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QI: MR Safety - Case-based Approach (Part 2) | Dom ...
T3-RCP40-2022
T3-RCP40-2022
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So just very briefly, this session, I want to point out, so we had a sister session that happened earlier. Hopefully many of you were at it. If not, if you have the virtual program, please go ahead and take a look at it. It was great. That one was called MR Safety from Program Creation to Best Practices. And that was really about roles and structure and things like that. This one is not going to be about structure. We're not going to necessarily justify a lot of stuff. It's not going to be just theory. The idea here is to give examples, to give an idea of reasoning and the way that some things are done. It's not so much about the what, but a little more about the how and the thought processes that are involved. I want to point out that when we're talking about all this MR Safety work, one thing I like to hammer home when I'm talking about it is the fact that this is really unreimbursed work. We're doing all this. It's going above and beyond for the patient. It's going above and beyond for the patient, and it's everyone. It's the physicians. It's the technologists. Even the physicists like us are doing our part. And so I think that it's really important to understand that we are doing this for the patient, and we're not necessarily getting back in terms of money and this lost time. And so this really is a labor of love for most of us, and doing what is best for the patient. So I will start off with a very quick example. These are two of the pages from one device, and there's something that's very interesting. So when you're going through, and if you were looking at an active implant and you want to say, hey, can I scan this thing on label, and what are the things I need to do, you will go through, and this actual document is probably about 40 pages long. But I'm picking out these two, and what I want you to look at real here, because I think this is a really interesting case. The first time, we've done about 600 to 800 devices in the last two years. And what I will say is this is the first time I've ever run into this. So you're looking, and what you see is that what I want to show you is taking the left side here is going to be 1.5 Tesla. The right side is going to be 3 Tesla. And if you look in these boxes, what's interesting about this is if you look at almost any other device, or every other device that I know of, when you look at what are the levels that you have to hit in order to scan this thing on label, 1.5 Tesla is almost invariably going to be easier to hit. And yet here, it's the exact opposite. If you want to be able to do this, it is 0.1 watts per kilogram for SAR to hit it at 1.5 Tesla. But if you go over, I do have a handy dandy little thing, but if you look over here, it's 10 times more. You have a 10 time higher limit if you want to go and scan in 3 Tesla. So this is the first time that we've actually had to have a discussion about, you know what, let's route this patient to a 3 Tesla magnet instead of a 1.5 Tesla because it's actually going to be easier and you're going to get better image quality. So that's the kind of thing hopefully you're going to see and talk about some of these things. By the way, if you're wondering, well, why is it more for 3 Tesla versus 1.5 when all the other devices seem to be opposite, unfortunately, I don't know. We're actually trying to figure that out from the vendor. It could be that there's something with residences, or it could be something as simple as they didn't test 3 Tesla before, they retested it recently with more modern ways of testing, they were able to raise that limit, but they didn't want to spend the money to do 1.5. I'm not actually sure why, but if I ever find out, I will make sure I put it into a talk. So with that, I am going to stop. So my talk is going to be about essentially getting the patient from outside the magnet to inside the magnet and all the steps that involve. I'll try to be quick, because I have about four cases that I do want to cover where the workflow does fall apart. But I want to start by at least giving a high-level overview of what our typical workflow looks like when we're trying to say yes to getting a patient into the scanner. All right. So the big part of this talk would be the third objective, which I've listed here out of the three objectives of this talk, interpreting the active implanted device manual and extracting the key information. All right. So we all know that scanning active devices is risky, and the risk comes from this interplay of forces, and that's what complicates the decision-making process. And getting to yes essentially requires these three key pillars, the screening, the communication, and coordination. And in our practice, I would say it's the MRSOs who have really kind of been leveraging their expertise and their training in holding these three pillars together. And that's the main point. If I could drive home one key point, the role of MRSOs and how critical they are in working up these active implanted devices and pulling all the resources together. All right. So everything always starts with