A form‐fitted three channel <sup>31</sup>P, two channel <sup>1</sup>H transceiver coil array for calf muscle studies at 7 <scp>T</scp>

Goluch, Sigrun; Kuehne, André; Meyerspeer, Martin; Kriegl, Roberta; Schmid, A.; Fiedler, G.; Herrmann, Tim; Mallow, Johannes; Hong, Seok-In; Cho, Zang-Hee; Bernarding, Johannes; Moser, Ewald; Laistler, Elmar

doi:10.1002/mrm.25339

Cited by 43 publications

(41 citation statements)

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“…Therefore, none of these possibilities constitutes a good option for dynamic examinations. Alternatively, it is possible to compensate for the B 1 + inhomogeneity of a surface coil by acquiring a map of the actual flip angle distribution, as was performed in this study using the method of Chmelík et al37 The use of RF coils with a more homogeneous B 1 + distribution29, 51 would also be beneficial.…”

Section: Discussionmentioning

confidence: 99%

Dynamic ³¹P–MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T

et al. 2016

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Phosphorus MRSI (31P–MRSI) using a spiral‐trajectory readout at 7 T was developed for high temporal resolution mapping of the mitochondrial capacity of exercising human skeletal muscle.The sensitivity and localization accuracy of the method was investigated in phantoms. In vivo performance was assessed in 12 volunteers, who performed a plantar flexion exercise inside a whole‐body 7 T MR scanner using an MR‐compatible ergometer and a surface coil. In five volunteers the knee was flexed (~60°) to shift the major workload from the gastrocnemii to the soleus muscle.Spiral‐encoded MRSI provided 16–25 times faster mapping with a better point spread function than elliptical phase‐encoded MRSI with the same matrix size. The inevitable trade‐off for the increased temporal resolution was a reduced signal‐to‐noise ratio, but this was acceptable. The phosphocreatine (PCr) depletion caused by exercise at 0° knee angulation was significantly higher in both gastrocnemii than in the soleus (i.e. 64.8 ± 19.6% and 65.9 ± 23.6% in gastrocnemius lateralis and medialis versus 15.3 ± 8.4% in the soleus).Spiral‐encoded 31P–MRSI is a powerful tool for dynamic mapping of exercising muscle oxidative metabolism, including localized assessment of PCr concentrations, pH and maximal oxidative flux with high temporal and spatial resolution.

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Section: Discussionmentioning

confidence: 99%

Dynamic ³¹P–MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T

et al. 2016

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“…Therefore, we used an oblique slab position trying to stay parallel to the coil as much as possible, but still in the gastrocnemius muscle. A more homogeneous B 1 + coverage could be achieved using a volume coil , an array of RF coils or simply a larger surface coil . This would be especially beneficial for human subjects with large layers of subcutaneous fat, which acts as a pad or cushion between the muscle and the coil .…”

Section: Discussionmentioning

confidence: 99%

Feasibility and repeatability of localized ³¹P‐MRS four‐angle saturation transfer (FAST) of the human gastrocnemius muscle using a surface coil at 7 T

