Lactate saturation limits bicarbonate detection in hyperpolarized 13C-pyruvate MRI of the brain

Nikolaj Bøgh; James T Grist; Camilla Westergaard Rasmussen; Lotte Bonde Bertelsen; Esben Søvsø Szocska Hansen; Jakob Blicher; Damian J Tyler; Christoffer Laustsen

doi:10.1002/mrm.29290

Lactate saturation limits bicarbonate detection in hyperpolarized¹³C-pyruvate MRI of the brain

Nikolaj Bøgh, James T Grist, Camilla Westergaard Rasmussen, Lotte Bonde Bertelsen, Esben Søvsø Szocska Hansen, Jakob Blicher, Damian J Tyler, Christoffer Laustsen

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

11 Citations (Scopus)

Abstract

Purpose: To investigate the potential effects of [1- ¹³C]lactate RF saturation pulses on [ ¹³C]bicarbonate detection in hyperpolarized [1- ¹³C]pyruvate MRI of the brain. Methods: Thirteen healthy rats underwent MRI with hyperpolarized [1- ¹³C]pyruvate of either the brain (n = 8) or the kidneys, heart, and liver (n = 5). Dynamic, metabolite-selective imaging was used in a cross-over experiment in which [1- ¹³C]lactate was excited with either 0° or 90° flip angles. The [ ¹³C]bicarbonate SNR and apparent [1- ¹³C]pyruvate-to-[ ¹³C]bicarbonate conversion (k _PB) were determined. Furthermore, simulations were performed to identify the SNR optimal flip-angle scheme for detection of [1- ¹³C]lactate and [ ¹³C]bicarbonate. Results: In the brain, the [ ¹³C]bicarbonate SNR was 64% higher when [1- ¹³C]lactate was not excited (5.8 ± 1.5 vs 3.6 ± 1.3; 1.2 to 3.3–point increase; p = 0.0027). The apparent k _PB decreased 25% with [1- ¹³C]lactate saturation (0.0047 ± 0.0008 s ⁻¹ vs 0.0034 ± 0.0006 s ⁻¹; 95% confidence interval, 0.0006–0.0019 s ⁻¹ increase; p = 0.0049). These effects were not present in the kidneys, heart, or liver. Simulations suggest that the optimal [ ¹³C]bicarbonate SNR with a TR of 1 s in the brain is obtained with [ ¹³C]bicarbonate, [1- ¹³C]lactate, and [1- ¹³C]pyruvate flip angles of 60°, 15°, and 10°, respectively. Conclusions: Radiofrequency saturation pulses on [1- ¹³C]lactate limit [ ¹³C]bicarbonate detection in the brain specifically, which could be due to shuttling of lactate from astrocytes to neurons. Our results have important implications for experimental design in studies in which [ ¹³C]bicarbonate detection is warranted.

Original language	English
Journal	Magnetic Resonance in Medicine
Volume	88
Issue	3
Pages (from-to)	1170-1179
Number of pages	10
ISSN	0740-3194
DOIs	https://doi.org/10.1002/mrm.29290
Publication status	Published - Sept 2022

Keywords

magnetic resonance imaging
hyperpolarized
astrocyte neuron lactate shuttle
metabolism
brain
pyruvate
GLUCOSE
ENERGY-METABOLISM
EXCHANGE

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@article{147a45c378ab44d092a745f56042f649,

title = "Lactate saturation limits bicarbonate detection in hyperpolarized 13C-pyruvate MRI of the brain",

abstract = "Purpose: To investigate the potential effects of [1- 13C]lactate RF saturation pulses on [ 13C]bicarbonate detection in hyperpolarized [1- 13C]pyruvate MRI of the brain. Methods: Thirteen healthy rats underwent MRI with hyperpolarized [1- 13C]pyruvate of either the brain (n = 8) or the kidneys, heart, and liver (n = 5). Dynamic, metabolite-selective imaging was used in a cross-over experiment in which [1- 13C]lactate was excited with either 0° or 90° flip angles. The [ 13C]bicarbonate SNR and apparent [1- 13C]pyruvate-to-[ 13C]bicarbonate conversion (k PB) were determined. Furthermore, simulations were performed to identify the SNR optimal flip-angle scheme for detection of [1- 13C]lactate and [ 13C]bicarbonate. Results: In the brain, the [ 13C]bicarbonate SNR was 64% higher when [1- 13C]lactate was not excited (5.8 ± 1.5 vs 3.6 ± 1.3; 1.2 to 3.3–point increase; p = 0.0027). The apparent k PB decreased 25% with [1- 13C]lactate saturation (0.0047 ± 0.0008 s −1 vs 0.0034 ± 0.0006 s −1; 95% confidence interval, 0.0006–0.0019 s −1 increase; p = 0.0049). These effects were not present in the kidneys, heart, or liver. Simulations suggest that the optimal [ 13C]bicarbonate SNR with a TR of 1 s in the brain is obtained with [ 13C]bicarbonate, [1- 13C]lactate, and [1- 13C]pyruvate flip angles of 60°, 15°, and 10°, respectively. Conclusions: Radiofrequency saturation pulses on [1- 13C]lactate limit [ 13C]bicarbonate detection in the brain specifically, which could be due to shuttling of lactate from astrocytes to neurons. Our results have important implications for experimental design in studies in which [ 13C]bicarbonate detection is warranted. ",

keywords = "magnetic resonance imaging, hyperpolarized, astrocyte neuron lactate shuttle, metabolism, brain, pyruvate, GLUCOSE, ENERGY-METABOLISM, EXCHANGE",

author = "Nikolaj B{\o}gh and Grist, {James T} and Rasmussen, {Camilla Westergaard} and Bertelsen, {Lotte Bonde} and {S{\o}vs{\o} Szocska Hansen}, Esben and Jakob Blicher and Tyler, {Damian J} and Christoffer Laustsen",

year = "2022",

month = sep,

doi = "10.1002/mrm.29290",

language = "English",

volume = "88",

pages = "1170--1179",

journal = "Magnetic Resonance in Medicine",

issn = "0740-3194",

publisher = "John Wiley & Sons Inc.",

number = "3",

}

Lactate saturation limits bicarbonate detection in hyperpolarized¹³C-pyruvate MRI of the brain. / Bøgh, Nikolaj; Grist, James T; Rasmussen, Camilla Westergaard et al.
In: Magnetic Resonance in Medicine, Vol. 88, No. 3, 09.2022, p. 1170-1179.