screening, and this is our typical screening process. It's a layered screening process, because always there are things fall through gaps and you want to make sure that you catch it at least at one of these layers. And the big stop is if at any of the steps we identify that there is an active device. At that point, it gets triaged to our MRSOs, where MRSOs act as a quarterback in communicating with the key stakeholders. So you have the schedulers, the coordinators, the vendors, the physicists, the radiologists, physicians. So all this communication is happening because all these stakeholders are involved in getting this device into the scanner. So MRSOs act as quarterback in getting all that communication together. Then when it comes to active devices, we have categorized them in three broad categories. When it can be scanned in normal mode, we don't require any physics review. If it's under normal mode, then we have a physics review and oversight. And if it's off-label, then you have physics review and radiology review. Main point here, only person who can say no is the radiologist. So anytime we are saying no to not scanning a device, it always needs a radiologist's approval with it. All right, so as it was mentioned by Dr. Sensogovic, the MR safety manuals come in all size and shapes and varieties. And it goes from simple like this, 1.5T, scanned in normal mode, to more complex, depending upon what part you're scanning and the SAR restrictions related to that, but then also time restriction, to even more complicated with ultra-low SAR. So unfortunately, there is no straightforward way of interpreting these manuals. You just have to take it one vendor at a time. And this is where I would really urge the community to come together and maybe come up with some structured way of creating these manuals, which are easy to interpret. So the information that we are really trying to extract from these manuals have kind of broken down into two. Information that's relevant for scheduling, whether we need a controller or not, what is the restriction on patient positioning, can a patient be scanned if they have a fever, and things like that. And then the information that is related for, needed for scanning. So what is the maximum field strength, what are the gradients, what kind of coils we need, what are the RF restrictions. So essentially, these are the 11 key pieces of information we are really trying to extract when we are trying to interpret the manuals. And then finally, it all comes together in communication, because having all this information distilled is not good enough. It has to be available at the point of care. And the best way to get this information at the point of care is to be in the medical record. So that is our standard practice now, where once the information is distilled, it gets put in the medical record. And as part of our MRSO check, a day ahead, our MRSO team goes through every single case that is scheduled for next day, and they review to make sure that there are no gaps in the screening process, and they initial it to make sure that they've done the check. And the last step is coordination. So now you have to make sure that all that information is available to you when you're there next to the patient. And that happens through Outlook invite, which talks about what implant we are scanning, what anatomy we are scanning, who is the MRSO who has reviewed it, and what are the key pieces of information we need to have handy when we are actually covering this case. And once we go through these three steps, this is how it all comes together. So this is a typical week of our active device coverage calendar. And again, this is all MRSOs working as quarterback, putting it all together, and condensing this information. So it's all accessible to us at the point of care. All right. So with all that comprehensive workflow, you would imagine that we are a well-oiled machine and we have no gaps. I wish I could say that. And that's what brings us to our case studies. And these cases are actually just from the last three to six months. It's not like these are old cases. So even with this comprehensive workflow, the complexity that we are dealing with does lend itself to gaps. And that's where reviewing these cases and iterating the workflow is the key. So let's start with the first case. This is an ED patient scheduled for MR lumbar spine. No screening history. Patient is ED, non-communicative. What do we do? Well, luckily, the patient got a CT scan right before the MRI was ordered, a CT of a head and CT of an abdomen. Looking at the scarred images, you can see there's a device. We got a closer look through L-spine X-ray. And actually, it's a kind of unique-looking device. And our MRSOs have gotten so good that they can look at a device and they can tell that, so this is actually a Nebra device. And we called the vendor, and we were able to get the information from the vendor about the make and model. The key here is one of the concerns would be, if the patient is sedated, then can we scan it on label? Luckily, in this case, that's a warning, not contraindication, but the big thing is turning off the device. And this is where we were able to work with the vendor to help turn off the device. But that's not