1. Institute of Neurological Sciences, Southern General Hospital, Glasgow
MRI safety overview
John McLean
Clinical Scientist
Institute of Neurological Sciences, Southern General Hospital, Glasgow
Tel:

2. 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

3. 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

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

5. 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

6. 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

7. Why all the fuss?

8. Why all the fuss?

9. Why all the fuss?

10. Why all the fuss?

11. Why all the fuss?

12. Why all the fuss?

13. Why all the fuss?

14. Why all the fuss?

15. Why all the fuss?

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

17. Some youtube videos
But MRI can be fun too

18. 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

19. MRI missile death
Michael Columbini

20. 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

21. 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

22. 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

23. 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

24. 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

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

26. 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

27. MRI death: pacemaker

28. 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

29. 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

30. Burns

31. Burns

32. Burns

33. 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

34. Patient positioning

35. 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

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

37. Patient monitoring equipment

38. Equipment in and around the controlled area
MR UNSAFE

39. Equipment in and around the controlled area
MR Conditional

40. Equipment in and around the controlled areaMR
SAFE

41. Equipment in and around the controlled area

42. 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)

43. 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

44. 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

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

46. 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

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