FDA Webinar

Moderator: Irene Aihie

06-24-21/11:00 am ET

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FDA Webinar Testing and Labeling Medical Devices for 

Safety in the Magnetic Resonance (MR) Environment

Moderator: Irene Aihie

June 24, 2021

11:00 am ET

Coordinator: Welcome and thank you for standing by. All parties' lines have been placed in

listen-only mode until the question-and-answer session of today's

conference. At that time if you'd like - wish to ask a question, please, press

star 1. Today's conference is also being recorded. If anyone disagrees, you

may disconnect at this time. It is now my pleasure to turn the call over to your

host, Ms. Irene Aihie. Thank you. And you may begin.

Irene Aihie: Thank you. Hello and welcome to today's FDA webinar. I'm Irene Aihie, of 

CDRH's Office of Communication and Education. On May 19, 2021 the FDA

issued the final guidance, testing and labeling medical devices for safety in the

magnetic resonance environment. This guidance document provides the

FDA's recommendations on testing to assess the safety and compatibility of

medical devices in the MR environment, and the recommended format for

magnetic resonance imaging safety information in medical device labeling.

Ensuring the safety of patients who use magnetic resonance imaging for

disease diagnosis and health management, is vital. Today Sunder Rajan, 
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Research Chemist in the Office of Science and Engineering Laboratories here 

at CDRH, will share information about the final guidance. Following the

presentation, we will open the line for your questions related to information

provided during the presentation. Now I give you Sunder Rajan. 

Sunder Rajan: Thank you, Irene. Good afternoon, everybody, and thanks for attending this 

webinar on the recent guidance document pertaining to the testing and

labeling of medical devices for safety in the MR environment. My name is

Sunder Rajan. I'm a scientist at the Office of Science and Engineering Labs, 

which is a part of CDRH. 

So listed here is what we hope to cover today in today's session. First, a quick

overview of the interactions of medical devices within the MR

environment. Then we move on to an overview of the existing approaches for

the safety testing. Then we will address the specific content of the new

guidance document. And finally, we'll end up with trying to address the

questions from the audience.

Okay. So this cartoon block here is a simplified depiction of the cylindrical

(bore) MRI system. The blue, red, and green zones in the middle, represent

regions inside the concentric cylindrical volumes that contain the

superconducting magnet windings in blue, the gradient coil in red, and the 

radiofrequency coil, radiofrequency resonator in green. The brown figure just 

pertains to the MRI subject. The static field, static magnetic field, is typically

1.5 or (3T) inside the bore of the magnet. And the dropoff in the magnetic

field away from the magnet, creates a spatial gradient of the static field.

These magnetic fields are responsible for attractive forces on magnetic

materials present in devices. In some devices these forces can also result in a

malfunction of the devices. Next, the gradient coil in red, they generate 
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timevarying magnetic fields. The amplitude of the magnetic fields generated

very linearly with distance from the iso- center. That is the center of the

magnet. These fields can induce device malfunction in active implants, tissue

stimulation or implant device case heating due to the induced currents and

associated voltages. 

Next, the body coil, body size RF resonators show in the green box. These 

create an intense electromagnetic field during the pulse sequence when the 

transmission of the RF pulse occurs. These intense EM fields that interact 

with metallic medical devices, just like a TV antenna effect, with potential for 

thermal injury to nearby tissue. The intense RF fields can also cause device 

malfunction of active devices, active medical devices, and possibly tissue 

stimulation from direct rectified radiofrequency voltages. 

So now I would like to provide a brief background of the regulatory landscape 

with regard to the MR safety testing for devices. For passive implants, we 

have had a suite of ASTM test standards for force and torque, image 

artifacts and RFheating. The most significant change in the recent

ASTM standard for RF heating now requires the expression of temperature 

changes scaled to the local background SAR rather than the whole body 

average SAR) 

Next, the last FDA guidance update on the subject was the one dedicated to 

the passive implant testing in December 2014. And with regard to the active 

devices, we have been informally aligned with the ongoing ISO/IEC 10974 

technical specification, although not formally recognized. Hence, there is a 

need for a comprehensive guidance document that covers all devices in the 

MR environment.
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So we issued this draft guidance in August of 2019 and it generated over 400 

or 500 comments. We have tried to address these as best as we can and we 

have now issued a final guidance last month. And so this webinar is to 

summarize the final guidance document and also address questions from the 

MR community. 

So - continuing on, here's a list of the consensus technical safety standards 

which are directly involved as I mentioned before. The ASTM tests 2052 

F2119, 2182, 2213, and (2203) are primarily for passive implants, the ISOTS 

10974 is primarily for active medical devices. And the IEC 60601-2-33 is the 

safety standard, for the essential performance of MRI equipment.

Here we define the scope of the final guidance. It applies to all medical 

devices that might be used in the MR environment. But it also excludes 

MR system components such as RF coils, special spacing pads that came with 

the MR system. The guidance document also provides recommendations for 

safety and compatibility assessments. Theree may be exceptions of - for 

novel device types,hat may require nonstandard approaches. This guidance 

also provides recommendations for labeling information to be included in the 

premarket submissions, PMAs and 510(k)s. 

I'm going to go through a few slides that list the terms used in the guidance in 

alphabetical order. These wording - the wording for this terminology is really 

being reproduced from the guidance document. And they are the same as 

what has been used historically in MR testing and they are some other 

standards as marked in italics. These are the active medical device, active 

implantable medical device, controlled access area.

Continuing further, passive implant, passive medical device, magnetic 

resonance environment, magnetic resonance system, and of course, the well-
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known MR safe, MR conditional, and MR unsafe. These are unchanged from 

before. 

