Improvement of T1 Determination of Hyperpolarized 129Xe in Mouse Brain under Controlled-Flow

Kimura, Atsuomi; Wakayama, Teruhiko; Narazaki, Michiko; Kawata, Yoko; Ueyama, Takeshi; Fujiwara, Hideaki

doi:10.2463/mrms.3.199

Cited by 6 publications

(9 citation statements)

References 15 publications

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“…T 1i measured in rats have ranged widely from 3.6 to 26 s and T 1i in humans was reported as 8 s for white matter and 14 s for gray matter . In our own work, T 1i measured in mouse brain was reported as 14.1 ± 1.6 s (± standard deviation (SD; n = 9) .…”

Section: Introductionmentioning

confidence: 61%

“…The origin of the peaks at around 198 ppm and 202 ppm are still unknown at present and needs to be determined in the future. To the authors' knowledge, the peak at around 210 ppm, which was identified as dissolved HP 129 Xe in the blood , has never been observed for mice .…”

Section: Resultsmentioning

confidence: 83%

“…In the present study, we derived a model suitable for analyzing the dynamics of HP 129 Xe in brain tissue on the same basis as that described in . Assuming that the Xe concentration in the alveoli has reached a steady state due to continuous HP 129 Xe ventilation, according to Fick's principle, the change of HP 129 Xe concentration in the brain tissue (C i ) is expressed as:

\frac{d C_{i} (t)}{d t} = F_{i} C_{a} - α C_{i}, with α = \frac{F_{i}}{λ_{i}} + \frac{1}{T_{1 i}},

where C a is the steady state concentration of HP 129 Xe in the arterial blood that reaches the brain tissue, λ i is the partition coefficient between the tissue and blood, and T 1i is the longitudinal relaxation time in the brain tissue.…”

Section: Methodsmentioning

confidence: 99%

“…Here, the destruction of polarization within the brain tissue caused by RF excitation at flip angle θ is taken into account as a period of a constant relaxation rate of f(1‐cosθ)/TR, where TR is the interval between two RF pulses and f denotes the portion of HP 129 Xe magnetization that remains in the brain tissue, after an interval of TR following destruction by an RF pulse . The time‐dependent 129 Xe NMR signal amplitude S(t) can be derived by solving Equation for the initial condition C i (0) = F i C a /α, which is given by the steady‐state condition of Equation , and is expressed as:

S (t) = η sin θ \cdot C_{i} (t) = η sin θ \cdot (\frac{F_{i} C_{a}}{β} + F_{i} C_{a} (\frac{1}{α} - \frac{1}{β}) exp (- β t)),

where η is the parameter that normalizes the concentration of HP 129 Xe in the brain tissue to the NMR signal amplitude.…”

Section: Methodsmentioning

confidence: 99%

“…To date, several studies have reported that the uptake and/or washout dynamics of HP 129 Xe in brain tissue were successfully pursued by time dependence of the dissolved phase NMR signal intensity . These reports also proposed theoretical models to analyze the dynamics and to determine the T 1i value; however, HP 129 Xe dynamics in the brain are affected by the lung physiological state, such as the respiration rate and pulmonary blood flow, which are the input functions of the analysis.…”

Section: Introductionmentioning

confidence: 99%

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Development of a fast method for quantitative measurement of hyperpolarized ¹²⁹Xe dynamics in mouse brain

et al. 2011

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A fast method has been established for the precise measurement and quantification of the dynamics of hyperpolarized (HP) xenon-129 ((129)Xe) in the mouse brain. The key technique is based on repeatedly applying radio frequency (RF) pulses and measuring the decrease of HP (129)Xe magnetization after the brain Xe concentration has reached a steady state due to continuous HP (129)Xe ventilation. The signal decrease of the (129)Xe nuclear magnetic resonance (NMR) signal was well described by a simple theoretical model. The technique made it possible to rapidly evaluate the rate constant α, which is composed of cerebral blood flow (CBF), the partition coefficient of Xe between the tissue and blood (λ(i)), and the longitudinal relaxation time (T(1i)) of HP (129)Xe in the brain tissue, without any effect of depolarization by RF pulses and the dynamics in the lung. The technique enabled the precise determination of α as 0.103 ± 0.018 s(-1) (± SD, n = 5) on healthy mice. To investigate the potential of this method for detecting physiological changes in the brain of a kainic acid (KA) -induced mouse model of epilepsy, an attempt was made to follow the time course of α after KA injection. It was found that the α value changes characteristically with time, reflecting the change in the physiological state of the brain induced by KA injection. By measuring CBF using (1)H MRI and (129)Xe dynamics simultaneously and comparing these results, it was suggested that the reduction of T(1i), in addition to the increase of CBF due to KA-induced epilepsy, are possible causes of the change in (129)Xe dynamics. Thus, the present method would be useful to detect a pathophysiological state in the brain and provide a novel tool for future brain study.

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Section: Introductionmentioning

confidence: 61%

Section: Resultsmentioning

confidence: 83%

\frac{d C_{i} (t)}{d t} = F_{i} C_{a} - α C_{i}, with α = \frac{F_{i}}{λ_{i}} + \frac{1}{T_{1 i}},

Section: Methodsmentioning

confidence: 99%

S (t) = η sin θ \cdot C_{i} (t) = η sin θ \cdot (\frac{F_{i} C_{a}}{β} + F_{i} C_{a} (\frac{1}{α} - \frac{1}{β}) exp (- β t)),

where η is the parameter that normalizes the concentration of HP 129 Xe in the brain tissue to the NMR signal amplitude.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Development of a fast method for quantitative measurement of hyperpolarized ¹²⁹Xe dynamics in mouse brain

et al. 2011

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Brain Imaging Using Hyperpolarized Xenon MRI

Hane¹,

Imai²,

Kimura³

et al. 2017

Hyperpolarized and Inert Gas MRI

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Hyperpolarized 129Xe dynamic study in mouse lung under spontaneous respiration: Application to murine tumor B16BL6 melanoma

Imai

Kimura

Ito

et al. 2010

European Journal of Radiology

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Improvement of T1 Determination of Hyperpolarized 129Xe in Mouse Brain under Controlled-Flow

Cited by 6 publications

References 15 publications

Development of a fast method for quantitative measurement of hyperpolarized ¹²⁹Xe dynamics in mouse brain

Development of a fast method for quantitative measurement of hyperpolarized ¹²⁹Xe dynamics in mouse brain

Brain Imaging Using Hyperpolarized Xenon MRI

Hyperpolarized 129Xe dynamic study in mouse lung under spontaneous respiration: Application to murine tumor B16BL6 melanoma

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Improvement of T1 Determination of Hyperpolarized 129Xe in Mouse Brain under Controlled-Flow

Cited by 6 publications

References 15 publications

Development of a fast method for quantitative measurement of hyperpolarized 129Xe dynamics in mouse brain

Development of a fast method for quantitative measurement of hyperpolarized 129Xe dynamics in mouse brain

Brain Imaging Using Hyperpolarized Xenon MRI

Hyperpolarized 129Xe dynamic study in mouse lung under spontaneous respiration: Application to murine tumor B16BL6 melanoma

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Development of a fast method for quantitative measurement of hyperpolarized ¹²⁹Xe dynamics in mouse brain

Development of a fast method for quantitative measurement of hyperpolarized ¹²⁹Xe dynamics in mouse brain