Proton magnetic resonance relaxation behavior of whole muscle with fatty inclusions.

Fullerton, Gary D.; Cameron, Ivan L.; Hunter, Keithley E.; Fullerton, H J

doi:10.1148/radiology.155.3.4001376

Cited by 23 publications

(11 citation statements)

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“…The lack of hydrogen bonding sites in the lipids limits their cross-relaxation properties with water, and the two components relax as if they were confined separately. Biphasic relaxation should therefore be anticipated (Fullerton et al, 1985). However, the T " and T # values were obtained from total mobile "H images and the biphasic character was indivisible as a result of an insufficient number of time-point determinations of relaxation times.…”

Section: Seedsmentioning

confidence: 99%

The development of blackcurrant fruit from flower to maturity: a comparative study by 3D nuclear magnetic resonance (NMR) micro‐imaging and conventional histology

Glidewell¹,

Williamson²,

Duncan³

et al. 1999

New Phytologist

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The development of fruits of blackcurrant (Ribes nigrum) cv. Ben Alder from flower to maturity was studied non-invasively by nuclear magnetic resonance (NMR) microscopy, using attached and detached fruits, and the images were compared with those from low temperature scanning electron microscopy (LTSEM) and conventional resin histology. The NMR images derived from 2-D and 3-D datasets showed the previously unreported growth of arillar tissues to the extent that they almost completely occlude the locular cavity, but LTSEM and resin histology revealed that no fusion occurs between the arillar tissues and the gelatinous sheath surrounding each seed, or between the arillar tissues and the endocarp. The discontinuities between these tissues cause magnetic inhomogenities which result in these structures being clearly resolved by gradient echo imaging sequences. During seed maturation the endosperm changed from high (bright) to low (dark) signal intensity as lipid reserves formed and solidified, whereas the gelatinous sheath had high signal intensity throughout maturation. The high lipid concentration in the seed was manifested by chemical shift effects in the images and the increasing viscosity of the endosperm was reflected in the decrease in spin-lattice (T " ) relaxation times. The funiculi, throughout development of seeds, appeared in NMR images with low signal intensity and 3-D surface-rendered reconstructions illustrated the complexity of the spatial array of seeds and funiculi arising from parietal placentas within the loculus. All other vascular tissues in the pericarp and placentas were resolved as a small bright core surrounded by a dark region, within a matrix of moderate signal intensity. Conventional microscopical studies then showed that the bright core discernible by NMR imaging encompassed an entire vascular bundle whereas the darker surrounding region represented small parenchyma cells with pronounced intercellular gas spaces. Other regions of the pericarp which included extremely large parenchyma cells, however, had few intercellular spaces and consequently gave rise to brighter regions of the image.Key words : NMR imaging, three-dimensional reconstruction, surface rendering, low temperature scanning electron microscopy (LTSEM), resin histology, Ribes nigrum. Blackcurrant (Ribes nigrum) and related taxa are important sources of vitamin C and the essential fatty acid, γ-linoleic acid, and the fruits are used extensively for the manufacture of juices, jams, preserves, alcoholic beverages and confectionery.*Author for correspondence (e-mail s.glidewell!scri.sari.ac.uk).We have previously examined by proton NMR microscopy the ripe fruits of gooseberry (Ribes grossularia) and made preliminary observations of mature fruits of blackcurrant (Williamson et al., 1992b) and studied freezing damage in flowers of R. nigrum (Brennan et al., 1997). The anatomy of mature fruits of redcurrant (R. rubrum) and R. nigrum was described by Winton (1902) and the floral development and vascular system in ...

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Section: Seedsmentioning

confidence: 99%

The development of blackcurrant fruit from flower to maturity: a comparative study by 3D nuclear magnetic resonance (NMR) micro‐imaging and conventional histology

Glidewell¹,

Williamson²,

Duncan³

et al. 1999

New Phytologist

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“…These results are contrary to what would be expected for a fast‐exchange model of muscle tissue (10, 11). On a T 1 timescale, however, there is no apparent distinction between these spin‐groups, indicating fast exchange on that timescale (8, 12–15). Due to technical limitations, these studies have been restricted to excised muscle tissues.…”

mentioning

confidence: 99%

Two‐dimensional time correlation relaxometry of skeletal muscle in vivo at 3 Tesla