where the complexity ends. Because we are scanning spine, we are going low SAR. And this will be the next talk that Dr. Zhou will present on how we manage devices when you have to go low SAR. And we did end up scanning this patient, and you can see this artifact from the spine device that was in his back. All right, so moving on to this case two. This is an MRI brain. This is a known VNS device. So we have scanned this patient before. And this patient was scanned multiple times three years ago. And then they come back. And this time, it just happens that battery is dead. So there's no power. And it had worked OK in the past, but we couldn't interrogate it this time. So conditions are quite straightforward in terms of scanning. You can do it in normal mode, especially if you're using the transmissive head coil. But the key is setting up the generator in the proper MRI settings. And since we can't do that, that's what makes it off-label. And Dr. Fernholz and Dr. Gibbs will, in their talk, go about how do we handle scenarios like these. In this case, we did end up scanning this patient with the radiologist's approval. And the patient was scanned on 1.5T SAR under 1.5 watt with a TR head coil. All right, so moving on to the third case. This is interoperative DBS placement request. Patient has a known DBS device. And we know the make and model. Everything was worked up. Appropriate checks was performed. Device was interrogated to set in the MRI mode. But when patient came down for the scan, it was completely missed that the patient had the device. And we ended up scanning the patient without any SAR or safety monitoring. The patient history, the patient had previously come for MRI. One lead was placed. And then the DBS was placed. We did do a workup, looked at the chest X-ray, where you can verify that there was a DBS device. And this was a second order for second lead placement. And that's what threw off the point of care communication. We rarely do DBS cases where we are scanning the patient for lead placement when the DBS is already in the system. And that's what tripped off our screening process. And even though it was marked that the patient has a DBS, it was completely missed. So this will be Dr. Flug and Dr. Bowman will be talking about what to do when we have incidents like this and how do we address those. In this case, we did got a lucky break because it just happens that our lead placement protocol is only two sequences. It's a localizer and a 3D gradient echo sequence with a TR head coil. So SAR was under 0.1 watt per kg. But I do want to put in a plug for the vendors here that we are missing B1-RMS information from the DICOM header. And this is something we need when we are retrospectively reviewing these cases for the safety evaluation. There was no way for me to tell what was the B1-RMS that was scanned for this patient. At least with the SAR information, we were good. All right, so last one is interventional MR. So this is a visualized case for ablation. Patient has a VNS. The reason I put it in here is of all the restrictions that come to the devices, the interventional MR has its own restrictions with patient positioning, coils, and scan times. And this is where Dr. Stafford is going to talk more about how we handle those scenarios. And in this case, it just happened to be a straightforward device. Mainly, since we're not doing transmissive head coil, we had to just make sure that we stayed in the required scan limit, and the scan was done successfully. So to wrap up, these are the main barriers to scan when it comes to scanning the devices that we have noticed in our practice. Incomplete screening from MR support goes a long way. Missing make and model, having vendor relations so you can reach out to them. Most vendors, if you just give them the patient information, they are able to tell the make and model. Access to up-to-date manuals, and hunting down manuals is just a nightmare. And I wish there was an easy way to have up-to-date access to manuals. And then also having x-rays available to verify the device location. So it is a teamwork, and we have scanned, like Dr. Sensay mentioned, over 900 patients in the last year and a half. So for the most part, it works when the team comes together, but then there are all these other gaps that are still remaining that we can address as a community. So with that, I do want to put in a plug for these great ISMRM posters that are available for reference, and I want to thank you for your attention. Thank you for the introduction. Here is our objective. The main objective is to understand and discuss the heating and the burning in MRI imaging. Then we will discuss how to prevent those burns and try to reduce the SAR values. Finally, I just give one of the case, go to the details, how to reduce the SAR. We know that RF plays the most important role in the MRI imaging. RF always includes two parts. One is the magnetic field, and the other one is the electric field. Actually, only the magnetic field contributes to the imaging. The electric field will contribute to the heating and the burning and the noise. Actually, most of the electric field is the side effects for MRI imaging. You need to understand RF, how to generate RF, and how to detect RF