Revisiting double diffusion encoding MRS in the mouse brain at 11.7T: Which microstructural features are we sensitive to?

Vincent, Mélissa; Palombo, Marco; Valette, Julien

doi:10.1016/j.neuroimage.2019.116399

Cited by 18 publications

(23 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interestingly, the intermediate behavior displayed by lactate, that is, more pronounced signal attenuation combined with narrower signal intensity angular modulation, is consistent with the fact that lactate is present in both ECS and ICS. These results are in line with past DDE measurements showing limited lactate signal angular modulation compared with purely intracellular metabolites, which considering the results of the present work is due to the presence of an important extracellular lactate pool with very limited angular modulation 22,58,73 . To the best of our knowledge, this is the first time that DDE‐MRS has been specifically performed in ECS, and we believe that DDE might actually be extremely powerful to successfully distinguish between ECS and ICS compartments.…”

Section: Discussionsupporting

confidence: 92%

“…DDE was performed using the sequence described in Vincent et al 58 Briefly, the sequence comprises two 180° pulses, each flanked by a pair of diffusion gradients, followed by a LASER localization module, as described above (TE_SE/TE_LASER = 71.2/25 ms). The t d was 28.5 ms for each block while the TM between the two diffusion blocks was fixed at 5.5 ms and δ was equal to 4.5 ms. A total diffusion weighting of 5 ms/μm 2 was applied, that is, 2.5 ms/μm 2 for each diffusion block.…”

Section: Methodsmentioning

confidence: 99%

“…To this end, we use state‐of‐the‐art DW‐MRS acquisition and processing strategies, while benefiting from the exquisite sensitivity of a 1 H cryoprobe at 11.7 T. First, a solution of sucrose, a well‐known marker of ECS due to the absence of sucrose transporter in the mammal brain, 28 is slowly infused in the mouse brain, either inside ventricles close to the hippocampus or in the prefrontal cortex. We then perform, in a voxel localized close to the injection site, that is, either around the hippocampus or in the prefrontal cortex, three types of DW‐MRS acquisitions in vivo to obtain complementary information on several key microstructural features 55–58 : (1) short‐range restriction using measurements at high b‐values up to 30 ms/μm 2 ; (2) longer‐range structures via ADC measurements for t d increasing up to 1 s; and (3) microscopic anisotropy, as revealed by DDE. We finally confirm, using cell dissociation followed by HR‐MAS spectroscopy, that sucrose indeed remains in ECS.…”

Section: Introductionmentioning

confidence: 99%

“…To this end, we use state-of-the-art DW-MRS acquisition and processing strategies, while benefiting from the exquisite sensitivity of a 1 H cryoprobe at 11.7 T. First, a solution of sucrose, a well-known marker of ECS due to the absence of sucrose transporter in the mammal brain, 28 is slowly infused in the mouse brain, either inside ventricles close to the hippocampus or in the prefrontal cortex. We then perform, in a voxel localized close to the injection site, that is, either around the hippocampus or in the prefrontal cortex, three types of DW-MRS acquisitions in vivo to obtain complementary information on several key microstructural features [55][56][57][58] After the whole volume of sucrose solution was injected, the cannula was left in place for 10 min before removal to prevent capillary suction of sucrose out of the tissues. The mouse was then transferred to the MRI room after stitching the skin of the animal (the dura was not repaired).…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Characterizing extracellular diffusion properties using diffusion‐weighted MRS of sucrose injected in mouse brain

et al. 2021

Self Cite

View full text Add to dashboard Cite

Brain water and some critically important energy metabolites, such as lactate or glucose, are present in both intracellular and extracellular spaces (ICS/ECS) at significant levels. This ubiquitous nature makes diffusion MRI/MRS data sometimes difficult to interpret and model. While it is possible to glean information on the diffusion properties in ICS by measuring the diffusion of purely intracellular endogenous metabolites (such as NAA), the absence of endogenous markers specific to ECS hampers similar analyses in this compartment. In past experiments, exogenous probes have therefore been injected into the brain to assess their apparent diffusion coefficient (ADC) and thus estimate tortuosity in ECS. Here, we use a similar approach in mice by injecting sucrose, a well‐known ECS marker, in either the lateral ventricles or directly in the prefrontal cortex. For the first time, we propose a thorough characterization of ECS diffusion properties encompassing (1) short‐range restriction by looking at signal attenuation at high b values, (2) tortuosity and long‐range restriction by measuring ADC time‐dependence at long diffusion times and (3) microscopic anisotropy by performing double diffusion encoding (DDE) measurements. Overall, sucrose diffusion behavior is strikingly different from that of intracellular metabolites. Acquisitions at high b values not only reveal faster sucrose diffusion but also some sensitivity to restriction, suggesting that the diffusion in ECS is not fully Gaussian at high b. The time evolution of the ADC at long diffusion times shows that the tortuosity regime is not reached yet in the case of sucrose, while DDE experiments suggest that it is not trapped in elongated structures. No major difference in sucrose diffusion properties is reported between the two investigated routes of injection and brain regions. These original experimental insights should be useful to better interpret and model the diffusion signal of molecules that are distributed between ICS and ECS compartments.

