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https://www.readbyqxmd.com/read/29327374/dynamic-coronary-mr-angiography-in-a-pig-model-with-hyperpolarized-water
#1
Kasper Wigh Lipsø, Esben Søvsø Szocska Hansen, Rasmus Stilling Tougaard, Christoffer Laustsen, Jan Henrik Ardenkjaer-Larsen
PURPOSE: To investigate dynamic coronary MR angiography using hyperpolarized water as a positive contrast agent. Hyperpolarization can increase the signal by several orders of magnitude, and has recently been translated to human cardiac application. The aim was to achieve large 1 H signal enhancement to allow high-resolution imaging of the coronary arteries. METHODS: Protons in D2 O were hyperpolarized by dissolution dynamic nuclear polarization. A total of 18 mL of hyperpolarized water was injected into the coronary arteries of healthy pigs (N = 9; 3 injections in 3 animals)...
January 12, 2018: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/29320888/comparative-studies-with-epr-and-mri-on-the-in-vivo-tissue-redox-status-estimation-using-redox-sensitive-nitroxyl-probes-influence-of-the-choice-of-the-region-of-interest
#2
Ken-Ichiro Matsumoto, James B Mitchell, Murali C Krishna
In vivo decay rates of a nitroxyl contrast agent were estimated by a MR redox imaging (MRRI) technique and compared with the decay rates obtained by the electron paramagnetic resonance spectroscopy (EPRS) and imaging (EPRI). MRRI is a dynamic imaging technique employing T1-weighted pulse sequence, which can visualize a nitroxyl-induced enhancement of signal intensity by T1-weighted contrast. EPR techniques can directly measure the paramagnetic nitroxyl radical. Both the squamous cell carcinoma (SCC) tumor-bearing and normal legs of a female C3H mouse were scanned by T1-weighted SPGR sequence at 4...
January 10, 2018: Free Radical Research
https://www.readbyqxmd.com/read/29316452/renal-clearable-quaternary-chalcogenide-nanocrystal-for-photoacoustic-magnetic-resonance-imaging-guided-tumor-photothermal-therapy
#3
Longfei Tan, Jing Wan, Weisheng Guo, Caizhang Ou, Tianlong Liu, Changhui Fu, Qiang Zhang, Xiangling Ren, Xing-Jie Liang, Jun Ren, Laifeng Li, Xianwei Meng
Ultrasmall Cu2ZnSnS4 (CZTS) nanocrystals with high near infrared (NIR) photothermal conversion abilities and peroxidase-mimic properties are synthesized and functionalized with bovine serum albumin (BSA) for rapid clearance multifunctional theranostic platform. Due to the presence of Cu (I) of CZTS@BSA, H2O2 could be decomposed to produce highly reactive oxygen species (ROS), catalyzed by intrinsic peroxidase like activity of CZTS. The CZTS@BSA possesses high NIR absorption and excellent photoacoustic (PA) imaging abilities...
January 2, 2018: Biomaterials
https://www.readbyqxmd.com/read/29304404/stable-gadolinium-based-nanoscale-lyophilized-injection-for-enhanced-mr-angiography-with-efficient-renal-clearance
#4
Kun Liu, Liang Dong, Yunjun Xu, Xu Yan, Fei Li, Yang Lu, Wei Tao, Huangyong Peng, Yadong Wu, Yang Su, Daishun Ling, Tao He, Haisheng Qian, Shu-Hong Yu
There is a great demand to develop high-relaxivity nanoscale contrast agents for magnetic resonance (MR) angiography with high resolution. However, there should be more focus on stability, ion leakage and excretion pathway of the intravenously injected nanoparticles, which are closely related to their clinic potentials. Herein, uniform ultrasmall-sized NaGdF4 nanocrystal (sub-10 nm) was synthesized using a facile high temperature organic solution method, and the nanocrystals were modified by a ligand-exchange approach using PEG-PAA di-block copolymer...
December 28, 2017: Biomaterials
https://www.readbyqxmd.com/read/29301434/targeted-tumor-dual-mode-ct-mr-imaging-using-multifunctional-polyethylenimine-entrapped-gold-nanoparticles-loaded-with-gadolinium
#5
Benqing Zhou, Zuogang Xiong, Peng Wang, Chen Peng, Mingwu Shen, Serge Mignani, Jean-Pierre Majoral, Xiangyang Shi
We report the construction and characterization of polyethylenimine (PEI)-entrapped gold nanoparticles (AuNPs) chelated with gadolinium (Gd) ions for targeted dual mode tumor CT/MR imaging in vivo. In this work, polyethylene glycol (PEG) monomethyl ether-modified PEI was sequentially modified with Gd chelator and folic acid (FA)-linked PEG (FA-PEG) was used as a template to synthesize AuNPs, followed by Gd(III) chelation and acetylation of the remaining PEI surface amines. The formed FA-targeted PEI-entrapped AuNPs loaded with Gd (FA-Gd-Au PENPs) were well characterized in terms of structure, composition, morphology, and size distribution...
