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

Out-
      side
 



 
 'Magnetic Field' 
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 'Magnetic Field' found in 5 terms [] and 219 definitions []
previous     66 - 70 (of 224)     next
Result Pages : [1]  [2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 ... ]
Searchterm 'Magnetic Field' was also found in the following services: 
spacer
News  (76)  Resources  (16)  Forum  (18)  
 
MR Compatibility
 
mri safety guidance
MRI Safety Guidance
If a device is to be labeled MR Safe, the following information should be provided:
•
Data demonstrating that when the device is introduced or used in the MRI environment (i.e. the MRI scan room) it does not pose an increased safety risk to the patient or other personnel,
•
a scientifically-based rationale for why data are not necessary to prove the safety of the device in the MR environment (for example, a passive device made entirely of a polymer known to be nonreactive in strong magnetic fields).

If a device is to be labeled MR Compatible, the following information should be provided:
•
Data demonstrating that when the device is introduced or used in the MRI environment, it is MR safe that it performs its intended function without performance degradation, and that it does not adversely affect the function of the MRI scanner (e.g. no significant image artifacts or noise). Any image artifact or noise due to the medical device should be quantified (e.g., % volume affected, signal to noise ratio),
•
a scientifically-based rationale for why data are not necessary to prove the compatibility of the device in the MRI environment.

Test Conditions:
The static magnetic field strength (Gauss (G) or Tesla (T)) to which the device was tested and demonstrated to be MRI 'safe', 'compatible', or 'intended for use in' should be related to typical machine ratings (e.g. 0.5 T, 1.5 T, 2.0 T, and shielded or unshielded magnet, etc).
The same conditions should be used for the spatial gradient (field strength per unit distance (i.e., G/cm)) in which the device was tested and demonstrated to be 'safe', 'compatible', or 'intended for use in'.
Also the RF transmitter power used during testing of the device, should be related to this typical machine ratings.
spacer
• For this and other aspects of MRI safety see our InfoSheet about MRI Safety.
• Patient-related information is collected in our MRI Patient Information.


• View the NEWS results for 'MR Compatibility' (2).Open this link in a new window.
 
Further Reading:
  Basics:
Newer Heart Devices Safe During MRI
Monday, 23 August 2004   by www.hospimedica.com    
  News & More:
Boston Scientific and Biophan in MRI Collaboration
Friday, 21 November 2003   by www.medimaging.net    
MRI safety targeted as new group offers credentialing test
Monday, 12 January 2015   by www.modernhealthcare.com    
FDA Releases New Guidance On Establishing Safety, Compatibility Of Passive Implants In MR Environments
Tuesday, 16 December 2014   by www.meddeviceonline.com    
Searchterm 'Magnetic Field' was also found in the following services: 
spacer
Radiology  (9) Open this link in a new windowUltrasound  (2) Open this link in a new window
MagnetForum -
related threads
 
A magnet is by definition an object with magnetic properties (magnetism) that attracts iron and produces a magnetic field. It can be a permanent magnet or an electromagnet.
Permanent magnets do not rely upon outside influences to generate their field. In permanent magnets are the atoms and molecules ordered in long range. The specific electron configuration and the distance of the atoms is what lead to this long range ordering. The electrons exist in a lower energy state if they all have the same orientation. Magnetic domains can be likened to microscopic neighborhoods in which there is a strong reinforcing interaction between particles, resulting in a high degree of order. The greater the degree of ordering within and between domains, the greater the resulting field will be. Long range ordering is one of the hallmarks of a ferromagnetic material.
A current carrying conductor for example a piece of wire, produces a magnetic field that encircles the wire. An electromagnet, in its simplest form, is a wire that has been coiled into one or more loops. This coil is known as a solenoid. The more loops of wire and the greater the current, the stronger the field will be.
Superconducting magnets are a special type of electromagnets, often used in MRI machines with high field strength.
spacer

• View the DATABASE results for 'Magnet' (669).Open this link in a new window


• View the NEWS results for 'Magnet' (315).Open this link in a new window.
 
Further Reading:
  Basics:
Magnetic Field
   by hyperphysics.phy-astr.gsu.edu    
  News & More:
Philips Signs Research Agreement to Explore New Magnet Technologies
Monday, 5 December 2022   by www.itnonline.com    
Impact of Magnetic Field Inhomogeneity on the Quality of Magnetic Resonance Images and Compensation Techniques: A Review
Saturday, 1 October 2022   by www.dovepress.com    
Magnetic seeds used to heat and kill cancer
Tuesday, 1 February 2022   by www.sciencedaily.com    
Harvard Scientists Create Nanoscale MRI
Monday, 28 April 2014   by www.meddeviceonline.com    
How Academic Research Solved the Puzzle of MRI and CAT Scanning
Monday, 21 April 2014   by www.engineering.com    
MRI Safety Resources 
Pregnancy - Safety Products - Cochlear Implant - Breast Implant - Stent
 
Magnetic Gradient
 
One of three linear magnetization waveforms superimposed on the main magnetic field at specific times within a pulse sequence to select the imaging region or provide necessary spatial localization information. A magnetic gradient is defined as the amount and direction of the linear rate of change of the magnetic field in space.
spacer

• View the DATABASE results for 'Magnetic Gradient' (5).Open this link in a new window


• View the NEWS results for 'Magnetic Gradient' (1).Open this link in a new window.
 
