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Searchterm 'Field Strength' was also found in the following services: 
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News  (13)  Resources  (3)  Forum  (7)  
 
CHORUS 1.5T™InfoSheet: - Devices -
Intro, 
Types of Magnets, 
Overview, 
etc.MRI Resource Directory:
 - Devices -
 
www.isoltech.co.kr/english/product/default.htm 'Next generation MRI system 1.5T CHORUS developed by ISOL Technology is optimized for both clinical diagnostic imaging and for research development.
CHORUS offers the complete range of feature oriented advanced imaging techniques- for both clinical routine and research. The compact short bore magnet, the patient friendly design and the gradient technology make the innovation to new degree of perfection in magnetic resonance.'
Device Information and Specification
CLINICAL APPLICATION
Whole body
CONFIGURATION
Short bore
Head, C-spine, L-spine, TMJ, Knee, Shoulder, General purpose, Phased Array System: 4 digital receiver channels (Up to 12 channels)
Optional
SYNCHRONIZATION
ECG/peripheral: Optional/yes, respiratory gating
PULSE SEQUENCES
Spin Echo, Gradient Echo, Fast Spin Echo, Inversion Recovery (STIR, Fluid Attenuated Inversion Recovery), FLASH, FISP, PSIF, Turbo Flash ( MPRAGE ),TOF MR Angiography, Standard echo planar imaging package (SE-EPI, GE-EPI), Optional: Advanced P.A. Imaging Package (up to 4 ch.), Advanced echo planar imaging package, Single Shot and Diffusion Weighted EPI, IR/FLAIR EPI
IMAGING MODES
2D/3D, Travelling Sat, Multi-Slab 3D, MTC and TONE Pulse Sequence, Fat/Water Suppression, Presaturation (up to 6 bands), Flow Compensation using GMR pulse, Multi-Slice, Multi-Group Imaging
SINGLE/MULTI SLICE
Image reconstruction time (2562 ) : 0.02 s
FOV
40 cm
BORE DIAMETER
or W x H
58 cm diameter (patient)
MAGNET WEIGHT
4050 kg
H*W*D
233 x 206 x 160 cm
COOLING SYSTEM TYPE
Water-cooled coil and air-cooled amplifier
CRYOGEN USE
0.07 L/hr helium
STRENGTH
20 mT/m (Upto 27 mT/m)
5-GAUSS FRINGE FIELD
2.5 m / 3.8 m
Passive and active
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Searchterm 'Field Strength' was also found in the following services: 
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Radiology  (5) Open this link in a new windowUltrasound  (2) Open this link in a new window
Cardiac PacemakerMRI Resource Directory:
 - Safety -
 
A pacemaker is a device for internal or external battery-operated cardiac pacing to overcome cardiac arrhythmias or heart block. All implanted electronic devices are susceptible to the electromagnetic fields used in magnetic resonance imaging. Therefore, the main magnetic field, the gradient field, and the radio frequency (RF) field are potential hazards for cardiac pacemaker patients.
The pacemaker's susceptibility to static field and its critical role in life support have warranted special consideration. The static magnetic field applies force to magnetic materials. This force and torque effects rise linearly with the field strength of the MRI machines. Both, RF fields and pulsed gradients can induce voltages in circuits or on the pacing lead, which will heat up the tissue around e.g. the lead tip, with a potential risk of thermal injury.
Regulations for pacemakers provide that they have to switch to the magnet mode in static magnetic fields above 1.0 mT. In MR imaging, the gradient and RF fields may mimic signals from the heart with inhibition or fast pacing of the heart. In the magnet mode, most of the current pacemakers will pace with a fix pulse rate because they do not accept the heartsignals. However, the state of an implanted pacemaker will be unpredictable inside a strong magnetic field. Transcutaneous controller adjustment of pacing rate is a feature of many units. Some achieve this control using switches activated by the external application of a magnet to open/close the switch. Others use rotation of an external magnet to turn internal controls. The fringe field around the MRI magnet can activate such switches or controls. Such activations are a safety risk.
Areas with fields higher than 0.5 mT (5 Gauss Limit) commonly have restricted access and/or are posted as a safety risk to persons with pacemakers.
mri safety guidance
MRI Safety Guidance
A Cardiac pacemaker is because the risks, under normal circumstances an absolute contraindication for MRI procedures.
Nevertheless, with special precaution the risks can be lowered. Reprogramming the pacemaker to an asynchronous mode with fix pacing rate or turning off will reduce the risk of fast pacing or inhibition. Reducing the SAR value reduces the potential MRI risks of heating. For MRI scans of the head and the lower extremities, tissue heating also seems to be a smaller problem. If a transmit receive coil is used to scan the head or the feet, the cardiac pacemaker is outside the sending coil and possible heating is very limited.
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• View the DATABASE results for 'Cardiac Pacemaker' (6).Open this link in a new window

