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Result : Searchterm 'Magnet' found in 97 terms [] and 515 definitions []
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Searchterm 'Magnet' was also found in the following services: 
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News  (897)  Resources  (213)  Forum  (82)  
 
Gastrointestinal Paramagnetic Contrast AgentsInfoSheet: - Contrast Agents - 
Intro, Overview, 
Characteristics, 
Types of, 
etc.MRI Resource Directory:
 - Contrast Agents -
 
Paramagnetic substances, for example Gd-DTPA solutions, are used as MRI oral contrast agents in gastrointestinal imaging to depict the lumen of the digestive organs. Different Gd-DTPA solutions or zeolites containing gadolinium can be used e.g., for diagnosis of delayed gastric emptying, diagnosis of Crohn's disease etc.
Low concentrations of gastrointestinal paramagnetic contrast agents cause a reduction in T1 relaxation time; consequently, these agents act on T1 weighted images by increasing the signal intensity of the bowel lumen. High concentrations cause T2 shortening by decreasing the signal, similar to superparamagnetic iron oxide. Gd-DTPA chelates are unstable at the low pH in the stomach, therefore buffering is necessary for oral use.

See also Gadopentetate Gastrointestinal, Gadolinium Zeolite, Negative Oral Contrast Agents, Gastrointestinal Superparamagnetic Contrast Agents, and Ferric ammonium citrate.
 
Images, Movies, Sliders:
 MR Colonography Gadolinium per Rectum  Open this link in a new window
      

Courtesy of  Robert R. Edelman
 
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Searchterm 'Magnet' was also found in the following services: 
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Radiology  (44) Open this link in a new windowUltrasound  (33) Open this link in a new window
Magnetic Resonance CholangiopancreaticographyMRI Resource Directory:
 - MRCP -
 
(MRCP) This MR imaging technique takes advantage of the high signal intensity of body fluids and acquires heavy T2 weighted images of the gall bladder, the pancreas and parts of the liver. Due to the T2 weighting, the liver and other solid parenchyma are signal suppressed and only fluid-filled structures in addition to the gall bladder, the bile and pancreatic ducts retain important signal intensity. Hepatobiliary contrast agents (e.g. Gadoxetic Acid, CMC 001) can be useful for enhancement of the bile ducts and better imaging of the biliary tract.
A 2D cholangiogram, often only one thick slice (a volume with a thickness of 4 - 8 cm, mostly coronal planned) or 5 - 6 radial placed slices, shows a view like single slices. If a 3D acquisition is used, the postprocessing function maximum intensity projection (MIP) can show reconstructions from multiple sides.
Radiology-tip.comradBiliary Contrast Agents
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Medical-Ultrasound-Imaging.comGallbladder Ultrasound
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• View the DATABASE results for 'Magnetic Resonance Cholangiopancreaticography' (3).Open this link in a new window

 
Further Reading:
  News & More:
Perspectum and Nuance Collaborate to Scale Access to AI-Enabled Integrated Digital Care Platforms to Improve Patient Care for Metabolic Disease
Friday, 9 December 2022   by www.itnonline.com    
MRI Resources 
Service and Support - Most Wanted - MRI Centers - Brain MRI - Portals - Mobile MRI Rental
 
Contrast Enhanced Magnetic Resonance AngiographyInfoSheet: - Sequences - 
Intro, 
Overview, 
Types of, 
etc.MRI Resource Directory:
 - MRA -
 
(CE MRA) Contrast enhanced MR angiography is based on the T1 values of blood, the surrounding tissue, and paramagnetic contrast agent.
T1-shortening contrast agents reduces the T1 value of the blood (approximately to 50 msec, shorter than that of the surrounding tissues) and allow the visualization of blood vessels, as the images are no longer dependent primarily on the inflow effect of the blood. Contrast enhanced MRA is performed with a short TR to have low signal (due to the longer T1) from the stationary tissue, short scan time to facilitate breath hold imaging, short TE to minimize T2* effects and a bolus injection of a sufficient dose of a gadolinium chelate.
Images of the region of interest are performed with 3D spoiled gradient echo pulse sequences. The enhancement is maximized by timing the contrast agent injection such that the period of maximum arterial concentration corresponds to the k-space acquisition. Different techniques are used to ensure optimal contrast of the arteries e.g., bolus timing, automatic bolus detection, bolus tracking, care bolus. A high resolution with near isotropic voxels and minimal pulsatility and misregistration artifacts should be striven for. The postprocessing with the maximum intensity projection (MIP) enables different views of the 3D data set.
Unlike conventional MRA techniques based on velocity dependent inflow or phase shift techniques, contrast enhanced MRA exploits the gadolinium induced T1-shortening effects. CE MRA reduces or eliminates most of the artifacts of time of flight angiography or phase contrast angiography. Advantages are the possibility of in plane imaging of the blood vessels, which allows to examine large parts in a short time and high resolution scans in one breath hold. CE MRA has found a wide acceptance in the clinical routine, caused by the advantages:
•
3D MRA can be acquired in any plane, which means that greater vessel coverage can be obtained at high resolution with fewer slices (aorta, peripheral vessels);
•
the possibility to perform a time resolved examination (similarly to conventional angiography);
•
no use of ionizing radiation; paramagnetic agents have a beneficial safety.
 
Images, Movies, Sliders:
 CE-MRA of the Carotid Arteries  Open this link in a new window
    
SlidersSliders Overview

 CE MRA of the Aorta  Open this link in a new window
    
SlidersSliders Overview

 CE-MRA of the Carotid Arteries Colored MIP  Open this link in a new window
    
SlidersSliders Overview

 
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• View the DATABASE results for 'Contrast Enhanced Magnetic Resonance Angiography' (14).Open this link in a new window


• View the NEWS results for 'Contrast Enhanced Magnetic Resonance Angiography' (2).Open this link in a new window.
 
Further Reading:
  Basics:
Contrast-Enhanced MR Angiography(.pdf)
   by ric.uthscsa.edu    
CONTRAST ENHANCED MR ANGIOGRAPHY – PRINCIPLES, APPLICATIONS, TIPS AND PITFALLS(.pdf)
  News & More:
CONTRAST-ENHANCED MRA OF THE CAROTIDS(.pdf)
PERIPHERAL VASCULAR MAGNETIC RESONANCE ANGIOGRAPHY(.pdf)
CONTRAST ENHANCED MRI OF THE LIVER STATE-OF-THE-ART(.pdf)
Searchterm 'Magnet' was also found in the following services: 
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News  (897)  Resources  (213)  Forum  (82)  
 
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.
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• View the DATABASE results for 'Very Small Superparamagnetic Iron Oxide Particles' (3).Open this link in a new window

Searchterm 'Magnet' was also found in the following services: 
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Radiology  (44) Open this link in a new windowUltrasound  (33) Open this link in a new window
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.
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• 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 
Jobs pool - Shielding - Spectroscopy pool - Colonography - MRCP - Corporations
 
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