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MR contrast agent

A-Ra Hong, Youngsun Kim, Tae Sup Lee, Sehoon Kim, Kwangyeol Lee, Gayoung Kim, Ho Seong Jang
In this study, intense single-band red-emitting upconversion nanophosphors (UCNPs) excited with 800 nm near infrared (NIR) light are reported. When a NaYF4 :Nd,Yb active-shell is formed on the 12.7 nm-sized NaGdF4 :Yb,Ho,Ce UCNP core, the core/shell (C/S) UCNPs show tunable emission from green to red depending on the Ce3+ concentration under excitation with 800 nm NIR light. Thirty mol% Ce3+ -doped C/S UCNPs exhibit single-band red emission peaking at 644 nm via a5 F5 →5 I8 transition of Ho3+ . A high Nd3+ concentration in the shell results in strong absorption at around 800 nm NIR light even though the shell thickness is not large, and small-sized C/S UCNPs (16...
March 16, 2018: ACS Applied Materials & Interfaces
Benjamin J Zimmerman, Austin T Mudd, Joanne E Fil, Ryan N Dilger, Bradley P Sutton
Accurate quantitative non-invasive assessments of arterial cerebral blood volume (aCBV) can greatly benefit the study of cerebral vascular health in both humans and in animal models. In recent years, progress has been made in the techniques available to quantify CBV with magnetic resonance imaging (MRI). Here, we compared a non-invasive technique, measuring inflowing vascular space occupancy with dynamic subtraction (iVASO-ds) with a contrast-based vascular space occupancy measurement in piglets. In addition, we measured how the iVASO-ds derived aCBV changed with piglet development from 4 weeks to 8 weeks...
March 11, 2018: Magnetic Resonance Imaging
Rita Sofia Garcia Ribeiro, Ashwini Ketkar-Atre, Ting Yin, Karim Louchami, Tom Struys, Ivo Lambrichts, Abdullah Sener, Willy Jean Malaisse, Marcel De Cuyper, Uwe Himmelreich
Pancreatic islets (PIs) transplantation is an alternative approach for the treatment of severe forms of type 1 diabetes (T1D). To monitor the success of transplantation, it is desirable to follow the location of engrafted PIs non-invasively. In vivo magnetic resonance imaging (MRI) of transplanted PIs is a feasible cell tracking method; however, this requires labeling with a suitable contrast agent prior to transplantation. We have tested the feasibility of cationic magnetoliposomes (MLs), compared to commercial contrast agents (Endorem and Resovist), by labeling insulinoma cells and freshly isolated rat PIs...
March 12, 2018: Journal of Personalized Medicine
Ashkan Heshmatzadeh Behzadi, Zerwa Farooq, Yize Zhao, George Shih, Martin R Prince
Purpose To determine if the increased dentate nucleus signal intensity following six or more doses of a linear gadolinium-based contrast agent (GBCA) (gadopentetate dimeglumine) changes at follow-up examinations performed with a macrocyclic GBCA (gadobutrol). Materials and Methods This retrospective study included 13 patients with increased dentate nucleus signal intensity following at least six (range, 6-18) gadopentetate dimeglumine administrations who then underwent at least 12 months of follow-up imaging with multiple (range, 3-29) gadobutrol-enhanced magnetic resonance (MR) examinations...
March 14, 2018: Radiology
Yu Zhang, Xiaoping Xiao, Ting Shu, Cai Jing, Xinlan Xiao, Yan-Shu Li, Zhongwei Zhang, Qun Tang
Manganese-based (chemically formulated of KMnF3) nanocrystal was evaluated as a liver-specific contrast agent for MR imaging, and also compare its imaging performance with those of two commercial hepatobiliary contrast media (Gd-EOB-DTPA and Mn-DPDP). KMnF3 nanocrystal was post-treated using plasma technique to cause severe defects, leading to appropriate water-dispersibility and high relaxivity. Severely defective KMnF3 nanocrystal (SD-KMnF3) is characteristic of high tolerance, as evidenced with cytotoxicity on macrophage cell, acute and subchronic toxicity on the healthy mouse...
