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Volume localized shift selective ¹³C spectroscopy using pulsed rotating frame transfer sequences with windows (PRAWN)

Banerjee

Chandrakumar

2011

Magnetic Resonance in Med

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“…While the efficiency of DEPT depends on accurate pulse angles, the efficiency of CP depends on the fulfillment of the Hartman-Hahn condition (i.e., matching of the 13 C and 1 H B 1 fields). Although CP has only been used in vivo at small bandwidths using WALTZ4 pulse trains (11,12), recent developments in high-resolution NMR have shown that broadband CP using optimized pulse trains is possible (13).…”

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Sensitivity‐enhanced ¹³C MR spectroscopy of the human brain at 3 Tesla

Klomp

Renema

Graaf

et al. 2005

Magnetic Resonance in Med

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A new coil design for sensitivity-enhanced 13 C MR spectroscopy (MRS) of the human brain is presented. The design includes a quadrature transmit/receive head coil optimized for 13 C MR sensitivity. Loss-less blocking circuits inside the coil conductors allow this coil to be used inside a homogeneous circularly polarized 1 H B 1 field for 1 H decoupled 13 C MRS. A quadrature 1 H birdcage coil optimized for minimal local RF heating makes broadband 1 H decoupling in the entire human brain possible at 3 Tesla while remaining well within international safety guidelines for RF absorption. Apart from a substantial increase in sensitivity compared to conventional small linear coils, the quadrature 13 C coil combined with the quadrature 1 H birdcage coil allows efficient cross polarization (CP) in the brain, resulting in an additional 3.5-fold sensitivity improvement compared to direct 13 C measurements without nuclear Overhauser enhancement (NOE) or polarization transfer. Combined with the gain in power efficiency, this setup allows broadband 1 H to 13 C CP over large areas of the brain.

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“…With the use of cross-relaxation by means of nuclear Overhauser enhancement (9), signal intensity can be changed anywhere from a complete cancellation up to a 1 þ g 1H /2g X enhancement, depending on molecular structure and environment. An even higher gain (g 1H / g X ) can be accomplished using cross-polarization (10)(11)(12) or using pulsed polarization transfer methods such as insensitive nuclei enhanced by polarization transfer (INEPT) (13,14) or distortionless enhancement of polarization transfer (DEPT) (15,16).…”

Section: Introductionmentioning

confidence: 99%

Polarization transfer for sensitivity‐enhanced MRS using a single radio frequency transmit channel

Klomp¹,

Kentgens²,

Heerschap³

2008

NMR in Biomedicine

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Polarization transfer techniques are used to enhance sensitivity and improve localization in multinuclear MRS, by transferring polarization from highly polarized or even hyperpolarized nuclei to less sensitive spin systems. Clinical MR scanners are in general not equipped with a second radio frequency (RF) transmit channel, making the conventional implementation of polarization transfer techniques such as distortionless enhanced polarization transfer (DEPT) impossible. Here we present a DEPT sequence using pulses sequentially that can be used on a single RF transmit channel (SC-DEPT). Theoretical simulations, phantom measurements, and in vivo results from human brain at 3 T show that the SC-DEPT method performs as well as the conventional DEPT method. The results indicate that an independent second RF transmit channel for simultaneous pulsing at different nuclear frequencies is not needed for polarization transfer, facilitating the use of these methods with common clinical systems with minor modifications in the RF architecture.

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Heteronuclear Cross Polarization for Enhanced Sensitivity ofin Vivo13C MR Spectroscopy on a Clinical 1.5 T MR System

Cited by 8 publications

References 31 publications

Volume localized shift selective ¹³C spectroscopy using pulsed rotating frame transfer sequences with windows (PRAWN)

Volume localized shift selective ¹³C spectroscopy using pulsed rotating frame transfer sequences with windows (PRAWN)

Sensitivity‐enhanced ¹³C MR spectroscopy of the human brain at 3 Tesla

Polarization transfer for sensitivity‐enhanced MRS using a single radio frequency transmit channel

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Heteronuclear Cross Polarization for Enhanced Sensitivity ofin Vivo13C MR Spectroscopy on a Clinical 1.5 T MR System

Cited by 8 publications

References 31 publications

Volume localized shift selective 13C spectroscopy using pulsed rotating frame transfer sequences with windows (PRAWN)

Volume localized shift selective 13C spectroscopy using pulsed rotating frame transfer sequences with windows (PRAWN)

Sensitivity‐enhanced 13C MR spectroscopy of the human brain at 3 Tesla

Polarization transfer for sensitivity‐enhanced MRS using a single radio frequency transmit channel

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Volume localized shift selective ¹³C spectroscopy using pulsed rotating frame transfer sequences with windows (PRAWN)

Volume localized shift selective ¹³C spectroscopy using pulsed rotating frame transfer sequences with windows (PRAWN)

Sensitivity‐enhanced ¹³C MR spectroscopy of the human brain at 3 Tesla