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Cardiac RisksMRI Resource Directory:
 - Safety -
 
During the MRI scan an augmentation of T waves is observed at fields used in standard imaging but this possible MRI side effect is completely reversible upon removal from the magnet. A field strength dependent increase in the amplitude of the ECG in rats has been observed during exposure to high homogeneous stationary magnetic fields, but this side effect is not transferable to standard imaging situations for humans.


MRI Safety Guidance
The minimum level at which augmentation can be observed is 0.3 T and increases by higher field strength. An augmentation in T-wave amplitude can occur instantaneously and is immediately reversible after exposure to the magnetic field ceased. There should be no abnormalities in the ECG in the later follow-up. Augmentation of the signal amplitude in the T-wave segment may result from superimposed electrical potential. No circulatory alterations coincide with the ECG changes. Therefore, no biological risks are believed to be associated with them.
For more MRI safety information see also Contraindications and MRI Risks.

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• For this and other aspects of MRI safety see our InfoSheet about MRI Safety.
• Patient-related information is collected in our MRI Patient Information.

 
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Further Reading:
  Basics:
A Primer on Medical Device Interactions with Magnetic Resonance Imaging Systems
   by govpulse.us    
MRI Safety Resources 
Pacemaker - Safety Products - Breast Implant - Nerve Stimulator - Cochlear Implant
 
MRI SafetyMRI Resource Directory:
 - Safety -
 
There are different types of contraindications that would prevent a person from being examined with an MRI scanner. MRI systems use strong magnetic fields that attract any ferromagnetic objects with enormous force. Caused by the potential risk of heating, produced from the radio frequency pulses during the MRI procedure, metallic objects like wires, foreign bodies and other implants needs to be checked for compatibility. High field MRI requires particular safety precautions. In addition, any device or MRI equipment that enters the magnet room has to be MR compatible. MRI examinations are safe and harmless, if these MRI risks are observed and regulations are followed.

Safety concerns in magnetic resonance imaging include:
the magnetic field strength;
possible 'missile effects' caused by magnetic forces;
the potential for heating of body tissue due to the application of the radio frequency energy;
the effects on implanted active devices such as cardiac pacemakers or insulin pumps;
magnetic torque effects on indwelling metal (clips, etc.);
the audible acoustic noise;
danger due to cryogenic liquids;
the application of contrast medium;


MRI Safety Guidance
It is important to remember when working around a superconducting magnet that the magnetic field is always on. Under usual working conditions the field is never turned off. Attention must be paid to keep all ferromagnetic items at an adequate distance from the magnet. Ferromagnetic objects which came accidentally under the influence of these strong magnets can injure or kill individuals in or nearby the magnet, or can seriously damage every hardware, the magnet itself, the cooling system, etc.. See MRI resources Accidents.
The doors leading to a magnet room should be closed at all times except when entering or exiting the room. Every person working in or entering the magnet room or adjacent rooms with a magnetic field has to be instructed about the dangers. This should include the patient, intensive-care staff, and maintenance-, service- and cleaning personnel, etc..
The 5 Gauss limit defines the 'safe' level of static magnetic field exposure. The value of the absorbed dose is fixed by the authorities to avoid heating of the patient's tissue and is defined by the specific absorption rate. Leads or wires that are used in the magnet bore during imaging procedures, should not form large-radius wire loops. Leg-to-leg and leg-to-arm skin contact should be prevented in order to avoid the risk of burning due to the generation of high current loops if the legs or arms are allowed to touch. The patient's skin should not be in contact with the inner bore of the magnet.
The outflow from cryogens like liquid helium is improbable during normal operation and not a real danger for patients.
The safety of MRI contrast agents is tested in drug trials and they have a high compatibility with very few side effects. The variations of the side effects and possible contraindications are similar to X-ray contrast medium, but very rare. In general, an adverse reaction increases with the quantity of the MRI contrast medium and also with the osmolarity of the compound.
See also 5 Gauss Fringe Field, 5 Gauss Line, Cardiac Risks, Cardiac Stent, dB/dt, Legal Requirements, Low Field MRI, Magnetohydrodynamic Effect, MR Compatibility, MR Guided Interventions, Claustrophobia, MRI Risks and Shielding.
Radiology-tip.comRadiation Safety,  Ionizing Radiation
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Radiology-tip.comUltrasound Safety,  Absorbed Dose
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• View the DATABASE results for 'MRI Safety' (42).Open this link in a new window


• View the NEWS results for 'MRI Safety' (13).Open this link in a new window.
 