signals. That's the coils, is very important. Two kind of coils. One is receive-only coils. Those coils only detect the RF signal. When other coil is transmitted receive, they can send transmitting the coils, transmitting the RF signal and detect the signal. Why those coils is important during MRI scan? You need to understand for the transmitted coils in XY plane, the area close to the coil element, the B1 values or the RF heating is significantly higher than the center. In the Z direction, you can see the isocenter is the B1 field, or the RF heating is significantly higher than outside the map area. Then the factor cause the RF heating, the environment, patient, and the MRI protocols. The environment, we consider the hardware and the room temperature humidity and the airflow setting. For a patient, the heating all depend on the conductivity, permittivity, and permeability, and the size and the mass of the patient. And also depend on the patient if they have the implants or not. For the individual, the protocols, you need to consider the series, spin-echo, gradient-echo, or fast-spin-echo, all the pulse sequence parameters, the TR parameter, number of slides, all kinds of... I think in the further section, we talk about how to measure the SAR. I think common, there's three terminology we measure the SAR, measure the heating. One is called SAR, SED, and B1-RMS. Actually SAR is measure the individual sequence. The SED, the SED is measure the total dose of the whole exam. Both the SAR and the SED is estimate. And also in the further section, we already discussed for different manufacturer, for different vendors, they are secret. How they evaluate those SAR, those SED, no one knows. Or they just estimate, everything is estimate. Actually I do some experiment in a different system, even the same sequence, the SAR and the SED is significantly different also. But the B1-RMS is more accurate because it's all dependent on pulse sequence design. As long as you give the sequence, then you can use the B1-RMS to calculate, to measure the SAR. Actually this is the output from the system. That's I think more manufacturer or more the device now they toward to evaluate the B1-RMS. I think the type of burn, we have to understand the proximity and the inductive heating and antenna. All those things, I think most of people already know, I will not go to the details. But just to show some of the case, like in the near field, it's conducted the elbow burn. This one is a skin-to-skin, the contact burns. Then a lot of the implant device, like the retina needs, the VNS retina needs, and the DBS, they can generate the high heat. Here we already know the heat can cause the burn, then how to control for the whole exam. Then I list a lot. Here they check and confirm if the MRI is necessary. That's dependent on radiologists and other physicians. Then the technologists have to consider remove the implant device, have patient change at the barrier, and make sure the burn fan is on, and position the patient correctly, not a skin-to-skin contact. And make sure the cable not form the loop, and the cable eye on the patient. And for the physicist, we can do a lot of things. And discuss with the radiologist that you can change the sequence from the single-shot spin-acre to the fast spin-acre to spin-acre to GIE. Because this sequence definitely we can significantly reduce the sun. Then checking the patient between the scans, and ensure the patient not too warm. A lot of device, they say, don't use a blanket. And also, if you have multiple orders together, like a C-spine, T-spine, L-spine, then you need to discuss the other physicians if we can reduce, or the radiologist can reduce the scan, or shorter the scan. Here, I listed how to reduce the sun. Here, we can increase the TR, then we can increase the acre space. We can decrease the received bandwidth, receive the phase encoding, decrease the frequency encoding, increase the partial imaging, Fourier transfer, and concatenations, and decrease the egg-train length, the phase oversampling, and change the RF mode, especially the soft mode, where significantly decrease the sun. Then remove the fat set, or decrease the duty cycle, decrease the flip angles, remove the magnetic transfer, then decrease number of slides, and spatial saturation. Of course, all those things you have to balance. The scanning time may change, significant change, and the image quality may significant change. You need to discuss with the radiologist and the physicist how to adjust those parameters. Another one, I just look at one of the case. For example, this is the Axial T2 images. How can we reduce the sun from 4.51 to 0.1? Because the 0.1, we can use for the DBS device. For example, here, the resolution is 0.6, 0.6, and 3 millimeters. Some of the slides is 44, then the regular TI is 2,000. The total time is about one minute. But unfortunately, for a regular patient, normal mode, maybe we can scan, because the head, the sun, is 4.51, but if this patient have a device, how can we reduce the sun? Here, I just give step by step. From 4.1, go to 2, go to 1.5, go to 1.3, go to 1, go to 0.8, 0.5, 0.28. Finally, we can make it less than 0.1. The first step, we go to the IF type, from fast to low sun. Then second step, we change the