 
Further Reading:
  Basics:
MRI in Patients with Implanted Devices: Current Controversies
Monday, 1 August 2016   by www.acc.org    
Magnetic resonance imaging in patients with cardiac pacemakers: era of MR Conditional designs
Thursday, 27 October 2011   by 7thspace.com    
  News & More:
Newer Heart Devices Safe During MRI
Monday, 23 August 2004   by www.hospimedica.com    
BIOTRONIK debuts pacemaker with continuous MRI sensor
Wednesday, 30 August 2023   by www.medicaldevice-network.com    
Patients with standard pacemakers, ICDs may safely undergo MRIs
Friday, 24 February 2017   by www.cardiovascularbusiness.com    
ITOCHU Named the Exclusive Distributor for ViewRay's MRI-Guided Radiation Therapy System in Japan
Thursday, 22 January 2015   by www.prnewswire.com    
Modern Implantable Heart Devices Safe For Use In MRI Scans
Wednesday, 16 March 2005   by www.sciencedaily.com    
MRI Resources 
Non-English - Resources - MRI Reimbursement - Raman Spectroscopy - Implant and Prosthesis pool - Hospitals
 
Cardiac StentForum -
related threadsMRI Resource Directory:
 - Safety -
 
The MRI safety of cardiac stents is dependent of the material, the examined part of the body and the used field strength. A susceptibility artifact is expected also in low magnetic fields, but less.
mri safety guidance
MRI Safety Guidance
Most of the used materials are non-magnetic, for this case there is no risk for movement caused through the magnetic field. If the cardiac stent is outside the region of the radio frequency pulse, also the risk of e.g. heating is low.
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• View the DATABASE results for 'Cardiac Stent' (4).Open this link in a new window

 
Further Reading:
  Basics:
Guidelines for the Management of Patients with Coronary Artery Stents Referred for MRI Procedures
Tuesday, 1 January 2019   by www.ismrm.org    
Searchterm 'Field Strength' was also found in the following services: 
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News  (13)  Resources  (3)  Forum  (7)  
 
ContraindicationsForum -
related threadsMRI Resource Directory:
 - Safety -
 
The principal contraindications of the MRI procedure are mostly related to the presence of metallic implants in a patient. The risks of MRI scans increase with the used field strength. In general, implants are becoming increasingly MR safe and an individual evaluation is carried out for each case.
mri safety guidance
MRI Safety Guidance
Some patients should not be examined in MRI machines, or come closer than the 5 Gauss line to the system.

Absolute Contraindications for the MRI scan:
•
electronically, magnetically, and mechanically activated implants
•
ferromagnetic or electronically operated active devices like automatic cardioverter defibrillators
•
metallic splinters in the eye
•
ferromagnetic haemostatic clips in the central nervous system (CNS)

Patients with absolute contraindications should not be examined or only with special MRI safety precautions. Patients with an implanted cardiac pacemaker have been scanned on rare occasions, but pacemakers are generally considered an absolute contraindication. Relative contraindications may pose a relative hazard, and the type and location of an implant should be assessed prior to the MRI examination.

Relative Contraindications for the MRI scan:
•
other pacemakers, e.g. for the carotid sinus
•
lead wires or similar wires (MRI Safety risk)
•
prosthetic heart valves (in high fields, if dehiscence is suspected)
•
haemostatic clips (body)
•

Osteosynthesis material is usually anchored so well in the patients that no untoward effect will result. Another effect on metal parts in the patient's body is the heating of these parts through induction. In addition, image quality may be severely degraded. The presence of other metallic implants such as surgical clips etc. should be made known to the MRI operators. Most of these materials are non-magnetic, but if magnetic, they can pose a hazard.

