Question 1
Does a template/fill out form for reporting exist? Is there a requirement for minimum information, or can anything be reported in any manner?

Toby
At present the FDA will accept whatever you send to them (for site-reporting). There are some standard elements for manufacturer reporting. We’re actually developing a report template that we’ll be sharing with everyone once it’s ready.

John
There is no template and reporting is largely free text hence the great variability in what gets reported and how. We will be doing a sample report in a future webinar.

Question 2
Has FDA agreed to make the “hidden” data available to the public? If so, where can we find those reports?

Toby
FDA has made statements about moving existing ‘hidden’ data to public databases, but I don’t know when or how… or even if MRI adverse events are among those that are concealed.

John
Not that I’m aware of.

Question 3
Can you demonstrate on MAUDE how to look up MRI safety reported events

Toby
If you go to the FDA’s MAUDE search website (www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/search.cfm), just input “LNH” for the product code, and define a date range for your search. This will catch only MRI-equipment-tagged adverse events. If, for example, an implant malfunctioned because of an interaction with an MR device, that adverse event might be filed under the implant (most likely), or under MRI (very rare), or under both (exceedingly rare).

John
N/A

Question 4
Burns seem to be the most likely adverse incident reported do you think that will change in the future with more modern equipment and staff increasing their MR safety knowledge?

Toby
Burns do continue to appear to be the most frequently reported MRI device-classified injury type. I don’t see technological changes on the horizon that will reduce the RF burn risks, so it boils down to individual sites following best practices. Unless accreditation organisations or licensing bodies start requiring best practices, I don’t expect significant changes in burn injury rates or frequency.

John
For every staff member getting wise, there is a fresh one coming in behind that is unwise. On the hardware side, there are definitely improvements in Rf technology but it is the power and frequency that are the issue especially when combiined with something that focuses the Rf like a wire, lead, cable, or conductive fibers. Lastly, in the absence of universal safety traiing and processes, theire will asways be deviation from best practices by those that “have always done it that way”.

Question 5
Is it necessary to use pads between thighs touching on patients with very large body habitus?

Toby
If the pelvis or legs of the patient are going to be receiving RF from the body coil, then yes, padding between thighs is one of your manufacturer’s recommended practices.

John
All areas of skin to skin should be padded to eliminate conductive loops in the body.

Question 6
if this is a localised burn due to something in the material, is the low ventilation and high room temperature really a factor? These factors would contribute to global whole body heating.

Toby
This question blends the causation for diffuse thermal loading and focal thermal. Yes, both are caused by RF, but let’s analogise to a bonfire. With a big enough bonfire, you could become overly-hot and uncomfortable just from hanging around it at a set distance for an extended period of time. Getting a burn from that same bonfire may involve a comparatively short exposure to a much closer bit of fire. The prevention to keep you from getting uncomfortably overheated (remove layers, greater airflow, etc…) are *not* what you’d use to keep from getting a focal burn from the bonfire. Yes, both are related to the heat of the fire, but the injury prevention steps are profoundly different.

John
Correct, but deviations from the manufacturers Instructions for Use (IFU) are never recommended.

Question 7
Is it advisable to remove undergarments as well? E.g. pelvic MR.

Toby
As little as 5 years ago I would have said that there was no benefit to removing undergarments. Today, with the proliferation of antimicrobial treatments and fabrics, where clothing can become electrically conductive, I think it is advisable to remove all street clothes garments that will be within the volume of RF deposition.

John
Yes it is.

Question 8
What are your personal best practice recommendations for heavily tattooed patients when it comes to burn injuries?

Toby
I recommend engaging the patient and advising them to alert you if they feel anything. Cold packs over the tattooed area (if it’s within the volume of RF deposition) may be a good prophylactic step, if there’s significant concern based on the size or shape of the tattoo, or it’s proximity to RF transmit.

John
Know about the tattoos, educate the patient, and be aware that burns happen fast. If there are tattoos with special inks, apply an ice pack as a heat sink

Question 9
We have a extremity-only MR unit should we still require patients to change out of clothes?

