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 'Ultrasmall Superparamagnetic Iron Oxide' 
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Result : Searchterm 'Ultrasmall Superparamagnetic Iron Oxide' found in 1 term [] and 16 definitions []
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Ultrasmall Superparamagnetic Iron OxideInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.
 
(USPIO) The class of the ultrasmall superparamagnetic iron oxide includes several chemically and pharmacologically very distinct materials, which may or may not be interchangeable for a specific use. Some ultrasmall SPIO particles (median diameter less than 50nm) are used as MRI contrast agents (Sinerem®, Combidex®), e.g. to differentiate metastatic from inflammatory lymph nodes. USPIO shows also potential for providing important information about angiogenesis in cancer tumors and could possibly complement MRI helping physicians to identify dangerous arteriosclerosis plaques.
Because of the disadvantageous large T2*//T1 ratio, USPIO compounds are less suitable for arterial bolus contrast enhanced magnetic resonance angiography than gadolinium complexes. The tiny ultrasmall superparamagnetic iron oxides do not accumulate in the RES system as fast as larger particles, which results in a long plasma half-life. USPIO particles, with a small median diameter (less than 10 nm), will accumulate in lymph nodes after an intravenous injection by e.g. direct transcapillary passage through endothelial venules. Once within the nodal parenchyma, phagocytic cells of the mononuclear phagocyte system take up the particles.
As a second way, USPIOs are subsequently taken up from then interstitium by lymphatic vessels and transported to regional lymph nodes. A lymph node with normal phagocytic function takes up a considerable amount and shows a reduction of the signal intensity caused by T2 shortening effects and magnetic susceptibility. Caused by the small uptake of the USPIOs in metastatic lymph nodes, they appear with less signal reduction, and permit the differentiation of healthy lymph nodes from normal-sized, metastatic nodes.
See also Superparamagnetic Contrast Agents, Superparamagnetic Iron Oxide, Very Small Superparamagnetic Iron Oxide Particles, Blood Pool Agents, Intracellular Contrast Agents.
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    • Liver Imaging
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Further Reading:
  Basics:
Comparison of Two Superparamagnetic Viral-Sized Iron Oxide Particles Ferumoxides and Ferumoxtran-10 with a Gadolinium Chelate in Imaging Intracranial Tumors
2002   by www.ajnr.org    
  News & More:
Optimized Labelling of Human Monocytes with Iron Oxide MR Contrast Agents
Sunday, 30 November 2003   by rsna2003.rsna.org    
10 SUMMARY AND FUTURE PERSPECTIVES
   by dissertations.ub.rug.nl    
MRI Resources 
Open Directory Project - Pathology - Homepages - Pacemaker - Diffusion Weighted Imaging - RIS
 
Blood Pool AgentsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
Blood pool agents (intravascular contrast agents) remain in the blood for a prolonged time compared with conventional contrast agents, which diffuse quickly into the interstitial space. Magnetic resonance angiography (MRA), cardiovascular imaging, or contrast enhanced MRIs are possible over an hour or more. This advantage over conventional MRI contrast media allows also higher resolution MRA of several territories using respiratory or cardiac gating techniques with a single contrast bolus.
Different types of blood pool contrast agents:
Ultrasmall superparamagnetic iron oxide (USPIO)
Gd Labeled Albumin
Chromium labeled red blood cells
Gd-DTPA labeled dextran
Blood pool MRI contrast agents with their longer intravascular circulation can be designed to be targeted to necrotic myocardium, to assess myocardial viability, or tumor directed to provide better diagnostic information for various tumors. A disadvantage of the use of blood pool agents for MRA is that the separation of arteries and veins is more difficult because they are present in both and the overlapping of those vessels is disturbing. This can be solved by e.g. different MIP segmentation algorithms.
See also Necrosis Avid Contrast Agent, Tumor Specific Agents, Feruglose, Gadofosveset Trisodium (Vasovist), Ultrasmall Superparamagnetic Iron Oxide and Contrast Medium.