And now we move onto addressing what are the hazards for medical devices 

in the MR environment. This slide lists all the possible hazards for medical 

devices. In contrast with the previous guidance that only addressed passive 

implants, we now also include the hazards that are relevant to the active 

medical devices. So the list now includes time varying gradient effects, , RF 

rectification effects, possible risk of tissue stimulation, potential device 

malfunction due to exposure of the EM fields. 

Moving onto reporting the results from testing - we recommend that you 

provide test report summaries and if applicable, the complete test 

reports should include a list of the hazards addressed by the test, the test 

equipment used, and include the results and all report elements as defined in 

the consensus standards. For computational modeling reports, verification 

and validation are important. And please follow the guidance reporting of 

computational modeling studies and medical device submissions. 

When the ASTM F2182 test method is used, translate the values of 

temperature increase degrees per volt per meter, degrees per volt per (KG), 

measured in the test, to an in vivo temperature increase. And scale for the 

exposure conditions, specified in the MR conditional labeling. Also we need 

a written narrative or testing summary including a discussion of the results 

and conclusion. I also wanted to call your attention in this regard, to the 

FDA guidance document, recommended content and format of 

nonclinical bench performance testing and pre-market submissions.

Here is an example of the test summary for a passive implant 40 mm in size 

provided in a tabular format. On the left a column for list for 
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hazards. Followed by the columns for the test method acceptance criteria, 

device configuration if applicable, summary of the tests, and where in the 

submission the test the reports are located. 

Now we move onto the important area of MR safety labeling. And the 

labeling should include sufficient unambiguous information for the 

healthcare professional, to determine whether a device can safely enter the 

environment. A separate section of the device labeling should be 

provided. It's titled MR Safety Information. And it should be based on 

assessments for the previously defined labels MR Safe, MR Unsafe, and MR 

Conditional Labeling, along with appropriate symbols from ASTM 2503. 

And it should also include a patient's medical device card with the appropriate 

MR safety information. We also ask that the same safety information be 

readily accessible on the manufacturer's Web site or by telephone. Here are 

the MR safety labels, which is the same as before - MR Safe, MR Conditional, 

and MR Unsafe as defined, and no change from the past on this.

So now we come to the meat of this, the MR conditional labeling for devices

that are anticipated to enter the MR system bore. This section has the most

significant changes relative to the legacy passive implant guidance. Although

the changes that we have introduced here are evolutionary rather than

something revolutionary, it's based on increasing complexity of devices and

labeling, and MR technology.

So first, the MR conditional symbol or the term MR conditional is the same as 

the previous version of the guidance. MR medical device card is again the 

same as the past versions. Nominal values of permitted static magnetic fields 

stregths, same as the previous version. But bracketing of the field is okay 
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based on sound scientific rationale. And the following information should be 

included when needed for the specific medical device. 

The nucleus being imaged. If no nucleus is listed it's presumed to be proton, 

which is also new for this guidance. And the scanner type is a cylindrical 

bore or not. The orientation of the magnetic field relative to the patient 

access. The spatial field gradient, I mean more than the previous ones, are 

new for this guidance. The spatial field gradient is the same as the previous 

version. And the maximum gradient slew rate for access is also new here, but 

is included in active medical implant labeling in the past. 

Continuing further, about the RF, we need details on the RF field exposure, 

the RF excitation for example, is it restricted to CP or a multichannel too, coil 

type? The maximum permitted SAR), Specific absorption rate, 

SAR. Operating mode. And please note that for devices in - used in the, or 

implanted in the lower extremity or in the head, brain, SAR is controlled by 

partial body SAR and head SAR. 

Next, the maximum B1 plus, B1 plus RMS value in Micro Tesla. The “mT” 

is a mistake, It should be a Micro Tesla, which can sometimes be specified as 

the primary option instead of SAR. If both are listed independently, implies 

both conditions are met simultaneously. Next is a scan duration and wait 

time, which is new to this guidance. The previous version of the guidance 

document had a reference to bench tests for 15 minutes, which caused 

challenges in the clinic because translating this information to the typical 

MR scans always was difficult and confusing. As more and more of the 

RF testing were derived from modeling and so on, it became difficult to use 

the 15 minute bench test data.
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And then also include the MR exam exclusion zones, information on patient 

conditioning, landmarking . The diagram showing these exclusions can also 

be very helpful. Imaging information - the information about image artifact I 

should say, is also required, although the quantitative information is not 

always needed.

Continuing along with labeling, include the instructions to be followed before 

and after the MR exams, if any, including additional instructions or 

information for safe use that might be needed over and above what we have 

here. Include information for active medical devices about how to proceed if 

an alarm signal is present from a medical device. And then finally, please 

include a statement that says that if the information about a specific parameter 

is not included, there are no conditions associated with the parameter. And 

this is also for your information. 

Here is something new coming from the requirement of needing scan 

duration in the labeling. This slide provides some further guidance on 

this. And it's especially useful for devices that were tested for 15 minutes of 

RF heating, and the possibility of extending the information to one hour 

scans. First of all, for devices that are less than 2 cm in all directions and 

sufficiently spread out more than 3 cm from other metallic devices, we don't 

require RF heating testing.

But we do require an MR conditional labeling that basically has a default label 

of SAR of 2 watts per kg in normal operating mode. Maximum scan time, 

one hour. Beyond that, you will need a cooling period. 

For devices greater than 2 cm we have two cases. If the devices are adjacent

to thermally sensitive tissue, examples are brain, eyes, neural tissue, then we 

have one limit which is - if the heating is less than or equal to 2 degrees in 15 
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minutes, in normal operating mode, then it can be labeled for an hour of 

continuousscanning without a break. 

