Institute of Neurological Sciences, Southern General Hospital, Glasgow MRI safety overview John McLean Clinical Scientist Institute of Neurological Sciences, Southern General Hospital, Glasgow Tel:0141 201 2120 Email: johnmclean@nhs.net

MRI safety: key points What is MRI? What are the risks? Why all the fuss? MRI deaths Burns from MRI How do we manage the risk Education and training

What is an MRI Scanner? MRI is an extremely powerful superconducting magnet High powered radiowaves to energise hydrogen protons Additional RF gradients to manipulate electromagnetic fields to enable the acquisition of images of the body

What are the risks? Metal in the high magnetic field Contraindicated implant in patient Patients with metal in their body Burns Noise

Why all the fuss about MRI safety? MRI uses an extremely powerful magnet The magnet is always on! The magnetic field reaches to the edge of the magnet room and beyond in some places i.e. The Magnetic field can exert an attractive force even at the edges of the room The magnetic field is silent

Why all the fuss about MRI safety? Ferromagnetic objects taken into the magnet room can become potentially fatal missiles People have died in MRI rooms because unsafe objects have been taken into the room Many serious impact injuries

Why all the fuss?

Why all the fuss?

Why all the fuss?

Why all the fuss?

Why all the fuss?

Why all the fuss?

Why all the fuss?

Why all the fuss?

Why all the fuss?

Why all the fuss? This is not how we get our patients to stay still!

Some youtube videos http://www.youtube.com/watch?v=plvIEf7JsKo http://www.youtube.com/watch?v=-5S9jmr9-7w http://www.youtube.com/watch?NR=1&v=vIQaGt_fkkw&feature=endscreen http://www.youtube.com/watch?v=byRIwDk21sw http://www.youtube.com/watch?v=7g5UVrOt2CI http://www.youtube.com/watch?v=5z33ZcDgavY But MRI can be fun too http://www.youtube.com/watch?v=M2OdAp7MJAI

It isn’t just a problem in other places? Scissors (more than once) Hand-held magnet for checking implants Metal support / frame Walking sticks with metal handles Coins These incidents or near misses were not generally a result of a lack of knowledge rather lapses in awareness or concentration Incidents are recorded and reviewed on DATIX

MRI missile death Michael Columbini http://www.youtube.com/watch?v=0nA-UceHMqc

MRI missile death Most recent death in MRI was an engineer in Morocco Small room, room being used for storage Service on blower motor, part ~ 14Kg Got too close to the magnet Incapacitated and found dead the next morning See the FDA MAUDE database Implications for lone working

How do we minimise the risk of missiles? Manage and control the environment Control persons entering the controlled area Control equipment entering the controlled area Control the patient journey Staff training

The Outer controlled area Generally referred to as ‘the controlled area’ Everyone entering this area must complete a MR safety checklist – no exceptions! Only authorised staff know the code for the door If an authorised member of staff lets someone into the controlled area they become responsible for them Always be vigilant of others in this area as well as observing your own safety Don’t be afraid to challenge a member of staff

The inner controlled area Generally referred to as ‘the magnet room’ Absolutely no metal to be taken into this area unless you are 100% sure it is not ferromagnetic and it has been tested by a MR physicist/ radiographer and is labelled as MR conditional (or with blue and white tape) Get into a routine of removing wallets/purses, jewellery, watches, car keys, pager, lanyards, piercings, mobile phones Pat yourself down before entering room Become paranoid

Staff must be checklisted before entering the controlled area The MRI checklist Staff must be checklisted before entering the controlled area Ensure staff member is safe to enter magnet room Raises awareness of the risks in MRI Patients should complete the checklist prior to attending for imaging MR checklist performed by an authorised member of staff The MRI checklist has two main functions To ensure the patient has no contraindicated implants / or metallic object inside them To sure they have no metallic objects on their person

MRI safety checklist All patients / comforter/ carer All staff/ visitors entering controlled area

Why all the fuss about patient implants? MHRA guidelines state that procedures should be in place to determine whether a patient has implants and whether they are MR safe, MR Conditional or MR Unsafe At INS pacemakers and aneurysm clips are absolute contraindications Majority of implants safe Complexity of medical implants increasing Many devices are MR conditional Duty bound to check safety of implant

MRI death: pacemaker

MRI death: Aneurysm clip 74 yr old lady referred for MRI scan Screening picked up that she had a aneurysm clip Scanning did not proceed Staff contacted surgeon to confirm type of implanted clip Staff checked clip, was deemed to be safe Patient was brought down to be scanned Severe haemorrhage and died Turns out the surgeon got the clip wrong The actual clip that was implanted was not safe for MRI

Burns Probably the most common cause of injury to patients in MRI (100’s of cases of burns reported) The MRI scanner uses high power radiofrequency waves These can lead to currents being induced in the tissue Where the loops are large enough these can lead to burns at skin contact points Large metallic implants are also a concern i.e. long orthopaedic implants Tattoos

Burns

Burns

Burns

Patient positioning The manufacturers provide specific guidance on positioning the patient The skin-skin or bore-skin contact points must be avoided by using the insulating/comfort pads provided Also avoid loops such as from hands being clasped, overlapping ankles, knees Use the pads provided to avoid these contact points This is particularly important in anaesthetised patients Also, perhaps more of a risk for patients wearing gowns rather than scrubs

Patient positioning

Burns from patient monitoring equipment Equipment leads and cables of monitoring equipment have also been known to cause injury in MRI Ensure the equipment you are using is MRI conditional or MRI safe MRI conditional does not mean MRI safe, know what the conditions are Know the safe conditions of use for your monitoring equipment i.e. do not take it over the red and white line on the scanning room floor

Patient monitoring equipment Baby arm, wrong pulse oximeter Haik et al 2009 A non-MRI compatible pulse oximeter

Patient monitoring equipment

Equipment in and around the controlled area MR UNSAFE

Equipment in and around the controlled area MR Conditional

Equipment in and around the controlled area MR SAFE

Equipment in and around the controlled area

Safety features of the MRI The MRI system is a CE marked device Additional features for safety are Ear protection must always be given to the patient A call button must be given to the patient It can be helpful to tape this to the patients gown Quick release bed top Detachable couch Retractable arm rests to help patient move on couch Emergency stop: cut power (red button on scanner) Quench (red button under plastic protection on wall...you should never need to touch this, alert authorised MR radiographer)

Other tips for safe practice You know your job and the service runs smoothly, however, be particularly mindful when: New staff are present Some change in upstream working practice occurs Patients from other hospitals Patient transported differently New equipment in the area Radiographers, Radiologists and MRI physics available to advise In the event of an emergency, remember where you are and don’t panic

Your responsibilities Ensure that you are safe to enter the magnet room Get into a routine of removing all your accessories Do not take anyone into the magnet room unless you know for certain they are safe Pat yourself down before entering room Observe the safety of others Know what to do in emergency situations

Education and training Ensure you have read, understood and signed the local rules for MRI Copies for Anaesthetists, ODP’s, nurses

Final thought MRI is an intrinsically safe technique made unsafe by people, implants, peripheral devices and bad procedures Provided the following are applied in practice, incidents should be very unlikely: No inappropriate objects (metal/ ferromagnetic) taken into the MR room Correct use of MR safe and conditional equipment Good implant screening of patient Ear protection Good patient positioning

….and just when you think you’ve seen it all! Ladycare magnet ...