Spatial Dependence of a Differential Shading Artifact in Images from Coil Arrays with Reactive Cross-talk at 1.5 T

Tropp, James; Schirmer, Timo

doi:10.1006/jmre.2001.2329

Cited by 5 publications

(3 citation statements)

References 4 publications

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“…We may dispose of intensity artifacts by noting that none of our phantom images display the signal voids which typically arise from reactive coupling; based upon an earlier quantitative analysis [13] we then estimate the crosstalk between neighboring receive loops as below −15 dB. This is consistent with the relatively clean delineation of the receive elements, as seen in the sensitivity maps from an oil phantom (cf Figure 2b).…”

Section: Methodssupporting

confidence: 73%

Multi-channel metabolic imaging, with SENSE reconstruction, of hyperpolarized [1-13C] pyruvate in a live rat at 3.0tesla on a clinical MR scanner

Tropp¹,

Lupo

Chen

et al. 2011

Journal of Magnetic Resonance

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We report metabolic images of 13C, following injection of a bolus of of hyperpolarized [1-13C] pyruvate in a live rat. The data were acquired on a clinical scanner, using custom coils for volume transmission and array reception. Proton blocking of all carbon resonators enabled proton anatomic imaging with the system body coil, to allow for registration of anatomic and metabolic images, for which good correlation was achieved, with some anatomic features (kidney and heart) clearly visible in a carbon image, without reference to the corresponding proton image. Parallel imaging with sensitivity encoding was used to increase the spatial resolution in the SI direction of the rat. The signal to noise ratio in was in some instances unexpectedly high in the parallel images; variability of the polarization among different trials, plus partial volume effects, are noted as a possible cause of this.

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Section: Methodssupporting

confidence: 73%

Multi-channel metabolic imaging, with SENSE reconstruction, of hyperpolarized [1-13C] pyruvate in a live rat at 3.0tesla on a clinical MR scanner

Tropp¹,

Lupo

Chen

et al. 2011

Journal of Magnetic Resonance

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“…However, changing the relative position of the coil elements to modify the size of the coil along with changes in loading associated with different head sizes alters the mutual inductive coupling between the array’s elements. Failure to adequately compensate for the changes in inductive coupling between the elements distorts the spatial profiles of the transmit B 1 from individual coils and decreases the array transmission performance [12]. …”

Section: Introductionmentioning

confidence: 99%

Transceiver-Phased Arrays for Human Brain Studies at 7 T

Avdievich

2011

Appl Magn Reson

190

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The paper describes technological advances in high-field (7 T) transceiver-phased arrays developed for magnetic resonance imaging of the human brain. The first part of this work describes an 8-element inductively decoupled split elliptical transceiver-phased array with selectable geometry, which provides an easy and efficient way of compensating for changes in mutual inductive coupling associated with difference in loading due to variability in head shape and size. The second part of the work describes a double-row 16-element (2 × 8) transceiver array to extend the homogeneous transmit B1 profile in the longitudinal direction. Multiplexing eight transmit channels between the two rows of the array provides homogeneous excitation over the entire volume. The final section describes design and construction of a double-tuned 31P/1H 16-element (8 at each frequency) array. The array improves transmission efficiency and B1 homogeneity at 1H frequency in comparison with 31P/1H quadrature transverse electromagnetic volume coil. For 31P studies, the array also improves transmission efficiency (38%), signal-to-noise ratio (SNR) for central brain locations (20%) and provides substantially greater SNR (up to 400%) for peripheral locations.

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“…The isolation between the surface coils in the array was evaluated using a small test coil positioned near the center of one of the surface coils (16). The coupling between the surface coils was evaluated by measuring signals at the preamplifier outputs referenced to the signal coming from the array coil with the test coil attached.…”

Section: Resultsmentioning

confidence: 99%

4 T actively detunable transmit/receive transverse electromagnetic coil and 4‐channel receive‐only phased array for ¹H human brain studies

Avdievich

Hetherington

2004

Magnetic Resonance in Med

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The design and construction of a 4 T transverse electromagnetic (TEM) transmit/receive head coil and a four-channel phased array receive-only RF system are described. To enable both high-resolution imaging of the entire brain and high-resolution spectroscopic imaging, active PIN diode decoupling was used in both the TEM resonator and each surface coil in the array. This configuration allows for both transmission and reception from the volume coil as well as reception from the phased array. The surface coils were decoupled by overlapping the coils and using preamplifier decoupling. Since at high frequencies construction of a lumped element matching quarter wavelength transformer, an important component of the preamplifier decoupling, becomes difficult, a transmission line approach was used. The system was tested and compared to a TEM volume transmit/receive head coil. A four-to sixfold improvement in signal-to-noise ratio from the sensitive volume of the array was achieved.

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Spatial Dependence of a Differential Shading Artifact in Images from Coil Arrays with Reactive Cross-talk at 1.5 T

Cited by 5 publications

References 4 publications

Multi-channel metabolic imaging, with SENSE reconstruction, of hyperpolarized [1-13C] pyruvate in a live rat at 3.0tesla on a clinical MR scanner

Multi-channel metabolic imaging, with SENSE reconstruction, of hyperpolarized [1-13C] pyruvate in a live rat at 3.0tesla on a clinical MR scanner

Transceiver-Phased Arrays for Human Brain Studies at 7 T

4 T actively detunable transmit/receive transverse electromagnetic coil and 4‐channel receive‐only phased array for ¹H human brain studies

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Spatial Dependence of a Differential Shading Artifact in Images from Coil Arrays with Reactive Cross-talk at 1.5 T

Cited by 5 publications

References 4 publications

Multi-channel metabolic imaging, with SENSE reconstruction, of hyperpolarized [1-13C] pyruvate in a live rat at 3.0tesla on a clinical MR scanner

Multi-channel metabolic imaging, with SENSE reconstruction, of hyperpolarized [1-13C] pyruvate in a live rat at 3.0tesla on a clinical MR scanner

Transceiver-Phased Arrays for Human Brain Studies at 7 T

4 T actively detunable transmit/receive transverse electromagnetic coil and 4‐channel receive‐only phased array for 1H human brain studies

Contact Info

Product

Resources

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4 T actively detunable transmit/receive transverse electromagnetic coil and 4‐channel receive‐only phased array for ¹H human brain studies