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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.

• 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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• Related Searches:
    • MRI Safety
    • MRI Scan
    • Magnetic Forces
    • Transmit Receive Coil
    • MRI Procedure
Further Reading:
A Primer on Medical Device Interactions with Magnetic Resonance Imaging Systems
Magnetic Resonance Imaging and Cardiac Pacemaker Safety at 1.5-Tesla(.pdf)
Magnetic Resonance Imaging in patients with ICDs and Pacemakers (.pdf)
2005   by    
  News & More:
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Monday, 23 August 2004   by    
Patients with standard pacemakers, ICDs may safely undergo MRIs
Friday, 24 February 2017   by    
Biotronik's new Ilivia ICDs and CRT-Ds with MRI AutoDetect receives CE approval
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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
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
cardiac pacemakers
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:
cochlear implants
other pacemakers, e.g. for the carotid sinus
insulin pumps and nerve stimulators
lead wires or similar wires (MRI Safety risk)
prosthetic heart valves (in high fields, if dehiscence is suspected)
haemostatic clips (body)
non-ferromagnetic stapedial implants
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.comRadiation Safety,  As Low As Reasonably Achievable
Radiology-tip.comUltrasound Safety

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

Further Reading:
Newer Heart Devices Safe During MRI
Monday, 23 August 2004   by    
Physics of MRI Safety
  News & More:
Implantable Infusion Pumps in the Magnetic Resonance (MR) Environment: FDA Safety Communication - Important Safety Precautions
Wednesday, 11 January 2017   by    
Codman Neuro develops new MRI-resistant programmable valve for treatment of hydrocephalus
Tuesday, 22 September 2015   by    
Modern Implantable Heart Devices Safe For Use In MRI Scans
Wednesday, 16 March 2005   by    
MRI Resources 
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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

• 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:
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
A Guide To Cardiac Imaging
  News & More:
New Imaging Technique Reveals Different Heart Motions by Age, Gender
Thursday, 10 December 2009   by    
Rockland Technimed: Tissue Viability Imaging
Saturday, 15 December 2007   by    
Searchterm 'Cardiac Pacemaker' was also found in the following services: 
News  (11)  Resources  (2)  
ImplantsForum -
related threadsMRI Resource Directory:
 - Safety -
Implants that involve magnets such as magnetic sphincters, stoma plugs, dental implants, etc., can be demagnetized by the MRI device. They should be removed prior to the examination.

MRI Safety Guidance
A particular danger is presented by small metallic surgical implants. Haemostatic or other clips in the CNS can move in their position. Dislocation by magnetic attraction or torque presents a risk in MRI examinations. There is a minimal risk in other parts of the body, because after the healing phase of six to eight weeks, fibrosis and encasement of the clip help to keep it in a stable position.
The label stainless steel is not a guarantee for non-ferromagnetic steel.
See also Cardiac Pacemaker and MRI Safety.

• View the DATABASE results for 'Implants' (13).Open this link in a new window

• View the NEWS results for 'Implants' (2).Open this link in a new window.
Further Reading:
Newer Heart Devices Safe During MRI
Monday, 23 August 2004   by    
FDA Releases New Guidance On Establishing Safety, Compatibility Of Passive Implants In MR Environments
Tuesday, 16 December 2014   by    
Pain, magnet displacement in MRI in patients with cochlear implants
Thursday, 20 November 2014   by    
Specific Absorption Rate: A Specious Dosimetric Means of Characterizing MRI-Related Implant Heating?
Wednesday, 3 December 2003   by    
  News & More:
ITOCHU Named the Exclusive Distributor for ViewRay's MRI-Guided Radiation Therapy System in Japan
Thursday, 22 January 2015   by    
BIOTRONIK Concludes Enrollment in Phase C of its ProMRI ICD Study
Wednesday, 21 January 2015   by    
FDA Approves MED-EL's SYNCHRONY Cochlear Implant
Friday, 23 January 2015   by    
FDA grants PMA-Supplement approval for Flowonix Medical's Prometra II system
Tuesday, 20 January 2015   by    
MRI Resources 
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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

See also the related poll result: 'MRI will have replaced 50% of x-ray exams by'
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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    
Casting patterns make MRI safer
Tuesday, 13 January 2015   by    
Working with MRI machines may cause vertigo: Study
Wednesday, 25 June 2014   by    
Novel Imaging Technique Improves Prostate Cancer Detection
Tuesday, 6 January 2015   by    
MRI Improves Breast Cancer Screening in Older BRCA Carriers
Monday, 5 January 2015   by    
MRI Resources 
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