Association Between Taurine Level in the Hippocampus and Major Depressive Disorder in Young Women: A Proton Magnetic Resonance Spectroscopy Study at 7T.

Background: Major depressive disorder (MDD) is characterized by depressed mood or loss of interest or pleasure. Generally, women are twice as likely as men to have depression. Taurine, a type of amino acid, plays critical roles in neuronal generation, differentiation, arborization, and formation of synaptic connections.

Correct Closure of the Left Atrial Appendage Reduces Stagnant Blood Flow and the Risk of Thrombus Formation: A Proof-of-Concept Experimental Study Using 4D Flow Magnetic Resonance Imaging.

Objective: The study was conducted to investigate the effect of correct occlusion of the left atrial appendage (LAA) on intracardiac blood flow and thrombus formation in patients with atrial fibrillation (AF) using four-dimensional (4D) flow magnetic resonance imaging (MRI) and three-dimensional (3D)-printed phantoms.

Materials And Methods: Three life-sized 3D-printed left atrium (LA) phantoms, including a pre-occlusion (i.e.

An aptamer-based magnetic resonance imaging contrast agent for detecting oligomeric amyloid-β in the brain of an Alzheimer's disease mouse model.

The oligomeric amyloid-β (oAβ) is a reliable feature for an early diagnosis of Alzheimer's disease (AD). Therefore, the objective of this study was to demonstrate imaging of oAβ deposits using our developed DNA aptamer called ob5 conjugated with gadolinium (Gd)-dodecane tetraacetic acid (DOTA) as a contrast agent for early diagnosis of AD using MRI. An oAβ-specific aptamer was developed by amide bond formation and conjugated to Gd-DOTA MRI contrast agent and/or cyanine5 (cy5).

Hypoxia-Responsive Luminescent CEST MRI Agent for and Tumor Detection and Imaging.

Hypoxia is a feature of most solid tumors and a key determinant of cancer growth and propagation. Sensing hypoxia effectively could lead to more favorable clinical outcomes. Here, we report a molecular antenna-based bimodal probe designed to exploit the complementary advantages of magnetic resonance (MR)- and optical-based imaging.

Patient-specific Hemodynamics of Severe Carotid Artery Stenosis Before and After Endarterectomy Examined by 4D Flow MRI.

Carotid endarterectomy (CEA) influences the carotid endoluminal anatomy, which results in hemodynamic changes before and after surgery. We investigated the hemodynamics of severe carotid artery stenosis before and after conventional endarterectomy with/without patch repair. An in vitro experiment utilizing carotid phantoms, which underwent a procedure that emulated CEA with/without the patch repair, was performed with a high-spatiotemporal resolution using 4D flow MRI.

Novel and facile criterion to assess the accuracy of WSS estimation by 4D flow MRI.

Four-dimensional flow magnetic resonance imaging (4D flow MRI) is a versatile tool to obtain hemodynamic information and anatomic information simultaneously. The wall shear stress (WSS), a force exerted on a vessel wall in parallel, is one of the hemodynamic parameters available with 4D flow MRI and is thought to play an important role in clinical applications such as assessing the development of atherosclerosis. Nevertheless, the accuracy of WSS obtained with 4D flow MRI is rarely evaluated or reported in literature, especially in the in vivo studies.

Photothermal-modulated drug delivery and magnetic relaxation based on collagen/poly(γ-glutamic acid) hydrogel.

Injectable and stimuli-responsive hydrogels have attracted attention in molecular imaging and drug delivery because encapsulated diagnostic or therapeutic components in the hydrogel can be used to image or change the microenvironment of the injection site by controlling various stimuli such as enzymes, temperature, pH, and photonic energy. In this study, we developed a novel injectable and photoresponsive composite hydrogel composed of anticancer drugs, imaging contrast agents, bio-derived collagen, and multifaceted anionic polypeptide, poly (γ-glutamic acid) (γ-PGA). By the introduction of γ-PGA, the intrinsic temperature-dependent phase transition behavior of collagen was modified to a low viscous sol state at room temperature and nonflowing gel state around body temperature.

Manganese-enhanced MR imaging of brain activation evoked by noxious peripheral electrical stimulation.

As imaging technology develops, magnetic resonance imaging (MRI) has furthered our understanding of brain function by clarifying the anatomical structure and generating functional imaging data related to information processing in pain conditions. Recent studies have reported that manganese (Mn(2+))-enhanced MRI (MEMRI) provides valuable information about the functions of the central nervous system. The aim of this study was to identify specific brain regions activated during noxious electric stimulation using high-resolution MEMRI.