Saab

Thompson

Marsh

et al. 2001

Magnetic Resonance in Med

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A hybrid two-dimensional relaxometry (2DR) sequence was used to simultaneously measure both the spin-spin (R 2 ) and spin-lattice relaxation rates (R 1 ) of skeletal muscle in vivo. The 2DR sequence involved a 180°inversion pulse followed by a variable delay time (30 values from 40 to 7000 ms); a projection presaturation (PP) scheme to localize a 16-ml cylindrical voxel; and a CPMG sequence (950 even echoes, effective echo spacing ‫؍‬ 1.2 ms, equilibrium time ‫؍‬ 12 s). The 2DR data were collected at 3.0 Tesla from the flexor digitorum profundus of eight healthy males, 26 ؎ 2 years old. Analysis was performed with a 2D version of the non-negative least-squares algorithm and a one-way ANOVA. All subjects exhibited at least three spin-groups (R 2 < 200 s Spin-lattice (R 1 ) and spin-spin relaxation rates (R 2 ) do not reflect instantaneous molecular configurations; they are average values that arise from a system of molecular environments (spin-groups) over a finite time period. A proper interpretation of relaxometry data requires a detailed understanding of the nature and timescale of processes that contribute to the averaging phenomenon. The exchange of entire water molecules between spin-groups is a predominant process (1,2). The exchange model of Zimmerman and Britten (3) predicts that fast exchange between m spin-groups would produce an averaged relaxation rate R i,avg :where P j and R i,j is the population fraction and relaxation rate of the jth spin-group respectively (⌺P j ϭ 1). Equation[1] yields monoexponential relaxation that would mask information about the individual spin-groups. On the other hand, relaxation rates would not be averaged at the slow-exchange limit, and multiexponential relaxation would be observed. The characterization of fast and slow exchange depends on the relaxation timescale defined by a particular relaxation parameter. For two spin-groups a and b, the exchange rate between them (k ab ) must be greater than, equal to, or less than the quantity R i,b -R i,a to meet the conditions of fast, intermediate, and slow exchange, respectively (4). The variable R i could represent either a spinlattice or a spin-spin relaxation rate, so it is possible for a system to be in fast exchange on a spin lattice relaxation (T 1 ) timescale (T i ϭ R i -1 ), but in slow or intermediate exchange on a spin-spin relaxation (T 2 ) timescale.This would be consistent with data from NMR studies of excised muscle, using (non-imaging) relaxometry techniques with optimal experimental parameters (5). For several decades, T 2 of excised muscle tissue has been described as multiexponential. About 80 -90% of the signal decay is characterized by one spin-group (T 2 ϭ 20 -40 ms), while 10 -15% of the signal arises from another (T 2 Ն 100 ms) (6 -9). These results are contrary to what would be expected for a fast-exchange model of muscle tissue (10,11). On a T 1 timescale, however, there is no apparent distinction between these spin-groups, indicating fast exchange on that timescale (8,(12)(13)(14)(15). Due to technica...

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“…All three cancers have relaxation times longer than those of their normal counterparts. The longer T I of the cancers is not caused by less fat, which if present in fractions greater than 2-370 can contribute a short T I component (38). The longer relaxation times in the cancers are not caused by more vascular space, which contains blood with a relatively long T I , 1 141 +-7 ms (SD, n = 4 C3H mice); on the contrary, there is less vascular space in two, and no change in one of the cancers.…”

Section: Resultsmentioning

confidence: 94%

Evidence for a contribution of paramagnetic ions to water proton spin‐lattice relaxation in normal and malignant mouse tissues

Negendank

Corbett

Crowley

et al. 1991

Magnetic Resonance in Med

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Paramagnetic ions complexed to proteins may lose, retain, or enhance solvent paramagnetic relaxation (SPR) relative to free solution. We measured T1 and T2 of three mouse cancers, their normal counterparts, and six additional tissues. Long T1 of cancers was not caused by necrosis or by different contents of water, fat, or blood. Dissociable (TCA-extractable) and nondissociable (ashed) Mn, Cu, and Fe were measured by AA. Cancers had less Mn, Cu, and Fe than did normal counterparts. All 12 tissues had inverse correlations between T1 and dissociable Mn and Cu. For Mn alone to account for reduced T1, the extent to which SPR of the Mn-protein complexes would be enhanced is by factors of 0.6 to 13, below the maximum observed in Mn-enzymes. Different amounts of paramagnetic ion-protein complexes may account for part of the differences in T1 of water protons in different tissues, and the longer T1 of cancer cell water may be caused in part by reduced amounts of such complexes.

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Proton magnetic resonance relaxation behavior of whole muscle with fatty inclusions.

Cited by 23 publications

References 0 publications

The development of blackcurrant fruit from flower to maturity: a comparative study by 3D nuclear magnetic resonance (NMR) micro‐imaging and conventional histology

The development of blackcurrant fruit from flower to maturity: a comparative study by 3D nuclear magnetic resonance (NMR) micro‐imaging and conventional histology

Two‐dimensional time correlation relaxometry of skeletal muscle in vivo at 3 Tesla

Evidence for a contribution of paramagnetic ions to water proton spin‐lattice relaxation in normal and malignant mouse tissues

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