Medical Technology

Contraindications for MRI Scanning



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Among the diagnostic techniques discovered in the last century, one of the most useful and safest technology is the MRI scan. MRI stands for magnetic resonance imaging and as the name suggest, it uses high powered magnetic fields and certain pulsatile radio-frequencies in order to determine the structural integrity of tissues in the body and from recent time, there is a newer use of the MRI called functional MRI in which the MRI detects the functional aspect of organs and tissues apart from its structural appearance.

Why is the MRI used?

It is one of the most detailed imaging techniques available to the medical sciences and it poses little risk to health as it do not depend on radiation as does a X-ray or a CT procedure. Therefore, the MRI is used in detecting abnormalities in the brain, lungs, heart, blood vessels, limbs, spine…etc and the number of specific conditions that can be diagnosed through this mode is countless.

What are the contraindications for its use?

Because of the high powered magnetic fields and pulsatile radio frequencies, the MRI may interfere with implanted devices in the body. This can pose a serious threat and therefore the person undergoing such scans needs to be evaluated for such devices beforehand. Among the instances where an implanted device makes the MRI contraindicated, permanent pacemakers, implanted defibrillator devices, cochlear implants, implanted nerve stimulators…etc will have to be highlighted. In general, it should be remembered that, the presence of electronically, magnetically, and mechanically activated implants are absolute contraindications for performing a MRI scan.

According to the NHS web site, presences of the following are also relative contraindications which require risk assessments by the clinicians before recommending for MRI. These include, aneurismal clips in the brain, prosthetic heart valves, metallic fragments near or inside the eye or blood vessels, implants in the eye, intracranial surgery to arrest bleeding, recently done joint replacement, penile implants used to relieve impotence…etc.

At the same time, the same web site indicates the possibility of intra-uterine devices interfering with the MRI scanning as there is a possibility of copper wires being present in the device. Therefore, presence of such devices along with presence of other metal fragments need to be informed to the radiographer beforehand.

Lastly, with all these contraindications and relative contraindications, it should be said that, many millions of MRI tests are performed worldwide and the development of complications following the procedure is almost unheard of and this has made the procedure one of the safest existing in the medical diagnostics.

Reference:

http://www.nhs.uk/Conditions/MRI-scan/Pages/Who-can-use-it.aspx

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