flip angle, go to 150 to 130. Then change the number of slides, then go to 44 to 36. Then change the TR, increase the TR. Then from 2,100 to 3,100, then echo space, we can increase from 7.6 to 10. Then turbo factor, reduce from 9 to 6. Then number of face encoding, we change it from 380 to 256. Then finally, we further reduce, we can further decrease number of slides. Then increase the TR, then decrease the flip angle, then remove the SMS. Of course, you have to consider the balance, the total scan time. Also, you can see which parameters will change the total scan time. Of course, we mainly consider try to keep the image quality for the ordering physician and for the radiologist. Finally, we get the slides in 16 slides, then TR is 7,500. Then we remove the SMS, then increase the resolution also. Then total time is increased. The good thing is the SAR is less than 0.1. Here is the reference. Thank you all. I'm Sam Fernholz from Mayo Clinic, Arizona. Yeah, I'm Wendy Gibbs. And I'm from the Barrow Neurological Institute in Phoenix. But I had the privilege of working with all these great educators at Mayo before this. So I have the perspective of both places, which are very, very different. The factors for deciding to scan off-label should be the same as any medical intervention, namely focusing on the risk-benefit of that exam and what are your alternatives. So that can involve discussing with the ordering provider what exact information are they trying to get and what the benefit of that might be for the course of care of your patient. And then, of course, what is going to be the risks to the patient when you are off-label. And to do that effectively, because those manuals, once in a while there's language in there that you might be able to infer what's going to happen if you are off-label. It pretty much never really does tell you what's going to happen if you're off-label. So you don't know if, like this stage, I'm about to plunge into the abyss, or if it is maybe not as risky as you might think. So as it's been summarized before, there's various hazards in the MRI environment. They include the static magnetic field, so ferrous objects, or the spatial gradient as you approach isocenter. The main one, the chief one, I would say, is RF heating. There's time-varying gradients and acoustic hazards. And when you do these off-label things, you might consider if it's going to be worth your time to get patient consent. And I hope you were here earlier to hear some opinions on what to do on that. I'm afraid I don't have time at the moment to discuss. So, there are strategies to mitigate that risk. We, again, don't know exactly what those risks might be if you're off-label, but starting with being very aware of what your on-label instructions are and how you are, say, violating those instructions. You want to be aware of the patient's health state, whether they have fever, whether their patient positioning is supine-prone, superman position, and these sorts of things. Their mental state, if they're anesthetized. You need to know your hardware of your scanner. Is it 1.5T, 3T, are there transmit-receive coils? And you can do some very clever things that we will introduce later with transmit-receive. And so, here's the RF heating field from a body transmit. It's larger than, say, if you do just the head transmit-receive coil. There's also a transmit-receive coil for the knee. That can be handy. To mitigate risk further, you can monitor the exam with an MR safety expert, like we just saw in the previous talk by Dr. Jell. And those protocol modifications, including less series, and that can mean either coordinating with the radiologist beforehand or during the exam to decide what you can cut. And because a large amount of the off-label exams in MRI might come from cardiac devices, I believe February 2011 or so was the first FDA-cleared device for MRI. So everything before that is off-label. Fortunately, there's emerging evidence to say what those risks might be. I encourage you to look them up. Here's some examples. Mostly, that risk is going to be cardiac risks managed by the electrophysiology team. To transition to the case-based part of this talk, when I approach a radiologist, say, namely Dr. Gibbs, I and the MRSO are gathering the triage identifies the patient has a device. Then they triage the patient has an off-label device for the exam that we would like to do. And so from then on, there's gathering information. So what is the patient state? What is the MR order? What is that device? And how are we violating those on-label instructions? And then being aware of what MR hardware do we have available? So I then go to the radiologist and present that information as, say, a packet, and then there's communication to the ordering provider, the scanning team, so that we can execute. And I say the reading radiologist there, too, because if I talk to one radiologist to get it cleared, it could be someone else on schedule to read that exam. So everyone needs to know what they're getting. So, Dr. Gibbs, the first case we have is there's a brain and neck MR angiography order. There's a suspected venous varix. This particular device is only on-label for the head exam using a transmit-receive coil. Can we be able to scan