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https://www.readbyqxmd.com/read/28088651/limitations-in-biexponential-fitting-of-nmr-inversion-recovery-curves
#1
Mohammed Salman Shazeeb, Christopher H Sotak
NMR relaxation agents have long been employed as contrast agents in MRI. In many cases, the contrast agent is confined to either (i) the vascular and/or extracellular compartment (EC), as is the case with gadolinium(III)-based agents, or (ii) the intracellular compartment (IC), as is the case with manganese(II) ions. The compartmentalization of contrast agents often results in tissue-water (1)H relaxation profiles that are well modeled as biexponential. It has long been recognized that water exchange between compartments modifies the biexponential relaxation parameters (amplitudes and rate constants) from those that would be found in the absence of exchange...
January 6, 2017: Journal of Magnetic Resonance
https://www.readbyqxmd.com/read/28079361/controllable-synthesis-of-smart-multifunctional-nanoscal-metal-organic-framework-for-magnetic-resonance-optical-imaging-and-targeted-drug-delivery
#2
Xuechuan Gao, Manjue Zhai, Weihua Guan, Jingjuan Liu, Zhiliang Liu, Alatangaole Damirin
As a result of their extraordinarily large surfaces and well-defined pores, the design of multifunctional metal-organic framework (MOF) is crucial for drug delivery while has been rarely reported. In this paper, a novel drug delivery system (DDS) based on nanoscale metal-organic framework (MOF) was developed for using in cancer diagnosis and therapy. This MOF based tumour targeting DDS was fabricated by a simple post-synthetic surface modification process. Firstly, magnetic mesoporous nanomaterial Fe-MIL-53-NH2 was devoted for encapsulating the drug and served as a magnetic resonance (MR) contrast agent...
January 12, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28078795/a-continuous-infusion-dynamic-mri-model-at-3-0-tesla-for-the-serial-quantitative-evaluation-of-microvascular-proliferation-in-an-animal-model-of-glioblastoma-multiforme
#3
Hunter R Underhill
PURPOSE: To develop a continuous-infusion dynamic MRI technique to characterize tumor-associated microvascular proliferation (MVP) in a rat brain model of glioblastoma multiforme. METHODS: The proposed model assumes effects due to tumor-associated MVP (eg, vascular permeability, K(trans) ; intravascular plasma fraction, vp ) cannot be individually separated and solves for a single parameter (k(vasc) ) that quantifies the T1 -weighted contrast enhancement from dynamic images acquired during continuous contrast agent (CA) infusion...
January 12, 2017: Magnetic Resonance in Medicine: Official Journal of the Society of Magnetic Resonance in Medicine
https://www.readbyqxmd.com/read/28078511/intra-individual-comparison-of-different-gadolinium-based-contrast-agents-in-the-quantitative-evaluation-of-c6-glioma-with-dynamic-contrast-enhanced-magnetic-resonance-imaging
#4
Ying Li, Gang Liu, Xin Lou, Zhiye Chen, Lin Ma
This experiment aimed to compare the ionic (Gadodiamide, Gd-DTPA-BMA) and non-ionic (Gadopentetate dimeglumine, Gd-DTPA) gadolinium-based contrast agents (GBCA) in the quantitative evaluation of C6 glioma with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). A C6 glioma model was established in 12 Wistar rats, and magnetic resonance (MR) scans were performed six days after tumor implantation. Imaging was performed using a 3.0-T MR scanner with a 7-inch handmade circular coil. Pre-contrast T1 mapping and dynamic contrast-enhanced T1WI after a bolus injection (0...
January 4, 2017: Science China. Life Sciences
https://www.readbyqxmd.com/read/28076937/in-vivo-imaging-techniques-a-new-era-for-histochemical-analysis
#5
A Busato, P Fumene Feruglio, P P Parnigotto, P Marzola, A Sbarbati
In vivo imaging techniques can be integrated with classical histochemistry to create an actual histochemistry of water. In particular, Magnetic Resonance Imaging (MRI), an imaging technique primarily used as diagnostic tool in clinical/preclinical research, has excellent anatomical resolution, unlimited penetration depth and intrinsic soft tissue contrast. Thanks to the technological development, MRI is not only capable to provide morphological information but also and more interestingly functional, biophysical and molecular...