November 2018: Drug Delivery
https://www.readbyqxmd.com/read/29300210/pediatric-brain-gadolinium-deposition-in-dentate-nucleus-and-globus-pallidus-on-unenhanced-t1-weighted-images-is-dependent-on-the-type-of-contrast-agent
#6
Young Jin Ryu, Young Hun Choi, Jung-Eun Cheon, Woo-Jin Lee, Subin Park, Ji Eun Park, Woo Sun Kim, In-One Kim
PURPOSE: The aim of this study was to identify the signal intensity (SI) changes in the dentate nucleus (DN) and the globus pallidus (GP) on unenhanced T1-weighted magnetic resonance (MR) images after multiple administration of gadolinium-based contrast agents (GBCAs) in children and compare those changes between linear and macrocyclic GBCAs. MATERIALS AND METHODS: This retrospective study was approved by the institutional review board and the requirement for informed consent was waived...
January 2, 2018: Investigative Radiology
https://www.readbyqxmd.com/read/29291165/construction-of-multifunctional-fe3o4-mtx-hbc-nanoparticles-for-mr-imaging-and-photothermal-therapy-chemotherapy
#7
Qiang Zhang, Wenjun Shan, Chaochao Ai, Zhiwei Chen, Tiantian Zhou, Xiaolin Lv, Xi Zhou, Shefang Ye, Lei Ren, Xiumin Wang
To accomplish effective cancer imaging and integrated therapy, the multifunctional nanotheranostic Fe3O4-MTX@HBc core-shell nanoparticles (NPs) were designed. A straightforward method was demonstrated for efficient encapsulation of magnetic NPs into the engineered virus-like particles (VLPs) through the affinity of histidine tags for the methotrexate (MTX)-Ni2+ chelate. HBc144-His VLPs shell could protect Fe3O4-MTX NPs from the recognition by the reticuloendothelial system as well as could increase their cellular uptake efficiency...
2018: Nanotheranostics
https://www.readbyqxmd.com/read/29290795/tumor-penetrating-peptide-conjugated-and-doxorubicin-loaded-t1-t2-dual-mode-mri-contrast-agents-nanoparticles-for-tumor-theranostics
#8
Lipeng Gao, Jing Yu, Yang Liu, Jinge Zhou, Lei Sun, Jing Wang, Jianzhong Zhu, Hui Peng, Weiyue Lu, Lei Yu, Zhiqiang Yan, Yiting Wang
The conventional chemotherapeutics could not be traced in vivo and provide timely feedback on the clinical effectiveness of drugs. Methods: In this study, a tumor-penetrating peptide RGERPPR (RGE) modified, Gd-DTPA conjugated, and doxorubicin (DOX) loaded Fe3O4@SiO2@mSiO2 nanoparticle drug delivery system (Fe3O4@SiO2@mSiO2/DOX-(Gd-DTPA)-PEG-RGE NPs) was prepared for tumor theranostics. Results: The Fe3O4@SiO2@mSiO2/DOX-(Gd-DTPA)-PEG-RGE NPs showed a z-average hydrodynamic diameter of about 90 nm, and a pH-sensitive DOX release profile...
2018: Theranostics
https://www.readbyqxmd.com/read/29290025/a-hybrid-optimization-strategy-for-registering-images-with-large-local-deformations-and-intensity-variations
#9
Zhang Li, Lucas J van Vliet, Jaap Stoker, Frans M Vos
PURPOSE: To develop a method for intra-patient registration of pre- and post-contrast abdominal MR images with large local deformations and large intensity variations. METHOD: A hybrid method is proposed to deal with this problem. It consists of two coupled techniques: (1) descriptor matching (DM) at the original resolution using a discrete optimization strategy to avoid getting trapped in a local minimum; (2) continuous optimization to refine the registration outcome based on autocorrelation of local image structure (ALOST)...
December 30, 2017: International Journal of Computer Assisted Radiology and Surgery
https://www.readbyqxmd.com/read/29288036/a-study-of-mri-gradient-echo-signals-from-discrete-magnetic-particles-with-considerations-of-several-parameters-in-simulations
#10
Paul Kokeny, Yu-Chung N Cheng, He Xie
Modeling MRI signal behaviors in the presence of discrete magnetic particles is important, as magnetic particles appear in nanoparticle labeled cells, contrast agents, and other biological forms of iron. Currently, many models that take into account the discrete particle nature in a system have been used to predict magnitude signal decays in the form of R2* or R2' from one single voxel. Little work has been done for predicting phase signals. In addition, most calculations of phase signals rely on the assumption that a system containing discrete particles behaves as a continuous medium...
