Degenerate mode birdcage volume coil for sensitivity‐encoded imaging

Lin, Fa‐Hsuan; Kwong, Kenneth K.; Huang, Ing-Jye; Belliveau, John W.; Wald, Lawrence L.

doi:10.1002/mrm.10632

Cited by 17 publications

(21 citation statements)

References 11 publications

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“…Most of the commonly used designs, such as the birdcage (1) and phased array coils (2), were developed well before the advent of parallel MRI. Some of these coils have been recently adapted for use in parallel imaging (3)(4)(5)(6)(7)(8)(9). In this article, we present a method for devising new coils with designer field profiles and apply it specifically to three examples with parallel MRI in mind.…”

Section: Introductionmentioning

confidence: 98%

Designer RF field profiles for parallel imaging applications

Willig-Onwuachi

Eagan

Shvàrtsman

et al. 2005

Concepts Magn. Reson.

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A method for designing specific nonuniform B 1 magnetic field patterns within a given coil volume is presented. This technique is applied to produce field patterns relevant to parallel MRI detector coils but could be applied more generally. Results that are particularly applicable to both SENSE and SMASH imaging are derived. A cylindrical geometry has been used for the application described here, but any geometry could be used in principle. The designer field of interest for the SMASH case is one that varies like sin(x). The basic approach for the SMASH coil derives coefficients for harmonics of the common sin() current distribution. The designer field used for the example SENSE coil is one that has a sharp spatial cutoff. The general technique used for the SENSE coil example is essentially a target field approach similar to that used for gradient coil design. The approach described herein is appropriate at low B 0 field strengths, when one can use quasi-static approximations for the field behavior.

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Section: Introductionmentioning

confidence: 98%

Designer RF field profiles for parallel imaging applications

Willig-Onwuachi

Eagan

Shvàrtsman

et al. 2005

Concepts Magn. Reson.

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“…Although RF coil arrays [2,3,4,5,6,7,8,9,10,11,12,13] have become more and more popular in MRI applications and essential to parallel transmission [14,15,16,17,18] and parallel imaging [19,20,21,22,23,24,25,26] to shorten the imaging time, RF volume coils still play an important role in MR signal excitation and reception for applications using regular MR methodology [27,28,29,30,31,32,33,34,35,36,37,38,39,40] and also parallel imaging [41,42]. Normally, a multimodal volume coil with N rungs or struts resonates at N /2 intrinsic modes [1,43,44,45] or N /2 + 1 modes [46,47].…”

Section: Introductionmentioning

confidence: 99%

Resonant Mode Reduction in Radiofrequency Volume Coils for Ultrahigh Field Magnetic Resonance Imaging

Pang

Xie

et al. 2011

Materials

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In a multimodal volume coil, only one mode can generate homogeneous Radiofrequency (RF) field for Magnetic Resonance Imaging. The existence of other modes may increase the volume coil design difficulties and potentially decreases coil performance. In this study, we introduce common-mode resonator technique to high and ultrahigh field volume coil designs to reduce the resonant mode while maintain the homogeneity of the RF field. To investigate the design method, the common-mode resonator was realized by using a microstrip line which was split along the central to become a pair of parallel transmission lines within which common-mode currents exist. Eight common-mode resonators were placed equidistantly along the circumference of a low loss dielectric cylinder to form a volume coil. Theoretical analysis and comparison between the 16-strut common-mode volume coil and a conventional 16-strut volume coil in terms of RF field homogeneity and efficiency was performed using Finite-Difference Time-Domain (FDTD) method at 298.2 MHz. MR imaging experiments were performed by using a prototype of the common-mode volume coil on a whole body 7 Tesla scanner. FDTD simulation results showed the reduced number of resonant modes of the common-mode volume coil over the conventional volume coil, while the RF field homogeneity of the two type volume coils was kept at the same level. MR imaging of a water phantom and a kiwi fruit showing the feasibility of the proposed method for simplifying the volume coil design is also presented.

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“…Due to spatially different sensitivity profiles of each mode, these modes have potential for parallel imaging. The standard homogeneous mode (first mode) and the first gradient mode (second mode) of an eight-rung low pass birdcage coil have been applied for SENSE imaging at 1.5 T successfully [9], and 2-fold acceleration was achieved with the average g-factor of 1.55.…”

Section: Introductionmentioning

confidence: 99%