Optimized radiofrequency coils for increased signal-to-noise ratio in magnetic resonance microscopy

Hurlston, S. E.; Cofer, Gary P.; Johnson, G. Allan

doi:10.1002/(sici)1098-1098(1997)8:3<277::aid-ima5>3.0.co;2-7

Cited by 27 publications

(8 citation statements)

References 7 publications

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“…The coil resistance can be easily derived by accounting for the conducting pathway geometry. For these calculations, we used the classic formula R = L / S, 20 where is the resistivity and L and S are the total conductor length and crosssectional area, respectively.…”

Section: Iid Coil Resistance Estimationmentioning

confidence: 99%

Hyperpolarized MRS surface coil: Design and signal‐to‐noise ratio estimation

et al. 2010

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Section: Iid Coil Resistance Estimationmentioning

confidence: 99%

Hyperpolarized MRS surface coil: Design and signal‐to‐noise ratio estimation

et al. 2010

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“…The shield effect can be simulated by modifying Eqs. [9]- [12] by inserting the terms relevant to the mutual inductance between the coils conductors and their images.…”

Section: Discussionmentioning

confidence: 99%

“…At high RF frequencies, the sample losses become dominant and it happens at clinical fields (>0.5T) (22). However, the behavior of the birdcage coil loaded by biological sample can be modeled by considering sample-induced resistance, estimated as described in literature (9)(10)(11)(12)(13)(14), as part of the resistive loss. After the calculation of loaded Q-factor, the application of Eq.…”

Section: Discussionmentioning

confidence: 99%

Birdcage coils: Equivalent capacitance and equivalent inductance

Giovannetti

2014

Concepts Magn Reson

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Birdcage coil is extensively used in MR systems thanks to its possibility to provide high signal‐to‐ noise ratio and high radiofrequency magnetic field homogeneity that guarantee a large field of view. This work describes how to schematize the birdcage coil in terms of an equivalent inductance and an equivalent capacitance, whose knowledge can be useful for coil design and characterization. In particular, the knowledge of equivalent capacitance and equivalent inductance permits to estimate theoretically coil resonant frequency, quality factors and matching circuit capacitor values in a quick way, while workbench tests permit to estimate coil resistance and sample‐induced resistance. The presented theory is validated for both lowpass and highpass birdcage coils.by using literature data. © 2014 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 44B: 32–38, 2014

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“…Coils resistance can be estimated with the classic formula R coil = ρl/S sup , where l and S sup are the total conductor length and cross-sectional area, respectively. 11 Calculation of resistance for a b radius circular loop constituted by a wire (cylindrical rod shapes) conductor with radius a, can be performed as 6 :…”

Section: Coil Resistance Calculationmentioning

confidence: 99%

Sensitivity estimation in circular and square loops

Giovannetti

2018

Concepts Magnetic Resonance

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Circular and square loops are the simplest design employed as radiofrequency coils for magnetic resonance applications. Being usually much smaller than the volume coils, these loop coils have higher signal‐to‐noise ratio (SNR) because they receive noises only from nearby regions. However, they have a relatively poor field homogeneity and, thus, are mainly used as receive coils. In this work, author describes a coil sensitivity estimation method based on a simulator which permits the characterization of loop coils performance, in terms of magnetic field patterns and coil losses, where this last term including conductor, sample, capacitor, radiative and soldering losses. The evaluation of coil sensitivity for circular and square loops was performed at different tuning frequencies usually used in clinical scanner (21, 64, and 128 MHz) and at different distances respect to the coil plane. Simulation data were acquired for circular loop radius between 0.5 and 4 cm and for square loop side sizes between 1 and 8 cm, with the scope of evaluating the loop sizes which maximize the sensitivity in dependence of the penetration depth in the sample region and therefore to design optimized coils for maximizing SNR in MR applications.

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Optimized radiofrequency coils for increased signal-to-noise ratio in magnetic resonance microscopy

Cited by 27 publications

References 7 publications

Hyperpolarized MRS surface coil: Design and signal‐to‐noise ratio estimation

Hyperpolarized MRS surface coil: Design and signal‐to‐noise ratio estimation

Birdcage coils: Equivalent capacitance and equivalent inductance

Sensitivity estimation in circular and square loops

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