If the heating of the device is greater than 2 degrees in 15 minute,s the sponsor 

needs to provide the appropriate safe continuous scan time followed by a 

cooling period. And I have to point out that a 6 degree increase is considered 

okay. Anything beyond 6 degrees we recommend a cooling time, 6 degrees 

being the 43 degree limit where we start, irreversible cell injury.

For devices greater than 2 cm, larger than 2 cm, near terminally less sensitive, 

that means not as sensitive tissue like muscle, then we have a different set of 

limits but now the limit is 4 degrees. So heating less than or equal to 4 

degrees in 15 minutes, in normal operating mode can be labeled for a whole 

hour of continuous scanning. Whereas if the heating is - higher than 4 degrees 

in 15 minutes, the sponsor needs to provide an appropriate scan time, with a 

cooling period based on a sound scientific rationale.

For devices anticipated to remain outside of the magnet bore, the key points 

are please include a MR conditional symbol directly on the medical device 

whenever possible. But why the positional conditions and the unambiguous 

positional conditions in terms of the maximum permissible static field, also 

known as the gaussline) restrictions, for example, 200 (gauss), include 

information directing the user on how to proceed when an alarm signal is 

present. If space permits, include the conditions of safe use on the medical 

device in a supplementary sign as defined by ASDM 2503. 

And finally, there is the small section on safety and MRI not evaluated. This 

is a legacy designation. Only applies to a very limited number of medical 

devices that have historically, that don't historically have any information 

about MR safety for complicated reasons beyond the scope of this 
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guidance. This designation does not apply to a device that has either a known 

adverse event in the MR, or has typically been labeled as 

MR conditional, isMR unsafe, , if the new medical device type contains 

ferromagnetic material,. is an active medical device or is a partially implanted 

medical device. 

And the labeling should include the following information - the device has not 

been evaluated for safety in the MR environment, has not been tested for 

heating or unmonitored movement. In the MR environment, the safety of the 

medical device in the MR environment is unknown, performing an MR exam 

on this person who has this device, may result in an injury or device 

malfunction. 

Here is an example of a MR conditional device and, you know, the 

MR conditional symbol, the yellow triangle is important, on the left. The 

conditions for safe use are listed in the two column table with the name of the 

condition on the left, like static field strength. And the safe use value 

condition on the right, on the right column. Please note that unlike the 

previous versions of labeling there is no value of a temperature indicated, only 

the safe scan duration. 

That kind of concludes what I have to say. This slide basically lists the 

URLs for the various resources, guidance documents, recognized consensus 

standards, guidance for multi-configurational devices, computational 

modeling studies, content and format of test reports and premarket notification 

for MR devices. And it's included in the guidance, so you should have it 

there. So that concludes what I have to say. 

If you have questions that cannot be addressed today either because I don't 

know the answer or it's more complicated, feel free to send your questions to 
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OSEL_CDRH. The underscore is difficult to see there, on the slide. But it's 

(OSOL_CDRH@FDA.HHS.gov. Thank you very much. I'm happy to

answer some questions. And I actually have, while we are waiting for the

question and answer to get stacked up, I have maybe four questions that were 

already provided to me by my colleagues. And I think I can just address them. 

Is that okay, Irene? 

Irene Aihie: Sure. I just want to let the operator make her announcements to get folks into 

the queue to ask questions. 

Sunder Rajan: Okay.

Irene Aihie: And then give you a little time to take a quick breather and then you can start 

off with some questions. Thank you so much, Sunder.

Sunder Rajan: Okay. 

Coordinator: Thank you. If you'd like to ask a question over the phone, please press star 

1. Please ensure your phone is unmuted and record your name so you can be 

introduced. Again, that is star 1 to ask a question. if you need to withdraw 

your request, please press star 2. One moment while we wait for questions to 

come in.

Sunder Rajan: Okay. So I can probably address one or two easy questions that came to me, 

while we are waiting. Why is it important to specify nucleus being imaged in 

the MR conditional labeling? The answer is the nucleus, for imaging specifies 

the Larmor frequency which is the frequency of the RF used or close to the 

frequency of the RF used. Since RF heating effects are frequency dependent,

the choice of nucleus can influence the extent of RF heating. 
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And let's see. I can - another one that came up was when both SAR and B1 

are listed, is it satisfactory to scan if either one is satisfied? And the answer to 

this is no. All conditions for safe use in the MR conditional labeling have to 

be met simultaneously. 

So please alter the pulse sequence parameters to bring both B1 plus and SAR 

within limits. I should point out that labeling - should typically be worked in 

a way to use B1+ limit primarily. And if - for systems that don't have B1 plus 

then use the conservatively prescribed SAR limit. I have one more. Should I 

go for one more? Okay. 

In one of the labeling slides the time temperature is based on 15 

minutes. Does that mean all labeling now needs to be derived for 15 

minutes? No. The 15 minute example was to make the transition from the 15 

minute bench testing that's used in ASFM F2182 to clinical setting. The 

choice of safe scan time and cooling time should be derived based on testing 

and sound scientific rationale.

Or last one, I have one last one. I think this might actually be an important 

one. For devices that demonstrate a high RF in use heating effect, can 

fractional whole body SAR be used in the labeling? We recommend actually, 

that you provide labeling for normal mode whenever possible, even if it 

means a shorter scan time, to compensate for it. This is because fractional 

SAR time as displayed on the MR systems may not be precise. 

