MR Safety

Magnet Issues

The Static Field is always on, some hospital workers don’t know this. This can lead to unfortunate accidents. The static field interacts with ferrous items in two ways:

Attractive Force

Torque effects

Pulsed rf can lead to burns

Inert Gases can lead to asphyxiation

Q: What difference does it make if you have a pt with an aneurysm treated with a “clip” or a “coil”?

A: Coils are safe, clips hay not be (see below)

Q: My patient has a heart valve, can they get an MRI?

A: Yes. The only heart valve that the literature used to say is "unsafe" is the relatively older Starr-Edwards pre-6000 series. It is unlikely to find a patient that has one of these valves. Apparently the party line is now all valves are safe.

Reference:

https://www.sciencedirect.com/science/article/pii/S110996661730475X#:~:text=Practically%2C%20all%20prosthetic%20heart%20valves,of%20up%20to%201.5%20T.

Gadolinium- Nephrogenic Systemic Fibrosis (NSF)

Use the correct calculator MDRD !

Please note, some “GFR” calculators ask for the pts weight. This will give you an incorrect value. The correct calculator, e.g.

http://www.kidney.org/professionals/kdoqi/gfr_calculator.cfm

gives a value normalized for weight [ mL/min/1.73 m], you only should enter age, creatinine, sex, and race. This calculator now has an option to adjust for body surface area. The 2015 ACR contrast manual does not comment on whether to use this option. Personal communication with Dr. Kanal from the ACR noted that we should not use this option and stick to the values normalized for weight (6/16).

An example of a calculator NOT to use:

http://touchcalc.com/calculators/cg

gives a result in mL/min

e.g. for white female Cr 2.0, age 65, weight 155, gives 31 or safe, while the correct calulator gives 26 or unsafe!

Can an MRI "explode" ?

https://awesomejelly.com/mri-machine-explodes-into-a-million-pieces-due-to-pressure-build-up/

References

Magnet Issues

Radiographics MR Safety 1999

http://radiographics.rsna.org/content/19/6/1641.full

Death from ferrous aneurysm clip

Klucznik RP, Carrier DA, Pyka R, Haid RW. Placement of a ferromagnetic intracerebral aneurysm clip in a magnetic field with a fatal outcome. Radiology 1993;187:855–856

http://radiology.rsna.org/content/187/3/855.short

RSNA members will have access

Blindness

See 1986 case report

http://www.ajnr.org/content/ajnr/7/2/243.full.pdf

(bonus question, what is the microagression?)

Pacemaker Death

http://www.telegraph.co.uk/news/uknews/1458421/Pacemaker-death-after-error-in-hospital.html

Death from Oxygen Cylinder

http://www.nytimes.com/2001/07/31/nyregion/boy-6-dies-of-skull-injury-during-mri.html

http://www.nytimes.com/2001/09/29/nyregion/hospital-fined-by-health-dept-in-death-of-boy-during-mri.html

GE Worker Death at Cornell from Asphyxiation