them? Yes. So, yeah, I just wanted to say that also, before I answer that question, working with the people at Mayo, it's a fantastic system, and we have physicists walking around helping us and educating us. And I know, I just wanted to make this comment, because many of you out there might be in a situation that I'm in now where we do not have physicists walking around, and we have to make these decisions. I'm not the MRMD. I kind of know, learning from these people, I was so fortunate to learn from their education when I was at Mayo, and our residents also. But now where I am, they just come in, they ask my fellow, they ask me. So we have to look at these, and this is kind of how we approach this. So, like you said, we're looking at something in the brain, this is a vascular case. So we're very fortunate, I'm neuro, so this is good for me. In vascular neuroimaging, we're fortunate to have a very easy alternative. So when we're looking at this case, I could say we can switch altogether from MRI to CTA, and that's what was done in this case. But they're not always so easy, as you'll see in the additional cases. So, Dr. Gibbs, our next case has a deep brain stimulator. They've had a complicated history where they've already had stereotactic radiosurgery treatments, and it's now dealing with intractable pain, and neurosurgery would like to continue treating surgically. There's a brain order for preoperative planning. It has incredibly low SAR, almost as low as you ever can see in these manuals. The exam will be under anesthesia, which puts it off-label, and there's that 30-minute limit, so we don't want to have to put the patient under, say, again and again and again with following-up sessions to get the entire protocol, very long protocol done. Do you have any advice? Yeah, so, and this actually had one more complication that I forgot to tell you. This case had been scheduled previously on a different scanner because they want, our trigeminal neuralgia team was doing research, and they actually had to reschedule the patient to put in this research sequence, which brings up an interesting point of this case. So, yeah, we have a patient. This is not life-threatening, but it is very important because it's intractable pain, so we want to do the study. We just have to figure out how, so that for us, it was not the physicist that comes to us where I am now. The technologist came and said, you know, we need to cut this down. What should we do? And those are the kind of decisions we need to make. So for this particular patient, for trigeminal neuralgia, I don't know if any of you all are neuro, we need this heavily T2-weighted high-resolution sequence to look at the nerves. Then we need also our axial pre- and post-3D T1s for the surgical planning. So we were able to cut it down to 30 minutes, amazingly. Now, one other point, too, is the research part. So we said, no way. But, like I said, this person was rescheduled to get that, and one thing that we had a discussion about amongst ourselves was, is it ethical to have a research study in a scenario where the patient could be harmed? We don't think so. Probably could've gotten there, we still cut it, just because I don't think that's probably the right thing to do in this situation. All right, and for our last case, this patient has a mass in their hand and wrist. Their previous exams have been inconclusive, and the next point of exam would be to do an MR. And their device is only on-label for head-only. However, it is off-label, but Dr. Gibbs, I believe we can very effectively mitigate the entire risk by intelligently using a transmit-receive knee coil with a Superman position, typically prone, sometimes supine, with the hand above. And if you pack tons of foam and you stick the wrist onto the surface of that knee coil, we can restrict the RF heating to just that hand. Can we go forward with the exam? Yeah, and this is another thing, an amazing benefit of where these great people are is that they can think of clever ideas like this. I don't know that I would've thought of that myself, but I think that sounds like a fantastic idea for this patient. All right, and the exam was pretty much totally fine. All right, and thank you for your attention. You know, the great thing about RSNA is you come to it, you come here to hear world experts talking about things. Unfortunately, I'm developing a reputation of being an expert of screwing up. So, what to do when an MR safety event occurs. I'm one of the, we have two MRMDs in Florida. I'm one of them, so this is how we approach these events. Now, as far as safety events we track at Mayo Clinic, we track all kinds of safety events throughout, I think we do, but as far as the MR environment specifically, there are sort of four things we care about the most. We've already discussed really all of them. Device issues, can they be scanned or not? Thermal injuries, you know, burns are the most reported event to the FDA for a number of complications, so you heard about that earlier this morning as well. The two that really get people to stay up at night usually are ferromagnetic objects going into zone four and then projectile events. So, these are the ones we're gonna be focusing on today, particularly the last two. So, first