Diffusion generated T1 and T2 contrast

Kaufmann, Ilja; Seiberlich, Nicole; Haase, Axel; Jakob, Peter M.

doi:10.1016/j.jmr.2008.02.008

Cited by 8 publications

(4 citation statements)

References 32 publications

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“…A transition zone between two compartments with two different R 1 values was observable in the signal profile. A comparable effect has already been observed and investigated by Kaufman et al 23 with T 1 -weighted high-resolution images. Thanks to the planar geometry (slice), all cells were subjected to the same conditions, which will be helpful to dissociate the several compartments involved in the theoretical model developed; here, there are two compartments, the cell layer and the culture medium.…”

Section: Discussionsupporting

confidence: 83%

Experimental system to detect a labeled cell monolayer in a microfluidic environment

Gargam

Darrasse

Raynaud

et al. 2015

Magnetic Resonance Imaging

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Section: Discussionsupporting

confidence: 83%

Experimental system to detect a labeled cell monolayer in a microfluidic environment

Gargam

Darrasse

Raynaud

et al. 2015

Magnetic Resonance Imaging

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“…The results of MSME imaging, relaxation and diffusion measurements also provide a clue toward nutrient and solvent exchange at the surface of colonies. The surface ring hyperintensity found in MSME imaging, is attributed to diffusion generated T 1 contrast as it appears most strongly under short TR (≤1500ms) [ 34 , 35 ]. Hyperintense rings are known to arise from porous organic surfaces in contact with bulk water [ 34 ].…”

Section: Discussionmentioning

confidence: 99%

“…The surface ring hyperintensity found in MSME imaging, is attributed to diffusion generated T 1 contrast as it appears most strongly under short TR (≤1500ms) [ 34 , 35 ]. Hyperintense rings are known to arise from porous organic surfaces in contact with bulk water [ 34 ]. Although the thickness of the colony fibrillary sheath is known to be circa 4–7 μm, the resulting ring phenomenon is much larger, in the order of 50 μm ( Fig 3 ) [ 18 ].…”

Section: Discussionmentioning

confidence: 99%

Non-invasive magnetic resonance imaging of oils in Botryococcus braunii green algae: Chemical shift selective and diffusion-weighted imaging

et al. 2018

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Botryococcus braunii is an oleaginous green algae with the distinctive property of accumulating high quantities of hydrocarbons per dry weight in its colonies. Large variation in colony structure exists, yet its implications and influence of oil distribution and diffusion dynamics are not known and could not be answered due to lack of suitable in vivo methods. This publication seeks to further the understanding on oil dynamics, by investigating naturally relevant large (700–1500μm) and extra-large (1500–2500μm) sized colonies of Botryococcus braunii (race B, strain Showa) in vivo, using a comprehensive approach of chemical shift selective imaging, chemical shift imaging and spin echo diffusion measurements at high magnetic field (17.6T). Hydrocarbon distribution in large colonies was found to be localised in two concentric oil layers with different thickness and concentration. Extra-large colonies were highly unstructured and oil was spread throughout colonies, but with large local variations. Interestingly, fluid channels were observed in extra-large colonies. Diffusion-weighted MRI revealed a strong correlation between colony heterogeneity, oil distribution, and diffusion dynamics in different parts of Botryococcus colonies. Differences between large and extra-large colonies were characterised by using T2 weighted MRI along with relaxation measurements. Our result, therefore, provides first non-invasive MRI means to obtain spatial information on oil distribution and diffusion dynamics in Botryococcus braunii colonies.

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“…Sometimes, slightly longer time‐intervals occurred that resulted from the necessity to adjust the MR sequence parameters after draining the nutrient solution. Additional acquisition of T 2 maps (Kaufmann et al, 2008) reduced the time resolution for plant 8 to 47.5 min.…”

mentioning

confidence: 99%

Functional repair of embolized vessels in maize roots after temporal drought stress, as demonstrated by magnetic resonance imaging

et al. 2009

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Summary• Xylem sap under high tension is in a metastable state and tends to cavitate, frequently leading to an interruption of the continuous water columns. Mechanisms of cavitation repair are controversially discussed.• Magnetic resonance (MR) imaging provides a noninvasive, high spatial and temporal resolution approach to monitor xylem cavitation, refilling, and functionality.• Spin density maps of drought-stressed maize taproots were recorded to localize cavitation events and to visualize the refilling processes; c. 2 h after release of the nutrient solution from the homemade MR imaging cuvette that received the root, late metaxylem vessels started to cavitate randomly as identified by a loss of signal intensity. After c. 6 h plants were rewatered, leading to a repair of water columns in five out of eight roots. Sap ascent during refilling, monitored with multislice MR imaging sequences, varied between 0.5 mm min −1 and 3.3 mm min −1. Flow imaging of apparently refilled vessels was performed to test for functional repair. Occasionally, a collapse of xylem vessels under tension was observed; this collapse was reversible upon rewatering.• Refilling was an all-or-none process only observed under low-light conditions. Absence of flow in some of the apparently refilled vessels indicates that functionality was not restored in these particular vessels, despite a recovery of the spin density signal.

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Diffusion generated T1 and T2 contrast

Cited by 8 publications

References 32 publications

Experimental system to detect a labeled cell monolayer in a microfluidic environment

Experimental system to detect a labeled cell monolayer in a microfluidic environment

Non-invasive magnetic resonance imaging of oils in Botryococcus braunii green algae: Chemical shift selective and diffusion-weighted imaging

Functional repair of embolized vessels in maize roots after temporal drought stress, as demonstrated by magnetic resonance imaging

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