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Further Reading:
  Basics:
Ablavar Prescribing Information
   by www.ablavar.com    
Lantheus Medical Imaging, Inc. Launches ABLAVAR™ (Gadofosveset Trisodium), a New Diagnostic Magnetic Resonance Angiography Agent
Wednesday, 20 January 2010   by www.radiopharm.com    
Blood-Pool Imaging Using Technetium-99m-Labeled Liposomes(.pdf)
   by jnm.snmjournals.org    
Blood pool imaging
   by www.bloodpoolagents.us    
  News & More:
Multimodal Nanoparticles for Quantitative Imaging(.pdf)
Tuesday, 13 December 2011   by alexandria.tue.nl    
MAGNETIC RESONANCE IMAGING OF FOCAL LIVER LESIONS(.pdf)
2002
MRI Resources 
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Contrast AgentsForum -
related threadsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
Contrast agents are chemical substances introduced to the anatomical or functional region being imaged, to increase the differences between different tissues or between normal and abnormal tissue, by altering the relaxation times. MRI contrast agents are classified by the different changes in relaxation times after their injection.
Positive contrast agents cause a reduction in the T1 relaxation time (increased signal intensity on T1 weighted images). They (appearing bright on MRI) are typically small molecular weight compounds containing as their active element Gadolinium, Manganese, or Iron. All of these elements have unpaired electron spins in their outer shells and long relaxivities.
Some typical contrast agents as gadopentetate dimeglumine, gadoteridol, and gadoterate meglumine are utilized for the central nervous system and the complete body; mangafodipir trisodium is specially used for lesions of the liver and gadodiamide for the central nervous system.
Negative contrast agents (appearing predominantly dark on MRI) are small particulate aggregates often termed superparamagnetic iron oxide (SPIO). These agents produce predominantly spin spin relaxation effects (local field inhomogeneities), which results in shorter T1 and T2 relaxation times.
SPIO's and ultrasmall superparamagnetic iron oxides (USPIO) usually consist of a crystalline iron oxide core containing thousands of iron atoms and a shell of polymer, dextran, polyethyleneglycol, and produce very high T2 relaxivities. USPIOs smaller than 300 nm cause a substantial T1 relaxation. T2 weighted effects are predominant.
A special group of negative contrast agents (appearing dark on MRI) are perfluorocarbons (perfluorochemicals), because their presence excludes the hydrogen atoms responsible for the signal in MR imaging.
The design objectives for the next generation of MR contrast agents will likely focus on prolonging intravascular retention, improving tissue targeting, and accessing new contrast mechanisms. Macromolecular paramagnetic contrast agents are being tested worldwide. Preclinical data shows that these agents demonstrate great promise for improving the quality of MR angiography, and in quantificating capillary permeability and myocardial perfusion.
Ultrasmall superparamagnetic iron oxide (USPIO) particles have been evaluated in multicenter clinical trials for lymph node MR imaging and MR angiography, with the clinical impact under discussion. In addition, a wide variety of vector and carrier molecules, including antibodies, peptides, proteins, polysaccharides, liposomes, and cells have been developed to deliver magnetic labels to specific sites. Technical advances in MR imaging will further increase the efficacy and necessity of tissue-specific MRI contrast agents.
See also Adverse Reaction and Nephrogenic Systemic Fibrosis.

See also the related poll result: 'The development of contrast agents in MRI is'
 