Hyaluronic acid derivative-coated nanohybrid liposomes for cancer imaging and drug delivery.

Nanohybrid liposomes coated with amphiphilic hyaluronic acid-ceramide (HACE) was fabricated for targeted delivery of anticancer drug and in vivo cancer imaging. Nanohybrid liposomes including doxorubicin (DOX) and Magnevist, a contrast agent for magnetic resonance (MR) imaging, with 120-130nm mean diameter and a narrow size distribution were developed. DOX release from the developed formulation was improved at acidic pH (pH5.

Ultra-small, uniform, and single bcc-phased Fe(x)Co(1-x)/graphitic shell nanocrystals for T1 magnetic resonance imaging contrast agents.

We have synthesized ultra-small and uniform Fe(x)Co(1-x)/graphitic carbon shell (Fe(x)Co(1-x)/GC) nanocrystals (x=0.13, 0.36, 0.

In vivo (1)H-MRS hepatic lipid profiling in nonalcoholic fatty liver disease: an animal study at 9.4 T.

The applicability of the in vivo proton magnetic resonance spectroscopy hepatic lipid profiling (MR-HLP) technique in nonalcoholic fatty liver disease was investigated. Using magnetic resonance spectroscopy, the relative fractions of diunsaturated (fdi), monounsaturated (fmono), and saturated (fsat) fatty acids as well as total hepatic lipid content were estimated in the livers of 8 control and 23 CCl4-treated rats at 9.4 T.

Hyaluronic acid-ceramide-based optical/MR dual imaging nanoprobe for cancer diagnosis.

Hyaluronic acid-ceramide (HACE)-based nanoprobes for magnetic resonance (MR) and optical imaging were developed for cancer diagnosis. Diethylenetriaminepentaacetic dianhydride (DTPA) was conjugated to HACE for the chelation of gadolinium (Gd) as an MR contrast agent. Cy5.

Europium-doped gadolinium sulfide nanoparticles as a dual-mode imaging agent for T1-weighted MR and photoluminescence imaging.

We present a facile synthesis of europium-doped gadolinium sulfide (GdS:Eu(3+)) opto-magnetic nanoparticles (NPs) via sonochemistry. Their photoluminescence and strong paramagnetic properties enable these NPs to be utilized as an in vitro cell imaging and in vivo T(1)-weighted MR imaging probe. The GdS:Eu(3+) NPs have a prominent longitudinal (r(1)) relaxivity value, which is a critical parameter for T(1)-weighted MR imaging.

Facile preparation of zwitterion-stabilized superparamagnetic iron oxide nanoparticles (ZSPIONs) as an MR contrast agent for in vivo applications.

We describe a simple method for synthesizing superparamagnetic nanoparticles (SPIONs) as small, stable contrast agents for magnetic resonance imaging (MRI) based on sulfobetaine zwitterionic ligands. SPIONs synthesized by thermal decomposition were coated with zwitterions to impart water dispersibility and high in vivo stability through the nanoemulsion method. Zwitterion surfactant coating layers are formed easily on oleic acid-stabilized SPIONs via hydrophobic and van der Waals interactions.

New method of manganese-enhanced Magnetic Resonance Imaging (MEMRI) for rat brain research.

Manganese (Mn(2+))-enhanced MRI (MEMRI) is known to provide insight into functional and anatomical biology. However, this method, which uses Mn(2+) as a MRI-detectable contrast agent, has drawbacks such as the toxicity to cells beyond a certain level of Mn(2+). In this study, we attempt to determine a new method of ICV administration, the optimal concentration of administered Mn(2+) and the optimal MEMRI acquisition time following administration.

Detection of iron-labeled single cells by MR imaging based on intermolecular double quantum coherences at 14 T.

To evaluate the efficiency and feasibility of intermolecular multiple quantum coherence (iMQC) magnetic resonance (MR) imaging for single cell detection, we obtained intermolecular double quantum coherence (iDQC) and conventional gradient echo (GE) images of macrophage cells labeled by contrast agents in gel. The iDQC images obtained with echo-planar readout visualized the labeled cells effectively and with a higher contrast than seen in conventional GE images, especially at low planar resolutions and with thick slices. This implies that iDQC imaging with contrast agents could be a good alternative to conventional MR imaging for detecting labeled single cells or cell tracking under favorable conditions.

