Rapid whole-brain quantitative magnetization transfer imaging using 3D selective inversion recovery sequences.

Selective inversion recovery (SIR) is a quantitative magnetization transfer (qMT) method that provides estimates of parameters related to myelin content in white matter, namely the macromolecular pool-size-ratio (PSR) and the spin-lattice relaxation rate of the free pool (R), without the need for independent estimates of ∆B, B, and T. Although the feasibility of performing SIR in the human brain has been demonstrated, the scan times reported previously were too long for whole-brain applications. In this work, we combined optimized, short-TR acquisitions, SENSE/partial-Fourier accelerations, and efficient 3D readouts (turbo spin-echo, SIR-TSE; echo-planar imaging, SIR-EPI; and turbo field echo, SIR-TFE) to obtain whole-brain data in 18, 10, and 7 min for SIR-TSE, SIR-EPI, SIR-TFE, respectively.

Quantitative magnetization transfer imaging of the human locus coeruleus.

The locus coeruleus (LC) is the major origin of norepinephrine in the central nervous system, and is subject to age-related and neurodegenerative changes, especially in disorders such as Parkinson's disease and Alzheimer's disease. Previous studies have shown that neuromelanin (NM)-sensitive MRI can be used to visualize the LC, and it is hypothesized that magnetization transfer (MT) effects are the primary source of LC contrast. The aim of this study was to characterize the MT effects in LC imaging by applying high spatial resolution quantitative MT (qMT) imaging to create parametric maps of the macromolecular content of the LC and surrounding tissues.

Longitudinal data for magnetic susceptibility of normative human brain development and aging over the lifespan.

The data presented in this article accompany the research article entitled "Longitudinal Atlas for Normative Human Brain Development and Aging over the Lifespan using Quantitative Susceptibility Mapping" (Zhang et al., 2018) [1]. The longitudinal evolution of magnetic susceptibility in human brain indicates critical characteristics of normal brain development and aging.

Quantifying MRI frequency shifts due to structures with anisotropic magnetic susceptibility using pyrolytic graphite sheet.

Magnetic susceptibility is an important source of contrast in magnetic resonance imaging (MRI), with spatial variations in the susceptibility of tissue affecting both the magnitude and phase of the measured signals. This contrast has generally been interpreted by assuming that tissues have isotropic magnetic susceptibility, but recent work has shown that the anisotropic magnetic susceptibility of ordered biological tissues, such as myelinated nerves and cardiac muscle fibers, gives rise to unexpected image contrast. This behavior occurs because the pattern of field variation generated by microstructural elements formed from material of anisotropic susceptibility can be very different from that predicted by modelling the effects in terms of isotropic susceptibility.

Quantitative susceptibility mapping (QSM) as a means to monitor cerebral hematoma treatment.

Background: Quantitative susceptibility mapping (QSM) offers a consistent hemorrhage volume measurement independent of imaging parameters.

Purpose: To investigate the magnetic susceptibility of intracerebral hemorrhage (ICH) as a quantitative measurement for monitoring treatment in hematoma patients.

Study Type: Prospective.

Longitudinal atlas for normative human brain development and aging over the lifespan using quantitative susceptibility mapping.

Longitudinal brain atlases play an important role in the study of human brain development and cognition. Existing atlases are mainly based on anatomical features derived from T1-and T2-weighted MRI. A 4D developmental quantitative susceptibility mapping (QSM) atlas may facilitate the estimation of age-related iron changes in deep gray matter nuclei and myelin changes in white matter.

Exploring the origins of echo-time-dependent quantitative susceptibility mapping (QSM) measurements in healthy tissue and cerebral microbleeds.

Quantitative susceptibility mapping (QSM) is increasingly used to measure variation in tissue composition both in the brain and in other areas of the body in a range of disease pathologies. Although QSM measurements were originally believed to be independent of the echo time (TE) used in the gradient-recalled echo (GRE) acquisition from which they are derived; recent literature (Sood et al., 2016) has shown that these measurements can be highly TE-dependent in a number of brain regions.

Histological Basis of Laminar MRI Patterns in High Resolution Images of Fixed Human Auditory Cortex.

Functional magnetic resonance imaging (fMRI) studies of the auditory region of the temporal lobe would benefit from the availability of image contrast that allowed direct identification of the primary auditory cortex, as this region cannot be accurately located using gyral landmarks alone. Previous work has suggested that the primary area can be identified in magnetic resonance (MR) images because of its relatively high myelin content. However, MR images are also affected by the iron content of the tissue and in this study we sought to confirm that different MR image contrasts did correlate with the myelin content in the gray matter and were not primarily affected by iron content as is the case in the primary visual and somatosensory areas.

A comparison of phase imaging and quantitative susceptibility mapping in the imaging of multiple sclerosis lesions at ultrahigh field.

Objective: The aim of this study was to compare the use of high-resolution phase and QSM images acquired at ultra-high field in the investigation of multiple sclerosis (MS) lesions with peripheral rings, and to discuss their usefulness for drawing inferences about underlying tissue composition.

Materials And Methods: Thirty-nine Subjects were scanned at 7 T, using 3D T 2*-weighted and T 1-weighted sequences. Phase images were then unwrapped and filtered, and quantitative susceptibility maps were generated using a thresholded k-space division method.

A 30-day clinical comparison of a novel interdental cleaning device and dental floss in the reduction of plaque and gingivitis.

Objective: To compare the safety and efficacy of a novel battery-operated interdental cleaning device (Oral-B Hummingbird) [ID], fitted with either a flossette or pick attachment, versus hand-held dental floss in the reduction of plaque and gingivitis when combined with manual tooth brushing over a 30-day period.

Methodology: This randomized, examiner blind, parallel group study assessed three treatment groups: ID/flossette (ID/F), ID/pick (ID/P), and unwaxed manual dental floss. All groups used the same soft manual toothbrush and toothpaste.

Comparison of two over-the-counter tooth whitening products using a novel system.

Tooth whitening is one of the most widely accepted esthetic procedures in dentistry. Various treatment options include in-office and prescribed at-home bleaching procedures, over-the-counter bleaching kits, and whitening dentifrices. This study evaluated and compared a 6% hydrogen peroxide tooth bleaching gel delivered on polyethylene film (HP) with an 18% carbamide peroxide brush-applied liquid gel (CP).

A clinical study of plaque removal with an advanced rechargeable power toothbrush and a battery-operated device.

Purpose: To compare the safety and efficacy of two recently introduced modern power toothbrushes with different characteristics.

Materials And Methods: This was a single-blind, randomized, crossover study which compared the ability of two power toothbrushes to remove plaque during a 2-minute brushing period. The two brushes were the Braun Oral-B 3D Excel (D17), a rechargeable toothbrush with an oscillating/rotating/pulsating action and the Colgate Actibrush, a battery-operated device with an oscillating/rotating action.