December 26, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/29277647/what-can-we-see-with-ivim-mri
#11
Denis Le Bihan
Intravoxel Incoherent Motion (IVIM) refers to translational movements which within a given voxel and during the measurement time present a distribution of speeds in orientation and/or amplitude. The IVIM concept has been used to estimate perfusion in tissues as blood flow in randomly oriented capillaries mimics a pseudo-diffusion process. IVIM-based perfusion MRI, which does not require contrast agents, has gained momentum recently, especially in the field oncology. In this introductory review the basic concepts, models, technical requirements and limitations inherent to IVIM-based perfusion MRI are outlined, as well as new, non-perfusion applications of IVIM MRI, such as virtual MR Elastography...
December 22, 2017: NeuroImage
https://www.readbyqxmd.com/read/29247752/insight-into-the-dynamic-of-gadolinium-based-contrast-agent-gbca-hypersensitivity-acquisition-persistence-and-disappearance
#12
Ingrid Boehm, Martin Hungerbühler, Johannes T Heverhagen
Anaphylaxis against gadolinium based contrast agents (GBCAs) has been reported in all severity grades but is less frequent than hypersensitivity/allergy against iodinated contrast materials. Once a patient acquires such an adverse reaction a life-long premedication is usually the consequence in concert with GBCA-enhanced MR-imaging procedures. The usefulness of this prophylaxis has been questioned, and discussed controversially during the past. The herein presented case may shed some light into the dynamic of contrast-medium-induced hypersensitivity reactions...
December 13, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/29247585/simultaneous-acquisition-of-mr-angiography-and-diagnostic-images-of-abdomen-at-view-sharing-multiarterial-phases-and-comparing-the-effect-of-two-different-contrast-agents
#13
Yoshifumi Noda, Satoshi Goshima, Tomohiro Namimoto, Norihiro Shinkawa, Masataka Nakagawa, Kimihiro Kajita, Hiroshi Kawada, Nobuyuki Kawai, Yukichi Tanahashi, Masayuki Matsuo, Kyongtae T Bae, Toshinori Hirai, Yasuyuki Yamashita
BACKGROUND: Simultaneous acquisition of magnetic resonance angiography (MRA) and diagnostic images is challenging in contrast-enhanced upper abdominal MRI. PURPOSE: To evaluate the image quality of MRA of the abdomen acquired simultaneously with diagnostic MR images, and to compare the contrast effect, conspicuity of aortic branches, and pancreatic lesions in MRA between gadobutrol and gadoterate meglumine. STUDY TYPE: Prospective. POPULATION: Eighty-eight patients with known and suspected upper abdominal disease...
December 16, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/29238782/a-new-heptadentate-picolinate-based-ligand-and-its-corresponding-gd-iii-complex-the-effect-of-pendant-picolinate-versus-acetate-on-complex-properties
#14
Bedika Phukan, Chandan Mukherjee, Raunak Varshney
To attain high relaxivity as well as stability, a new water-soluble, water-coordinated Gd(iii) complex, which was synthesised by reacting equimolar amounts of picolinate-based ligand H4peada and GdCl3·xH2O at pH ∼ 6.5, was examined. The number of inner sphere water molecules (q) in the complex was found to be 1.7 ± 0.1 from luminescence lifetime measurements of its Tb(iii) congener, complex 2. At 1.41 T, 25 °C, and pH = 7.4, the longitudinal relaxivity (r1) value of the complex was found to be 6.08 mM-1 s-1, which remained almost constant in the pH range 4-10...
December 13, 2017: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/29230805/uspio-labeling-in-m1-and-m2-polarized-macrophages-an-in-vitro-study-using-a-clinical-magnetic-resonance-scanner
#15
Chiara Zini, Mary Anna Venneri, Selenia Miglietta, Damiano Caruso, Natale Porta, Andrea Isidori, Daniela Fiore, Daniele Gianfrilli, Vincenzo Petrozza, Andrea Laghi
BACKGROUND: To evaluate USPIO labeling in different macrophage populations using a clinical 3.0T MR unit with optical and electron microscopy as the gold standard. METHODS: Human monocytic cell line were differentiated into macrophages. Afterwards M0 macrophages were incubated with IL-4 and IL-13 in order to obtain M2 polarized macrophages or with IFN-gamma and LPS for classical macrophage activation (M1). These groups were incubated with USPIO MR contrast agent (P904) for 36 hours; M0, M0+P904, M1+P904 and M2+P904 were analyzed in gel phantoms with a 3...
