Quantitative sodium MR imaging of native versus transplanted kidneys using a dual-tuned proton/sodium (1H/23Na) coil: initial experience

Moon, Chan Hong; Furlan, Alessandro; Kim, Junghwan; Zhao, Tiejun; Shapiro, Ron; Bae, Kyongtae T.

doi:10.1007/s00330-014-3138-5

Cited by 19 publications

(21 citation statements)

References 26 publications

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“…A higher Q value is positively correlated with a narrower resonance peak. The Q-factor can also be estimated as Q = ωL/R, where ω is the resonance frequency, L is the inductance of the circuit, and R is the resistance (9). A coil circuit is usually designed to increase the Q-factor when the coil is unloaded.…”

Section: Image Analysismentioning

confidence: 99%

Radiofrequency Coil Design for in vivo Sodium Magnetic Resonance Imaging of Mouse Kidney at 9.4T

Lim

Woo

Choe

et al. 2018

Investig Magn Reson Imaging

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The objective of this study was to describe a radiofrequency (RF) coil design for in vivo sodium magnetic resonance imaging (MRI) for use in small animals. Accumulating evidence has indicated the importance and potential of sodium imaging with improved magnet strength (> 7T), faster gradient, better hardware, multi-nucleus imaging methods, and optimal coil design for patient and animal studies. Thus, we developed a saddle-shaped sodium volume coil with a diameter/ length of 30/30 mm. To evaluate the efficiency of this coil, bench-level measurement was performed. Unloaded Q value, loaded Q value, and ratio of these two values were estimated to be 352.8, 211.18, and 1.67, respectively. Thereafter, in vivo acquisition of sodium images was performed using normal mice (12 weeks old; n = 5) with a twodimensional gradient echo sequence and minimized echo time to increase spatial resolution of images. Sodium signal-to-noise ratio in mouse kidneys (renal cortex, medulla, and pelvis) was measured. We successfully acquired sodium MR images of the mouse kidney with high spatial resolution (approximately 0.625 mm) through a combination of sodium-proton coils.

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Section: Image Analysismentioning

confidence: 99%

Radiofrequency Coil Design for in vivo Sodium Magnetic Resonance Imaging of Mouse Kidney at 9.4T

Lim

Woo

Choe

et al. 2018

Investig Magn Reson Imaging

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“…Although a lower corticomedullary sodium gradient has been demonstrated in kidney allografts in comparison to native kidneys, sodium imaging has neither been able to reflect kidney function in kidney transplantation patients (Moon et al, 2014), nor in healthy individuals with a variety of eGFRs (Haneder et al, 2013), and is therefore not discussed in detail. However, it must be pointed out that preliminary experimental results in other kidney disease states, such as acute tubular necrosis, have shown changes in sodium imaging (Maril et al, 2006; Atthe et al, 2009), Similar to sodium MRI, hemodynamic response imaging has only been applied in experimental settings in animals thus far (Milman et al, 2013, 2014) .…”

Section: Conventional Vs Functional Mri For the Assessment Of Subclimentioning

confidence: 99%

Innovative Perspective: Gadolinium-Free Magnetic Resonance Imaging in Long-Term Follow-Up after Kidney Transplantation

et al. 2017

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Since the mid-1980s magnetic resonance imaging (MRI) has been investigated as a non- or minimally invasive tool to probe kidney allograft function. Despite this long-standing interest, MRI still plays a subordinate role in daily practice of transplantation nephrology. With the introduction of new functional MRI techniques, administration of exogenous gadolinium-based contrast agents has often become unnecessary and true non-invasive assessment of allograft function has become possible. This raises the question why application of MRI in the follow-up of kidney transplantation remains restricted, despite promising results. Current literature on kidney allograft MRI is mainly focused on assessment of (sub) acute kidney injury after transplantation. The aim of this review is to survey whether MRI can provide valuable diagnostic information beyond 1 year after kidney transplantation from a mechanistic point of view. The driving force behind chronic allograft nephropathy is believed to be chronic hypoxia. Based on this, techniques that visualize kidney perfusion and oxygenation, scarring, and parenchymal inflammation deserve special interest. We propose that functional MRI mechanistically provides tools for diagnostic work-up in long-term follow-up of kidney allografts.

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“…The large loops allow the coils to penetrate deeper into the body, and the quadrature orientation of the two loops achieved better efficiency than a single coil alone, reducing the required transmit voltages and improving the signal‐to‐noise ratio (SNR) performance. A custom‐built dual‐resonant (sodium/hydrogen) coil consisting of a central linear sodium loop (long axis, 18 cm) and a surrounding sodium butterfly loop (Springer and European Radiology, 24, 2014, 1320–1326, Quantitative sodium MR imaging of native versus transplanted kidneys using a dual‐tuned proton/sodium (1H/23Na) coil: initial experience, Moon CH, Furlan A, Kim JH, Zhao T, Shapiro R, Bae KT. Figures and .…”

Section: Sodium Imaging For Body Applications: Coil Topologiesmentioning

confidence: 99%

“…Figure c shows a custom dual‐resonant (sodium/hydrogen) coil consisting of a central linear sodium loop that is decoupled from a surrounding sodium butterfly loop . On the opposite side of the structure is a similar configuration with a linear proton loop and surrounding proton butterfly loop.…”

Section: Sodium Imaging For Body Applications: Coil Topologiesmentioning

confidence: 99%

“…Phased array coils typically require a separate (preferably homogeneous) coil for transmit. Transmit coils may include birdcage coils or a large surface coil that surrounds the array . Transmit‐only coils require the coil to be tuned during the high transmit RF voltages and detuned during receive with an array and, although some systems are enabled for large negative dc biases , the most common technique for non‐proton transmit‐only coils is the use of serial diodes that are forward biased during transmit and unbiased during receive, to create a low and high impedance, respectively, in the coil .…”

Section: Sodium Imaging For Body Applications: Coil Topologiesmentioning

confidence: 99%

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Sodium MRI radiofrequency coils for body imaging

et al. 2015

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The proliferation of high-field whole-body systems, advances in gradient performance and refinement of signal-to-noise ratio (SNR)-efficient short-TE sequences suitable for sodium imaging have led to a resurgence of interest in sodium imaging for body applications. With this renewed interest has come increased demand for SNR-efficient sodium coils. Efficient coils can significantly increase SNR in sodium imaging, allowing higher resolutions and/or shorter scan times. In this work, we focus on body imaging applications of sodium MRI, and review developments in MRI radiofrequency (RF) coil topologies for sodium imaging. We first provide a brief discussion of RF coil design considerations in sodium imaging. This is followed by an overview of common coil topologies, their advantages and disadvantages, and examples of each.

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Quantitative sodium MR imaging of native versus transplanted kidneys using a dual-tuned proton/sodium (1H/23Na) coil: initial experience

Cited by 19 publications

References 26 publications

Radiofrequency Coil Design for in vivo Sodium Magnetic Resonance Imaging of Mouse Kidney at 9.4T

Radiofrequency Coil Design for in vivo Sodium Magnetic Resonance Imaging of Mouse Kidney at 9.4T

Innovative Perspective: Gadolinium-Free Magnetic Resonance Imaging in Long-Term Follow-Up after Kidney Transplantation

Sodium MRI radiofrequency coils for body imaging

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