Nonlinear parameter estimation with physics-constrained spectral-spatial priors for highly accelerated chemical exchange saturation transfer MRI.

To develop a nonlinear, model-based parameter estimation method directly from incomplete measurements in - space for robust spectral analysis in highly accelerated chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI).. A CEST-specific, separable nonlinear model, which describes spectral decomposition using multi-pool Lorentzian functions (conventional magnetization transfer (MT), direct saturation of water signals (DS), amide, amine, and nuclear Overhauser effect) derived from the steady-state Bloch McConnel equation, is incorporated into a measurement model in CEST MRI.

Variable-density velocity-selective magnetization preparation for non-contrast-enhanced peripheral MR angiography.

Velocity-selective (VS) magnetization preparation has shown great promise for non-contrast-enhanced (NCE) magnetic resonance angiography (MRA) with the ability to generate positive angiographic contrast directly using a single 3D acquisition. However, existing VS-MRA methods have an issue of aliased saturation around a certain velocity, known as velocity field-of-view (vFOV), which can cause undesired signal loss in arteries. This study aimed to develop a new version of the VS preparation pulse sequence that overcomes the aliased saturation problem in conventional VS preparation.

Genetic variants that modify neuroendocrine gene expression and foraging behavior of .

The molecular mechanisms underlying diversity in animal behavior are not well understood. A major experimental challenge is determining the contribution of genetic variants that affect neuronal gene expression to differences in behavioral traits. In , the neuroendocrine transforming growth factor-β ligand, DAF-7, regulates diverse behavioral responses to bacterial food and pathogens.

Genetic Variants That Modify the Neuroendocrine Regulation of Foraging Behavior in .

The molecular mechanisms underlying diversity in animal behavior are not well understood. A major experimental challenge is determining the contribution of genetic variants that affect neuronal gene expression to differences in behavioral traits. The neuroendocrine TGF-beta ligand, DAF-7, regulates diverse behavioral responses of to bacterial food and pathogens.

Robust unenhanced peripheral magnetic resonance angiography using single-slab 3D chemical-shift-encoded GRASE.

To develop a novel, unenhanced magnetic resonance angiography (MRA) exploiting cardiac-gated, single-slab 3D chemical-shift-encoded gradient- and spin-echo (GRASE) imaging for robust background suppression.The proposed single-slab 3D GRASE employs variable-flip-angles (VFA) in the refocusing radio-frequency (RF) pulse train to promote sensitivity to blood flow as well as imaging encoding efficiency. Phase encoding blips are inserted between adjacent lobes of the switching readout gradients such that chemical shift-induced phase information is encoded into different locations in k-space.

Whole-Neck Non-Contrast-Enhanced MR Angiography Using Velocity Selective Magnetization Preparation.

This study aimed to optimize velocity-selective magnetic resonance angiography (VS-MRA) protocols for whole-neck angiography and demonstrate its feasibility in healthy subjects with comparisons to clinical 3D time-of-flight (TOF) angiography. To help optimize VS-MRA protocols, 2D phase-contrast (PC) flow imaging and 3D B and B field mappings were performed on five healthy volunteers. Based on these measurements, a slab-selective (SS) inversion preparation was applied prior to a VS saturation preparation to further suppress venous blood, while the VS preparation pulse was designed with compensation for field offsets.

A prospective patient registry to monitor safety, effectiveness, and utilisation of bedaquiline in patients with multidrug-resistant tuberculosis in South Korea.

Background: Multidrug-resistant tuberculosis (MDR-TB) represents a major public health concern, with an ongoing need for new effective treatments. Bedaquiline is an oral diarylquinoline that has shown encouraging treatment success and culture conversion rates in MDR-TB.

Methods: A South Korean patient registry was set up across 19 centres between 2016 and 2018 for the prospective collection of data from patients with MDR-TB who received either a bedaquiline-containing or a non-bedaquiline-containing regimen.

Automated Detection of Surgical Implants on Plain Knee Radiographs Using a Deep Learning Algorithm.

: The number of patients who undergo multiple operations on a knee is increasing. The objective of this study was to develop a deep learning algorithm that could detect 17 different surgical implants on plain knee radiographs. : An internal dataset consisted of 5206 plain knee antero-posterior X-rays from a single, tertiary institute for model development.

