Magnetic Resonance - Technology Information Portal Welcome to MRI Technology
Info
  Sheets

Out-
      side
 



 
 'superparamagnetic' 
SEARCH FOR    
 
  2 3 5 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Result : Searchterm 'superparamagnetic' found in 5 terms [] and 37 definitions []
1 - 5 (of 42)     next
Result Pages : [1]  [2 3 4 5 6 7 8 9]
Searchterm 'superparamagnetic' was also found in the following services: 
spacer
News  (7)  Forum  (1)  
 
Superparamagnetic Iron OxideInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.
 
(SPIO) Relatively new types of MRI contrast agents are superparamagnetic iron oxide-based colloids (median diameter greater than 50nm). These compounds consist of nonstoichiometric microcrystalline magnetite cores, which are coated with dextrans (in ferumoxide) or siloxanes (in ferumoxsil). After injection they accumulate in the reticuloendothelial system (RES) of the liver (Kupffer cells) and the spleen. At low doses circulating iron decreases the T1 time of blood, at higher doses predominates the T2* effect.
SPIO agents are much more effective in MR relaxation than paramagnetic agents. Since hepatic tumors either do not contain RES cells or their activity is reduced, the contrast between liver and lesion is improved. Superparamagnetic iron oxides cause noticeable shorter T2 relaxation times with signal loss in the targeted tissue (e.g., liver and spleen) with all standard pulse sequences. Magnetite, a mixture of FeO and Fe2O3, is one of the used iron oxides. FeO can be replaced by Fe3O4.
Use of these colloids as tissue specific contrast agents is now a well-established area of pharmaceutical development. Feridex®, Endorem™, GastroMARK®, Lumirem®, Sinerem®, Resovist® and more patents pending tell us that the last word in this area is not said.
Some remarkable points using SPIO:
•
A minimum delay of about 10 min. between injection (or infusion) and MR imaging, extends the examination time.
•
Cross-section flow void in narrow blood vessels may impede the differentiation from small liver lesions.
•
Aortic pulsation artifacts become more pronounced.


See also Superparamagnetism, Superparamagnetic Contrast Agents and Classifications, Characteristics, etc..
spacer
 
• Share the entry 'Superparamagnetic Iron Oxide':  Facebook  Twitter  LinkedIn  
 
• Related Searches:
    • Hepatobiliary Contrast Agents
    • Superparamagnetism
    • Superparamagnetic Contrast Agents
    • Blood Pool Agents
    • Ferromagnetism
 
Further Reading:
  Basics:
IMAGE CONTRAST IN MRI(.pdf)
   by www.assaftal.com    
  News & More:
How to stop using gadolinium chelates for magnetic resonance imaging: clinical-translational experiences with ferumoxytol
Saturday, 5 February 2022   by www.ncbi.nlm.nih.gov    
Polysaccharide-Core Contrast Agent as Gadolinium Alternative for Vascular MR
Monday, 8 March 2021   by www.diagnosticimaging.com    
Poly (dopamine) coated superparamagnetic iron oxide nanocluster for noninvasive labeling, tracking, and targeted delivery of adipose tissue-derived stem cells
Tuesday, 5 January 2016   by www.nature.com    
Longitudinal MRI contrast enhanced monitoring of early tumour development with manganese chloride (MnCl2) and superparamagnetic iron oxide nanoparticles (SPIOs) in a CT1258 based in vivo model of prostate cancer
Wednesday, 11 July 2012   by www.biomedcentral.com    
MRI Resources 
Examinations - Hospitals - Jobs - Societies - Software - Contrast Agents
 
Superparamagnetic Contrast AgentsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
Small particles of ferrite are used as superparamagnetic contrast medium in MR imaging (appearing predominantly dark on MRI). These agents exhibit strong T1 relaxation properties, and due to susceptibility differences to their surroundings also produce a strongly varying local magnetic field, which enhances T2 relaxation to darken the contrast media containing structures.
Superparamagnetic contrast agents are also known by the abbreviation SPIO's (small particle iron oxide or superparamagnetic iron oxide) and USPIO's (ultrasmall particle iron oxide or ultrasmall superparamagnetic iron oxide).
Two types of USPIO will be available on the market as blood pool agents, while SPIO's have been used as darkening contrast agents for liver imaging. As particulate matter they are taken up by the RES. Very small particles of less than 300 nanometers also remain intravascular for a prolonged period of time and thus can serve as blood pool agents.