December 12, 2017: Journal of Cellular Physiology
https://www.readbyqxmd.com/read/29230607/the-effect-of-high-count-rates-on-cardiac-perfusion-quantification-in-a-simultaneous-pet-mr-system-using-a-cardiac-perfusion-phantom
#16
Jim O' Doherty, Zacharias Chalampalakis, Paul Schleyer, Muhummad Sohaib Nazir, Amedeo Chiribiri, Paul K Marsden
BACKGROUND: PET-MRI is under investigation as a new strategy for quantitative myocardial perfusion imaging. Consideration is required as to the maximum scanner count rate in order to limit dead-time losses resulting from administered activity in the scanner field of view during the first pass of the radiotracer. RESULTS: We performed a decaying-source experiment to investigate the high count-rate performance of a PET-MR system (Siemens mMR) over the expected range of activities during a clinical study...
December 11, 2017: EJNMMI Physics
https://www.readbyqxmd.com/read/29218620/the-impact-of-injector-based-contrast-agent-administration-in-time-resolved-mra
#17
Johannes Budjan, Ulrike I Attenberger, Stefan O Schoenberg, Hubertus Pietsch, Gregor Jost
OBJECTIVES: Time-resolved contrast-enhanced MR angiography (4D-MRA), which allows the simultaneous visualization of the vasculature and blood-flow dynamics, is widely used in clinical routine. In this study, the impact of two different contrast agent injection methods on 4D-MRA was examined in a controlled, standardized setting in an animal model. METHODS: Six anesthetized Goettingen minipigs underwent two identical 4D-MRA examinations at 1.5 T in a single session...
December 7, 2017: European Radiology
https://www.readbyqxmd.com/read/29216303/three-dimensional-self-gated-cardiac-mr-imaging-for-the-evaluation-of-myocardial-infarction-in-mouse-model-on-a-3t-clinical-mr-system
#18
Xiaoyong Zhang, Bensheng Qiu, Zijun Wei, Fei Yan, Caiyun Shi, Shi Su, Xin Liu, Jim X Ji, Guoxi Xie
PURPOSE: To develop and assess a three-dimensional (3D) self-gated technique for the evaluation of myocardial infarction (MI) in mouse model without the use of external electrocardiogram (ECG) trigger and respiratory motion sensor on a 3T clinical MR system. METHODS: A 3D T1-weighted GRE sequence with stack-of-stars sampling trajectories was developed and performed on six mice with MIs that were injected with a gadolinium-based contrast agent at a 3T clinical MR system...
2017: PloS One
https://www.readbyqxmd.com/read/29208312/gadolinium-deposition-in-the-paediatric-brain-t1-weighted-hyperintensity-within-the-dentate-nucleus-following-repeated-gadolinium-based-contrast-agent-administration
#19
J R Young, I Orosz, M A Franke, H J Kim, D Woodworth, B M Ellingson, N Salamon, W B Pope
AIM: To determine whether repeated gadolinium-based contrast agent administration (GBCA) in children is associated with the development of increased T1-weighted signal intensity within the cerebellar dentate nucleus. MATERIALS AND METHODS: With institutional review board approval for this The Health Insurance Portability and Accountability Act-compliant retrospective study, a cohort of 41 patients under the age of 18 years who underwent at least four contrast-enhanced magnetic resonance imaging (MR) examinations of the brain from 2005 to 2015 were identified...
December 2, 2017: Clinical Radiology
https://www.readbyqxmd.com/read/29205171/engineered-core-shell-magnetic-nanoparticle-for-mr-dual-modal-tracking-and-safe-magnetic-manipulation-of-ependymal-cells-in-live-rodents
#20
Yung-Kang Peng, Cathy N P Lui, Yu-Wei Chen, Shang-Wei Chou, Pi-Tai Chou, Ken K L Yung, S C Edman Tsang
Tagging recognition group(s) on superparamagnetic iron oxide is known to aid localisation (imaging), stimulation and separation of biological entities using magnetic resonance imaging (MRI) and magnetic agitation/separation (MAS) techniques. Despite the wide applicability of iron oxide nanoparticles in T 2-weighted MRI and MAS, the quality of the images and safe manipulation of the exceptionally delicate neural cells in a live brain are currently the key challenges. Here, we demonstrate the engineered manganese oxide clusters-iron oxide core-shell nanoparticle as an MR dual-modal contrast agent for neural stem cells (NSCs) imaging and magnetic manipulation in live rodents...
December 5, 2017: Nanotechnology
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