Further Reading:
  News & More:
Magnetic fields drive drug-loaded nanoparticles to reduce blood vessel blockages in an animal study
Monday, 19 April 2010   by www.eurekalert.org    
Active Noise Control of Magnetic Resonance Imaging Scanner Using Inverse Modeling Technique
Monday, 19 April 2010   by www.acoustics.org    
Searchterm 'Magnetic Field' was also found in the following services: 
spacer
News  (76)  Resources  (16)  Forum  (18)  
 
Magnetic Resonance Imaging MRI
 
(MRI) Magnetic resonance imaging is a noninvasive medical imaging technique that uses the interaction between radio frequency pulses, a strong magnetic field and body tissue to obtain images of slices/planes from inside the body. These magnets generate fields from approx. 2000 times up to 30000 times stronger than that of the Earth. The use of nuclear magnetic resonance principles produces extremely detailed pictures of the body tissue without the need for x-ray exposure and gives diagnostic information of various organs.
Measured are mobile hydrogen nuclei (protons are the hydrogen atoms of water, the 'H' in H20), the majority of elements in the body. Only a small part of them contribute to the measured signal, caused by their different alignment in the magnetic field. Protons are capable of absorbing energy if exposed to short radio wave pulses (electromagnetic energy) at their resonance frequency. After the absorption of this energy, the nuclei release this energy so that they return to their initial state of equilibrium.
This transmission of energy by the nuclei as they return to their initial state is what is observed as the MRI signal. The subtle differing characteristic of that signal from different tissues combined with complex mathematical formulas analyzed on modern computers is what enables MRI imaging to distinguish between various organs. Any imaging plane, or slice, can be projected, and then stored or printed.
The measured signal intensity depends jointly on the spin density and the relaxation times (T1 time and T2 time), with their relative importance depending on the particular imaging technique and choice of interpulse times. Any motion such as blood flow, respiration, etc. also affects the image brightness.
Magnetic resonance imaging is particularly sensitive in assessing anatomical structures, organs and soft tissues for the detection and diagnosis of a broad range of pathological conditions. MRI pictures can provide contrast between benign and pathological tissues and may be used to stage cancers as well as to evaluate the response to treatment of malignancies. The need for biopsy or exploratory surgery can be eliminated in some cases, and can result in earlier diagnosis of many diseases.

See also MRI History and Functional Magnetic Resonance Imaging (fMRI).
 
Images, Movies, Sliders:
 CE-MRA of the Carotid Arteries Colored MIP  Open this link in a new window
    
SlidersSliders Overview

 Anatomic Imaging of the Lumbar Spine  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 Normal Dual Inversion Fast Spin-echo  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 Breast MRI Images T2 And T1 Pre - Post Contrast  Open this link in a new window
 Anatomic Imaging of the Shoulder  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 
spacer

• View the DATABASE results for 'Magnetic Resonance Imaging MRI' (9).Open this link in a new window


• View the NEWS results for 'Magnetic Resonance Imaging MRI' (222).Open this link in a new window.
 
Further Reading:
  Basics:
Bringing More Value to Imaging Departments With MRI
Friday, 4 October 2019   by www.itnonline.com    
A Short History of the Magnetic Resonance Imaging (MRI)
   by www.teslasociety.com    
On the Horizon - Next Generation MRI
Wednesday, 23 October 2013   by thefutureofthings.com    
MRI's inside story
Thursday, 4 December 2003   by www.economist.com    
  News & More:
High-resolution MRI enables direct imaging of neuronal activity - DIANA – direct imaging of neuronal activity
Friday, 18 November 2022   by physicsworld.com    
New MRI technique can 'see' molecular changes in the brain
Thursday, 5 September 2019   by medicalxpress.com    
How new MRI technology is transforming the patient experience
Tuesday, 14 May 2019   by newsroom.gehealthcare.com    
Metamaterials boost sensitivity of MRI machines
Thursday, 14 January 2016   by www.eurekalert.org    
MRI technique allows study of wrist in motion
Monday, 6 January 2014   by www.healthimaging.com    
New imaging technology promising for several types of cancer
Thursday, 29 August 2013   by medicalxpress.com    
MRI method for measuring MS progression validated
Thursday, 19 December 2013   by www.eurekalert.org    
Searchterm 'Magnetic Field' was also found in the following services: 
spacer
Radiology  (9) Open this link in a new windowUltrasound  (2) Open this link in a new window
Magnetic SusceptibilityForum -
related threads
 
(c) Magnetic susceptibility is the degree of magnetization of a material in response to a magnetic field. Paramagnetic materials strengthen the magnetic field, diamagnetic materials weaken it. The magnetic susceptibility of ferromagnetic substances is not linear; this is called differential susceptibility.
Differences in magnetic susceptibilities are a frequent cause of MRI artifacts.

See also Susceptibility Artifact, Magnetism, Diamagnetism, Paramagnetism, Ferromagnetism.
spacer

• View the DATABASE results for 'Magnetic Susceptibility' (15).Open this link in a new window

 
Further Reading:
  Basics:
Metal-Induced Artifacts in MRI
   by www.ajronline.org    
Magnetic susceptibility
   by en.wikipedia.org    
MRI Resources 
MRI Training Courses - Pediatric and Fetal MRI - Bioinformatics - Used and Refurbished MRI Equipment - Safety Training - Education pool
 
previous      66 - 70 (of 224)     next
Result Pages : [1]  [2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 ... ]
 Random Page
 
Share This Page
FacebookTwitterLinkedIn

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



MRI is trending to low field magnets :
reduced costs will lead to this change 
AI will close the gap to high field 
only in remote areas 
is only temporary 
never 

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. [ 28 March 2024]
Terms of Use | Privacy Policy | Advertising
 [last update: 2024-02-26 03:41:00]