Further Reading:
  Basics:
MRI Safety
2001   by www.fda.gov    
What MRI Sequences Produce the Highest Specific Absorption Rate (SAR), and Is There Something We Should Be Doing to Reduce the SAR During Standard Examinations?
Thursday, 16 April 2015   by www.ajronline.org    
Contrast Agents: Safety Profile
   by www.clinical-mri.com    
  News & More:
Implantable Infusion Pumps in the Magnetic Resonance (MR) Environment: FDA Safety Communication - Important Safety Precautions
Wednesday, 11 January 2017   by www.fda.gov    
Newer Heart Devices Safe During MRI
Monday, 23 August 2004   by www.hospimedica.com    
FDA Releases New Guidance On Establishing Safety, Compatibility Of Passive Implants In MR Environments
Tuesday, 16 December 2014   by www.meddeviceonline.com    
Modern Implantable Heart Devices Safe For Use In MRI Scans
Wednesday, 16 March 2005   by www.sciencedaily.com    
MRI Resources 
Fluorescence - Developers - Blood Flow Imaging - Research Labs - Lung Imaging - Health
 
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
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    
Making Pacemakers and ICDs MRI-Safe
Wednesday, 8 March 2017   by www.mddionline.com    
Patients with standard pacemakers, ICDs may safely undergo MRIs
Friday, 24 February 2017   by www.cardiovascularbusiness.com    
Biotronik's new Ilivia ICDs and CRT-Ds with MRI AutoDetect receives CE approval
Wednesday, 3 February 2016   by www.pharmabiz.com    
ITOCHU Named the Exclusive Distributor for ViewRay's MRI-Guided Radiation Therapy System in Japan
Thursday, 22 January 2015   by www.prnewswire.com    
Medtronic Gets Japanese Approval, Launches Evera MRI
Monday, 10 November 2014   by www.pcbdesign007.com    
Modern Implantable Heart Devices Safe For Use In MRI Scans
Wednesday, 16 March 2005   by www.sciencedaily.com    
MRI Resources 
Distributors - Services and Supplies - Health - Cardiovascular Imaging - DICOM - MR Myelography
 
Cardiovascular ImagingMRI Resource Directory:
 - Cardiovascular Imaging -
 
Cardiovascular MR imaging includes the complete anatomical display of the heart with CINE imaging of all phases of the heartbeat. Ultrafast techniques make breath hold three-dimensional coverage of the heart in different cardiac axes feasible. Cardiac MRI provides reliable anatomical and functional assessment of the heart and evaluation of myocardial viability and coronary artery disease by a noninvasive diagnostic imaging technique.
Cardiovascular MRI offers potential advantages over radioisotopic techniques because it provides superior spatial resolution, does not use ionizing radiation, has no imaging orientations constraints and contrast resolution better than echocardiography. It also offers direct visualization and characterization of atherosclerotic plaques and diseased vessel walls and surrounding tissues in cardiovascular research.
MRI perfusion approaches measure the alteration of regional myocardial magnetic properties after the intravenous injection of contrast agents and assess the extent of injury after a myocardial infarction and the presence of myocardial viability with a technique based on late enhancement. Extracellular MRI contrast agents, like Gd-DTPA, accumulate only in irreversibly damaged myocardium after a time period of at least 10 minutes.
This type of patients may also have an implanted cardiac stent, bypass or a cardiac pacemaker and special caution should be observed on the MRI safety and the contraindications. While a number of coronary stents have been tested and reported to be MRI compatible, coronary stents must be assessed on an individual basis, with the medical team weighing the risks and benefits of the MRI procedure.
Cardiac MRI overview:
Coronary angiography,
Coronary Angiography with D-Tagging
Myocardial perfusion imaging and viability
Calculation of ventricular volume, myocardial mass and wall thickness
Functional parameters
Description of a stenosis or aneurysma
Anatomical display of the heart, vessels and the surrounding tissue
Cardiovascular MRI has become one of the most effective noninvasive imaging techniques for almost all groups of heart and vascular disease.

 
Images, Movies, Sliders:
 Angulation of Cardiac Planes Cine Images of Septal Infarct  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 Left Circumflex Ischemia First-pass Contrast Enhancement  Open this link in a new window
      

Courtesy of  Robert R. Edelman

 Delayed Myocardial Contrast Enhancement from Infarct  Open this link in a new window
 
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• View the DATABASE results for 'Cardiovascular Imaging' (18).Open this link in a new window


• View the NEWS results for 'Cardiovascular Imaging' (6).Open this link in a new window.
 
