Practical design of a 4 Tesla double-tuned RF surface coil for interleaved 1H and 23Na MRI of rat brain

Alecci, Marcello; Romanzetti, Sandro; Kaffanke, J.; Celik, Avdo; Wegener, Hans Peter; Shah, N. Jon

doi:10.1016/j.jmr.2006.04.011

Cited by 75 publications

(116 citation statements)

References 26 publications

(66 reference statements)

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“…The circuit design described in the paper produced a significant improvement in achievable in vivo SNR compared to the current state-of-the art design [20] by specifically separating and ensuring optimal decoupling between the 1 H and 23 Na channels. The design also benefits from an ability to independently tune and match each channel, thereby ensuring that an optimal sensitivity is achieved for each sample imaged.…”

Section: Discussionmentioning

confidence: 99%

“…where S and N are the mean signal amplitude in a central region of interest (ROI) and the mean noise in a background ROI, respectively [20].…”

Section: (Equation 3)mentioning

confidence: 99%

“…As a result, deriving a meaningful conclusion from such low resolution data in recently published studies has proved difficult [1,18,19]. Attempts have been made to improve the achievable SNR in 23 Na-MRI by developing optimal radiofrequency resonators [20], although it is clear that higher spatial-temporal resolution is required if 23 Na-MRI is to realize its considerable potential in in vivo studies.…”

Section: Introductionmentioning

confidence: 99%

“…The second approach, the transformer-coupled design [23], achieves the double-tuned state through two physically separated, but strongly coupled resonance structures, which are both tuned to the same resonance frequency [24] or each to one of the target frequencies [20] prior to resonator coupling. In the latter case, blocking circuits [20] are required to limit the lower resonance mode to only a single resonator and to create two ports for the measurement of the two separate frequency signals.…”

Section: Introductionmentioning

confidence: 99%

“…In the latter case, blocking circuits [20] are required to limit the lower resonance mode to only a single resonator and to create two ports for the measurement of the two separate frequency signals. An inductively-coupled 31 P/ 1 H surface coil was designed using this principle [24], however, the connection of two coaxial cables without interference on the higher frequency channel is extremely difficult using this resonator design, which invariably lowers the achievable SNR.…”

Section: Introductionmentioning

confidence: 99%

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The design of a double-tuned two-port surface resonator and its application to in vivo Hydrogen- and Sodium-MRI

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et al. 2012

Journal of Magnetic Resonance

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The design and construction of a two-port surface transceiver resonator for both 1 H-and 23 Na-MRI in the rodent brain at 7T is described. Double-tuned resonators are required for accurately co-registering multi-nuclei data sets, especially when the time courses of 1 H and 23 Na signals are of interest as, for instance, when investigating the pathological progression of ischaemic stroke tissue in vivo. In the current study, a single-element two-port surface resonator was developed wherein both frequency components were measured with the same detector element but with each frequency signal routed along different output channels.This was achieved by using the null spot technique, allowing for optimal variable tuning and matching of each channel in situ within the MRI scanner. The 23 Na signal to noise ratio, measured in the ventricles of the rat brain, was increased by a factor of four compared to recent state-of-the-art rat brain studies reported in the literature. The resonator's performance was demonstrated in an in vivo rodent stroke model, where regional variations in 1 H apparent diffusion coefficient maps and the 23 Na signal were recorded in an interleaved fashion as a function of time in the acute phase of the stroke without having to exchange, re-adjust, or re-connect resonators between scans. Using the practical construction steps described in this paper, this coil design.

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Section: Discussionmentioning

confidence: 99%

“…where S and N are the mean signal amplitude in a central region of interest (ROI) and the mean noise in a background ROI, respectively [20].…”

Section: (Equation 3)mentioning

confidence: 99%