Generalized self-calibrating simultaneous multi-slice MR image reconstruction from 3D Fourier encoding perspective.

This work introduces a novel, k-space based one-step solution for simultaneous multi-slice MR image reconstruction from 3D Fourier encoding perspective. With undersampled SMS imaging, image reconstruction suffers from both inter-slice leakages and in-plane aliasing artifacts. Aliasing separation becomes further challenging in the presence of discrepancies between calibration and imaging.

Microwave-Assisted Extract for Cosmetic Applications.

Recently, utilizing natural bioactive compounds for active ingredients in cosmetics has become a growing worldwide trend. More and more studies aim to identify the sources of herbal ingredients for applications in the pharmaceutical and cosmetic fields. Additionally, in order to optimize the safety of natural ingredients, choosing an environmentally friendly extraction method also plays an important role.

SNR-Enhanced, Rapid Electrical Conductivity Mapping Using Echo-Shifted MRI.

Magnetic resonance electrical impedance tomography (MREIT) permits high-spatial resolution electrical conductivity mapping of biological tissues, and its quantification accuracy hinges on the signal-to-noise ratio (SNR) of the current-induced magnetic flux density (). The purpose of this work was to achieve SNR-enhanced rapid conductivity imaging by developing an echo-shifted steady-state incoherent imaging-based MREIT technique. In the proposed pulse sequence, the free-induction-decay signal is shifted in time over multiple imaging slices, and as a result is exposed to a plurality of injecting current pulses before forming an echo.

FID-calibrated simultaneous multi-slice fast spin echo with long trains of hard pulses.

. To develop a novel, free-induction-decay (FID)-calibrated single-shot simultaneous multi-slice fast spin echo (SMS-FSE) with very long hard pulse trains for high encoding efficiency and low energy deposition..

Assessing the reproducibility of high temporal and spatial resolution dynamic contrast-enhanced magnetic resonance imaging in patients with gliomas.

Temporal and spatial resolution of dynamic contrast-enhanced MR imaging (DCE-MRI) is critical to reproducibility, and the reproducibility of high-resolution (HR) DCE-MRI was evaluated. Thirty consecutive patients suspected to have brain tumors were prospectively enrolled with written informed consent. All patients underwent both HR-DCE (voxel size, 1.

Joint Reconstruction of Vascular Structure and Function Maps in Dynamic Contrast Enhanced MRI Using Vascular Heterogeneity Priors.

This work introduces a novel, joint reconstruction of vascular structure and microvascular function maps directly from highly undersampled data in k - t space using vascular heterogeneity priors for high-definition, dynamic contrast-enhanced (DCE) MRI. In DCE MRI, arteries and veins are characterized by rapid, high uptake and wash-out of contrast agents (CA). On the other hand, depending on CA uptake and wash-out signal patterns, capillary tissues can be categorized into highly perfused, moderately perfused, and necrotic regions.

Single-shot pseudo-centric EPI for magnetization-prepared imaging.

Purpose: To implement a single-shot centric-reordered EPI (1sh-CenEPI), which reduces TE significantly, thus enabling to improve SNR for magnetization-prepared imaging.

Methods: We proposed a 1sh-CenEPI in which grouped oscillating readout gradients, phase-encoding blips within each group, and big phase-encoding jumps between two consecutive groups are incorporated to encode whole k-space from the center to the edges in a single shot. The concept was tested on phantoms and human brains at 3 T.

Clinical Implications of Neurological Comorbidities and Complications in ICU Patients with COVID-19.

Clinical implications of neurological problems during intensive care unit (ICU) care for coronavirus disease 2019 (COVID-19) patients are unknown. This study aimed to describe the clinical implications of preexisting neurological comorbidities and new-onset neurological complications in ICU patients with COVID-19. ICU patients who were isolated and treated for COVID-19 between 19 February 2020 and 3 May 2020, from one tertiary hospital and one government-designated branch hospital were included.

Rapid three-dimensional steady-state chemical exchange saturation transfer magnetic resonance imaging.

Purpose: To make clinically feasible whole-brain chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) by enhancing imaging efficiency.