March 12, 2018: Nanotechnology
Giuseppe Ferrauto, Enza Di Gregorio, Daniela Delli Castelli, Silvio Aime
PURPOSE: Magnetic resonance imaging has been used extensively to track in vivo implanted cells that have been previously labeled with relaxation enhancers. However, this approach is not suitable to track multiple cell populations, as it may lead to confounding results in case the contrast agent is released from the labeled cells. This paper demonstrates how the use of CEST agents can overcome these issues. After encapsulating paramagnetic lanthanide shift reagents, we may shift the absorption frequency of the intracellular water resonance (δIn ), thus generating frequency-encoding CEST responsive cells that can be visualized in the MR image by applying the proper RF irradiation...
March 7, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Wui K Chong, Virginie Papadopoulou, Paul A Dayton
Microbubble ultrasound contrast agents (UCAs) were recently approved by the Food and Drug administration for non-cardiac imaging. The physical principles of UCAs, methods of administration, dosage, adverse effects, and imaging techniques both current and future are described. UCAs consist of microbubbles in suspension which strongly interact with the ultrasound beam and are readily detectable by ultrasound imaging systems. They are confined to the blood pool when administered intravenously, unlike iodinated and gadolinium contrast agents...
March 5, 2018: Abdominal Radiology
Xuan Mei, Wei Wang, Liang Yan, Tingting Hu, Ruizheng Liang, Dan Yan, Min Wei, David G Evans, Xue Duan
Recently, theranostic has drawn tremendous attention by virtue of the nanotechnology development and new material exploration. Herein, we reported a novel theranostic system by loading Au nanoclusters (AuNCs) and Chlorin e6 (photosensitizer, Ce6) onto the monolayer nanosheet surface of Gd-doped layered double hydroxide (Gd-LDH). The as-prepared Ce6&AuNCs/Gd-LDH exhibits a largely enhanced fluorescence quantum yield (QY) of 18.5% relative to pristine AuNCs (QY = 3.1%) as well as superior T1 magnetic resonance imaging (MRI) performance (r1  = 17...
February 19, 2018: Biomaterials
Zixuan Lin, Yang Li, Pan Su, Deng Mao, Zhiliang Wei, Jay J Pillai, Abhay Moghekar, Matthias van Osch, Yulin Ge, Hanzhang Lu
PURPOSE: Many brain diseases are associated with an alteration in blood-brain barrier (BBB) and its permeability. Current methods using contrast agent are primarily sensitive to major leakage of BBB to macromolecules, but may not detect subtle changes in BBB permeability. The present study aims to develop a novel non-contrast MRI technique for the assessment of BBB permeability to water. METHODS: The central principle is that by measuring arterially labeled blood spins that are drained into cerebral veins, water extraction fraction (E) and permeability-surface-area product (PS) of BBB can be determined...
March 1, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
Alexander Liu, Rohan S Wijesurendra, Joanna M Liu, Andreas Greiser, Michael Jerosch-Herold, John C Forfar, Keith M Channon, Stefan K Piechnik, Stefan Neubauer, Rajesh K Kharbanda, Vanessa M Ferreira
BACKGROUND: Novel cardiac magnetic resonance (CMR) stress T1 mapping can detect ischemia and myocardial blood volume changes without contrast agents and may be a more comprehensive ischemia biomarker than myocardial blood flow. OBJECTIVES: This study describes the performance of the first prospective validation of stress T1 mapping against invasive coronary measurements for detecting obstructive epicardial coronary artery disease (CAD), defined by fractional flow reserve (FFR <0...
March 6, 2018: Journal of the American College of Cardiology
Lei Pei, Jingjing Xu, Minming Zhang
OBJECTIVE: To explore the correlation between the number of previous gadolinium-based contrast agent administrations and high signal intensity (SI) in the cerebrum nucleus on unenhanced T1 -weighted magnetic resonance images. METHODS: Thirty-nine patients who previously underwent at least three contrast-enhanced brain MRI examinations were enrolled in the study. The right globus pallidus, right thalamus, right dentate nucleus, pons and white matter of right frontal lobe were selected as region of interests (ROI)...
