Double-Quantum Filtered NMR of Ordered Biological Tissues

Shinar, Hadassah; Eliav, Uzi

doi:10.1002/9780470034590.emrstm0132

Cited by 4 publications

(11 citation statements)

References 24 publications

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“…During the creation time, τ, the second‐rank tensors T 2,±1 are formed by quadrupolar interaction. During the double‐quantum evolution time, t DQ , DQ coherence (T 2,±2 ) is selected and as a result the tensors T 1,±1 are removed . The third 90° pulse converts the tensors T 2,±2 into T 2,±1 , and from there into T 1,±1 during the second τ period.…”

Section: Methodsmentioning

confidence: 99%

“…Deuteron NMR has been found to be ideally suited for investigation of tissues consisting of ordered structures for the following 3 reasons: (1) The quadrupolar interaction is significantly larger than the dipolar interaction, and therefore its residual interaction, due to anisotropic motion, is larger; and (2) the proton exchange causing averaging from dipolar interaction is not affecting the residual quadrupolar interaction; and (3) the native water can readily be exchanged with D 2 O. During the past 2 decades, some of the authors of the present paper have conducted double‐quantum‐filtered (DQF) 2 H experiments on various nervous system components, including sciatic and optic nerves and spinal cords immersed in D 2 O. This method improves the distinction between various compartments and tissues on the basis of their specific quadrupolar splittings, 2ω Q , where ω Q is the residual quadrupolar interaction …”

Section: Introductionmentioning

confidence: 99%

“…During the past 2 decades, some of the authors of the present paper have conducted double‐quantum‐filtered (DQF) 2 H experiments on various nervous system components, including sciatic and optic nerves and spinal cords immersed in D 2 O. This method improves the distinction between various compartments and tissues on the basis of their specific quadrupolar splittings, 2ω Q , where ω Q is the residual quadrupolar interaction …”

Section: Introductionmentioning

confidence: 99%

“…This method has previously been implemented for the study of various nervous system tissues, where τ ~ 0.8 ms yielded a prominent signal with a splitting of 500‐600 Hz . A detailed study of D 2 O in the spinal cord showed that this splitting originates predominantly from white matter myelin water .…”

Section: Introductionmentioning

confidence: 99%

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New insight into the organization of myelin water using deuterium NMR

Eliav

Wehrli

2020

Magnetic Resonance in Med

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Purpose: Myelin water is commonly characterized by its short proton T 2 relaxation time, suggesting strong association with the polar head groups of the bilayer constituents. Deuterium NMR of water in ordered structures exhibits splittings as a result of quadrupolar interactions that are observable using the double-quantum filter. The purpose of the current study was to identify and characterize the water populations. Methods: The 2 H double-quantum-filtered spectroscopic experiments were conducted at 62 MHz (9.4 T) on a sample of reconstituted myelin from ovine spinal cord after exchange of native water with D 2 O. Results: Signals passing the double-quantum filter were attributed to 2 water pools: 1 consisting of a doublet of 650-Hz splitting, and a second unsplit signal. Similar signals were observed in the sciatic and optic nerves and in the spinal cord. Further, data suggest that diffusion of water molecules in these 2 pools (D app ≤ 5 × 10 −7 cm 2 /s) is either hindered or restricted. An estimate of exchange lifetime of 10-15 ms between water pertaining to the single peak and that of the split peaks suggests exchange occurs in a slow-intermediate rate regime. Further distinction between the 2 pools was obtained from T 1 measurements. Deuterons belonging to the doublet resonance were found to have short T 1 , estimated to be on the order of 10-20 ms, whereas those corresponding to the single peak were close to that of bulk D 2 O. Conclusion: The results suggest that myelin extract water consists of 2 hindered populations with distinct degrees of anisotropic motion that can be studied by 2 H double-quantum-filtered NMR. K E Y W O R D SD 2 O, diffusion, double quantum, micelles, myelin, quadrupolar interaction

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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New insight into the organization of myelin water using deuterium NMR

Eliav

Wehrli

2020

Magnetic Resonance in Med

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“…In the DQF‐MT pulse sequence, single‐rank single‐quantum coherences T 1,±1 (given by

\mp {normalI}_{\pm} / \sqrt{2}

) were obtained after the application of the first 90° pulse and evolved during the creation time τ/2 to become second rank tensors T 2,±1 , which consist of product operators such as

{normalI}_{\pm}^{1} {normalI}_{z}^{2}

. These were filtered through double quantum coherences T 2,±2 (

{normalI}_{\pm}^{1} {normalI}_{\pm}^{2} / 2

) by suitable phase cycling . The filtered tensors reverted to T 2,±1 by application of the third pulse and then evolved during the second τ/2 (reconversion) period into T 1,±1 .…”

Section: Introductionmentioning

confidence: 99%

Characterization and mapping of dipolar interactions within macromolecules in tissues using a combination of DQF, MT and UTE MRI

2012

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In the present work it is shown that by combining the double quantum filtered, magnetization transfer (DQF-MT) and the ultra-short TE (UTE) MRI methods it is possible to obtain contrast between tissue compartments based on the following characteristics: (a) the residual dipolar coupling interaction within the biomacromolecules, which depends on their structure, (b) residual dipolar interactions within the water molecules, and (c) the magnetization exchange rate between biomacromolecules and water. The technique is demonstrated in rat tail specimen where the collagenous tissue, such as tendons and the annulus pulposus of the disc are highlighted in these images, and their macromolecular properties along with those of bones and muscles can be characterized. DQF-MT UTE MRI also holds promise because collagenous tissues that typically are invisible in conventional MRI experiments produce significant signal intensities using this approach.

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Identification of water compartments in spinal cords by ²H double quantum filtered NMR

Eliav

Shinar

2020

NMR in Biomedicine

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In 2H double quantum filtered (DQF) NMR, the various water compartments are characterized by their different residual quadrupolar interactions. The spectral separation between the different signals enables the measurement of the relaxation of each compartment and the magnetization transfer (MT) between them. In the current study, five water compartments were identified in the 2H DQF spectra of porcine spinal cord. The most prominent signal was the pair of satellites with a quadrupolar splitting of about 550 Hz. 2H DQF MRI optimized for the 550 Hz quadrupolar splitting indicated that this signal originated mainly from the white matter and it was assigned to the myelin water. This splitting does not change upon changing the orientation of the spinal cord relative to the magnetic field, indicating a liquid crystalline nature. Another site exhibiting splitting of about 1500 Hz was assigned to collagenous connective tissue. The narrow central peak was assigned to a combination of intra‐ and inter‐axonal water. The assignment of the other two sites is not certain and requires further study. The rates of MT between the various sites were recorded.

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Double-Quantum Filtered NMR of Ordered Biological Tissues

Cited by 4 publications

References 24 publications

New insight into the organization of myelin water using deuterium NMR

New insight into the organization of myelin water using deuterium NMR

Characterization and mapping of dipolar interactions within macromolecules in tissues using a combination of DQF, MT and UTE MRI

Identification of water compartments in spinal cords by ²H double quantum filtered NMR

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Double-Quantum Filtered NMR of Ordered Biological Tissues

Cited by 4 publications

References 24 publications

New insight into the organization of myelin water using deuterium NMR

New insight into the organization of myelin water using deuterium NMR

Characterization and mapping of dipolar interactions within macromolecules in tissues using a combination of DQF, MT and UTE MRI

Identification of water compartments in spinal cords by 2H double quantum filtered NMR

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Identification of water compartments in spinal cords by ²H double quantum filtered NMR