In vivo oxygen-17 NMR for imaging brain oxygen metabolism at high field

Zhu, Xiao Hong; Chen, Wei

doi:10.1016/j.pnmrs.2011.04.002

Cited by 46 publications

(88 citation statements)

References 88 publications

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“…Additionally, 13 C MRS studies (in animal and human) allows the correlation between neuronal glucose oxidation and neuronal activity, and revealed high oxidative metabolism demand during neuronal activation Chhina et al, 2001;Hyder et al, 1996Hyder et al, , 1997. In vivo 17 O NMR may also be used to directly and non-invasively determine CMR O2 (Mateescu, 2003;Zhu and Chen, 2011;Zhu et al, 2005) with high reliability and reproducibility (Zhu et al, 2007), as well as the simultaneous in vivo measurements of CBF (Zhu et al, 2013), which may help unraveling the role of oxidative metabolism during functional activity.…”

Section: Discussionmentioning

confidence: 99%

Are glutamate and lactate increases ubiquitous to physiological activation? A 1H functional MR spectroscopy study during motor activation in human brain at 7Tesla

Xin²,

et al. 2014

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a b s t r a c t a r t i c l e i n f oRecent studies at high field (7 Tesla) have reported small metabolite changes, in particular lactate and glutamate (below 0.3 μmol/g) during visual stimulation. These studies have been limited to the visual cortex because of its high energy metabolism and good magnetic resonance spectroscopy (MRS) sensitivity using surface coil. The aim of this study was to extend functional MRS (fMRS) to investigate for the first time the metabolite changes during motor activation at 7 T. Small but sustained increases in lactate (0.17 μmol/g ± 0.05 μmol/g, p b 0.001) and glutamate (0.17 μmol/g ± 0.09 μmol/g, p b 0.005) were detected during motor activation followed by a return to the baseline after the end of activation. The present study demonstrates that increases in lactate and glutamate during motor stimulation are small, but similar to those observed during visual stimulation. From the observed glutamate and lactate increase, we inferred that these metabolite changes may be a general manifestation of the increased neuronal activity. In addition, we propose that the measured metabolite concentration increases imply an increase in ΔCMR O2 that is transiently below that of ΔCMR Glc during the first 1 to 2 min of the stimulation.© 2014 Elsevier Inc. All rights reserved. IntroductionFunctional MR spectroscopy (fMRS) provides direct insights into brain metabolism by investigating the metabolic response of the brain to a physiological stimulus. The high spectral resolution and signal-tonoise ratio (SNR) of fMRS at high field (N3 Tesla) improve the accuracy and precision of the quantification of many brain metabolites (Mekle et al., 2009;Tkac et al., 2001Tkac et al., , 2009. In addition to the increased chemical shift dispersion, a high time resolution is of advantage for the characterization of the small transient changes observed. Recent fMRS studies (Lin et al., 2012;Mangia et al., 2007b;Schaller et al., 2013) at high field (7 Tesla) reported small metabolite concentration changes during visual stimulation (around 0.2 μmol/g). In particular, a very small lactate concentration increase between 10 and 23% has been observed. Recently, functional diffusion-weighted MRS has been used to investigate metabolite ADC changes as a potential consequence of micro structural changes during activation (Branzoli et al., 2013).The lactate increase observed during visual stimulation has been suggested to explain the mismatch of cerebral metabolic rate of change for glucose (ΔCMR Glc ) (or cerebral blood flow, CBF) and cerebral metabolic rate of change for oxygen (ΔCMR O2 ) during brain activation. However, many studies have reported different results concerning the transient mismatch of ΔCMR Glc , CBF and ΔCMR O2 during functional activity (reviewed in Buxton (2010)). The characterization of these changes has been reported in positron emission tomography (PET) (Fox and

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Section: Discussionmentioning

confidence: 99%

Are glutamate and lactate increases ubiquitous to physiological activation? A 1H functional MR spectroscopy study during motor activation in human brain at 7Tesla

Xin²,

et al. 2014

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“…For example, rapid T 2 mapping can be used for in vivo quantification of Ca 2+ uptake in myocardium by MEMRI (21, 22). Fast T 2 mapping is also necessary to investigate mitochondria oxidation in mouse hearts using 17 O MRI, where the relaxation rate R 2 of myocardial tissue is linearly dependent on the concentration of metabolic H 2 17 O generated after breathing 17 O 2 gas (23). While our current study demonstrated the utility of our technique in following the dynamic uptake of Mn 2+ in myocardium at a high temporal resolution, a major limitation of the current study is the lack of validation with diseased mouse models.…”

Section: Discussionmentioning

confidence: 99%

Rapid T₂ mapping of mouse heart using the carr–purcell–meiboom–gill sequence and compressed sensing reconstruction