And although we recognize that in some instances we may not have any other 

viable option other than to use a fractional SAR, one option of course is that 

we might be able to, with more testing, come up with a B1 plus based

labeling, which is more precise. Thank you.
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Irene Aihie: Thank you so much, Sunder. It looks like we have some questions in the 

queue. Before our operator gets our participants into ask questions, Sunder 

can you go back to the final slide of the presentation so that folks can see the 

resources? Thank you so much. All right, (Sandy)...

Sunder Rajan: The resources? This one? You want this one? 

Irene Aihie: Either that - we can go back to - yes, either that one or that last slide. Perfect.

Sunder Rajan: Okay. The last slide only has the email and the - okay, good. I'll leave it 

here.

Irene Aihie: Thank you. Okay, (Sandy). It's all yours. 

Coordinator: All right. The first question (Carol Barons). You may go ahead.

(Carol Barons): Hi. Sunder, we have a question. We've been getting a lot of people with new 

orthopedic implants in the spine and a lot of the hardware is saying from the 

companies, system has not been evaluated for safety, treating migration, or 

compatibility in the MRI environment. And that it said, you know, you can 

cause heating too for the patient, may result in injury. So what do we do with 

something like that? We have a (three Tesla).

Sunder Rajan: Yes. You asked me the most difficult question I was anticipating. And that 

slide that I talked about the safety untested that I believe may end up, may be 

coming from some of those sources. I don't have a good solution except one.-

Wwhen you see those, appeal to the sponsor and encourage them to come in 

for MR conditional labeling. And we will be happy to provide as much help if 

possible, to facilitate that. In the absence of that really I don't have a good 

answer for you. 
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(Carol Barons): Okay. All right. 

((Crosstalk))

Woman: ...benefits? 

Sunder Rajan: I'm sorry?

Woman: Scan the patient for the radiologist, is it risk versus benefit?

Sunder Rajan: Yes. it is absolutely - it is really then up to the radiologist to make the 

assessment based on risk/benefit. And I have to point out that there is ample 

evidence, ample clinical data and testing and knowledge in this area. So I 

would venture to guess that, you know, radiologists should be able to make a 

an informed assessment of the risk to scan or not to scan. 

For instance, we know now that, , small devices, linear dimension of around 4 

or 5 cm don't heat significantly. So we can go back in the literature and look 

at some of this data. So there's a lot of information there for a physicist and 

radiologist to get some kind of an estimate. But it would be a - it's clearly an 

off label practice and it's something up to the radiologist and clinical practice 

to decide, rather than anything that I can offer at this time. 

Woman: Okay. All right. Thank you. So encourage the company. 

Coordinator: The next question comes from (Frank Shellock). You may go ahead. 

(Frank Sherlock): Hi. This is (Frank Sherlock). Sunder, on the examples that you showed for 

the MR labeling for the passive implant, I noticed that nowhere in that - on 
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that document that it even states MR conditional, only the icon was 

presented. So I suspect it was intended to have a MR conditional term added 

to it just as points of reference similar to what's been done previously. The 

other thing is it looks like there's no information for artifacts in a particular 

value. This just indicates that the artifacts are present and potentially may be 

necessary to adjust your pulse sequences if the implant is in the area of 

interest. 

Can you comment on that? And then I have one other follow up question. 

Sunder Rajan: Okay. So thanks (Frank). Thanks for your question and for pointing out this 

information - this request about - or the clarification needed for image 

artifact. We believe that for most of the devices where the image artifact is 

produced is - and it's not really that relevant to the particular MR exam 

because it's not in the plane or further away. It doesn't necessarily provide the 

technologist with a go/no go decision for starting the scan. 

So we are paying less attention to the quantitative nature of the artifact and I 

still recommend that you do the ASTM tests and make a statement about 

it. But it's less important now as we have seen over the last few years that this 

is not used for MR imaging decisions. 

However, in some cases it can be very important. In cases where you need to 

follow up with an MRI scan around an aneurysm coil and you could have a 

potential artifact that can cause a confound, then it becomes quite 

important. Or if there is a need, if the indication used for the device suggests 

the need for MR imaging information around the implant, then it has to be 

provided based on the type of imaging scans that are going to be used in the 

clinic. 
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(Frank Sherlock): Right.

Sunder Rajan: Does that clarify, (Frank)?

(Frank Sherlock): Yes. And then anyway, the other question that I had was can you explain 

briefly, RF rectification; how it's tested; and the relevance for the 

MRI labeling for an active implant? 

Sunder Rajan: Okay. The - it goes a little bit beyond the scope of this - of what I had in mind 

today. But this is a test used for active medical implants. 

(Frank Sherlock): Right.

Sunder Rajan: And when the pulse generator used in these active medical implants, have 

circuitry inside them, the voltage is generated from the long leads, assuming 

the device has leads. Just like the tips of the leads, the voltages can cause 

heating in the neighboring tissue, it can also generate voltages using the same 

principle into, inside the IPG. 

And these voltages and the circuitry present in them can essentially act like a 

rectifier and cause a voltage that now doesn't oscillate at the radio frequency, 

but oscillates at a slower frequency. And these voltages can stimulate tissue, 

or have the potential to stimulate tissue.

And the ISO TS document that I talked about, has a detailed procedure and a 

network used to test for this. You can actually test for this using an 

oscilloscope and the appropriate testing network. 

(Frank Sherlock): Thank you. And thanks for the webinar today. 
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Sunder Rajan: Thanks. 

Coordinator: The next question comes from (Megan Sajab). 

