Quantitative spectroscopic imaging of the human brain

Pan, Jullie W.; Twieg, Donald B.; Hetherington, Hoby P.

doi:10.1002/mrm.1910400305

Cited by 88 publications

(104 citation statements)

References 17 publications

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“…The absence of effect on the transmission efficiency also supports the effectiveness of the detuning network. We also evaluated the effectiveness of the phased array detuning by acquiring B 1 maps on a human head at the 1 H frequency with and without phased array inserted (25). Both maps were very practically the same and for that reason are not shown.…”

Section: Design Of the Rf Coils And Evaluation Proceduresmentioning

confidence: 99%

4T Actively detuneable double-tuned 1H/31P head volume coil and four-channel 31P phased array for human brain spectroscopy

Avdievich

Hetherington

2007

Journal of Magnetic Resonance

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Typically 31 P in vivo magnetic resonance spectroscopic studies are limited by SNR considerations. Although phased arrays can improve the SNR; to date 31 P phased arrays for high-field systems have not been combined with 31 P volume transmit coils. Additionally, to provide anatomical reference for the 31 P studies, without removal of the coil or patient from the magnet, double-tuning ( 31 P/ 1 H) of the volume coil is required. In this work we describe a series of methods for active detuning and decoupling enabling use of phased arrays with double-tuned volume coils. To demonstrate these principles we have built and characterized an actively detuneable 31 P/ 1 H TEM volume transmit/ fourchannel 31 P phased array for 4 T magnetic resonance spectroscopic imaging (MRSI) of the human brain. The coil can be used either in volume-transmit/array-receive mode or in TEM transmit/receive mode with the array detuned. Three-fold SNR improvement was obtained at the periphery of the brain using the phased array as compared to the volume coil.

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Section: Design Of the Rf Coils And Evaluation Proceduresmentioning

confidence: 99%

4T Actively detuneable double-tuned 1H/31P head volume coil and four-channel 31P phased array for human brain spectroscopy

Avdievich

Hetherington

2007

Journal of Magnetic Resonance

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“…[NAA] GM and [NAA] WM represent the NAA concentrations in gray (9.9 mmol/L) and white matter (10.5 mmol/L), respectively (Hetherington et al, 1996;Pan et al, 1998;Pouwels and Frahm, 1998). The glucose concentration in gray and white matter is obtained according to (Kusmierz et al, 1989).…”

Section: Magnetic Resonance Imaging and Spectroscopymentioning

confidence: 99%

Differentiation of Glucose Transport in Human Brain Gray and White Matter

Graaf

Pan

Telang

et al. 2001

J Cereb Blood Flow Metab

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Summary:Localized 1 H nuclear magnetic resonance spectroscopy has been applied to determine human brain gray matter and white matter glucose transport kinetics by measuring the steady-state glucose concentration under normoglycemia and two levels of hyperglycemia. Nuclear magnetic resonance spectroscopic measurements were simultaneously performed on three 12-mL volumes, containing predominantly gray or white matter. The exact volume compositions were determined from quantitative T 1 relaxation magnetic resonance images. The absolute brain glucose concentration as a function of the plasma glucose level was fitted with two kinetic transport models, based on standard (irreversible) or reversible MichaelisMenten kinetics. The steady-state brain glucose levels were similar for cerebral gray and white matter, although the white matter levels were consistently 15% to 20% higher. The ratio of the maximum glucose transport rate, V max , to the cerebral metabolic utilization rate of glucose, CMR Glc , was 3.2 ± 0.10 and 3.9 ± 0.15 for gray matter and white matter using the standard transport model and 1.8 ± 0.10 and 2.2 ± 0.12 for gray matter and white matter using the reversible transport model. The Michaelis-Menten constant K m was 6.2 ± 0.85 and 7.3 ± 1.1 mmol/L for gray matter and white matter in the standard model and 1.1 ± 0.66 and 1.7 ± 0.88 mmol/L in the reversible model. Taking into account the threefold lower rate of CMR Glc in white matter, this finding suggests that blood-brain barrier glucose transport activity is lower by a similar amount in white matter. The regulation of glucose transport activity at the blood-brain barrier may be an important mechanism for maintaining glucose homeostasis throughout the cerebral cortex.

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“…CSF water was used as the standard to normalize the spectroscopy data. 36 Integrated intensities of the three singlet peaks were corrected for coil loading, receiver gain, and normalized to the mean proton density MRI intensity of four CSF regions of interest (ROI). The CSF ROI's were positioned entirely within the lateral ventricles of a proton density image that was acquired during the same session as the spectroscopy data.…”

Section: Spectral Analysismentioning

confidence: 99%

1H MRSI comparison of white matter and lesions in primary progressive and relapsing-remitting MS

et al. 2000

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Objective-To compare brain metabolite levels in patients with primary progressive (PP) and relapsing remitting (RR) MS and controls. Hypotheses: (1) creatine (Cr), a putative marker of gliosis, is elevated and N-acetylaspartate (NAA), a putative marker of axonal density and functional integrity, is reduced in PPMS lesions and normal appearing white matter (NAWM) compared to control white matter; (2) The pattern of metabolite change in PPMS is different than in RRMS.Methods-MRI and proton magnetic resonance spectroscopic imaging ( 1 H MRSI) were collected from 15 PPMS patients, 13 RRMS patients, and 20 controls.Results-Cr was increased in PPMS NAWM compared to controls (P=0.035), and compared to RRMS NAWM (P=0.038). Cr was increased in focal MRI lesions from PPMS compared to lesions from RRMS (P=0.044) and compared to control white matter (P=0.041). NAA was similarly reduced in PPMS and RRMS NAWM compared to control. NAA was similarly reduced in PPMS and RRMS lesions, compared to control white matter.Conclusions-Creatine is higher in PPMS than RRMS NAWM and focal lesions. This observation is consistent with the notion that progressive disability in PPMS reflects increased gliosis and axonal loss whereas disability in RRMS reflects the cumulative effects of acute inflammatory lesions and axonal loss.

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Quantitative spectroscopic imaging of the human brain

Cited by 88 publications

References 17 publications

4T Actively detuneable double-tuned 1H/31P head volume coil and four-channel 31P phased array for human brain spectroscopy

4T Actively detuneable double-tuned 1H/31P head volume coil and four-channel 31P phased array for human brain spectroscopy

Differentiation of Glucose Transport in Human Brain Gray and White Matter

1H MRSI comparison of white matter and lesions in primary progressive and relapsing-remitting MS

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