Toby
I would recommend changing them for projectile risk safety, yes. Depending on your unit, however, the RF field may be much smaller than whole-body systems, so steps like changing patients for RF heating risks may be limited to the anatomy being imaged and that which is immediately adjacent.

John
Agreed with Toby on this. Rf issues are far less likely on extremity systems.

Question 10
what about ink stamp on clothing, I have found this to produce artefact on image, could this also produce heating?

Toby
If it produces artefact, it’s probably at greater risk of being electrically conductive and heating under the right MR conditions. Another reason to change all patients.

John
If it contains materials that can cause an artifact by altering th elocal B0 field then it is definitely at risk for heating if exposed to the Rf field

Question 11
if you are using receive only coils what is the risk of burns in areas other than what you are scanning. Ex. scanning foot but leaving underwear on…. just curious… we typically remove.

Toby
Receive-only coils are – from an MR safety standpoint – completely irrelevant. The only thing we’re concerned about is the transmitting RF source. From the data I’ve seen (from a limited number of scanner models), it seems that the greatest RF power comes from the ends of the body coil, probably about 1 foot / 30 cm from isocenter, at / near the surface of the bore wall. I am quite concerned about body tissues against the bore wall in this region (30 cm S or I of isocenter), so yes, there are concerns about burns not immediately at the area being imaged if you’re using the body coil for transmit.

John
It depends on the body part being scanned. If Rf is pulsed with the body coil, the hot spots can be quite a was from isocenter (up to 30 cm depending on the bore length and type of body coil). The greates risk is always in the direct path of the rf but the “fringe” rf can pose a risk.

Question 12
Are facilities offering scrub pants to wear, or do they remove underwear and double gown?

Toby
This varies from site to site. Scrub pants are great, but even if you use gowns, a double-gown for patients who are uncomfortable with the possibility of exposure may be an effective solution.

John
Both scrubs and gowns re in common use and he removal of underwear is strongly recommended.

Question 13
Is it necessary to gown every patient on a 1.5T?

Toby
The key difference between 1.5 and 3.0 is *not* the amount of RF (contrary to popular wisdom), it’s the frequency of RF. It is entirely possible to produce burns at 1.5, so it is definitely a best practice to gown all patients, even at 1.5.

John
Burns happen with all field strengths so yes change every patient at 1.5T.

Question 14
Do you recommend that all patients change out of underwear?

Toby
Yes, if the underwear region witll be within the volume of RF deposition. If you think that this is more than you want to figure out, study by study, then the simpliest ‘universal’ practice is to strip-to-skin all MR patients, and provide them with gowns / scrubs.

John
Every time unless there are special circumstances.

Question 15
The SAR question has not been explained properly. First what is the cause of SAR increase during Scan, and what is it effect to quality of images and effect to patients?

Toby
RF is what is used to produce signal for MR images. Starve a scan for RF, and you starve your images for signal. SAR is increased by numerous user-defined settings, from ‘under the hood’ elements like specific flip angles, to more direct echo-train length. Anything that accelerates a sequence (completed in shorter time) increases SAR.

John
SAR is quite complicated if you dig into the nuances of hard and soft pulses etc. For practical purposes, SAR goes up if you.

Question 16
What do you think it is the perfect temperature room wise in order to avoid burns?

Toby
Room temperature has almost nothing to do with burns, but has a lot to do with diffuse thermal loading. MR manufacturers generally recommend keeping your magnet room at somewhere between 67° – 70° F to help patients better handle the diffuse thermal loading. It also helps your MR equipment run better (if the equipment gets too warm it’s supposed to automatically reduce the amount of SAR it can deliver to patients).

John
Agreed.

Question 17
I’ve been told by an applications specialist that my scanner does not require pads because there is built in distance. Have you heard of this before?

Toby
If that’s the case, then your apps specialist should be able to point you to the section of the operators manual that says so. If there’s a discrepancy between what the manufacturer puts in print and what their people are willing to tell you, go with what’s in print.