(Megan Sajab): Yes. Hello. I have a few questions around products that fall under the 

definition of MR safe. First question is that the guidance appears to 

recommend a patient medical device card for all implanted medical 

devices. However, the FDA guidance on medical device patient labeling only 

recommends patient implant cards for implants intended to be implanted for 

more than one year. Could FDA comment if implants that will not be 

implanted for longer than one year, are expected to have implant cards, and 

particularly for implanted devices that are MR safe and don't have any risk 

information to convey? 

Sunder Rajan: So let me clarify. You would like to find out if MR safe devices implanted for 

less than one year, would still need an MR implant card?

(Megan Sajab): Yes.

Sunder Rajan: Am I correct? Okay.

(Megan Sajab): Yes.

Sunder Rajan: All right. I do not know the policy answer to this question. And I will note it 

down and see if I can - we can resolve this. Or if you can send me an email 

on the other - on the email link, I will try to respond to that. But my opinion 

is that it's probably not catastrophic for - from an MR perspective, but an 

implant card might be important for other reasons or - yes, besides the MR 

scan. So at any rate, I will wait to talk to my better informed colleagues about 

this, and get back to you. 
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(Megan Sajab): All right. Thank you. Another question I have is for non-electrically

conductive devices that fall within the definition of MR safe based off their 

material composition, can you clarify if heating testing is expected? 

Sunder Rajan: No. It's not - it's not necessary to do RF heating testing for devices that have 

conductivity similar to that of tissue, non-conductive or plastic.

(Megan Sajab): All right. Thank you. And then similarly, for image artifact testing, is that 

limited only to implants with metallic or magnetic material? 

Sunder Rajan: I would say generally yes, but there could be material that's impregnated with 

iron oxide. A good example I can give you is if you take a piece of tape from 

an old cassette machine that looks like plastic, you know, audio cassette

machines, that has iron oxide in it. And if you put it on top of the skin, you

will see it effect the image under it. - You will get a dark artifact from it. So...

(Megan Sajab): Okay.

Sunder Rajan: ...so it - the answer is if you - based on your knowledge of the material you 

can provide a scientific rationale that there is going to be no artifact, then of 

course you don't need to worry about it.

(Megan Sajab): Okay. Thank you. 

Coordinator: The next question comes from (Dasan Dalecia). You may go ahead. Ma'am, 

you may go ahead. Please check your mute button.

(Dasan Dalecia): Is this for (Dasan Dalecia)? 
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Coordinator: Yes.

(Dasan Dalecia): Okay. Thank you. I had two questions regarding medical device card that's 

recommended for medical devices in the guidance document. My first 

question is what is the expected implementation timing for the card 

requirement? And are there requirements on how it can deliver for 

example, electronically for hospitals and then they can print it? Or what is 

the matter of delivery if you can please comment on that, especially in regards 

to passive implant?

Sunder Rajan: We don't have a clear - I do not believe we have a clear requirement that it 

should be paper or electronic. In my opinion, as soon as the patient has an 

implant, they must have access to that information in a card and the card can 

be printable for all that I care new technology, might not have a card, but 

they might have an electronic version. But for now, let's just go with the card, 

with the paper card as prescribed.

(Dasan Dalecia): And does it matter if delivery doesn't need to be part of the packaging or it can 

be provided separately onto the patient? 

Sunder Rajan: I'm sorry. I don't know the answer to that question, if it can be provided 

separately to the patient. Again, this is something I might have to get back to 

you on. So if you could just send an email to that address, I can check with 

the policy people and get back to you on that. 

(Dasan Dalecia): Okay. Thank you. And my second question is how does CDRH intend 

toreview information in premarket submissions? Will it be just thereview of 

proposed content on the implant itself, or will there be some level of 

assessment like (field) assessment at some point, as well? 
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Sunder Rajan: Well we - typically, when we view the premarket submissions and the 

MR testing, we look at the testing and then we see how consistent it is for the 

labeling. And if everything works out fine then you go and check the implant 

card, what is provided in the documentation for the implant card, an see if the 

format is adequate, clear, and we go from there. So it's checked at that time. 

(Dasan Dalecia): Okay. Thank you very much.

Sunder Rajan: Okay. 

Coordinator: Before we go any further, please limit your questions to one per 

person. Thank you. One question per person. Mr. (Paul Lawson), you may 

go ahead.

(Paul Lawson): Hello. My question is we manufacture MR coils. So you said that excludes 

from the scope of this. My question is are you coming out with a similar 

guidance for accessories such as coils, in the future? Thank you.

Sunder Rajan: I don't believe so. There may already be some standards out there for coils 

and coil heating and so on. - I don't know of any plans to provide a guidance 

just for MR coils. 

(Paul Lawson): Thank you. 

Coordinator: Our next question comes from (Glen Sellner). Sir, you may go ahead.

(Glen Sellner): Hi. We have currently MR conditional labeling that's been approved by

FDA in 2019. Our device is small. It's less than 2 cm and our current labeling 

includes largely everything that you provided in the example. My question is, 
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is since our labeling was approved in 2019 does it need to be updated based 

on new guidance, if that comes out? Or are we sort of grandfathered in? 

Sunder Rajan: I believe it's grandfathered in. But if you come back with a device 

modification and it needs a new 510(k), there is a pretty good chance you 

would have to update your labeling. 

(Glen Sellner): Thank you.

Coordinator: Our next question comes from Guy. You may go ahead.

(Guy): Hello. Thank you. Thank you for the review of the guidance. I wanted to ask 

if the labels suggested MRI for unsafe products must include a projectile

hazard (text) or can it have only the Red Cross symbol as in the 

ASDMstandard, assuming the product is not allowed - or the labeling to enter 

the MRI environment? 

Sunder Rajan: I would strongly recommend a projectile symbol if you believe there is that

risk. If you believe this device is going to be used around the MR environment 

and there is a potential for accidental use near a magnet, I would strongly 

recommend an MR unsafe symbol and a projectile symbol. 