November 28, 2016: European Journal of Histochemistry: EJH
https://www.readbyqxmd.com/read/28075559/one-component-supramolecular-filament-hydrogels-as-theranostic-label-free-magnetic-resonance-imaging-agents
#6
Lye Lin Lock, Yuguo Li, Xinpei Mao, Hanwei Chen, Verena Staedtke, Renyuan Bai, Wang Ma, Ran Lin, Yi Li, Guanshu Liu, Honggang Cui
Gadolinium (Gd)-based compounds and materials are the most commonly used magnetic resonance imaging (MRI) contrast agents in the clinic; however, safety concerns associated with their toxicities in the free ionic form have promoted the development of new generations of metal-free contrast agents. Here we report a supramolecular strategy to convert an FDA-approved anticancer drug, Pemetrexed (Pem), to a molecular hydrogelator with inherent chemical exchange saturation transfer (CEST) MRI signals. The rationally designed drug-peptide conjugate can spontaneously associate into filamentous assemblies under physiological conditions and consequently form theranostic supramolecular hydrogels for injectable delivery...
January 11, 2017: ACS Nano
https://www.readbyqxmd.com/read/28072576/ultrasonic-computed-tomography-imaging-of-iron-oxide-nanoparticles
#7
Or Perlman, Haim Azhari
Iron oxide nanoparticles (IONPs) are becoming increasingly used and intensively investigated in the field of medical imaging. They are currently FDA approved for magnetic resonance imaging (MRI), and it would be highly desirable to visualize them by ultrasound as well. Previous reports using the conventional ultrasound B-scan (pulse-echo) imaging technique have shown very limited detectability of these particles. The aim of this study is to explore the feasibility of imaging IONPs using the through-transmission ultrasound methodology and demonstrate their detectability using ultrasonic computed tomography (UCT)...
February 7, 2017: Physics in Medicine and Biology
https://www.readbyqxmd.com/read/28071883/individually-stabilized-superparamagnetic-nanoparticles-with-controlled-shell-and-size-leading-to-exceptional-stealth-properties-and-high-relaxivities
#8
Andrea Lassenberger, Andrea Scheberl, Andreas Stadlbauer, Alexander Stiglbauer, Thomas Helbich, Erik Reimhult
Superparamagnetic iron oxide nanoparticles (SPION) have received immense interest for biomedical applications, with the earliest first clinical application as negative constrast agent in being for magnetic resonance imaging (MRI). However, the first generation MRI contrast agents with dextran-enwrapped, polydisperse, iron oxide nanoparticle clusters are limited to imaging of liver and spleen; this is related to their poor colloidal stability in biological media and inability to evade clearance by the reticuloendothelial system...
January 10, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28070598/advanced-mri-assessment-to-predict-benefit-of-anti-programmed-cell-death-1-protein-immunotherapy-response-in-patients-with-recurrent-glioblastoma
#9
Lei Qin, Xiang Li, Amanda Stroiney, Jinrong Qu, Jeffrey Helgager, David A Reardon, Geoffrey S Young
INTRODUCTION: We describe the imaging findings encountered in GBM patients receiving immune checkpoint blockade and assess the potential of quantitative MRI biomarkers to differentiate patients who derive therapeutic benefit from those who do not. METHODS: A retrospective analysis was performed on longitudinal MRIs obtained on recurrent GBM patients enrolled on clinical trials. Among 10 patients with analyzable data, bidirectional diameters were measured on contrast enhanced T1 (pGd-T1WI) and volumes of interest (VOI) representing measurable abnormality suggestive of tumor were selected on pGdT1WI (pGdT1 VOI), FLAIR-T2WI (FLAIR VOI), and ADC maps...
January 9, 2017: Neuroradiology
https://www.readbyqxmd.com/read/28069551/first-in-vivo-mri-study-on-theranostic-dendrimersomes
#10
Miriam Filippi, Valeria Catanzaro, Deyssy Patrucco, Mauro Botta, Lorenzo Tei, Enzo Terreno
Amphiphilic Janus-dendrimers are able to self-assemble into nanosized vesicles named dendrimersomes. We recently synthesized the 3,5-C12-EG-(OH)4 dendrimer that generates dendrimersomes with very promising safety and stability profiles, that can be loaded with different contrast agents for in vivo imaging. In this contribution, nanovesicles were loaded with both the Magnetic Resonance Imaging (MRI) reporter GdDOTAGA(C18)2 and the glucocorticoid drug Prednisolone Phosphate (PLP), in order to test their effective potential as theranostic nanocarriers on murine melanoma tumour models...