See also MRI safety, Pregnancy, Claustrophobia and Tattoos.
Radiology-tip.comradRadiation Safety,  As Low As Reasonably Achievable
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Medical-Ultrasound-Imaging.comUltrasound Safety
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• View the DATABASE results for 'Contraindications' (11).Open this link in a new window

 
Further Reading:
  Basics:
MRI in Patients with Implanted Devices: Current Controversies
Monday, 1 August 2016   by www.acc.org    
Newer Heart Devices Safe During MRI
Monday, 23 August 2004   by www.hospimedica.com    
Physics of MRI Safety
   by www.aapm.org    
FDA Releases New Guidance On Establishing Safety, Compatibility Of Passive Implants In MR Environments
Tuesday, 16 December 2014   by www.meddeviceonline.com    
  News & More:
Women with permanent make-up tattoos suffer horrific facial burns after going in for MRI scans - which create an electric current in the ink
Monday, 4 July 2016   by www.dailymail.co.uk    
Positive diagnosis for neural therapeutic implants
Tuesday, 19 April 2016   by medicalxpress.com    
Codman Neuro develops new MRI-resistant programmable valve for treatment of hydrocephalus
Tuesday, 22 September 2015   by www.news-medical.net    
Searchterm 'Field Strength' was also found in the following services: 
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Radiology  (5) Open this link in a new windowUltrasound  (2) Open this link in a new window
ContrastForum -
related threads
 
Contrast is the relative difference of signal intensities in two adjacent regions of an image.
Due to the T1 and T2 relaxation properties in magnetic resonance imaging, differentiation between various tissues in the body is possible. Tissue contrast is affected by not only the T1 and T2 values of specific tissues, but also the differences in the magnetic field strength, temperature changes, and many other factors. Good tissue contrast relies on optimal selection of appropriate pulse sequences (spin echo, inversion recovery, gradient echo, turbo sequences and slice profile).
Important pulse sequence parameters are TR (repetition time), TE (time to echo or echo time), TI (time for inversion or inversion time) and flip angle. They are associated with such parameters as proton density and T1 or T2 relaxation times. The values of these parameters are influenced differently by different tissues and by healthy and diseased sections of the same tissue.
For the T1 weighting it is important to select a correct TR or TI. T2 weighted images depend on a correct choice of the TE. Tissues vary in their T1 and T2 times, which are manipulated in MRI by selection of TR, TI, and TE, respectively. Flip angles mainly affect the strength of the signal measured, but also affect the TR/TI/TE parameters.
Conditions necessary to produce different weighted images:
T1 Weighted Image: TR value equal or less than the tissue specific T1 time - TE value less than the tissue specific T2 time.
T2 Weighted Image: TR value much greater than the tissue specific T1 time - TE value greater or equal than the tissue specific T2 time.
Proton Density Weighted Image: TR value much greater than the tissue specific T1 time - TE value less than the tissue specific T2 time.

See also Image Contrast Characteristics, Contrast Reversal, Contrast Resolution, and Contrast to Noise Ratio.
 
Images, Movies, Sliders:
 Fetus (Brain) and Dermoid in Mother  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 Circle of Willis, Time of Flight, MIP  Open this link in a new window
    
SlidersSliders Overview

 Anatomic MRI of the Knee 1  Open this link in a new window
    
SlidersSliders Overview

 Anatomic Imaging of the Liver  Open this link in a new window
      

 Brain MRI Inversion Recovery  Open this link in a new window
    
 
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• View the DATABASE results for 'Contrast' (373).Open this link in a new window


• View the NEWS results for 'Contrast' (77).Open this link in a new window.
 
Further Reading:
  Basics:
Magnetic resonance imaging
   by www.scholarpedia.org    
MRI's inside story
Thursday, 4 December 2003   by www.economist.com    
Image Characteristics and Quality
   by www.sprawls.org    
  News & More:
A natural boost for MRI scans
Monday, 21 October 2013   by www.eurekalert.org    
A groundbreaking new graphene-based MRI contrast agent
Friday, 8 June 2012   by www.nanowerk.com    
New MRI Chemical Offers Amazing Contrast
Friday, 22 January 2010   by news.softpedia.com    
MRI Resources 
Distributors - Pediatric and Fetal MRI - Quality Advice - Sequences - MRI Reimbursement - Safety Training
 
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