(Guy): Okay. Thank you very much.

Sunder Rajan: And if it is anywhere inside by some chance, where it can be quickly moved 

and I would strongly recommend it tethered so it's not something that can be 

walking around. Yes. 

(Guy): Thank you.
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Sunder Rajan: I mean this is again, from FDA's perspective, I know the labeling is important, 

but I may have overstepped a little bit the clinical practice. But that's the 

reason we asked this is we want to minimize the risk of it accidentally being 

used.

(Guy): Okay.

Coordinator: Our next question comes from (Amanda Penticost).

(Amanda Penticost): Hi. Thank you so much for your time.

Sunder Rajan: Hi.

(Amanda Penticost): I have a question regarding the like when labeling - when you're saying 

that you don't do - you haven't done the MR testing. So our company 

manufactures screws and plates, you know, very basic orthopedic 

implants. However, this isn't something that has been tested in the past but I 

know from experience and talking to others in the industry, that these are 

increasingly being tested whether that's a marketing decision or there's any 

regulatory pressure I’m not sure. 

So I wanted to get your input on, you know, is the FDA going to require this 

type of testing to be done on those types of implants? Or is it 

(unintelligible)?

Sunder Rajan: Yes. Go ahead.

(Amanda Penticost): Oh, I just want to say or is it (unintelligible) discretion?

Sunder Rajan: I'm sorry. The last part, you faded a little bit. Could you repeat?
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(Amanda Penticost): Oh. Or is it still up to the discretion of the company? 

Sunder Rajan: Okay. So this comes back to the fact that - or reasons that I personally don't 

understand. It may have to do with deeper policy reasons that certain devices 

either because testing methods were not available, it was not least 

burdensome, were less about testing and ended up that untested labeling. But 

my understanding is going forward, it's going to be mandatory for all devices, 

all implants I should say, to have MR testing unless you can convince 

somebody that this patient is never going to have an MR scan. 

(Amanda Penticost): Right. So I guess when submitting 510(k)s should we, you know, should 

we - do you think we should start doing this preemptively or, you know, 

would our reviewer, you know, give us information and say hey, we really 

think you should do this testing? Or will the guidance be updated to give, you 

know, a little bit more information for the types of devices, making it more 

clear...

Sunder Rajan: Okay.

(Amanda Penticost): ...that it's needed? 

Sunder Rajan: Here's where I want to separate my opinion from what I, you know, I want to 

say that in my opinion, I think it's better to do it preemptively because it's 

good for the patient, it ravoids the delay when the patient gets scanned. And 

you are positioned well in terms of the market, and you don't need to worry 

about the risk of things getting delayed. But the real questions within your 

organization, there is always the pre-submission process where you can 

approach the review division and pose this. 
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And my understanding is that MR conditional labeling is now required in all 

review divisions, all the review divisions at CDRH, unless there is a very clear 

signal that this is a let's say an investigational device, an IDE clinical trial and 

that there are some really very persuasive reasons why that cannot be done; 

MR can't be done.

(Amanda Penticost): Awesome. Thank you so much. 

Sunder Rajan: Okay.

Coordinator: The next question comes from (Spencer Parent). You may go ahead.

(Spencer Parent): Hi. (Spencer Parent) from (Health Assure). My question is in regards to 

multi-configurational devices, specifically at the page 11 there's an update that 

says in some cases when a large number of variables are present a risk based 

assessment to determine the percentile for the heating comparison rather than 

a worst case approach, could be used. Will there be an update to the 

FDA guidance of RF testing of multi-configurational devices, specifically in 

regards to this worst case analysis? 

Sunder Rajan: Okay. First off, we haven't actually started writing a guidance on that, 

although we have talked about it so my guess if anything, it's probably a few 

years away. I would strongly recommend that you reach out or send us an 

email and we'll be happy to engage with you one on one and give us our best 

thinking on that. 

(Spencer Parent): Will do. Thank you very much.

Sunder Rajan: Okay. 
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Coordinator: The next question comes from (Alison Young). You may go ahead.

(Alison Young): Hi there. Can you hear me?

Sunder Rajan: Yes.

(Alison Young): I just wanted to clarify...

Sunder Rajan: Go ahead. I can hear you. 

(Alison Young): ...for the patient (unintelligible). Can you clarify what content is required or 

not? Is it just the MR symbol or is there also a statement required or can that 

be provided electronically or within the IFU? 

Sunder Rajan: Okay. That's a very good question because we have struggled with this 

because of the limited space available. And we've been more flexible in 

this. And essentially, trying to put in the most important information. It 

doesn't have to be a full reproduction of the whole MR conditional labeling 

page. It can be a subset that you think is the most important. And what was 

the second part of your question? 

(Alison Young): Does that need to be provided on a physical patient implant card or would it 

be sufficient to provide the symbol on the patient implant card and provide the 

statement to the rest of the MR information within the (ISU) or in some 

electronic form?

Sunder Rajan: Yes. This was kind of related to before. I think we definitely need the symbol 

and we would probably need other summary information in the implant card 

as well. And the rest of it is of course, the IFU should be comprehensive 

anyway. So...
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(Alison Young): Okay. Thank you.

Sunder Rajan: Okay.

Coordinator: The next question comes from (Tobias Gilk). You may go ahead.

(Tobias Gilk): Thank you very much. Thank you, Sunder for the presentation. I'm - my 

question is really asking for a clarification on what I heard as some conflicting 

information. So as I heard it in the body of your presentation, where you were 

talking about labeling and you talked about going back to the SAR versus B1 

RMS question. 