John
The plaintiffs attorney will call this hearsay. If it is not in writing in the manufacturers IFU then it is just not true.

Question 18
Do you think I would be beneficial for Manufacturers to provide more transmit receive coils?

Toby
Oh hell yes! With the growing number and diffusion of implants and devices, the ability to effectively collimate RF by using anatomy-specific T/R coils would be of great safety value.

John
I think the vendor that does this will get my vote for vendor of the year.

Question 19
Is there a concern for thighs touching if underwear is removed and bottoms are not available?

Toby
If the L-spine or pelvis or legs are in the volume of RF deposition, then yes, I would have a concern about touching thighs. A towel or blanket could provide the separation if the site doesn’t want to use scrub pants.

John
Yes. Conductive body loops are a challenge regardless of skivvie status.

Question 20
SAR-as name (Specific Absorption Rate). Absorption of RF energy can also result in warming of the body.

Toby
SAR *does* produce diffuse warming of the patient. Like my bonfire analogy, above, RF can produce significant warming *and* it can produce burns, through different aspects of the RF transmission.

John
The primary effect of Rf energy on biological tissues is heating due to resistive losses. SAR is the rate of heating.

Question 21
I have applied other RF pulses, Used smaller flip angles, lower TR, and fewer slices to help reduce the SAR level. This has been my remedy.

Toby
You’ve identified a few of the RF / SAR reduction techniquest that a skilled tech can use to help reduce total RF exposure!

John
Good job though shorter TR’s will actually increase SAR so making the TR longer is the best choice there. Anything that mitigates B1 will lower SAR. Other alternatives are switching to Spin Echo instead of FSE and using gradient based sequences where possible.

Question 22
On the Tattoos, Techs need to know where it was obtained, Sometimes places like the prisons do not use proper tools.

Toby
I would treat homemade tattoos with greater scepticism, but because tattoo inks aren’t regulated, I have very little confidence in the ink composition even if a patient were to tell me that they got a tattoo from a reputable studio.

John
Prison tattoos are famously low tech but rarely contain ferrous components. All tattoos should be treated equally. Establish a process than works and use it every time. It is the only way to ensure safety to the greatest extent possible.

Question 23
My facility is purchasing a new magnet. We are remodelling our suite to accommodate this new magnet. Are we now required to install a FDS in the updated suite?

Toby
Ferromagnetic detection systems have been requirements of the Facility Guidelines Institute (FGI) Guidelines publication since 2010. TJC cites the 2010 FGI as their ‘default’ design standard, if your state doesn’t have a standard, and TJC further states that if a state standard doesn’t provide guidance for a specific element that TJC’s referenced standard (2010 FGI) does, then you need to follow the TJC standard for that element. So if you’re in one of the majority of states that reference a 2010 or later FGI for your facility type, yes, you’re required to include ferromagnetic detection systems (FMDS) in the design and construction. And if you’re a TJC-accredited facility, anywhere, and your state standard doesn’t explicitly put forward a different FMDS standard, then – as I understand it – you must conform to the 2010 FGI criteria (which is to provide FMDS).

John
Yes. The states all have their own guidelines for what you must do though few states have yet evevolved to consider FMD’s. In the absence of a position on them, the default is the Facilities Guidelines Institute (FGI) standards which require FMDS for all new constructions. Metrasens has produced a useful summary of the current regulatory environment regarding FMDS https://www.metrasens.com/mri-safety/mri-safety-guidelines/

Question 24
What is SED?

Toby
SED is an acronym for Specific Energy Dose. It’s synonymous with Specific Absorbed Energy (SAE), which I think is a more descriptive term. It’s a measure of the total estimated amount of RF energy that a patient absorbs from all the sequences run.

John
Specific Energy Dose. SED is the cumulative measure of energy over time. SAR is the mass normalised rate of deposition and SED is SAR x ACTUAL Scan Time.

Question 25
Can a Radiologist give permission to go above the SED limits?