et al. 2015

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Phosphorus (31P) MRS, combined with saturation transfer (ST), provides non‐invasive insight into muscle energy metabolism. However, even at 7 T, the standard ST method with T 1 app measured by inversion recovery takes about 10 min, making it impractical for dynamic examinations. An alternative method, i.e. four‐angle saturation transfer (FAST), can shorten the examination time. The aim of this study was to test the feasibility, repeatability, and possible time resolution of the localized FAST technique measurement on an ultra‐high‐field MR system, to accelerate the measurement of both Pi‐to‐ATP and PCr‐to‐ATP reaction rates in the human gastrocnemius muscle and to test the feasibility of using the FAST method for dynamic measurements.We measured the exchange rates and metabolic fluxes in the gastrocnemius muscle of eight healthy subjects at 7 T with the depth‐resolved surface coil MRS (DRESS)‐localized FAST method. For comparison, a standard ST localized method was also used. The measurement time for the localized FAST experiment was 3.5 min compared with the 10 min for the standard localized ST experiment. In addition, in five healthy volunteers, Pi‐to‐ATP and PCr‐to‐ATP metabolic fluxes were measured in the gastrocnemius muscle at rest and during plantar flexion by the DRESS‐localized FAST method.The repeatability of PCr‐to‐ATP and Pi‐to‐ATP exchange rate constants, determined by the slab‐selective localized FAST method at 7 T, is high, as the coefficients of variation remained below 20%, and the results of the exchange rates measured with the FAST method are comparable to those measured with standard ST.During physical activity, the PCr‐to‐ATP metabolic flux decreased (from F CK = 8.21 ± 1.15 mM s−1 to F CK = 3.86 ± 1.38 mM s−1) and the Pi‐to‐ATP flux increased (from F ATP = 0.43 ± 0.14 mM s−1 to F ATP = 0.74 ± 0.13 mM s−1).In conclusion, we could demonstrate that measurements in the gastrocnemius muscle are feasible at rest and are short enough to be used during exercise with the DRESS‐localized FAST method at 7 T. © 2015 The Authors. NMR in Biomedicine published by John Wiley & Sons Ltd.

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“…To compensate for the low sensitivity of MR systems to 31 P, surface coils that offer very high sensitivity in their close vicinity are often applied for organ-specific 31 P-MR investigations [17], [18], [19], [20]. These are commonly constructed as simple single loops; however, several complex coil-arrays that provide higher sensitivity and better volume coverage have been introduced recently [21], [22], [23], [24]. While the receive sensitivity of such RF-probes is undoubtedly superior, their transmit efficiency, particularly at ultra-high fields, may be insufficient [23], [25].…”

Section: Introductionmentioning

confidence: 99%

In-vivo 31P-MRS of skeletal muscle and liver: A way for non-invasive assessment of their metabolism

Valkovič

Chmelík

Krššák

2017

Analytical Biochemistry

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In addition to direct assessment of high energy phosphorus containing metabolite content within tissues, phosphorus magnetic resonance spectroscopy (31P-MRS) provides options to measure phospholipid metabolites and cellular pH, as well as the kinetics of chemical reactions of energy metabolism in vivo. Even though the great potential of 31P-MR was recognized over 30 years ago, modern MR systems, as well as new, dedicated hardware and measurement techniques provide further opportunities for research of human biochemistry. This paper presents a methodological overview of the 31P-MR techniques that can be used for basic, physiological, or clinical research of human skeletal muscle and liver in vivo. Practical issues of 31P-MRS experiments and examples of potential applications are also provided. As signal localization is essential for liver 31P-MRS and is important for dynamic muscle examinations as well, typical localization strategies for 31P-MR are also described.

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A form‐fitted three channel ³¹P, two channel ¹H transceiver coil array for calf muscle studies at 7 T

Cited by 43 publications

References 61 publications

Dynamic ³¹P–MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T

Dynamic ³¹P–MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T

Feasibility and repeatability of localized ³¹P‐MRS four‐angle saturation transfer (FAST) of the human gastrocnemius muscle using a surface coil at 7 T

In-vivo 31P-MRS of skeletal muscle and liver: A way for non-invasive assessment of their metabolism

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A form‐fitted three channel 31P, two channel 1H transceiver coil array for calf muscle studies at 7 T

Cited by 43 publications

References 61 publications

Dynamic 31P–MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T

Dynamic 31P–MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T

Feasibility and repeatability of localized 31P‐MRS four‐angle saturation transfer (FAST) of the human gastrocnemius muscle using a surface coil at 7 T

In-vivo 31P-MRS of skeletal muscle and liver: A way for non-invasive assessment of their metabolism

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A form‐fitted three channel ³¹P, two channel ¹H transceiver coil array for calf muscle studies at 7 T

Dynamic ³¹P–MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T

Dynamic ³¹P–MRSI using spiral spectroscopic imaging can map mitochondrial capacity in muscles of the human calf during plantar flexion exercise at 7 T

Feasibility and repeatability of localized ³¹P‐MRS four‐angle saturation transfer (FAST) of the human gastrocnemius muscle using a surface coil at 7 T