MRI magic-angle effect in femorotibial cartilages of the red kangaroo

Ali, Tonima S.; Thibbotuwawa, Noyel Deegayu Namal Bandara; Gu, Yuantong; Momot, Konstantin I.

doi:10.1016/j.mri.2017.07.010

Cited by 6 publications

(5 citation statements)

References 44 publications

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“…Therefore, MD is a computational tool that is widely used to understand the dynamics of liquid water (see, e.g., refs − , , , and − ). In turn, the dynamics of water and the resulting spin-relaxation properties enable the interrogation of the structure and organization of materials and biological tissues. − As the long-term aim of this research is to understand the NMR spin-relaxation properties of water in detail, this study has focused on the dynamics of the H–H vector of the water molecule on the time scales relevant to 1 H spin relaxation at high magnetic field (1–20 T). In this article, we present our study of the rotational dynamics of the intramolecular proton–proton vectors of liquid water using molecular dynamics simulations at nonextreme temperatures and pressures.…”

Section: Introductionmentioning

confidence: 99%

Rotational-Diffusion Propagator of the Intramolecular Proton–Proton Vector in Liquid Water: A Molecular Dynamics Study

Madhavi

Weerasinghe²,

Momot

2017

J. Phys. Chem. B

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The rotational motion of water molecules plays the dominant role in determining NMR spin-relaxation properties of liquid water and many biological tissues. The traditional theory of NMR spin relaxation predominantly uses the assumption that the reorientational dynamics of water molecules is described by a continuous-time rotational-diffusion random walk with a single rotational-diffusion coefficient. However, recent experimental and theoretical studies have demonstrated that water reorientation occurs by large, discrete angular jumps superimposed on a continuous-time rotational-diffusion process. We have investigated the rotational-diffusion propagator of the proton-proton (H-H) vector of water molecules in liquid water at 298 K using molecular dynamics (MD) simulations. Analysis of the MD-simulated reorientational trajectories reveals that reorientation of the intramolecular H-H vector occurs through a combination of the two mechanisms: rotational diffusion proper and discrete large-angle jumps. We demonstrate that, empirically, the rotational-diffusion propagator of the intramolecular H-H vector in liquid water can be described in terms of multiple rotational-diffusion coefficients. A model with two rotational-diffusion coefficients was found to provide a reasonable (albeit imperfect) fit of the MD-simulated propagator on the time scales relevant to NMR spin relaxation near room or physiological temperature (picoseconds to nanoseconds). We report the apparent values of the two rotational-diffusion coefficients determined from the propagator analysis at 298 K and discuss their physical meaning.

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Section: Introductionmentioning

confidence: 99%

Rotational-Diffusion Propagator of the Intramolecular Proton–Proton Vector in Liquid Water: A Molecular Dynamics Study

Madhavi

Weerasinghe²,

Momot

2017

J. Phys. Chem. B

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“…The MA effect is important in clinical MRI, where it is alternately seen either as an unwanted imaging artifact complicating the interpretation of MR images or a source of information about tissue organization and microstructure. A considerable body of musculoskeletal radiology literature concerns the need for identification and adequate correction of the MA effect in clinical MRI. − On the other hand, the effect can be exploited to gain quantitative imaging information characterizing microstructural, biomechanical, or compositional properties of biological tissues. ,,− …”

Section: Magnetic Resonance Imaging and The Magic-angle Effectmentioning

confidence: 99%

Hydrated Collagen: Where Physical Chemistry, Medical Imaging, and Bioengineering Meet

Momot

2022

J. Phys. Chem. B

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“…Usually they even have a preferred direction which can observed by so-called split lines (Below, Arnoczky, Dodds, Kooima, & Walter, 2002;Jeffery et al, 1991;Meachim, Denham, Emery, & Wilkinson, 1974). The structure of cartilage is mostly similar throughout different animal species (Ali, Thibbotuwawa, Gu, & Momot, 2017;Mancini et al, 2019;Nissi et al, 2006).…”

Section: Cartilagementioning

confidence: 99%

Relaxation anisotropy of quantitative MRI parameters in biological tissues

Hänninen

Liimatainen

Hanni

et al. 2022

Preprint

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Quantitative MR relaxation parameters vary in their sensitivity to the orientation of the tissue in the magnetic field. In this study, the orientation dependence of multiple relaxation parameters was assessed in various tissues. Ex vivo samples of different tissue types were prepared either from bovine knee (tendon, cartilage) or mouse (brain, spinal cord, heart, kidney), and imaged at 9.4 T MRI with T1, T2, CW-T1ρ, adiabatic T1ρ and T2ρ, and RAFF2-4 sequences at five different orientations with respect to the main magnetic field. Relaxation anisotropy of the measured parameters was quantified and evaluated. Highly ordered collagenous tissues, cartilage and tendon, presented the highest relaxation anisotropy for T2, CW-T1ρ with spin-lock power < 1 kHz, Ad-T2ρ and RAFF2-4. Maximally, anisotropy was 75% in cartilage and 30% in tendon. In the other measured soft tissues, anisotropy was less than 10% for all the parameters. T1 and Ad-T1ρ exhibit little to no observable anisotropy. The results confirm that highly ordered collagenous tissues have properties that induce remarkable relaxation anisotropy, whereas for the other soft tissues investigated, the effect is less prominent. Quantitative comparison of anisotropies between relaxation parameters highlights the importance of sequence choice and design in MR imaging.

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MRI magic-angle effect in femorotibial cartilages of the red kangaroo

Cited by 6 publications

References 44 publications

Rotational-Diffusion Propagator of the Intramolecular Proton–Proton Vector in Liquid Water: A Molecular Dynamics Study

Rotational-Diffusion Propagator of the Intramolecular Proton–Proton Vector in Liquid Water: A Molecular Dynamics Study

Hydrated Collagen: Where Physical Chemistry, Medical Imaging, and Bioengineering Meet

Relaxation anisotropy of quantitative MRI parameters in biological tissues

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