Dataset Information

Assessment of Rapid Hepatic Glycogen Synthesis in Humans Using Dynamic ¹³C Magnetic Resonance Spectroscopy.

ABSTRACT: Carbon-13 magnetic resonance spectroscopy (MRS) following oral intake of ¹³C-labeled glucose is the gold standard for imaging glycogen metabolism in humans. However, the temporal resolution of previous studies has been >13 minutes. Here, we describe a high-sensitivity ¹³C MRS method for imaging hepatic glycogen synthesis with a temporal resolution of 1 minute or less. Nuclear magnetic resonance spectra were acquired from the liver of 3 healthy volunteers, using a ¹³C clamshell radiofrequency transmit and paddle-shaped array receive coils in a 3 Tesla magnetic resonance imaging system. Following a 15-minute baseline ¹³C MRS scan of the liver, [1-¹³C]-glucose was ingested and ¹³C MRS data were acquired for an additional 1-3 hours. Dynamic change of the hepatic glycogen synthesis level was analyzed by reconstructing the acquired MRS data with temporal resolutions of 30 seconds to 15 minutes. Plasma levels of ¹³C-labeled glucose and lactate were measured using gas chromatography-mass spectrometry. While not detected at baseline ¹³C MRS, [1-¹³C]-labeled ?-glucose and ?-glucose and glycogen peaks accumulated rapidly, beginning as early as ~2 minutes after oral administration of [1-¹³C]-glucose. The [1-¹³C]-glucose signals peaked at ~5 minutes, whereas [1-¹³C]-glycogen peaked at ~25 minutes after [1-¹³C]-glucose ingestion; both signals declined toward baseline levels over the next 1-3 hours. Plasma levels of ¹³C-glucose and ¹³C-lactate rose gradually, and approximately 20% of all plasma glucose and 5% of plasma lactate were ¹³C-labeled by 2 hours after ingestion. Conclusion: We observed rapid accumulation of hepatic [1-¹³C]-glycogen following orally administered [1-¹³C]-glucose, using a dynamic ¹³C MRS method with a temporal resolution of 1 minute or less. Commercially available technology allows high temporal resolution studies of glycogen metabolism in the human liver.

SUBMITTER: Stender S

PROVIDER: S-EPMC7049683 | biostudies-literature | 2020 Mar

REPOSITORIES: biostudies-literature

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Assessment of Rapid Hepatic Glycogen Synthesis in Humans Using Dynamic 13C Magnetic Resonance Spectroscopy.

Stender Stefan S Zaha Vlad G VG Malloy Craig R CR Sudderth Jessica J DeBerardinis Ralph J RJ Park Jae Mo JM

Hepatology communications 20200104 3

Carbon-13 magnetic resonance spectroscopy (MRS) following oral intake of 13C-labeled glucose is the gold standard for imaging glycogen metabolism in humans. However, the temporal resolution of previous studies has been >13 minutes. Here, we describe a high-sensitivity 13C MRS method for imaging hepatic glycogen synthesis with a temporal resolution of 1 minute or less. Nuclear magnetic resonance spectra were acquired from the liver of 3 healthy volunteers, using a 13</s ...[more]

PMID: 32140658

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Project description:Conventional proton MRS has been successfully utilized to noninvasively assess tissue biochemistry in conditions that result in large changes in metabolite levels. For more challenging applications, namely, in conditions which result in subtle metabolite changes, the limitations of vendor-provided MRS protocols are increasingly recognized, especially when used at high fields (≥3 T) where chemical shift displacement errors, B0 and B1 inhomogeneities and limitations in the transmit B1 field become prominent. To overcome the limitations of conventional MRS protocols at 3 and 7 T, the use of advanced MRS methodology, including pulse sequences and adjustment procedures, is recommended. Specifically, the semiadiabatic LASER sequence is recommended when TE values of 25-30 ms are acceptable, and the semiadiabatic SPECIAL sequence is suggested as an alternative when shorter TE values are critical. The magnetic field B0 homogeneity should be optimized and RF pulses should be calibrated for each voxel. Unsuppressed water signal should be acquired for eddy current correction and preferably also for metabolite quantification. Metabolite and water data should be saved in single shots to facilitate phase and frequency alignment and to exclude motion-corrupted shots. Final averaged spectra should be evaluated for SNR, linewidth, water suppression efficiency and the presence of unwanted coherences. Spectra that do not fit predefined quality criteria should be excluded from further analysis. Commercially available tools to acquire all data in consistent anatomical locations are recommended for voxel prescriptions, in particular in longitudinal studies. To enable the larger MRS community to take advantage of these advanced methods, a list of resources for these advanced protocols on the major clinical platforms is provided. Finally, a set of recommendations are provided for vendors to enable development of advanced MRS on standard platforms, including implementation of advanced localization sequences, tools for quality assurance on the scanner, and tools for prospective volume tracking and dynamic linear shim corrections.

Dataset Information

Assessment of Rapid Hepatic Glycogen Synthesis in Humans Using Dynamic ¹³C Magnetic Resonance Spectroscopy.

Publications

Assessment of Rapid Hepatic Glycogen Synthesis in Humans Using Dynamic <sup>13</sup>C Magnetic Resonance Spectroscopy.

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