May 25, 2017: Zhejiang da Xue Xue Bao. Yi Xue Ban, Journal of Zhejiang University. Medical Sciences
Darren G Woodside, Eric A Tanifum, Ketan B Ghaghada, Ronald J Biediger, Amy R Caivano, Zbigniew A Starosolski, Sayadeth Khounlo, Saakshi Bhayana, Shahrzad Abbasi, John W Craft, David S Maxwell, Chandreshkumar Patel, Igor V Stupin, Deenadayalan Bakthavatsalam, Robert V Market, James T Willerson, Richard A F Dixon, Peter Vanderslice, Ananth V Annapragada
Inflammation drives the degradation of atherosclerotic plaque, yet there are no non-invasive techniques available for imaging overall inflammation in atherosclerotic plaques, especially in the coronary arteries. To address this, we have developed a clinically relevant system to image overall inflammatory cell burden in plaque. Here, we describe a targeted contrast agent (THI0567-targeted liposomal-Gd) that is suitable for magnetic resonance (MR) imaging and binds with high affinity and selectivity to the integrin α4β1(very late antigen-4, VLA-4), a key integrin involved in recruiting inflammatory cells to atherosclerotic plaques...
February 27, 2018: Scientific Reports
Jan Hovener, Andrey N Pravdivtsev, Bryce Kidd, C Russel Bowers, Stefan Glöggler, Kirill V Kovtunov, Markus Plaumann, Rachel Katz-Brull, Kai Buckenmaier, Alexej Jerschow, Francesca Reineri, Thomas Theis, Roman V Shchepin, Shawn Wagner, Niki M M Zacharias, Pratip Bhattacharya, Eduard Y Chekmenev
NMR is one of the most versatile and useful physical effects used for human imaging, chemical analysis and the elucidation of molecular structures. Yet, the full potential of NMR is hardly ever used, because only a small fraction of the nuclear spin ensemble is polarized - i.e. aligned with the applied static magnetic field. This fraction is termed nuclear spin polarization P. As a result, no more than a few parts per million of all nuclear spins effectively contribute to the signal in all magnetic fields (B0) available for NMR or MRI today...
February 27, 2018: Angewandte Chemie
R Kleinloog, J J M Zwanenburg, B Schermers, E Krikken, Y M Ruigrok, P R Luijten, F Visser, L Regli, G J E Rinkel, B H Verweij
BACKGROUND AND PURPOSE: Aneurysm volume pulsation is a potential predictor of intracranial aneurysm rupture. We evaluated whether 7T MR imaging can quantify aneurysm volume pulsation. MATERIALS AND METHODS: In Stage I of the study, 10 unruptured aneurysms in 9 patients were studied using a high-resolution (0.6-mm, isotropic) 3D gradient-echo sequence with cardiac gating. Semiautomatic segmentation was used to measure aneurysm volume (in cubic millimeters) per cardiac phase...
February 22, 2018: AJNR. American Journal of Neuroradiology
Yu-Dong Xiao, Cong Ma, Jun Liu, Hua-Bing Li, Shun-Ke Zhou, Zi-Shu Zhang
Gadoxetic acid (Gd-EOB-DTPA) is a hepatocyte-specific magnetic resonance (MR) contrast agent, which has been increasingly used in recent years. However, it has been reported that Gd-EOB-DTPA related transient severe motion (TSM) is sometimes observed during the hepatic arterial phase of MR imaging, which may influence image quality. Since the hepatic arterial phase of contrast enhancement is used for the diagnosis of hepatocellular carcinoma, it is crucial to obtain a decent arterial phase imaging. The present study analyzed motion in patients receiving Gd-EOB-DTPA, comparing a single arterial phase acquisition to a five arterial phase acquisition to determine whether the multiphase acquisition was able to alleviate the TSM-related hepatic arterial MR imaging artifact...