Toby
In my opinion, the risks associated with an MR exam should best determined by the supervising physician for that patient / exam. Some system software will not let you go above the SED limit (for a specific patient identifier, but if someone were to enter a different patient ID…). Again, in my opinion yes the physician should be able to allow an exam to exceed SED limits depending on the exam, rest periods, body habitues, etc…

John
If the radiologist deems it medically necessary then they are free to go above the SED limits. They are, however, not released from responsibility for the consequences should something go wrong.

Question 26
Do we go beyond the SED limit with a Joule waning? we operate at first level.

Toby
Joule’s are the units of measurement of total energy for SED. First Level is a rate of energy transfer (how fast you’re pumping RF energy into the patient). First level is when you’re pumping RF energy into a patient at between 2 W/kg and 4 W/kg (the highest rate without a IRB / research key). If you exceed SED warnings, that means that you’ve already put a significant amount of RF energy (heat) into that patient. If they’re uncomfortable and sweaty, then continuing at a lower SAR rate (normal mode, instead of first level) might allow the patient to cool off some while you’re still imaging. For thermal loading concerns, slowing the study down may provide significant benefits.

John
N/A

Question 27
SAR is weight and height dependent. Do sites always enter the patient’s accurate height and weight? Measured by the tech or rely on the patient to report it.

Toby
SAR is weight- (actually mass-) dependent. The MR manufacturers have computer models of different body shapes / types, based on height, weight, and gender, and the SAR is estimated based on the body habitus model that the MR system chooses (based on what you input for height, weight, and gender). Different sites do different things… I’ve seen sites take info directly from a patient screening form without ever validating it, and I know of sites that actually weigh and measure each MR patient. It’s all over the map right now. I’ll be excited when the MR system (table weight sensors and pre-scan) help directly validate the input data.

John
Agree on all points.

Question 28
What do you about patients that don’t tell you about an implant because they want to have the MRI done no matter what? We have had a couple patients inform us that they are going to stop telling places what they have.

Toby
This is a tough one. Most of our screening is predicated on the idea that patients have an interest in sharing their full and accurate medical history. When the patient thinks his/her interest is best served by lying to the MR provider, we have real problems. We need medical records that travel with the patient, and we also need providers who aren’t scared of their own shadows and will work to try and find safe ways to provide indicated MR exams.

John
Sadly, you will never be able to save patients from themselves every time. In the case of implants containing ferromagnetic components, there is an accumulating body of peer-reviewed evidence indicating the efficacy of Metrasens’ Ferroguard Screener FMDS system in detecting unexpected implants. One example being a study led by Mayo Clinic showing a 99% sensitivity to the detection of implanted cardiac pacemakers. https://mayoclinic.pure.elsevier.com/en/publications/augmenting-mri-safety-screening-processes-reliable-identification/ Beyond this, be diligent, document everything and know that you are doing your best.

Question 29
Surely each site has to control its own oxygen cylinders?

Toby
Some sites see MRI as such a small part of their overall enterprise that they don’t see it as important enough to implement enterprise-wide standards, which means that a smorgasbord of tanks are floating around the facility. If MRI *thinks* they’ve got a handle on their own tanks, but might get mixed up with other tanks from the rest of the hospital, then that’s when problems occur. Not that hospitals need to go to 100% aluminium tanks (though some hospitals have), but all hospitals should have enterprise-level policies that at least acknowledge the importance of tank identification for MR, and not make MR’s life more complicated.

John
They do indeed, but few do so with a plan that includes training, education, labelling, and contingencies for testing.

Question 30
Our facility has changed out all our tanks to MRI conditional Aluminium tanks.

Toby
This greatly reduces the opportunity for error, but remember my ambulance anecdote, even if every tank in the facility is MR Conditional, there’s still the opportunity for tanks to come in from the outside. I congratulate your hospital on taking this important preventative step.

John
Excellent, but they need to leave your care to get filled and there is no assurance you will get the exact same tanks back.

