MR properties of water in saturated soils and resulting loss of MRI signal in water content detection at 2 tesla

Hall, Luis J.; Amin, M. H. G.; Dougherty, E; Šanda, Martin; Votrubová, Jana; Richards, Keith; Chorley, Richard J.; Cı́slerová, Milena

doi:10.1016/s0016-7061(97)00065-7

Cited by 61 publications

(66 citation statements)

References 11 publications

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“…T 2 depends strongly on t E , so this is hard to compare. However, the reported relaxation times are in the range reported by Hall et al [12] for several soils, e.g. Korkusova Hut sandy loam which has comparable texture with T 2 = 0.9 ms for t E =1ms and t 1 = 90 ms at 40% saturation.…”

Section: Fig (3) Showsmentioning

confidence: 54%

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Relaxation in a Natural Soil: Comparison of Relaxometric Imaging, T1– T2 Correlation and Fast-Field Cycling NMR

Haber‐Pohlmeier¹

2010

TOMRJ

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Longitudinal and transverse relaxation times are used to characterise the pore system of a natural Kaldenkirchen sandy loam. Here we present new results obtained by relaxometric imaging (MEMS) and two-dimensional T 1 -T 2 correlation relaxometry, and compare these with available T 1 -relaxation time distributions of water obtained by the analysis of fast field cycling relaxometry (FFC) data. The soil shows relatively broad bimodal distribution functions P(T 1 ) and P(T 2 ) with a T 1 /T 2 ratio of about 2:1. The average T 1 as well as the spatial distribution, which are obtained from the relaxometric imaging corresponds well to the relaxometric results. From the analysis of the field dependent FFC data at low field including T 1 data obtained at high field the basic locally averaged relaxation mechanism is derived from the dispersion curve, i.e. the dependence of the relaxation rate from the magnetic field strength over five orders of magnitudes. From this we conclude that two-dimensional diffusion at locally flat surfaces controls the relaxation, i.e. the shapes of the distribution functions are controlled by surface relaxation.

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Section: Fig (3) Showsmentioning

confidence: 54%

“…transverse relaxation times due to small pore sizes and high content of paramagnetic ions [12]. The soil shows T 1 in the range of about 50 ms and T 2 of about 3 ms.…”

Section: T 1 -T 2 Correlationmentioning

confidence: 93%

Relaxation in a Natural Soil: Comparison of Relaxometric Imaging, T1– T2 Correlation and Fast-Field Cycling NMR

Haber‐Pohlmeier¹

2010

TOMRJ

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“…The 40-µs encoding time profiles were acquired to compare the validity of using a short encoding time (40 µs) against profiles produced by fitting the T * 2 -mapping data to [2].…”

Section: Methodsmentioning

confidence: 99%

“…The T * 2 impact is defined directly by the ratio (t p /T * 2 ) in Eqs. [1] and [2] and can be evaluated by using T * 2 -mapping when both the t p and the gradient values are systematically varied to keep the field of view constant (9). T 1 manifests itself through signal saturation for sequential sampling or through the transient effects for centric sampling.…”

Section: Figmentioning

confidence: 99%

Water Content Profiles with a 1D Centric SPRITE Acquisition

Mastikhin

Mullally

MacMillan

et al. 2002

Journal of Magnetic Resonance

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“…Science be as small as 0.2% of the overall liquid content (19). Therefore, to avoid misinterpreting MRI results, knowledge of the relaxation properties of individual sample components is required.…”

Section: Imagingmentioning

confidence: 99%