January 6, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/28067975/assessment-of-acute-thermal-damage-volumes-in-muscle-using-magnetization-prepared-3d-t2-weighted-imaging-following-mri-guided-high-intensity-focused-ultrasound-therapy
#11
Robert M Staruch, Joris Nofiele, Jamie Walker, Chenchen Bing, Ananth J Madhuranthakam, April Bailey, Young-Sun Kim, Avneesh Chhabra, Dennis Burns, Rajiv Chopra
PURPOSE: To evaluate magnetization-prepared 3D T2 -weighted magnetic resonance imaging (MRI) measurements of acute tissue changes produced during ablative MR high-intensity focused ultrasound (MR-HIFU) exposures. MATERIALS AND METHODS: A clinical MR-HIFU system (3T) was used to generate thermal lesions (n = 24) in the skeletal muscles of three pigs. T1 -weighted, 2D T2 -weighted, and magnetization-prepared 3D T2 -weighted sequences were acquired before and after therapy to evaluate tissue changes following ablation...
January 9, 2017: Journal of Magnetic Resonance Imaging: JMRI
https://www.readbyqxmd.com/read/28067926/dual-functional-lipid-like-nanoparticles-for-delivery-of-mrna-and-mri-contrast-agents
#12
X Luo, B Li, X Zhang, W Zhao, A Bratasz, B Deng, D W McComb, Y Dong
Multi-functional nanomaterials possess unique properties, facilitating both therapeutic and diagnostic applications among others. Herein, we developed dual-functional lipid-like nanoparticles for simultaneous delivery of mRNA and magnetic resonance imaging (MRI) contrast agents in order to express functional proteins and provide real-time visualization. TT3-Gd18 LLNs were identified as a lead formulation, which was able to encapsulate 91% of mRNA and 74% of Gd. This formulation showed a comparable or a slightly higher delivery efficiency of mRNA compared to the initial TT3 LLNs...
January 9, 2017: Nanoscale
https://www.readbyqxmd.com/read/28066811/ph-dependent-cellular-internalization-of-paramagnetic-nanoparticle
#13
Branislava Janic, Mohammed Pi Bhuiyan, James R Ewing, Meser M Ali
A hallmark of the tumor microenvironment in malignant tumor is extracellular acidosis, which can be exploited for targeted delivery of drugs and imaging agents. A pH sensitive paramagnetic nanoaparticle (NP) is developed by incorporating GdDOTA-4AmP MRI contrast agent and pHLIP (pH Low Insertion Peptide) into the surface of a G5-PAMAM dendrimer. pHLIP showed pH-selective insertion and folding into cell membranes, but only in acidic conditions. We demonstrated that pHLIP-conjugated Gd44-G5 paramagnetic nanoparticle binds and fuses with cellular membrane at low pH, but not at normal physiological pH, and that it promotes cellular uptake...
August 26, 2016: ACS Sensors
https://www.readbyqxmd.com/read/28066805/evaluation-of-soft-tissue-sarcoma-response-to-preoperative-chemoradiotherapy-using-dynamic-contrast-enhanced-magnetic-resonance-imaging
#14
Wei Huang, Brooke R Beckett, Alina Tudorica, Janelle M Meyer, Aneela Afzal, Yiyi Chen, Atiya Mansoor, James B Hayden, Yee-Cheen Doung, Arthur Y Hung, Megan L Holtorf, Torrie J Aston, Christopher W Ryan
This study aims to assess the utility of quantitative dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) parameters in comparison with imaging tumor size for early prediction and evaluation of soft tissue sarcoma response to preoperative chemoradiotherapy. In total, 20 patients with intermediate- to high-grade soft tissue sarcomas received either a phase I trial regimen of sorafenib + chemoradiotherapy (n = 8) or chemoradiotherapy only (n = 12), and underwent DCE-MRI at baseline, after 2 weeks of treatment with sorafenib or after the first chemotherapy cycle, and after therapy completion...
December 2016: Tomography: a Journal for Imaging Research
https://www.readbyqxmd.com/read/28064499/poly-glycerol-used-for-constructing-mixed-polymeric-micelles-as-t1-mri-contrast-agent-for-tumor-targeted-imaging
#15
Yi Cao, Min Liu, Kunchi Zhang, Guangyue Zu, Ye Kuang, Xiaoyan Tong, Dangsheng Xiong, Renjun Pei
There was much interest in the development of nanoscale delivery vehicles based on polymeric micelles to realize the diagnostic and therapeutic applications in biomedicine. Here, with the purpose of constructing a micellar magnetic resonance imaging (MRI) contrast agent (CA) with well biocompatibility and targeting specificity, two types of amphiphilic diblock polymers, mPEG-PG(DOTA(Gd))-b-PCL and FA-PEG-b-PCL, were synthesized to form mixed micelles by coassembly. The nanostructure of the resulting micellar system consisted of poly(caprolactone) (PCL) as core and poly(glycerol) (PG) and poly(ethylene glycol) (PEG) as shell, simultaneously modified with DOTA(Gd) chelates and folic acid (FA), which afforded functions of MRI contrast enhancement and tumor targeting...
