MRI measurement of cell volume fraction in the perfused rat hippocampal slice

Buckley, David L.; Bui, Jonathan D.; Phillips, M. Ian; Blackband, Stephen J.

doi:10.1002/(sici)1522-2594(199909)42:3<603::aid-mrm25>3.0.co;2-q

Cited by 9 publications

(4 citation statements)

References 21 publications

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“…The derived parameters including fractional anisotropy (FA), diffusivity and apparent diffusion coefficient (ADC) intrinsic to tissue cellularity have been employed to evaluate the cell size and microdynamics of brain tissue [22], [23]. Altered diffusion properties could reflect the variations of fiber density, myelination and cell membrane permeability in the context of physiological and pathological scenarios [24], [25].…”

Section: Introductionmentioning

confidence: 99%

Diurnal Microstructural Variations in Healthy Adult Brain Revealed by Diffusion Tensor Imaging

et al. 2014

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Biorhythm is a fundamental property of human physiology. Changes in the extracellular space induced by cell swelling in response to the neural activity enable the in vivo characterization of cerebral microstructure by measuring the water diffusivity using diffusion tensor imaging (DTI). To study the diurnal microstructural alterations of human brain, fifteen right-handed healthy adult subjects were recruited for DTI studies in two repeated sessions (8∶30 AM and 8∶30 PM) within a 24-hour interval. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial (λ//) and radial diffusivity (λ⊥) were compared pixel by pixel between the sessions for each subject. Significant increased morning measurements in FA, ADC, λ// and λ⊥ were seen in a wide range of brain areas involving frontal, parietal, temporal and occipital lobes. Prominent evening dominant λ⊥ (18.58%) was detected in the right inferior temporal and ventral fusiform gyri. AM-PM variation of λ⊥ was substantially left side hemisphere dominant (p<0.05), while no hemispheric preference was observed for the same analysis for ADC (p = 0.77), λ// (p = 0.08) or FA (p = 0.25). The percentage change of ADC, λ//, λ⊥, and FA were 1.59%, 2.15%, 1.20% and 2.84%, respectively, for brain areas without diurnal diffusivity contrast. Microstructural variations may function as the substrates of the phasic neural activities in correspondence to the environment adaptation in a light-dark cycle. This research provided a baseline for researches in neuroscience, sleep medicine, psychological and psychiatric disorders, and necessitates that diurnal effect should be taken into account in following up studies using diffusion tensor quantities.

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Section: Introductionmentioning

confidence: 99%

Diurnal Microstructural Variations in Healthy Adult Brain Revealed by Diffusion Tensor Imaging

et al. 2014

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“…To use this result to compare the cellular proliferation rates of cancerous and non-cancerous cells we recall that tumours of radius three cell widths, which corresponds to a r tum of approximately 80 µm (Casciari et al, 1992; Buckley et al, 1999) will typically consist of only proliferating cells (LaRue et al, 2004). For this value of r tum , the tumour radius, we find that the non-cancerous cells must initially proliferate approximately 50% as quickly as the cancerous cells.…”

Section: Introductionmentioning

confidence: 99%

Tumour angiogenesis: The gap between theory and experiments

Schofield¹,

Gaffney²,

Gatenby³

et al. 2011

Journal of Theoretical Biology

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A common experimental technique for viewing in vivo angiogenesis utilises tumours implanted into a test animal cornea. The cornea is avascular but the tumour promotes vascularisation from the limbus and the new blood vessels can be readily observed through the transparent cornea. Many of the early mathematical models for tumour angiogenesis used this scenario as their experimental template and as such assumed that there is a large gap, of the order of 2 mm, between the tumour and neighbouring vasculature at the onset of angiogenesis. In this work we consider whether the assumption that there is a significant gap between the tumour and neighbouring vasculature is unique to intra-cornea tumour implants, or whether this characterises avascular tumour growth more generally. To do this we utilise a simple scaling argument, derive a multi-compartment model for tumour growth, and consider in vivo images. This analysis demonstrates that the corneal implant experiments and the corresponding mathematical models cannot be applied to a clinical setting.

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“…The vast majority of ex vivo MR microscopy studies to date have employed discontinuous perfusion as a part of their imaging protocol so as to eliminate flow artifacts arising from moving perfusate 39 40 41 42 43 44 45 46 . While control experiments in these studies have reported MR signal stability using intermittent perfusion methods, metabolic studies have shown that tissue explants benefit physiologically from the continuous turnover of perfusate 47 48 .…”

Section: Discussionmentioning

confidence: 99%

A Microperfusion and In-Bore Oxygenator System Designed for Magnetic Resonance Microscopy Studies on Living Tissue Explants

Flint

Menon

Hansen

et al. 2015

Sci Rep

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Spectrometers now offer the field strengths necessary to visualize mammalian cells but were not designed to accommodate imaging of live tissues. As such, spectrometers pose significant challenges—the most evident of which are spatial limitations—to conducting experiments in living tissue. This limitation becomes problematic upon trying to employ commercial perfusion equipment which is bulky and—being designed almost exclusively for light microscopy or electrophysiology studies—seldom includes MR-compatibility as a design criterion. To overcome problems exclusive to ultra-high magnetic field environments with limited spatial access, we have designed microperfusion and in-bore oxygenation systems capable of interfacing with Bruker’s series of micro surface-coils. These devices are designed for supporting cellular resolution imaging in MR studies of excised, living tissue. The combined system allows for precise control of both dissolved gas and pH levels in the perfusate thus demonstrating applicability for a wide range of tissue types. Its compactness, linear architecture, and MR-compatible material content are key design features intended to provide a versatile hardware interface compatible with any NMR spectrometer. Such attributes will ensure the microperfusion rig’s continued utility as it may be used with a multitude of contemporary NMR systems in addition to those which are currently in development.

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MRI measurement of cell volume fraction in the perfused rat hippocampal slice

Cited by 9 publications

References 21 publications

Diurnal Microstructural Variations in Healthy Adult Brain Revealed by Diffusion Tensor Imaging

Diurnal Microstructural Variations in Healthy Adult Brain Revealed by Diffusion Tensor Imaging

Tumour angiogenesis: The gap between theory and experiments

A Microperfusion and In-Bore Oxygenator System Designed for Magnetic Resonance Microscopy Studies on Living Tissue Explants

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