See also the related poll result: 'The development of contrast agents in MRI is'
spacer

• View the DATABASE results for 'Superparamagnetic Contrast Agents' (12).Open this link in a new window

 
Further Reading:
  News & More:
Optimized Labelling of Human Monocytes with Iron Oxide MR Contrast Agents
Sunday, 30 November 2003   by rsna2003.rsna.org    
Poly (dopamine) coated superparamagnetic iron oxide nanocluster for noninvasive labeling, tracking, and targeted delivery of adipose tissue-derived stem cells
Tuesday, 5 January 2016   by www.nature.com    
MRI Resources 
Shoulder MRI - Anatomy - Directories - Patient Information - Pediatric and Fetal MRI - Stimulator pool
 
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.
spacer

• View the DATABASE results for 'Ultrasmall Superparamagnetic Iron Oxide' (16).Open this link in a new window


• View the NEWS results for 'Ultrasmall Superparamagnetic Iron Oxide' (2).Open this link in a new window.
 
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    
Searchterm 'superparamagnetic' was also found in the following services: 
spacer
News  (7)  Forum  (1)  
 
Very Small Superparamagnetic Iron Oxide ParticlesInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
(VSOP) A new class of contrast agents with smaller particle size than SPIO or USPIO with advantages for MR angiography, caused through a longer plasma half-life.

See also Ultrasmall Superparamagnetic Iron Oxide and Superparamagnetic Iron Oxide.
spacer

• View the DATABASE results for 'Very Small Superparamagnetic Iron Oxide Particles' (3).Open this link in a new window

MRI Resources 
Diffusion Weighted Imaging - - Sequences - Cardiovascular Imaging - Contrast Enhanced MRI - Brain MRI
 
Gastrointestinal Superparamagnetic Contrast AgentsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
Gastrointestinal (GI) superparamagnetic contrast agents are used in MRI to improve the visualization of e.g., the intestinal tract, the pancreas (see MRCP), etc. Disadvantages are susceptibility artifacts e.g., dependent on delayed imaging or large volumes resulting in artifacts in the colon and distal small bowel loops related to higher concentration of the particles and absorption of the fluid.
Different types of MRI gastrointestinal superparamagnetic contrast agents:
•
Magnetite albumin microsphere

Usually gastrointestinal superparamagnetic contrast media consist of small iron oxide crystals (ferrites), which produce a signal reduction in the stomach and bowel after oral administration. The T2 shortening caused by these particles is produced from the local magnetic field inhomogeneities associated with the large magnetic moments of superparamagnetic particles. Ferrites are iron oxides of the general formula Fe203.MO, where M is a divalent metal ion and may be mixed with Fe3O4 in different preparations. Ferrites can produce symptoms of nausea after oral administration, as well as flatulence and a transient rise in serum iron. Embedding in inert substances reduce side effects by decreasing the absorption and interaction with body tissues. Combining these contrast materials with polymers such as polyethylene glycol or cellulose, or with sugars such as dextrose, results in improved T1 and/or T2 relaxivity compared with that of the contrast agent alone.

See also Negative Oral Contrast Agents, Gastrointestinal Diamagnetic Contrast Agents, Relaxivity, and Combination Oral Contrast Agents.
spacer

• View the DATABASE results for 'Gastrointestinal Superparamagnetic Contrast Agents' (6).Open this link in a new window

 
Further Reading:
  Basics:
Negative GI Contrast Agents
   by www.mritutor.org    
MRI Resources 
Homepages - MRI Accidents - Journals - Crystallography - Shoulder MRI - Distributors
 
     1 - 5 (of 42)     next
Result Pages : [1]  [2 3 4 5 6 7 8 9]
 Random Page
 
Share This Page
FacebookTwitterLinkedIn

MR-TIP    
Community   
User
Pass
Forgot your UserID/Password ?    



Personalized protocols (age, gender, body habitus, etc.) lead to :
more automated planning 
improved patient comfort 
better diagnostics 
optimized image quality 
nothing 

Look
      Ups





MR-TIP.com uses cookies! By browsing MR-TIP.com, you agree to our use of cookies.

Magnetic Resonance - Technology Information Portal
Member of SoftWays' Medical Imaging Group - MR-TIP • Radiology-TIP • Medical-Ultrasound-Imaging • 
Copyright © 2003 - 2024 SoftWays. All rights reserved. [ 29 March 2024]
Terms of Use | Privacy Policy | Advertising
 [last update: 2024-02-26 03:41:00]