Comparison of four 31P single‐voxel MRS sequences in the human brain at 9.4 T

Dorst, Johanna; Ruhm, Loreen; Avdievich, NI; Bogner, Wolfgang; Henning, A

doi:10.1002/mrm.28658

Cited by 12 publications

(35 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Signal contribution from outside this region appears to be very small, including the peripheral regions covering the connective tissues and skull (closer to the RF coil, likely with larger B1) and the deep brain region covering the subcortical and frontal tissues (further away from the RF coil, likely with smaller B1). It is estimated that the coil-sensitive volume within the brain posterior is $ 150 mL, comparable with a volume of 125 mL (or 5 x 5 x 5 cm 3 ) selected by an ISIS sequence in the same region using a surface coil mode, as reported by Dorst et al 34 One may anticipate a larger coil-sensitive region with less B1 variation by using an AHP pulse or even the standard Philips spredrex (sinc)…”

Section: Signal Origin and Measurement Issuesmentioning

confidence: 66%

“…pulse, likely at the cost of SNR (Figure S3). Further work may be needed to explore the feasibility of using a localized sequence (such as optimized SV-ISIS 34 ), because developing the capability of detecting from a specific tissue and volume is of great value for certain clinical applications.…”

Section: Signal Origin and Measurement Issuesmentioning

confidence: 99%

“…While the exact origin is not clear, it may be a mixture of acquisition artefact and background signals from sources such as the residual magnetization of the skull and membrane phospholipids, 35,36 various less mobile nucleotide species bound to membranes and immobile cellular structures, 37,38 and macromolecules containing diphosphate moieties (such as poly [ADP-ribose] and its derivatives with histones, synthesized from NAD + substrate). 39 Baseline artifact from imperfect datapoints at the beginning of time-domain FID signal may be corrected, in principle, by proper linear prediction, 34 or reduced by delayed FID sampling, or eliminated by excitation with AHP or alike pulses (Figure S3).…”

Section: Signal Origin and Measurement Issuesmentioning

confidence: 99%

See 2 more Smart Citations

³¹P‐MRS of healthy human brain: Measurement of guanosine diphosphate mannose at 7 T

Ren

Sherry

2021

NMR in Biomedicine

View full text Add to dashboard Cite

Guanosine diphosphate mannose (GDP-Man) is the donor substrate required for mannosylation in the synthesis of glycoproteins, glycolipids and the newly discovered glycoRNA. Normal GDP-Man biosynthesis plays a crucial role in support of a variety of cellular functions, including cell recognition, cell communication and immune responses against viruses. Here, we report the detection of GDP-Man in human brain for the first time, using 31 P MRS at 7 T. The presence of GDP-Man is evidenced by the detection of a weak 31 P doublet at À10.7 ppm that can be assigned to the phosphomannosyl group (Pβ) of the GDP-Man molecule. This weak but well-resolved signal lies 0.9 ppm upfield of UDP(G) Pβ-multiplet from a mixture of UDP-Glc, UDP-Gal, UDP-GlcNAc and UDP-GalNAc. In reference to ATP (2.8 mM), the concentration of GDP-Man in human brain was estimated to be 0.02 ± 0.01 mM, about 15-fold lower than the total concentration of UDP(G) (0.30 ± 0.04, N = 17) and consistent with previous reports of UDP-Man in cells and brain tissue extracts measured by highperformance liquid chromatography. The reproducibility of the measured GDP-Man between test and 2-week retest was 21% ± 15% compared with 5% ± 4% for UDP(G) (N = 7). The measured concentrations of GDP-Man and UDP(G) are linearly correlated ([UDP(G)] = 4.3 [GDP-Man] + 0.02, with R = 0.66 and p = 0.0043), likely reflecting the effect of shared sugar precursors, which may vary among individuals in response to variation in nutritional intake and consumption. Given that GDP-Man has another set of doublet (Pα) at À8.3 ppm that overlaps with NAD(H) and UDP(G)-Pα signals, the amount of GDP-Man could potentially interfere with the deconvolution of these mixed signals in composition analysis. Importantly, this new finding may be useful in advancing our understanding of glycosylation and its role in the development of cancer, as well as infectious and neurodegenerative diseases.

show abstract

Section: Signal Origin and Measurement Issuesmentioning

confidence: 66%

Section: Signal Origin and Measurement Issuesmentioning

confidence: 99%

Section: Signal Origin and Measurement Issuesmentioning

confidence: 99%

See 1 more Smart Citation

³¹P‐MRS of healthy human brain: Measurement of guanosine diphosphate mannose at 7 T

Ren

Sherry

2021

NMR in Biomedicine

View full text Add to dashboard Cite

show abstract

“…All data were acquired at a 9.4 T whole-body MRI scanner (Siemens, Erlangen, Germany) using a home-built double-tuned 20-loop 31 P/ 1 H head array 26 . To increase B 1 + for 31 P single-voxel spectroscopy in the occipital lobe, the entire RF power was applied only to the three bottom surface coil elements using an unbalanced three-way Wilkinson power splitter, as described recently 24 .…”