In the body of your presentation I thought I heard you say at one point, that if 

the label, if the MR conditional label says SAR) or B1 RMS you may use the 

less restrictive of the two even if the more restrictive one, if the value for a 

particular pulse sequence exceeds the limit, that would be considered on label 

because the labeling specifically defines or in the MR conditional label.

However, if the label doesn't specify or then it should be understood to be and 

because in your response at the end of your presentation where you have the 

pre-submitted questions, you made it sound like and is the operative 

condition. 

And earlier you made it sound like if or is present in the label you can use 

or. And I’m hoping you can just clarify this because there are a number of 

existing MR conditional labels out in the world, some of which simply list 

both and some of which explicitly state or. Are those the same thing 

irrespective of the presence of the word or, or are they defining two distinct 

sets of conditions?
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Sunder Rajan: Okay. Thanks, Toby) Thanks for clarifying and letting me know that I 

managed to confuse the situation a little bit. The first scenario is very clear, 

which is if there are listed in bullet point one after the other, or in the list of 

bullet points, without any further specification then they have to both be - it's 

very simple, very straightforward, all the conditions listed on the 

MR conditional labeling, listing one after the other had to be true. Okay? So 

there's no confusion about that.

The second scenario is if they have an or and then it really is the same bullet 

point except that it's one or the other, even though that's not my preferable 

format if it says that, you are okay with using one or the other. But I was also 

talking about the situation where typically you will have a preferred choice , 

which is B1 plus RMS. 

And in those cases use B1 plus RMS unless B1 plus RMS is not available on 

your MRI system. It's on display on your MRI system, in which case you 

have no choice but to use the SAR value, SAR limit that's shown in the 

MR conditional labeling. Does that help?

(Tobias Gilk): Yes. I just - for the purpose of putting into practical application existing 

labeling, if a label just lists, you know, (SOR) of X, B1 plus (RMS) of Y, 

without an or operator in the labeling then the...

Sunder Rajan: Yes.

(Tobias Gilk): ...understanding is you have to comply with both criteria to...

Sunder Rajan: Right.
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(Tobias Gilk): ...produce an on label scan. 

Sunder Rajan: Correct.

(Tobias Gilk): But I want to make sure I completely understand the other option. And that is 

if the or operator is present...

Sunder Rajan: Yes.

(Tobias Gilk): ...complying with one even if the other one is exceeded for a specific pulse 

sequence, the FDA's interpretation is that would be an on label study.

Sunder Rajan: Yes. It's the or. Even though that - I have not seen that, if something like that 

happens, that's the way it will be - can be interpreted. And, you know, that's 

correct.

(Tobias Gilk): Thank you for the clarification. I appreciate it. 

Coordinator: Our next question comes from (Ragu). You may go ahead.

(Ragu): Hi. Thank you for the presentation so far. My question is more on the science 

side. So when you mentioned about the rectification which I believe mostly is 

from a nonlinear element (unintelligible), is it safe to assume that having this 

component of (unintelligible) below or inside a titanium case, which is 

conductive even when non-magnetic, helps from (clarification) from the 

(unintelligible)? 

Sunder Rajan: You're treading in territory that I don't know much about. I don't think it 

depends necessarily on the case. I think it's, as you mentioned, it's the 

circuitry and a physical connection of the rectified voltage wave forms, to be 
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back reflected via the wires. It doesn't necessarily depend on the case 

design. It really depends on the voltage incident and the port, and how that 

port voltage, what happens to the port voltage because of the components 

inside your device. 

(Ragu): Okay. Thank you.

Sunder Rajan: Okay. 

Coordinator: Our next question comes from (Suchan). You may go ahead.

(Suchan): Thank you. What if my device is a biodegradable implant device in the knee 

or the shoulder region? What kind of MR testing does this invoke?

Sunder Rajan: Well, I would say unless you are 100 % sure or can provide a good reason

why a person with a biodegradable implant will not get an MRI scan, you

would have to follow the same paradigm. Now, I know that an average

metallic implant is not biodegradable to that extent, that it does disappear. So

you're probably not talking about the conventional material. You're talking

probably about something (special). 

(Suchan): Correct.

Sunder Rajan: I have at this point, a priority, no idea what the conductivity is or the magnetic

properties of such a device. So I would recommend that you go through this 

exercise of understanding the risks. And if you or the experts in your

company are unsure please go through the pre-submission process or send an

email to the email link there, and maybe we can try to figure out if the risks

are so insignificant that we don't have to worry about MRI testing. 
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(Suchan): Okay. Sounds good. Thank you.

Sunder Rajan: Okay. 

Coordinator: The next question comes from (Yashika). You may go ahead. 

(Yashika): Thank you. Hi Sunder. Thank you for the wonderful webinar. My question is 

our company manufacturers things which are placed in the carotid 

artery. And I wanted to understand how important or how informative to 

define the cooling period in the scan duration.

Sunder Rajan: How - so you said your company makes a carotid stent or a carotid device...

(Yashika): Yes. 

Sunder Rajan: ...that's placed in the carotid artery and you...

(Yashika): Yes. 

Sunder Rajan: ...want to know what is the extent of the cooling period? 

(Yashika): No. Should we define the cooling period or should we just follow it is less 

than 2 cm than we don't have to define it, you know, the - on the slide that you 

had shown? 

Sunder Rajan: Yes. I mean I think if it's less than 2 cm does not require RF heating and you 

can use that canned MR conditional labeling that I showed in that slide or it's 

in the guidance document as well. And the idea is if you need - if you believe 

that the scan - if you want to get a labeling for a scan longer than an hour then 

you need to come up with a cooling item or cooling time. But if you - if the 
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one hour scan which is typically adequate for MR scans, then you're 

okay. You just need - if it's less than 2 cm you can use the canned language.

