Development and evaluation of a multichannel endorectal RF coil for prostate MRI at 7T in combination with an external surface array

Ertürk, Mehmet; Tian, Jinfeng; Moortele, Pierre-François Van de; Adriany, Gregor; Metzger, Gregory J.

doi:10.1002/jmri.25099

Cited by 19 publications

(20 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For particular torso targets, such coil developments may also be sufficient to minimize the current limitations observed at 10.5T by providing competitive SNR performance compared to RF coils used at 7T. In the case of the prostate, it may be possible to achieve SNRs with the use of a body coil alone at 10.5T that approaches that of 7T studies acquired with an endorectal coil . Note that high‐resolution imaging enabled by SNR increases is often accompanied by longer acquisition times and, possibly, higher power deposition attributable to the image orientations needed to reduce motion artifacts and the requirement to encode all spins in the slice/volume of excitation.…”

Section: Discussionmentioning

confidence: 99%

“…In the case of the prostate, it may be possible to achieve SNRs with the use of a body coil alone at 10.5T that approaches that of 7T studies acquired with an endorectal coil. [75][76][77] Note that high-resolution imaging enabled by SNR increases is often accompanied by longer acquisition times and, possibly, higher power deposition attributable to the image orientations needed to reduce motion artifacts and the requirement to encode all spins in the slice/ volume of excitation. However, the more complex B + 1 pattern at higher fields improves the spatial encoding capability, which, together with the SNR gain, can improve the parallel imaging performance, leading to a reduction in acquisition time.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

First in‐vivo human imaging at 10.5T: Imaging the body at 447 MHz

Ertürk

Grant

et al. 2019

Magnetic Resonance in Med

Self Cite

View full text Add to dashboard Cite

Purpose To investigate the feasibility of imaging the human torso and to evaluate the performance of several radiofrequency (RF) management strategies at 10.5T. Methods Healthy volunteers were imaged on a 10.5T whole‐body scanner in multiple target anatomies, including the prostate, hip, kidney, liver, and heart. Phase‐only shimming and spoke pulses were used to demonstrate their performance in managing the B1+ inhomogeneity present at 447 MHz. Imaging protocols included both qualitative and quantitative acquisitions to show the feasibility of imaging with different contrasts. Results High‐quality images were acquired and demonstrated excellent overall contrast and signal‐to‐noise ratio. The experimental results matched well with predictions and suggested good translational capabilities of the RF management strategies previously developed at 7T. Phase‐only shimming provided increased efficiency, but showed pronounced limitations in homogeneity, demonstrating the need for the increased degrees of freedom made possible through single‐ and multispoke RF pulse design. Conclusion The first in‐vivo human imaging was successfully performed at 10.5T using previously developed RF management strategies. Further improvement in RF coils, transmit chain, and full integration of parallel transmit functionality are needed to fully realize the benefits of 10.5T.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

First in‐vivo human imaging at 10.5T: Imaging the body at 447 MHz

Ertürk

Grant

et al. 2019

Magnetic Resonance in Med

Self Cite

View full text Add to dashboard Cite

show abstract

“…To validate numerical computations, matching experiments and simulations were performed using an ∼18L torso‐sized phantom filled with a saline solution (4.5 g/L NaCl, 1 g/l CuSO 4 ), with electrical properties (ε r = 77.8; σ = 0.82 S/m) and (ε r = 77.5; σ = 0.85 S/m) at 7.0 and 10.5 tesla 1 H Larmor frequencies, respectively. Experiments were conducted on 7.0T and 10.5T whole‐body scanners (Siemens Healthcare, Erlangen, Germany) with identical data acquisition protocols.…”

Section: Methodsmentioning

confidence: 99%

Toward imaging the body at 10.5 tesla

Ertürk

Eryaman

et al. 2016

Magnetic Resonance in Med

Self Cite

106

View full text Add to dashboard Cite

Purpose To explore the potential of performing body imaging at 10.5T compared to 7.0T through evaluating the transmit/receive performance of similarly configured dipole antenna arrays. Methods Fractionated dipole antenna elements for 10.5T body imaging were designed and evaluated using numerical simulations. Transmit performance of antenna arrays inside the prostate, kidneys and heart were investigated and compared to those at 7.0T using both phase-only RF shimming and multi-spoke pulses. Signal-to-noise ratio (SNR) comparisons were also performed. A 10-channel antenna array was constructed to image the abdomen of a swine at 10.5T. Numerical methods were validated with phantom studies at both field strengths. Results Similar power efficiencies were observed inside target organs with phase-only shimming, but RF non-uniformity was significantly higher at 10.5T. Spokes RF pulses allowed similar transmit performance with accompanying local SAR increases of 25–90% compared to 7.0T. Relative SNR gains inside the target anatomies were calculated to be >2-fold higher at 10.5T, and 2.2-fold SNR gain was measured in a phantom. Gradient echo and fast spin echo imaging demonstrated the feasibility of body imaging at 10.5T with the designed array. Conclusion While comparable power efficiencies can be achieved using dipole antenna arrays with static shimming at 10.5T; increasing RF non-uniformities underscore the need for efficient, robust and safe parallel transmission methods.

show abstract

“…However, UHF‐MRI is hindered by radiofrequency (RF)‐related limitations, such as interferences, rapid signal attenuation and high energy deposition . These problems can be overcome using local transmit arrays with multiple transceive elements and RF phase shimming …”

Section: Introductionmentioning

confidence: 99%

Design of a forward view antenna for prostate imaging at 7 T

et al. 2018

View full text Add to dashboard Cite

PurposeTo design a forward view antenna for prostate imaging at 7 T, which is placed between the legs of the subject in addition to a dipole array.Materials and methodsThe forward view antenna is realized by placing a cross‐dipole antenna at the end of a small rectangular waveguide. Quadrature drive of the cross‐dipole can excite a circularly polarized wave propagating along the axial direction to and from the prostate region. Functioning of the forward view antenna is validated by comparing measurements and simulations. Antenna performance is evaluated by numerical simulations and measurements at 7 T.ResultsSimulations of B 1 + on a phantom are in good correspondence with measurements. Simulations on a human model indicate that the signal‐to‐noise ratio (SNR), specific absorption rate (SAR) efficiency and SAR increase when adding the forward view antenna to a previously published dipole array. The SNR increases by up to 18% when adding the forward view antenna as a receive antenna to an eight‐channel dipole array in vivo.ConclusionsA design for a forward view antenna is presented and evaluated. SNR improvements up to 18% are demonstrated when adding the forward view antenna to a dipole array.

show abstract

Development and evaluation of a multichannel endorectal RF coil for prostate MRI at 7T in combination with an external surface array

Cited by 19 publications

References 36 publications

First in‐vivo human imaging at 10.5T: Imaging the body at 447 MHz

First in‐vivo human imaging at 10.5T: Imaging the body at 447 MHz

Toward imaging the body at 10.5 tesla

Design of a forward view antenna for prostate imaging at 7 T

Contact Info

Product

Resources

About