Section: Methodsmentioning

confidence: 99%

“…The primary goal of this study was to demonstrate a method to measure 31 P T 2 relaxation times of J-coupled metabolites without frequency-selective refocusing or homonuclear decoupling, as was done in previous studies 24,25 . Therefore, TE series spectra over a broad frequency range were acquired with a stimulated echo acquisition mode (STEAM) localization sequence optimized in a previous study 24 entailing a high SNR per unit of time, which is a critical factor for T 2 measurements. J-modulation of the 31 P metabolites was then considered in the fitting routine using Vespa in combination with LCModel 20,21 .…”

Section: Introductionmentioning

confidence: 99%

³¹P Transversal Relaxation Times and Metabolite Concentrations in the Human Brain at 9.4T

Dorst

Borbáth

Ruhm

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

A method to estimate phosphorus (31P) transversal relaxation times (T2) of coupled spin systems is demonstrated. Additionally, intracellular and extracellular pH (pHext, pHint) and relaxation corrected metabolite concentrations are reported. Echo time (TE) series of 31P metabolite spectra were acquired using STEAM localization. Spectra were fitted using LCModel with accurately modeled Vespa basis sets accounting for J−evolution of the coupled spin systems. T2s were estimated by fitting a single exponential two−parameter model across the TE series. Fitted inorganic phosphate frequencies were used to calculate pH, and relaxation times were used to determine the brain metabolite concentrations. The method was demonstrated in the healthy human brain at a field strength of 9.4T. T2 relaxation times of ATP and NAD are the shortest between 8 ms and 20 ms, followed by T2s of inorganic phosphate between 25 ms and 50 ms, and PCr with a T2 of 100 ms. Phosphomonoesters and −diesters have the longest T2s of about 130 ms. Measured T2s are comparable to literature values and fit in a decreasing trend with increasing field strengths. Calculated pHs and metabolite concentrations are also comparable to literature values

show abstract

Phosphorus transversal relaxation times and metabolite concentrations in the human brain at 9.4 T

et al. 2022

Self Cite

View full text Add to dashboard Cite

A method to estimate phosphorus ( 31 P) transversal relaxation times (T 2 s) of coupled spin systems is demonstrated. Additionally, intracellular and extracellular pH and relaxation-corrected metabolite concentrations are reported. Echo time (TE) series of 31 P metabolite spectra were acquired using stimulated echo acquisition mode (STEAM) localization. Spectra were fitted using LCModel with accurately modeled Versatile Simulation, Pulses and Analysis (VeSPA) basis sets accounting for J-evolution of the coupled spin systems. T 2 s were estimated by fitting a single exponential twoparameter model across the TE series. Fitted inorganic phosphate frequencies were used to calculate pH, and estimated relaxation times were used to determine the relaxation-corrected brain metabolite concentrations on an assumption of 3 mM γ-ATP. The method was demonstrated in healthy human brain at a field strength of 9.4 T. T 2 times of ATP and nicotinamide adenine dinucleotide (NAD) were shortest between 8 and 20 ms, followed by T 2 s of inorganic phosphate between 25 and 50 ms, and phosphocreatine with a T 2 of 100 ms. Phosphomonoesters and phosphodiesters had the longest T 2 s of about 130 ms. The measured T 2 s are comparable with literature values and fit in a decreasing trend with increasing field strengths. Calculated pHs and metabolite concentrations are also comparable with literature values.

show abstract

Comparison of four 31P single‐voxel MRS sequences in the human brain at 9.4 T

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 12 publications

References 70 publications

³¹P‐MRS of healthy human brain: Measurement of guanosine diphosphate mannose at 7 T

³¹P‐MRS of healthy human brain: Measurement of guanosine diphosphate mannose at 7 T

³¹P Transversal Relaxation Times and Metabolite Concentrations in the Human Brain at 9.4T

Phosphorus transversal relaxation times and metabolite concentrations in the human brain at 9.4 T

Contact Info

Product

Resources

About

Comparison of four 31P single‐voxel MRS sequences in the human brain at 9.4 T

Abstract: This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Cited by 12 publications

References 70 publications

31P‐MRS of healthy human brain: Measurement of guanosine diphosphate mannose at 7 T

31P‐MRS of healthy human brain: Measurement of guanosine diphosphate mannose at 7 T

31P Transversal Relaxation Times and Metabolite Concentrations in the Human Brain at 9.4T

Phosphorus transversal relaxation times and metabolite concentrations in the human brain at 9.4 T

Contact Info

Product

Resources

About

³¹P‐MRS of healthy human brain: Measurement of guanosine diphosphate mannose at 7 T

³¹P‐MRS of healthy human brain: Measurement of guanosine diphosphate mannose at 7 T

³¹P Transversal Relaxation Times and Metabolite Concentrations in the Human Brain at 9.4T