Open half‐volume quadrature transverse electromagnetic coil for high‐field magnetic resonance imaging

Peshkovsky, Alexey S.; Kennan, Richard P.; Fabry, Mary E.; Avdievich, NI

doi:10.1002/mrm.20422

Cited by 20 publications

(27 citation statements)

References 20 publications

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“…A detailed comparison of the performances of these two coils, and a comparison of the half-volume TEM with the fullvolume TEM coil transmit/surface coil array receive system, which is commonly considered an optimal configuration in terms of its SNR, are presented elsewhere (13). To evaluate the noise correlation between two modes of the half-volume TEM coil, we measured the noise correlation matrix in the central plane using noise images (no RF pulse) obtained separately for each mode.…”

Section: Discussionmentioning

confidence: 99%

“…1b) were made degenerate and combined in quadrature to form a transmit/receive quadrature half-volume coil. Details about the tuning and matching of the half-volume TEM coil are presented elsewhere (13). Isolation between two modes was greater than 20 dB.…”

Section: Methodsmentioning

confidence: 99%

“…2. At the beginning of the experiment both modes were individually tuned and matched as previously described (13). Since there was no difference in tuning and matching between two different acquisitions, no additional tuning was required.…”

Section: Methodsmentioning

confidence: 99%

“…The term "half-volume" in this work refers to a semicircular coil design of 180°of arc. This design provides a relatively uniform RF magnetic field, B 1 , while it retains high sensitivity due to a better filling factor (tighter fit) and a limited RF excitation volume (13).…”

mentioning

confidence: 99%

“…For example, two intrinsically degenerate homogeneous modes of a full-volume coil do not provide sufficient difference in amplitudes for g-factor minimization. On the other hand, the modes of the half-volume coil have very different spatial profiles (13) and consequently can be utilized for SENSE parallel imaging.…”

mentioning

confidence: 99%

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SENSE imaging with a quadrature half‐volume transverse electromagnetic (TEM) coil at 4T

Avdievich

Peshkovsky

Kennan

et al. 2006

Magnetic Resonance Imaging

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Purpose:To demonstrate the feasibility of high-field SENSE imaging of large objects, such as the human head, using a semicircular (half-volume) coil for both transmission and multi-channel reception. Materials and Methods:As a proof of concept, we present experimental data obtained using a seven-element halfvolume (180°of arc) transmit/receive quadrature transverse electromagnetic (TEM) coil. SENSE images of the human brain were acquired with a reduction factor of R ϭ 2, using two degenerate linear modes of the same coil as independent receive channels at 4T. Since the need for additional hardware (i.e., a separate set of receive coils) is eliminated, the design can be substantially simplified. Results:The experimental data demonstrate that linear modes of the half-volume TEM coil have essentially no noise correlation, and their sensitivity profiles satisfy the requirement for small g-factors. Also, this type of coil provides efficient transmission with a relatively large uniform region and a reception profile that is more uniform than that of the surface coils. Conclusion:We demonstrate the feasibility of SENSE imaging using a half-volume coil. Half-volume coils allow reduced total power deposition compared to full-volume coils, and may replace the latter in body imaging applications in which the target region of interest (ROI) is smaller than the entire torso.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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SENSE imaging with a quadrature half‐volume transverse electromagnetic (TEM) coil at 4T

Avdievich

Peshkovsky

Kennan

et al. 2006

Magnetic Resonance Imaging

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Quadrature TEM Surface Coil

Avdievich

2011

Encyclopedia of Magnetic Resonance

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An improved trap design for decoupling multinuclear RF coils

Meyerspeer

Roig

Gruetter

et al. 2013

Magnetic Resonance in Med

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Purpose: Multinuclear magnetic resonance spectroscopy and imaging require a radiofrequency probe capable of transmitting and receiving at the proton and non-proton frequencies. To minimize coupling between probe elements tuned to different frequencies, LC (inductor-capacitor) traps blocking current at the 1 H frequency can be inserted in non-proton elements. This work compares LC traps with LCC traps, a modified design incorporating an additional capacitor, enabling control of the trap reactance at the low frequency while maintaining 1 H blocking. Methods: Losses introduced by both types of trap were analysed using circuit models. Radiofrequency coils incorporating a series of LC and LCC traps were then built and evaluated at the bench. LCC trap performance was then confirmed using 1 H and 13 C measurements in a 7T human scanner. Results: LC and LCC traps both effectively block interaction between non-proton and proton coils at the proton frequency. LCC traps were found to introduce a sensitivity reduction of 562%, which was less than half of that caused by LC traps.

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Open half‐volume quadrature transverse electromagnetic coil for high‐field magnetic resonance imaging

Cited by 20 publications

References 20 publications

SENSE imaging with a quadrature half‐volume transverse electromagnetic (TEM) coil at 4T

SENSE imaging with a quadrature half‐volume transverse electromagnetic (TEM) coil at 4T

Quadrature TEM Surface Coil

An improved trap design for decoupling multinuclear RF coils

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