High field volume coil with unbalance current distribution for MRI applications of rodents

2010 ◽  
Author(s):  
O. R. Marrufo ◽  
J. Hernández ◽  
A. O. Rodríguez ◽  
Maria-Ester Brandan ◽  
Flora Herrera-Martinez ◽  
...  
Author(s):  
Karthik Lakshmanan ◽  
Martijn Cloos ◽  
Ryan Brown ◽  
Riccardo Lattanzi ◽  
Daniel K. Sodickson ◽  
...  

Purpose. To revisit the “loopole,” an unusual coil topology whose unbalanced current distribution captures both loop and electric dipole properties, which can be advantageous in ultra-high-field MRI. Methods. Loopole coils were built by deliberately breaking the capacitor symmetry of traditional loop coils. The corresponding current distribution, transmit efficiency, and signal-to-noise ratio (SNR) were evaluated in simulation and experiments in comparison to those of loops and electric dipoles at 7 T (297 MHz). Results. The loopole coil exhibited a hybrid current pattern, comprising features of both loops and electric dipole current patterns. Depending on the orientation relative to B0, the loopole demonstrated significant performance boost in either the transmit efficiency or SNR at the center of a dielectric sample when compared to a traditional loop. Modest improvements were observed when compared to an electric dipole. Conclusion. The loopole can achieve high performance by supporting both divergence-free and curl-free current patterns, which are both significant contributors to the ultimate intrinsic performance at ultra-high field. While electric dipoles exhibit similar hybrid properties, loopoles maintain the engineering advantages of loops, such as geometric decoupling and reduced resonance frequency dependence on sample loading.


1994 ◽  
Vol 32 (4) ◽  
pp. 492-498 ◽  
Author(s):  
Han Wen ◽  
Andrew S. Chesnick ◽  
Robert S. Balaban

2002 ◽  
Vol 47 (5) ◽  
pp. 990-1000 ◽  
Author(s):  
J.T. Vaughan ◽  
G. Adriany ◽  
M. Garwood ◽  
E. Yacoub ◽  
T. Duong ◽  
...  

2013 ◽  
Vol 484 ◽  
pp. 300-304 ◽  
Author(s):  
Ryusei Itoh ◽  
Yuki Oga ◽  
So Noguchi ◽  
Hajime Igarashi ◽  
Hiroshi Ueda

Author(s):  
T. F. Kelly ◽  
P. J. Lee ◽  
E. E. Hellstrom ◽  
D. C. Larbalestier

Recently there has been much excitement over a new class of high Tc (>30 K) ceramic superconductors of the form A1-xBxCuO4-x, where A is a rare earth and B is from Group II. Unfortunately these materials have only been able to support small transport current densities 1-10 A/cm2. It is very desirable to increase these values by 2 to 3 orders of magnitude for useful high field applications. The reason for these small transport currents is as yet unknown. Evidence has, however, been presented for superconducting clusters on a 50-100 nm scale and on a 1-3 μm scale. We therefore planned a detailed TEM and STEM microanalysis study in order to see whether any evidence for the clusters could be seen.A La1.8Sr0.2Cu04 pellet was cut into 1 mm thick slices from which 3 mm discs were cut. The discs were subsequently mechanically ground to 100 μm total thickness and dimpled to 20 μm thickness at the center.


1998 ◽  
Vol 184-185 (1-2) ◽  
pp. 339-342 ◽  
Author(s):  
L Parthier
Keyword(s):  

1971 ◽  
Vol 32 (C1) ◽  
pp. C1-943-C1-945
Author(s):  
M. W. van TOL ◽  
M. MATSUURA ◽  
N. J. POULIS
Keyword(s):  

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-393-C8-394 ◽  
Author(s):  
S. Miura ◽  
T. Kaneko ◽  
S. Abe ◽  
G. Kido ◽  
H. Yoshida ◽  
...  

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-505-C8-506 ◽  
Author(s):  
J. J. M. Franse ◽  
R. J. Radwaski ◽  
S. Sinnema

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