January 9, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/28060285/preparation-and-in-vitro-characterization-of-dendrimer-based-contrast-agents-for-magnetic-resonance-imaging
#16
Serhat Gündüz, Tanja Savić, Đorđe Toljić, Goran Angelovski
Paramagnetic complexes of gadolinium(III) with acyclic or macrocyclic chelates are the most commonly used contrast agents (CAs) for magnetic resonance imaging (MRI). Their purpose is to enhance the relaxation rate of water protons in tissue, thus increasing the MR image contrast and the specificity of the MRI measurements. Current clinically approved contrast agents are low molecular weight molecules that are rapidly cleared from the body. The use of dendrimers as carriers of paramagnetic chelators can play an important role in the future development of more efficient MRI contrast agents...
December 4, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28059423/strategies-for-sensing-neurotransmitters-with-responsive-mri-contrast-agents
#17
Goran Angelovski, Éva Tóth
A great deal of research involving multidisciplinary approaches is currently dedicated to the understanding of brain function. The complexity of physiological processes that underlie neural activity is the greatest hurdle to faster advances. Among imaging techniques, MRI has great potential to enable mapping of neural events with excellent specificity, spatiotemporal resolution and unlimited tissue penetration depth. To this end, molecular imaging approaches using neurotransmitter-sensitive MRI agents have appeared recently to study neuronal activity, along with the first successful in vivo MRI studies...
January 6, 2017: Chemical Society Reviews
https://www.readbyqxmd.com/read/28059418/highly-versatile-spion-encapsulated-plga-nanoparticles-as-photothermal-ablators-of-cancer-cells-and-as-multimodal-imaging-agents
#18
Balasubramanian Sivakumar, Ravindran Girija Aswathy, Rebeca Romero-Aburto, Trevor Mitcham, Keith A Mitchel, Yutaka Nagaoka, Richard R Bouchard, Pulickel M Ajayan, Toru Maekawa, Dasappan Nair Sakthikumar
We have designed versatile polymeric nanoparticles with cancer cell specific targeting capabilities via aptamer conjugation after the successful encapsulation of curcumin and superparamagnetic iron oxide nanoparticles (SPIONs) inside a PLGA nanocapsule. These targeted nanocomposites were selectively taken up by tumor cells, under in vitro conditions, demonstrating the effectiveness of the aptamer targeting mechanism. Moreover, the nanocomposite potentially functioned as efficient multiprobes for optical, magnetic resonance imaging (MRI) and photoacoustic imaging contrast agents in the field of cancer diagnostics...
January 6, 2017: Biomaterials Science
https://www.readbyqxmd.com/read/28050622/correlation-between-quantitative-and-semiquantitative-parameters-in-dce-mri-with-a-blood-pool-agent-in-rectal-cancer-can-semiquantitative-parameters-be-used-as-a-surrogate-for-quantitative-parameters
#19
Rebecca A P Dijkhoff, Monique Maas, Milou H Martens, Nikolaos Papanikolaou, Doenja M J Lambregts, Geerard L Beets, Regina G H Beets-Tan
PURPOSE: The aim of this study was to assess correlation between quantitative and semiquantitative parameters in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in rectal cancer patients, both in a primary staging and restaging setting. MATERIALS AND METHODS: Nineteen patients were included with DCE-MRI before and/or after neoadjuvant therapy. DCE-MRI was performed with gadofosveset trisodium (Ablavar(®), Lantheus Medical Imaging, North Billerica, Massachusetts, USA)...
January 3, 2017: Abdominal Radiology
https://www.readbyqxmd.com/read/28048364/we-fg-207a-01-introduction-to-dedicated-breast-ct-early-studies
#20
S Vedantham
: Mammography-based screening has been a valuable imaging tool for the early detection of non-palpable lesions and has contributed to significant reduction in breast cancer associated mortality. However, the breast imaging community recognizes that mammography is not ideal, and in particular is inferior for women with dense breasts. Also, the 2-D projection of a 3-D organ results in tissue superposition contributing to false-positives. The sensitivity of mammography is breast-density dependent...
June 2016: Medical Physics
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