Synthesis of highly magnetic graphite-encapsulated FeCo nanoparticles using a hydrothermal process.

The graphite encapsulation of metal alloy magnetic nanoparticles has attracted attention for biological applications because of the high magnetization of the encapsulated particles. However, most of the synthetic methods have limitations in terms of scalability and economics because of the demanding synthetic conditions and low yields. Here, we show that well controlled graphite-encapsulated FeCo core-shell nanoparticles can be synthesized by a hydrothermal method, simply by mixing Fe/Co with sucrose as a carbon source.

The use of the fusion protein RGD-HSA-TIMP2 as a tumor targeting imaging probe for SPECT and PET.

The human serum albumin tissue inhibitor of metalloproteinase 2 (HSA-TIMP2) is known to possess antitumor activity, which has been attributed to its ability to inhibit endothelial cell proliferation by binding to integrin receptors. In this study, a fusion protein, cyclic arginine-glycine-aspartate (RGD)-HSA-TIMP2, formed by conjugating HSA-TIMP2 with a RGD peptide, and its (123)I- and (68)Ga-labeled compounds, were synthesized and evaluated with in vivo tumor imaging using single photon emission computed tomography (SPECT) and positron emission tomography (PET). RGD-HSA-TIMP2 was synthesized by covalent bonding of the RGD peptide to the side chain amino groups of HSA-TIMP2 from a two-step reaction involving from activation with N-succinimidyl iodoacetate.

Feasibility of FAIR imaging for evaluating tumor perfusion.

Purpose: To evaluate the feasibility of flow-sensitive alternating inversion recovery (FAIR) for measuring blood flow in tumor models.

Materials And Methods: In eight mice tumor models, FAIR and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was performed. The reliability for measuring blood flow on FAIR was evaluated using the coefficient of variation of blood flow on psoas muscle.

Perfluorodecalin/[InGaP/ZnS quantum dots] nanoemulsions as 19F MR/optical imaging nanoprobes for the labeling of phagocytic and nonphagocytic immune cells.

Multimodal imaging contrast agents with unique magnetic resonance (MR) and optical imaging capabilities have great potentials in the diagnosis and therapy of disease. Using a rational materials design approach, the bimodal imaging contrast agent, perfluorodecalin (PFD)/[InGaP/ZnS quantum dots (QDs)] composite nanoemulsions is developed in this study. (19)F molecules in the PFD/[InGaP/ZnS QDs] nanoemulsions provide a (19)F-based MR imaging capability, while fluorescent QDs dispersed in PFD nanodroplets provide an optical imaging modality.

Multiplexed imaging of therapeutic cells with multispectrally encoded magnetofluorescent nanocomposite emulsions.

Here, we describe the fabrication of multispectrally encoded nanoprobes, perfluorocarbon (PFC)/quantum dots (QDs) nanocomposite emulsions, which could provide both multispectral MR and multicolor optical imaging modalities. Our strategy exploited the combination of the multispectral MR properties of four different PFC materials and the multicolor emission properties of three different colored CdSe/ZnS QDs. The PFC/QDs nanocomposite emulsions were fabricated by exchanging hydrophobic ligands coated onto CdSe/ZnS QDs using 1H,1H,2H,2H-perfluorooctanethiol, which renders the QDs to be dispersible in the PFC liquids.

Magnetic resonance microscopic imaging based on high-order intermolecular multiple-quantum coherences.

Most imaging studies using intermolecular multiple-quantum coherences (iMQCs) have focused on the two-spin dipolar interactions--zero and double quantum coherences. Here, we report the results of various experimental studies to assess the feasibility of magnetic resonance microscopy with high-order iMQCs in model systems at 7 and 14 T. Experimental results demonstrated that the iMQC microscopic images with high coherence orders are readily observable at high field and have unique contrast depending on the sample microstructure and coherence order.

In vivo magnetic resonance microscopy of differentiation in Xenopus laevis embryos from the first cleavage onwards.

Differentiation inside a developing embryo can be observed by a variety of optical methods but hardly so in opaque organisms. Embryos of the frog Xenopus laevis--a popular model system--belong to the latter category and, for this reason, are predominantly being investigated by means of physical sectioning. Magnetic resonance imaging (MRI) is a noninvasive method independent of the optical opaqueness of the object.