Chen

Jiang

et al. 2016

Magnetic Resonance Imaging

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Purpose To develop and prove preliminary validation of a fast in vivo T2 mapping technique for mouse heart. Materials and Methods MRI experiments were performed on a 7T animal scanner. The standard Carr-Purcell-Meiboom-Gill (CPMG) sequence was modified to minimize the effect of stimulated echoes for accurate T2 quantification. The acquisition was further accelerated with the compressed sensing approach. The accuracy of the proposed method was first validated with both phantom experiments and numerical simulations. In vivo T2 measurement was performed on seven mice in a manganese-enhanced MRI study. Results In phantom studies, T2 values obtained with the modified CPMG sequence are in good agreement with the standard spin-echo method (P > 0.05). Numerical simulations further demonstrated that with the application of the compressed sensing approach, fast T2 quantification with a spatial resolution of 2.3 mm can be achieved at a high temporal resolution of one minute per slice. With the proposed technique, an average T2 value of 25 msec was observed for mouse heart at 7T and this number decreased significantly after manganese infusion (P < 0.001). Conclusion A rapid T2 mapping technique was developed and assessed, which allows accurate T2 quantification of mouse heart at a temporal resolution of one minute per slice.

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“…Although there is a similarity between PET and 17 O MR imaging methods, only the latter specifically detects the metabolically generated H 2 17 O without confounding signals from 17 O 2 and this merit significantly simplifies both imaging procedure and post-imaging quantification of CMRO 2 (see review articles (Zhu and Chen, 2011; Zhu et al, 2005) and the cited references therein). Several studies have also shown the ability of high-field MR scanners to greatly improve the 17 O detection sensitivity (Lu et al, 2012; Thelwall et al, 2003; Zhu et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Simultaneous and noninvasive imaging of cerebral oxygen metabolic rate, blood flow and oxygen extraction fraction in stroke mice

Zhu

Chen

et al. 2013

NeuroImage

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Many brain diseases have been linked to abnormal oxygen metabolism and blood perfusion; nevertheless, there is still a lack of robust diagnostic tools for directly imaging cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow (CBF), as well as the oxygen extraction fraction (OEF) that reflects the balance between CMRO2 and CBF. This study employed the recently developed in vivo 17O MR spectroscopic imaging to simultaneously assess CMRO2, CBF and OEF in the brain using a preclinical middle cerebral arterial occlusion mouse model with a brief inhalation of 17O-labeled oxygen gas. The results demonstrated high sensitivity and reliability of the noninvasive 17O-MR approach for rapidly imaging CMRO2, CBF and OEF abnormalities in the ischemic cortex of the MCAO mouse brain. It was found that in the ischemic brain regions both CMRO2 and CBF were substantially lower than that of intact brain regions, even for the mildly damaged brain regions that were unable to be clearly identified by the conventional MRI. In contrast, OEF was higher in the MCAO affected brain regions. This study demonstrates a promising 17O MRI technique for imaging abnormal oxygen metabolism and perfusion in the diseased brain regions. This 17O MRI technique is advantageous because of its robustness, simplicity, noninvasiveness and reliability: features that are essential to potentially translate it to human patients for early diagnosis and monitoring of treatment efficacy.

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In vivo oxygen-17 NMR for imaging brain oxygen metabolism at high field

Cited by 46 publications

References 88 publications

Are glutamate and lactate increases ubiquitous to physiological activation? A 1H functional MR spectroscopy study during motor activation in human brain at 7Tesla

Are glutamate and lactate increases ubiquitous to physiological activation? A 1H functional MR spectroscopy study during motor activation in human brain at 7Tesla

Rapid T₂ mapping of mouse heart using the carr–purcell–meiboom–gill sequence and compressed sensing reconstruction

Simultaneous and noninvasive imaging of cerebral oxygen metabolic rate, blood flow and oxygen extraction fraction in stroke mice

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In vivo oxygen-17 NMR for imaging brain oxygen metabolism at high field

Cited by 46 publications

References 88 publications

Are glutamate and lactate increases ubiquitous to physiological activation? A 1H functional MR spectroscopy study during motor activation in human brain at 7Tesla

Are glutamate and lactate increases ubiquitous to physiological activation? A 1H functional MR spectroscopy study during motor activation in human brain at 7Tesla

Rapid T2 mapping of mouse heart using the carr–purcell–meiboom–gill sequence and compressed sensing reconstruction

Simultaneous and noninvasive imaging of cerebral oxygen metabolic rate, blood flow and oxygen extraction fraction in stroke mice

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Rapid T₂ mapping of mouse heart using the carr–purcell–meiboom–gill sequence and compressed sensing reconstruction