thing I'd say is, you heard it before this morning in an earlier session, be prepared. If you have a serious adverse event or an adverse event, safety event in an MR environment, do you know what to do? Like, if it happens right now, what are you going to do? Is that clear to you, what your role should be and what you need to be doing? So, before an event occurs, have a plan. Know what to do, who you can make the event to, and then when you should do it. So, for us at Mayo Clinic Florida, we kind of have two varieties for this. One is a projectile event that strikes somebody. It can be the patient, it can be the staff, it doesn't matter. Take care of the person involved first. Are they okay, make them stabilize, whatever it is. Once that is finished, the MRSO and supervisor, the MRMDs and the chair of the department want to be notified within the hour. 24 hours a day, seven days a week, 365 days a year. This actually was a policy instituted by our chair. He's like, I want to know this before anybody else does, once the patient is stabilized. Now, if it's a projectile event without injury or a zone four breach or a thermal injury, which are probably a little bit less acute, take care of the patient. We should all be notified within a day or so. All of our MR techs have the cell phone number of our MRSO and our supervisor. And those two people have my cell phone number and the chair's cell phone number, so they know how to get a hold of us and that's the plan that we have in our system. So, the event, this actually happened to us in January. We had a patient who presented to MR for an outpatient abdominal scan. The patient sat on the MR table, began to lie down when a locker key was pulled from her hand into the magnet bore, striking her in the head above the right eye. The key was removed from the magnet. The patient said, I want to keep going, so we proceeded with the scan. And then I was notified during the scan. So, what I did, first I suppressed the urge to curse very loudly. I'm only human too, you don't want to do this, but that's what happens. So, first thing I did was, I called the tech during the scan, asked how's the patient doing and what, according to him, happened. He goes, well, the key was in the hand, she laid down and it came loose. And usually with projectile events, nobody sees anything. They lay down, next thing you hear, they hear a crash and something's in the magnet bore. That's kind of what happened here too. The patient was doing fine to him and he wanted to proceed from this. I asked the tech if he was okay. This is a traumatic event for everybody involved. I mean, this was a seasoned tech with 20 years of experience. He is still taking care of the patient. I want to make sure he is supported to know that he can still do his job appropriately and is not too upset about what's happening. He was beating himself up too, as you might imagine. I evaluated the patient after the scan before discharge. So, I was called in to go see the patient. I did an exam. She had a small laceration between her eyebrow and her upper eyelid on the right side with a little bit of swelling. It was basically just a scratch. Her extraocular motions were intact. She could see things. She had no real pain, just a little bit of swelling. So, we were lucky, one centimeter inferiorly, this would have been a severe gastrophic event. There was a note in the chart documenting the event. And I referred the case of the root cause analysis to our own department. So, this was the culprit. So, this is our locker keys that patients use to change into a MR-safe dress when they get into the department. And so, the key is non-ferromagnetic. The wristband is not magnetic, but the key ring is supposed to be non-ferrous, but it was in this case, and that was the problem. Also, the wristband was not present, so there was no visual cue to detect that the key was still in the patient's hand. So, event analysis. Now, when you do root cause analysis, there's all kinds of tools you can use, as you may have heard at other quality discussions. You can use a fishbone diagram for a single event, a Pareto chart's usually not all that helpful. One thing that we lose a lot in Florida, which I kind of like, is the five whys. It's a way to drill down a questioning process to figure out an underlying cause for an event that actually happened. So, I had our techs go through this process for them, how they perceive what are the problems with this event. So, the issue was, locker key struck a patient in the right orbit. Why? Two little branches for this top branch. The ferrous key ring was on the zone four table where the scanner could pull it. Why? The ferrous keys are still being used in MR. Why? Because ferrous keys and rings had not been systematically replaced with non-ferrous, although we had thought they had been. Bottom branch. The wrist bungee was not affixed to the key ring in this case. There was no visual cue to see that it was there. Why? The missing bungee was not known to the tech. So, this is what the techs came up with. I thought it was all pretty reasonable, but there was still sort of an underlying assumption, which I think maybe they kind of glossed over, which I asked, which is, why are we bringing keys into zone four in