March 2018: Experimental and Therapeutic Medicine
Seung-Jun Lee, Hee-Jin Kim, Yong-Min Huh, Il Won Kim, Jae Hyun Jeong, Jin-Chul Kim, Jong-Duk Kim
Superparamagnetic iron oxide nanoparticles (SPIONs) are actively used as highly sensitive imaging probes to provide contrast in MRI. In this study, we propose the use of SPIONs encapsulated with antibody-conjugated poly(lactic-co-glycolic acid) (PLGA) as a potent theragnostic agent. The SPIONs were synthesized by a chemical co-precipitation method of ferric and ferrous ions, and subsequently encapsulated with PLGA by using an emulsification-diffusion method. Herceptin was chemically conjugated to the SPION-encapsulating PLGA nanoparticles to target the human epidermal growth factor receptor 2 (Her2/neu) overexpressing breast cancers...
March 1, 2018: Journal of Nanoscience and Nanotechnology
Yajie Zhang, Tingting Zhang, Min Liu, Ye Kuang, Guangyue Zu, Kunchi Zhang, Yi Cao, Renjun Pei
Magnetic resonance imaging is a powerful diagnostic technology with high spatial resolution and non-invasion. The contrast agents have significant effect on the resolution of the MR imaging. However, the commercial contrast agents (CAs) usually consist of individual Gd3+ chelated with a low molecular weight acyclic or cyclic ligand, and these small-molecule CAs are usually subjected to nonspecificity, thus leading to rapid renal clearance and modest contrast enhancement for tumor imaging. In recent years, the nanostructured materials conjugated with aptamers were widely used and opened a new door in biomedical imaging due to excellent specificity, non-immunogenicity, easily synthesis and chemical modification of aptamers...
June 1, 2018: Journal of Nanoscience and Nanotechnology
Benjamin Leporq, Jean-Luc Daire, Catherine M Pastor, Pierre Deltenre, Christine Sempoux, Sabine Schmidt, Bernard E Van Beers
The purpose of this study was to develop and perform initial validation of dynamic MR imaging enhanced with gadoxetic acid as hepatobiliary contrast agent to quantify hepatic perfusion and hepatocyte function in patients with chronic liver disease. Free-breathing, dynamic gadoxetic acid-enhanced MR imaging was performed at 3.0 T using a three-dimensional time-resolved angiography sequence with stochastic trajectories during 38 minutes. A dual-input three-compartment model was developed to derive hepatic perfusion and hepatocyte function parameters...
February 12, 2018: Clinical Science (1979-)
Qingyan Jia, Jiechao Ge, Weimin Liu, Xiuli Zheng, Shiqing Chen, Yongmei Wen, Hongyan Zhang, Pengfei Wang
Recent studies indicate that carbon dots (CDs) can efficiently generate singlet oxygen (1 O2 ) for photodynamic therapy (PDT) of cancer. However, the hypoxic tumor microenvironment and rapid consumption of oxygen in the PDT process will severely limit therapeutic effects of CDs due to the oxygen-dependent PDT. Thus, it is becoming particularly important to develop a novel CD as an in situ tumor oxygenerator for overcoming hypoxia and substantially enhancing the PDT efficacy. Herein, for the first time, magnetofluorescent Mn-CDs are successfully prepared using manganese(II) phthalocyanine as a precursor...
February 13, 2018: Advanced Materials
Shaohui Zheng, Jiwon Han, Zhen Jin, Chang-Sei Kim, Sukho Park, Kyu-Pyo Kim, Jong-Oh Park, Eunpyo Choi
Multifunctional polymeric micelles were developed as a promising dual tumor-targeted drug delivery platform for magnetic resonance (MR) imaging and combined photothermal-chemotherapy. HA-C16 copolymers were synthesized via peptide formation process with subsequent co-encapsulation of therapeutic agent docetaxel (DTX) and superparamagnetic iron oxide nanoparticles (SPIONs) to form the multifunctional micelles. The micelles exhibited uniform nanosize and remarkable colloidal stability in aqueous solution. The sustained drug release behavior from HA micelles was observed over the test period...
February 5, 2018: Colloids and Surfaces. B, Biointerfaces
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