Methods: A novel, whole-brain three-dimensional (3D) steady-state CEST MRI method was introduced by utilizing a time-efficient, fat-suppressed excitation followed by rapid, segmented 3D echo-planar-imaging with incoherent undersampling in k-ω space. Missing signals and CEST-specific spectral images were then jointly estimated directly from incomplete measurements using model-based reconstruction and robust spectral analysis.

Immediate activation of chemosensory neuron gene expression by bacterial metabolites is selectively induced by distinct cyclic GMP-dependent pathways in Caenorhabditis elegans.

Dynamic gene expression in neurons shapes fundamental processes in the nervous systems of animals. However, how neuronal activation by different stimuli can lead to distinct transcriptional responses is not well understood. We have been studying how microbial metabolites modulate gene expression in chemosensory neurons of Caenorhabditis elegans.

Association of scar distribution with epicardial electrograms and surface ventricular tachycardia QRS duration in nonischemic cardiomyopathy.

Introduction: The association of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) with epicardial and surface ventricular tachycardia (VT) electrogram features, in nonischemic cardiomyopathy (NICM), is unknown. We sought to define the association of LGE and viable wall thickness with epicardial electrogram features and exit site paced QRS duration in patients with NICM.

Methods: A total of 19 patients (age 53.

Model-Based High-Definition Dynamic Contrast Enhanced MRI for Concurrent Estimation of Perfusion and Microvascular Permeability.

This work introduces a model-based, high-definition dynamic contrast enhanced (DCE) MRI for concurrent estimation of perfusion and microvascular permeability over the whole brain. A time series of reference-subtracted signals is decomposed into one component that reflects main contrast dynamics and the other one that includes residual contrast agents (CA) and background signals. The former is described by linear superposition of a finite number of basic vectors trained from an augmented set of data that consists of tracer-kinetic model driven signal vectors and patient-specific measured ones.

Status of international normalized ratio control and treatment patterns in patients with nonvalvular atrial fibrillation taking vitamin K antagonist with or without antiplatelet therapy: Results from KORAFII registry.

Background: Studies have shown that the concomitant use of a vitamin K antagonist (VKA) and an antiplatelet (APL) drug increased the bleeding risk and was less effective at preventing ischemic events. This study aimed to investigate the control status of international normalized ratio (INR) and the discontinuation rate of a VKA in patients taking VKA plus an APL drug compared with those taking a VKA alone.

Methods: Data were extracted from the KORean Atrial Fibrillation Investigation II registry, a multicenter noninterventional prospective observational study.

Biocompatibility evaluation of bioprinted decellularized collagen sheet implanted in vivo cornea using swept-source optical coherence tomography.

Corneal transplantation by full-thickness penetrating keratoplasty with human donor tissue is a widely accepted treatment for damaged or diseased corneas. Although corneal transplantation has a high success rate, a shortage of high-quality donor tissue is a considerable limitation. Therefore, bioengineered corneas could be an effective solution for this limitation, and a decellularized extracellular matrix comprises a promising scaffold for their fabrication.

A Comparison Study of Marginal and Internal Fit Assessment Methods for Fixed Dental Prostheses.

Numerous studies have previously evaluated the marginal and internal fit of fixed prostheses; however, few reports have performed an objective comparison of the various methods used for their assessment. The purpose of this study was to compare five marginal and internal fit assessment methods for fixed prostheses. A specially designed sample was used to measure the marginal and internal fit of the prosthesis according to the cross-sectional method (CSM), silicone replica technique (SRT), triple scan method (TSM), micro-computed tomography (MCT), and optical coherence tomography (OCT).

Association of regional myocardial conduction velocity with the distribution of hypoattenuation on contrast-enhanced perfusion computed tomography in patients with postinfarct ventricular tachycardia.

Background: Cardiac magnetic resonance imaging has been shown to be beneficial for identification of the ventricular tachycardia (VT) substrate before catheter ablation. Contrast-enhanced perfusion multidetector computed tomography (CEP-MDCT) is more generalizable to clinical practice, and wall thickness and regional hypoenhancement on CEP-MDCT can identify potential substrate sites, albeit with decreased specificity.

Objective: The purpose of this study was to evaluate the association between wall thickness and attenuation on CEP-MDCT with local conduction velocity (CV) and electrogram abnormalities in patients with postinfarct VT.