show abstract

Section: Discussionsupporting

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Characterizing extracellular diffusion properties using diffusion‐weighted MRS of sucrose injected in mouse brain

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…We note that more advanced DW-MRI acquisition schemes such as B-tensor encoding (64) parcellation of the brain cyto-architecture (Figure 9 and 10). As shown in Figure 10 (18,19), while recent works using DDE showed that this acquisition scheme can help disentangling different sources of DW-MRI signal that can be linked to different features of the underpinning tissue microstructure (69)(70)(71)(72). Future works will focus on harnessing the orthogonal information offered by these advanced acquisition schemes in order to maximize the sensitivity and specificity of the measured DW-MRI signal to the soma contribution.…”

Section: Discussionmentioning

confidence: 99%

SANDI: A compartment-based model for non-invasive apparent soma and neurite imaging by diffusion MRI

et al. 2020

Self Cite

View full text Add to dashboard Cite

This work introduces a compartment-based model for apparent cell body (namely soma) and neurite density imaging (SANDI) using non-invasive diffusion-weighted MRI (DW-MRI). The existing conjecture in brain microstructure imaging trough DW-MRI presents water diffusion in white (WM) and grey (GM) matter as restricted diffusion in neurites, modelled by infinite cylinders of null radius embedded in the hindered extra-neurite water. The extra-neurite pool in WM corresponds to water in the extra-axonal space, but in GM it combines water in the extra-cellular space with water in soma. While several studies showed that this microstructure model successfully describe DW-MRI data in WM and GM at b3 ms/m 2 , it has been also shown to fail in GM at high b values (b>>3 ms/m 2 ). Here we hypothesize that the unmodelled soma compartment may be responsible for this failure and propose SANDI as a new model of brain microstructure where soma is explicitly included. We assess the effects of size and density of soma on the direction-averaged DW-MRI signal at high b values and the regime of validity of the model using numerical simulations and comparison with experimental data from mouse (bmax = 40 ms/m 2 ) and human (bmax = 10 ms/m 2 ) brain. We show that SANDI defines new contrasts representing new complementary information on the brain cyto-and myelo-architecture. Indeed, we show for the first-time maps from 25 healthy human subjects of MR soma and neurite signal fractions, that remarkably mirror contrasts of histological images of brain cyto-and myelo-architecture. Although still under validation, SANDI might provide new insight into tissue architecture by introducing a new set of biomarkers of potential great value for biomedical applications and pure neuroscience.

show abstract

Diffusion‐weighted MR spectroscopy: Consensus, recommendations, and resources from acquisition to modeling

Ligneul,

Najac,

Döring

et al. 2023

Magnetic Resonance in Med

Self Cite

View full text Add to dashboard Cite

Brain cell structure and function reflect neurodevelopment, plasticity, and aging; and changes can help flag pathological processes such as neurodegeneration and neuroinflammation. Accurate and quantitative methods to noninvasively disentangle cellular structural features are needed and are a substantial focus of brain research. Diffusion‐weighted MRS (dMRS) gives access to diffusion properties of endogenous intracellular brain metabolites that are preferentially located inside specific brain cell populations. Despite its great potential, dMRS remains a challenging technique on all levels: from the data acquisition to the analysis, quantification, modeling, and interpretation of results. These challenges were the motivation behind the organization of the Lorentz Center workshop on “Best Practices & Tools for Diffusion MR Spectroscopy” held in Leiden, the Netherlands, in September 2021. During the workshop, the dMRS community established a set of recommendations to execute robust dMRS studies. This paper provides a description of the steps needed for acquiring, processing, fitting, and modeling dMRS data, and provides links to useful resources.

show abstract

Revisiting double diffusion encoding MRS in the mouse brain at 11.7T: Which microstructural features are we sensitive to?

Cited by 18 publications

References 40 publications

Characterizing extracellular diffusion properties using diffusion‐weighted MRS of sucrose injected in mouse brain

Characterizing extracellular diffusion properties using diffusion‐weighted MRS of sucrose injected in mouse brain

SANDI: A compartment-based model for non-invasive apparent soma and neurite imaging by diffusion MRI

Diffusion‐weighted MR spectroscopy: Consensus, recommendations, and resources from acquisition to modeling

Contact Info

Product

Resources

About