Question 31
Its not just the cylinder that needs to be checked its also the regulator! We have had the regulators changed out on our cylinder tanks and replaced with ferrous ones.

Toby
You are correct. Even if the regulator doesn’t have enough ferrous material to make it a projectile risk, the regulator’s function may be significantly compromised (delivering less or more than indicated) if it has ferromagnetic components that are supposed to move freely within the assembly when it’s close to the MR scanner. Make sure that *all* components are MR Conditional / MR Safe.

John
Correct. Also the holders and any tie downs and attachments should also be checked

Question 32
I think once the facility an the entire patient care staff is educated on the colour coded that is fine to use.

Toby
This greatly reduces the opportunity for error, but remember my ambulance anecdote, even if every tank in the facility is MR Conditional, there’s still the opportunity for tanks to come in from the outside.

John
Except when new staff come in, colours fade, a casual employee is colourblind, or someone forgets. I firmly believe that proper labelling and vigilant testing are the key to safety and that colours are distracting

Question 33

How do we discern if patients are really in need of oxygen cylinders or are just plain claustrophobic? Upon reading the Colombini incident, I discovered that the child needed personnel support (his parents) by his side and not oxygen cylinder, which could potentially have prevented said MR – related fatalities?

Toby
In the Colombini incident, while comfort from a parent might have reduced or eliminated the need for sedation, the boy needed the oxygen because his respiratory function appears to have been suppressed due to the amount of sedative that he’d been given (at which point he needed supplemental O2). It is quite possible that we can reduce the rates of sedation through better handling of the anxiety portions of an MR study, but there will remain needs for safe O2 tank practices in MR.

John
Columbini was suffering from low 02 saturation and the facilities main supply tank ran dry. E anaesthesiologist called for help and a portable UNSAFE tank was brought into the room

Question 34
“Why do vendors supply headphones that fit head coils, but don’t give adequate hearing protection?” (as stating in manual)

Do you see issues with risk/benefit assessment not including informed consent? What happens when the risk occurs even after assessment?

Why are SAR calculations based on “well” patients, when we mainly scan “unwell” patients?”

Toby
“If I understand your headphone question, check the literature because often they say that the headphones are supposed to be used *with earplugs*, not instead of earplugs. Make sure you understand what the manufacturer indicates for the use of their product(s).

I think risk/benefit should become a ‘baked in’ component of all MR patient screenings. If the identified risks rise to the level where they’re unusual for the study, then it should move towards informed consent.

Risk assessments don’t mean that a decision to proceed means that there aren’t any risks, only that the assessment indicates that there aren’t more risks than should allow this particular study to go forward. There can still be negative outcomes, but we do everything within our power to reduce the likelihood of those outcomes, while maximising the benefits of the study. It’s not 100%, but we can get pretty darn close for most situations when we practice with an informed risk/benefit process.

SAR models *do* take into account sick patients, and typically exclude febrile patients, and do seek to limit total diffuse patient thermal loading. They don’t base models on the sickest of the sick, but they are built with a degree of latitude. The presumption being that if you have a febrile and obese patient who really should have an MR study, then the radiologist and technologist can tailor the study to the specific physiologic needs and limitations of that patient.”

John
N/A

Question 35
Would you be willing to share slides? I would love to share some with my staff at my facility?

Toby
The recording is available through the Metrasens website for your staff and colleagues to watch any time they want.

John
N/A

Question 36
Thank you. Informative. Question for Tobias related more towards MR room design and planning. What recommended resources do you use, as an architect, use to meet the design (shielding and safety) requirements?

Toby
I recommend consulting the newest (2018) FGI document, and some great resources from the VA, including the VA’s MRI Safety Directive. In the next several months we also hope to see a new Imaging Design Guide from the VA with more resources. Metrasens has also recently made available a resource pack for architects that covers general aspects of MRI facility design for ferromagnetic safety, and some specific guidance for the effective incorporation of ferromagnetic detection systems (FMDS) https://www.metrasens.com/architects-mri-safety-guide/

John
N/A

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