(Yashika): Thank you. Thank you.

Sunder Rajan: Okay. 

Coordinator: The next question comes from (Chen Wee Lee). You may go 

ahead. Sir? Mr. (Lee)...

Sunder Rajan: Go ahead. I think he got the answer already.

Coordinator: I have. Just one moment. Let me bring up the next one. The next one is Ms. 

(just) (Lucy)? You may go ahead. Ma'am, you may go ahead. Let me bring

up the next one. Just one moment. The next one is (Andrea Lara). You may

go ahead.

(Andrea Lara): Hi. Can you hear me? 

Sunder Rajan: Yes. 

(Andrea Lara): Perfect. I had a follow up question regarding the patient implant card. So if 

we were to add the MR symbol and also the (CISU) symbol, would that be 

sufficient for us to just include the detailed information on the MR scan and 

the conditions within theIFU)? 

Sunder Rajan: I - as I recommended previously, I think it is important to add a couple of key 

constraints, especially the SAR). If there is a SAR constraint, you know, the -

what we used to have in the first three bullet points, know all of your bullets) 

from the past guidance. And so - we have some flexibility on what we're 
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going to add. But I leave it up to you to come up with the - your best shot on 

what you can put on a small card that provides the most information. Does 

that make sense? 

(Andrea Lara): Yes. 

Sunder Rajan: Okay. 

Coordinator: And our next question comes from (Margaret Clippo). You may go ahead.

(Margaret Clippo): Hi. Yes. This is another follow up question regarding the patient implant 

card. Would it be sufficient to provide, similar to the last question, the 

MR conditional symbol plus a link to a Web site where the sole information 

would be provided, providing all of - that information would appear on the 

Web site? Because I believe providing the (SOR) information would make 

the card quite large and might require some additional testing in terms of, you 

know, redoing packaging validations and other things like that. So I'd just like 

some comment on that. 

Sunder Rajan: My gut feeling is again to repeat we need to put in succinctly the key pieces of 

information. I - although I can again, if you left your email and the question 

specifically what you have in mind, I can check with some of my colleagues 

to see what they think is reasonable. But generally speaking, I'm not in favor 

of just having a symbol and nothing else in there. 

(Margaret Clippo): Okay. Thank you. We'll likely follow up with an email as you 

recommended.

Sunder Rajan: Okay. Thank you. Yes. 
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Coordinator: At this time there are no additional questions in the queue. If you'd like to ask

a question, please press star 1, unmute your phone and record your

name. Once again, if you'd like to ask a question please hit star 1, unmute 

your phone and record your name. One moment while we wait for any

additional questions.

Irene Aihie: Thank you so much, Operator. It looks like we have a question in the queue?

Coordinator: One moment while I get their name. 

Irene Aihie: Thank you. 

Coordinator: I'm sorry. I believe the name is (Paris). I'm not for sure. I can't hear it. Or 

(Parish)? 

(Steve Parich): Yes. That's correct.

Coordinator: Can you speak up louder, sir?

(Steve Parich): Sure. The name is (Steve Parich). 

Coordinator: You may go ahead.

Sunder Rajan: (Steve), go ahead. Ask your question. 

Irene Aihie: (Steve), please go ahead with your question.

(Steve Parich): Well I had a question about the MR unsafe symbol. So on page 19 of the 

guidance it states that with non-implanted medical devices the MR unsafe 

label should appear directly on the medical device if possible. 
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So that should appear is obviously subject to interpretation, as well as the if 

possible. Is it following the typical FDA requirements that if there's room on 

the device then you should put it on the device?

Sunder Rajan: Yes. I think our thinking was if there is space on the device, please put a label 

on it. 

(Steve Parich): Okay.

Sunder Rajan: Simple as that. 

(Steve Parich): All right. Well, what if you only had it in your IFU and you didn't have it on 

the product label? We should eventually try to migrate to adding it to the 

product label, correct?

Sunder Rajan: Yes. Yes. 

(Steve Parich): Okay. Okay. Very good. Thank you.

Coordinator: This one I also can barely hear. I believe it's Mr. (Lee). You may go 

ahead. Sir, you may go ahead. Hello? Please check your mute button. I'm 

sorry, we cannot hear you, sir. 

Irene Aihie: Thank you, Operator. Do we have any further questions?

Coordinator: No. There are no additional questions. 

Irene Aihie: Sunder, before I close would you - do you have any closing remarks?
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Sunder Rajan: No. Thanks everybody, for coming to the webinar. And I know that it's a 

complicated topic with lots of moving parts. And if something was not clear 

feel free to reach out to me and I'll try to help as much as possible. Thank 

you. 

Irene Aihie: Thank you, Sunder. Again, this is Irene Aihie. We appreciate your

participation and thoughtful questions. Today's presentation and transcript

will be made available on the CDRH Learn Web page at

www.FDA.gov/Training/CDRHLearn, by Friday, July 2nd. If you have 

additional questions about today's presentation please use the contact 

information provided at the end of the slide presentation. 

As always, we appreciate your feedback. Following the conclusion of today's 

live webinar, please complete a short 13-question survey about your FDA

CDRH webinar experience. The survey can be found at

www.FDA.gov/CDRHWebinar, immediately following the conclusion of 

today's live webinar. Again, thank you for participating and this concludes 

today's webinar. 

Coordinator: Thank you for joining. You may now disconnect. And have a wonderful rest

of your day. Speakers, please stand by.

END