Further Reading:
  Basics:
Cardiac MRI - Technical Aspects Primer
Wednesday, 7 August 2002
Coronary Artery Disease: Combined Stress MR Imaging Protocol-One-Stop Evaluation of Myocardial Perfusion and Function1
   by radiology.rsnajnls.org    
A Guide To Cardiac Imaging
   by www.simplyphysics.com    
  News & More:
New Imaging Technique Reveals Different Heart Motions by Age, Gender
Thursday, 10 December 2009   by www.sciencedaily.com    
Rockland Technimed: Tissue Viability Imaging
Saturday, 15 December 2007   by www.onemedplace.com    
MRI Resources 
Brain MRI - Contrast Enhanced MRI - Safety pool - Quality Advice - Collections - MRI Reimbursement
 
MRI Procedure
 
The MRI device is located within a specially shielded room (Faraday cage) to avoid outside interference, caused by the use of radio waves very close in frequency to those of ordinary FM radio stations.
The MRI procedure can easily be performed through clothing and bones, but attention must be paid to ferromagnetic items, because they will be attracted from the magnetic field. A hospital gown is appropriate, or the patient should wear clothing without metal fasteners and remove any metallic objects like hairpins, jewelry, eyeglasses, clocks, hearing aids, any removable dental work, lighters, coins etc., not only for MRI safety reasons. Metal in or around the scanned area can also cause errors in the reconstructed images (artifacts). Because the strong magnetic field can displace, or disrupt metallic objects, people with an implanted active device like a cardiac pacemaker cannot be scanned under normal circumstances and should not enter the MRI area.
The MRI machine can look like a short tunnel or has an open MRI design and the magnet does not completely surround the patient. Usually the patient lies on a comfortable motorized table, which slides into the scanner, depending on the MRI device, patients may be also able to sit up. If a contrast agent is to be administered, intravenous access will be placed. A technologist will operate the MRI machine and observe the patient during the examination from an adjacent room. Several sets of images are usually required, each taking some minutes. A typical MRI scan includes three to nine imaging sequences and may take up to one hour. Improved MRI devices with powerful magnets, newer software, and advanced sequences may complete the process in less time and better image quality.
Before and after the most MRI procedures no special preparation, diet, reduced activity, and extra medication is necessary. The magnetic field and radio waves are not felt and no pain is to expect.
Movement can blur MRI images and cause certain artifacts. A possible problem is the claustrophobia that some patients experience from being inside a tunnel-like scanner. If someone is very anxious or has difficulty to lie still, a sedative agent may be given. Earplugs and/or headphones are usually given to the patient to reduce the loud acoustic noise, which the machine produces during normal operation. A technologist observes the patient during the test. Some MRI scanners are equipped with televisions and music to help the examination time pass.
MRI is not a cheap examination, however cost effective by eliminating the need for invasive radiographic procedures, biopsies, and exploratory surgery. MRI scans can also save money while minimizing patient risk and discomfort. For example, MRI can reduce the need for X-ray angiography and myelography, and can eliminate unnecessary diagnostic procedures that miss occult disease.
See also Magnetic Resonance Imaging MRI, Medical Imaging, Cervical Spine MRI, Claustrophobia, MRI Risks and Pregnancy.
For Ultrasound Imaging (USI) see Ultrasound Imaging Procedures at US-TIP.com.

See also the related poll result: 'MRI will have replaced 50% of x-ray exams by'
 
Images, Movies, Sliders:
 Brain MRI Images Axial T2  Open this link in a new window
      

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

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

 Breast MRI Images T2 And T1 Pre - Post Contrast  Open this link in a new window
 Sagittal Knee MRI Images T1 Weighted  Open this link in a new window
      

 
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• View the DATABASE results for 'MRI Procedure' (11).Open this link in a new window


• View the NEWS results for 'MRI Procedure' (6).Open this link in a new window.
 
Further Reading:
  News & More:
Metamaterials boost sensitivity of MRI machines
Thursday, 14 January 2016   by www.eurekalert.org    
Casting patterns make MRI safer
Tuesday, 13 January 2015   by www.engineeringcapacity.com    
Working with MRI machines may cause vertigo: Study
Wednesday, 25 June 2014   by www.cos-mag.com    
Novel Imaging Technique Improves Prostate Cancer Detection
Tuesday, 6 January 2015   by health.ucsd.edu    
MRI Improves Breast Cancer Screening in Older BRCA Carriers
Monday, 5 January 2015   by www.cancernetwork.com    
MRI Resources 
Research Labs - Calculation - MRA - Absorption and Emission - Pregnancy - Process Analysis
 
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