Rotating Frame Relaxation Time Mapping for the Visualization of the Sinoatrial Node Without Contrast Agent.

Late gadolinium-enhanced cardiovascular magnetic resonance (LGE-CMR) has been used to visualize the sinoatrial node (SAN) structure. In this study, we aimed to investigate the rotating frame relaxation (RAFF2 and T) time mapping to characterize the SAN structure in the heart ex vivo without a contrast agent. Ex vivo swine heart tissues were scanned on a 7 T vertical bore preclinical and a 3 T clinical MRI system.

Quantitative magnetic resonance imaging of the atrioventricular conduction axis based on the rotating-frame relaxation maps: Comparison with T, T, and magnetization transfer.

Background: Noninvasive visualization and characterization of the atrioventricular conduction axis (AVCA) can help avoid iatrogenic injury and improve the accuracy of heart rhythm therapy guidance.

Objective: This study aimed to identify the AVCA structure using noninvasive rotating-frame relaxation-time mappings (relaxation along a fictitious field in the second rotating-frame relaxation time [T] and longitudinal rotating-frame relaxation time [T]) in ex vivo swine hearts.

Methods: Ex vivo swine heart tissue blocks were scanned on a 3T clinical magnetic resonance imaging system.

Effects of collagen and chondroitin sulfate on relaxation at multiple magnetic field strengths.

Purpose: To elucidate the connection between MRI relaxation properties of articular cartilage and tissue composition, in terms of collagen and chondroitin sulfate (CS). Additional aims were to determine the effect of different magnetic field strengths, as well as the effect of concentrations of the components on relaxation properties.

Methods: A series of MRI phantoms consisting of gels containing collagen and chondroitin sulfate were prepared with final concentrations of collagen in the range 20-60 mg/g and the CS concentration in the range 0-40 mg/g.

Anisotropy of T and T relaxation time in articular cartilage at 3 T.

Purpose: The anisotropy of R and R relaxation rates in articular cartilage contains information about the collagenous structure of the tissue. Here we determine and study the anisotropic and isotropic components of T and T relaxation parameters in articular cartilage with a clinical 3T MRI device. Furthermore, a visual representation of the topographical variation in anisotropy is given via anisotropy mapping.

Assessing post-traumatic changes in cartilage using T dispersion parameters.

Degeneration of cartilage can be studied non-invasively with quantitative MRI. A promising parameter for detecting early osteoarthritis in articular cartilage is T, which can be tuned via the amplitude of the spin-lock pulse. By measuring T at several spin-lock amplitudes, the dispersion of T is obtained.

Dipolar Relaxation of Water Protons in the Vicinity of a Collagen-like Peptide.

Quantitative magnetic resonance imaging is one of the few available methods for noninvasive diagnosis of degenerative changes in articular cartilage. The clinical use of the imaging data is limited by the lack of a clear association between structural changes at the molecular level and the measured magnetic relaxation times. In anisotropic, collagen-containing tissues, such as articular cartilage, the orientation dependency of nuclear magnetic relaxation can obscure the content of the images.

Chemical shift extremum of Xe(aq) reveals details of hydrophobic solvation.

The Xe chemical shift in an aqueous solution exhibits a non-monotonic temperature dependence, featuring a maximum at 311 K. This is in contrast to most liquids, where the monotonic decrease of the shift follows that of liquid density. In particular, the shift maximum in water occurs at a higher temperature than that of the maximum density.

Xenon NMR of liquid crystals confined to cylindrical nanocavities: a simulation study.

Applications of liquid crystals (LCs), such as smart windows and the ubiquitous display devices, are based on controlling the orientational and translational order in a small volume of LC medium. Hence, understanding the effects of confinement to the liquid crystal phase behaviour is essential. The NMR shielding of (129)Xe atoms dissolved in LCs constitutes a very sensitive probe to the details of LC environment.

Constant-pressure simulations of Gay-Berne liquid-crystalline phases in cylindrical nanocavities.

Applications of liquid crystals (LCs) are based on controlling the orientational and translational order of the medium. One important way of control is via confinement. In this work, uniaxial thermotropic LCs confined to nanosized cylindrical cavities are studied using isobaric parallel tempering (PT) Monte Carlo (MC) simulations.