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaper › Journal article › Research › peer-review

TY - JOUR

T1 - Lactate saturation limits bicarbonate detection in hyperpolarized 13C-pyruvate MRI of the brain

AU - Bøgh, Nikolaj

AU - Grist, James T

AU - Rasmussen, Camilla Westergaard

AU - Bertelsen, Lotte Bonde

AU - Søvsø Szocska Hansen, Esben

AU - Blicher, Jakob

AU - Tyler, Damian J

AU - Laustsen, Christoffer

PY - 2022/9

Y1 - 2022/9

N2 - Purpose: To investigate the potential effects of [1- 13C]lactate RF saturation pulses on [ 13C]bicarbonate detection in hyperpolarized [1- 13C]pyruvate MRI of the brain. Methods: Thirteen healthy rats underwent MRI with hyperpolarized [1- 13C]pyruvate of either the brain (n = 8) or the kidneys, heart, and liver (n = 5). Dynamic, metabolite-selective imaging was used in a cross-over experiment in which [1- 13C]lactate was excited with either 0° or 90° flip angles. The [ 13C]bicarbonate SNR and apparent [1- 13C]pyruvate-to-[ 13C]bicarbonate conversion (k PB) were determined. Furthermore, simulations were performed to identify the SNR optimal flip-angle scheme for detection of [1- 13C]lactate and [ 13C]bicarbonate. Results: In the brain, the [ 13C]bicarbonate SNR was 64% higher when [1- 13C]lactate was not excited (5.8 ± 1.5 vs 3.6 ± 1.3; 1.2 to 3.3–point increase; p = 0.0027). The apparent k PB decreased 25% with [1- 13C]lactate saturation (0.0047 ± 0.0008 s −1 vs 0.0034 ± 0.0006 s −1; 95% confidence interval, 0.0006–0.0019 s −1 increase; p = 0.0049). These effects were not present in the kidneys, heart, or liver. Simulations suggest that the optimal [ 13C]bicarbonate SNR with a TR of 1 s in the brain is obtained with [ 13C]bicarbonate, [1- 13C]lactate, and [1- 13C]pyruvate flip angles of 60°, 15°, and 10°, respectively. Conclusions: Radiofrequency saturation pulses on [1- 13C]lactate limit [ 13C]bicarbonate detection in the brain specifically, which could be due to shuttling of lactate from astrocytes to neurons. Our results have important implications for experimental design in studies in which [ 13C]bicarbonate detection is warranted.

AB - Purpose: To investigate the potential effects of [1- 13C]lactate RF saturation pulses on [ 13C]bicarbonate detection in hyperpolarized [1- 13C]pyruvate MRI of the brain. Methods: Thirteen healthy rats underwent MRI with hyperpolarized [1- 13C]pyruvate of either the brain (n = 8) or the kidneys, heart, and liver (n = 5). Dynamic, metabolite-selective imaging was used in a cross-over experiment in which [1- 13C]lactate was excited with either 0° or 90° flip angles. The [ 13C]bicarbonate SNR and apparent [1- 13C]pyruvate-to-[ 13C]bicarbonate conversion (k PB) were determined. Furthermore, simulations were performed to identify the SNR optimal flip-angle scheme for detection of [1- 13C]lactate and [ 13C]bicarbonate. Results: In the brain, the [ 13C]bicarbonate SNR was 64% higher when [1- 13C]lactate was not excited (5.8 ± 1.5 vs 3.6 ± 1.3; 1.2 to 3.3–point increase; p = 0.0027). The apparent k PB decreased 25% with [1- 13C]lactate saturation (0.0047 ± 0.0008 s −1 vs 0.0034 ± 0.0006 s −1; 95% confidence interval, 0.0006–0.0019 s −1 increase; p = 0.0049). These effects were not present in the kidneys, heart, or liver. Simulations suggest that the optimal [ 13C]bicarbonate SNR with a TR of 1 s in the brain is obtained with [ 13C]bicarbonate, [1- 13C]lactate, and [1- 13C]pyruvate flip angles of 60°, 15°, and 10°, respectively. Conclusions: Radiofrequency saturation pulses on [1- 13C]lactate limit [ 13C]bicarbonate detection in the brain specifically, which could be due to shuttling of lactate from astrocytes to neurons. Our results have important implications for experimental design in studies in which [ 13C]bicarbonate detection is warranted.

KW - magnetic resonance imaging

KW - hyperpolarized

KW - astrocyte neuron lactate shuttle

KW - metabolism

KW - brain

KW - pyruvate

KW - GLUCOSE

KW - ENERGY-METABOLISM

KW - EXCHANGE

U2 - 10.1002/mrm.29290

DO - 10.1002/mrm.29290

M3 - Journal article

C2 - 35533254

SN - 0740-3194

VL - 88

SP - 1170

EP - 1179

JO - Magnetic Resonance in Medicine

JF - Magnetic Resonance in Medicine

IS - 3

ER -