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Courtesy of  Robert R. Edelman
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Courtesy of  Robert R. Edelman
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Radiology-tip.comContrast Agents,  Safety of Contrast Agents
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Radiology-tip.comUltrasound Contrast Agents,  Ultrasound Contrast Agent Safety
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Further Reading:
  Basics:
New guidelines urge caution on use of contrast agents during MR scans
Tuesday, 8 August 2017   by www.dotmed.com    
Manganese-based MRI contrast agents: past, present and future
Friday, 4 November 2011   by www.ncbi.nlm.nih.gov    
A safer approach for diagnostic medical imaging
Monday, 29 September 2014   by www.eurekalert.org    
Drastic market changes with MRI contrast media and PET radiopharmaceuticals emerging as most promising segments
Thursday, 21 October 2004   by www.news-medical.net    
  News & More:
Sodium MRI May Show Biomarker for Migraine
Friday, 1 December 2017   by psychcentral.com    
Manganese-based MRI contrast agent may be safer alternative to gadolinium-based agents
Wednesday, 15 November 2017   by www.eurekalert.org    
3D 'bone maps' could spot early signs of osteoporosis
Monday, 27 February 2017   by www.gmanetwork.com    
New Study Sheds Light on Safety of Gadolinium-Based Contrast Agents
Wednesday, 29 November 2017   by www.empr.com    
Engineered atherosclerosis-specific zinc ferrite nanocomplex-based MRI contrast agents
Monday, 18 January 2016   by 7thspace.com    
A natural boost for MRI scans
Monday, 21 October 2013   by www.eurekalert.org    
For MRI, time is of the essence A new generation of contrast agents could make for faster and more accurate imaging
Tuesday, 28 June 2011   by scienceline.org    
Searchterm 'Ultrasmall Superparamagnetic Iron Oxide' was also found in the following service: 
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FerumoxtranInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.
 
Short name: Ami 227, generic name: Ferumoxtran, (USPIO)
Ferumoxtran is a substance of the class of ultrasmall superparamagnetic iron oxide used as a lymph node specific contrast agent for MRI.
See also Combidex®, Sinerem® and Ultrasmall Superparamagnetic Iron Oxide.
Partner(s): Cytogen Corporation, National Cancer Institute. An approvable letter was received from the U.S. Food and Drug Administration for Combidex in June 2000. Advanced Magnetics, Inc. has submitted a complete response to the approvable letter received from the U.S. Food and Drug Administration, which was accepted by the FDA and assigned a user fee goal date of March 30, 2005. In Europe, a Dossier (the European equivalent of a NDA) was submitted by Advanced Magnetics' European partner, Guerbet SA, to the European Medicines Evaluations Agency in December 1999. (Sinerem® is the brand name for this USPIO in Europe manufactured by Guerbet, Combidex® by Advanced Magnetics for the U.S. market)
Advanced Magnetics, Inc. changed its name in July 2007 to AMAG Pharmaceuticals Inc
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Further Reading:
  Basics:
Superparamagnetic Iron Oxide–enhanced MR Imaging of Head and Neck Lymph Nodes1
Comparison of Two Superparamagnetic Viral-Sized Iron Oxide Particles Ferumoxides and Ferumoxtran-10 with a Gadolinium Chelate in Imaging Intracranial Tumors
2002   by www.ajnr.org    
  News & More:
Optimized Labelling of Human Monocytes with Iron Oxide MR Contrast Agents
Sunday, 30 November 2003   by rsna2003.rsna.org    
Ultrasmall Superparamagnetic Particles of Iron Oxide-enhanced in vivo MRI of human atherosclerotic plaques.(.pdf)
MRI Resources 
Functional MRI - Pregnancy - Resources - Abdominal Imaging - Devices - Case Studies
 
Intracellular Contrast AgentsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
Contrast agent with a preferential intracellular distribution.
Intracellular agents (such as manganese derivatives and ultrasmall superparamagnetic iron oxide), exhibit a flow- and metabolism-dependent uptake. These properties may allow delayed imaging, similar to isotopic methods.
Phospholipid liposomes are rapidly sequestered by the cells in the reticuloendothelial system (RES), primarily in the liver. For imaging of the liver, liposomes may be labeled with MR contrast medium, both positive (T1-shortening) paramagnetic media, and negative (T2-shortening) superparamagnetic media.
Several other nonliposome MR contrast media are also taken up by the RES, e.g.:
superparamagnetic iron oxide (SPIO)
ultrasmall superparamagnetic iron oxide (USPIO)
monocrystalline iron oxide nanoparticle (MION)

Other MR contrast agents accumulate selectively in the hepatocytes, e.g.:
gadoxetic acid (Gd-EOB-DTPA)
gadobenate dimeglumine (Gd-BOPTA)
mangafodipir trisodium (Mn-DPDP)
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MRI Resources 
Mass Spectrometry - Pacemaker - Pediatric and Fetal MRI - Anatomy - MRI Technician and Technologist Career - Sequences
 
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