the first place? And so, in discussing this, the idea is that in our scanners, we had plastic hooks along the inside wall of the scan room. The patient would come in, and then the last check that the tech would do is ask the patient for the key. They'd give it to the tech, and they would hang it on the wall, so that way the patient could see the key is always in the room with them. I said, well, basically, I think we've proven this is not a sustainable practice. So, action areas for improvement. Store locker keys outside of zone four. Ensure our locker keys are completely non-ferrous. Ensure they have a wrist bungee attached, because I think the most important one was this. So, and for a temporary fix we did is we just bought some plastic hooks from Target and put them outside the scanner room. And then we actually had facilities construct this little device where you could, you know, hang up a couple of keys. You also had a transparent bin to put in glasses. That was outside the door to the scan room. So, now our process for the techs is that when they go to the door, they stop, ask the patient for the key, remind them, is there anything else on you that could potentially be unsafe in the magnet, put that in the storage bin, and then go forth and scan the patient. Now, event reporting. We had an event. Are we required to report this event? And if so, to who? So, any adverse event that results in serious harm or death needs to be reported to the Agency for Healthcare Administration and the Joint Commission as a sentinel event. And then also, depending what state you're living in, perhaps a state agency, that varies from state to state. So, this was not a serious event that caused harm or serious harm or death. If it hit her about an inch lower, it would have been, so we were lucky. What is covered by the events that cause death or serious injury of the patient associated with the introduction of a metallic object in MR? Events related to material inside the patient's body or things outside the patient's body. Items, whether or not they're known to the disclosed facility staff. And it captures the event of projectiles including retained foreign objects, external projectiles, and pacemakers. So, a summary, what I suggest is, they've been mentioned several times before this morning. Have a plan. Know what you're going to do with a severe event before one happens. Evaluate your safety process to identify areas of improvement. This actually was pretty straightforward for us. Don't let the keys go into the room. Not rocket science, but that's something you have to do sometimes. The AHCA and the Joint Commission must be notified when serious adverse events occur. And again, thank you for your attention. Enjoy the rest of the meeting. I'm gonna dovetail very nicely off of what Dr. Bowman brought in. And I'm gonna talk about a safety case that happened in an interventional environment. And so, on the way there, hopefully we'll talk a little bit about how interventions are different than the normal procedures. But I decided not to do anything super esoteric. So this is your standard run-of-the-mill, this-can-happen-to-you sort of event. Not the laser burned the brain. So this is where we're going with it. What's the procedure that I'm gonna use? Well, we do some MR-guided brachytherapy. We're doing this experimentally in 3T. And this is basically where we take an ultrasound-guided procedure. We do it in the fringe. And so we lock everything down in the fringe of the magnet. And we do a normal guided procedure where we place the T and O. And if there's any additional needles that need to be placed for a boost, those get placed at that time too. Then we take the patient, we transfer them into the MRI, and we check for the placement. And if we're done, we get the dosimetry images for planning. If they need to be modified, we can now take the patient back out, go back to the original fringe field arena, and then modify and go through this until they're happy with the implant. The normal way of doing this is we do ultrasound-guided up in the OR. You have to recover the patient. If you wanna get your dosimetry images before the procedure, they have to go down to MRI. After they're done with MRI, if you're happy with everything, you're not gonna do anything again, you're going off to get your treatment. So that's kinda how that happens. So after we're done with this, the patient's gonna be transferred out, they're gonna do dosimetry and planning, and they're gonna get their HDR treatment. And like I said, this one's being done under an IRB. So what I wanted to point out here, I don't know if I, can you guys see? There we go. I wanted to point out here, we use the five gauss line to identify two different arenas. That's not because there's anything magic about objects floating into the magnet with a five gauss line. That is defined basically as a hazard area for things like magnetic switches like you'd find in a pacemaker. So it's really for medical devices. But it's useful because this is a standard diagnostic suite, and we have five gauss lines identified there, and we can operate in those two arenas so it's a nice visual cue. If you're really gonna proactively design a suite for interventions, you may wanna have 100 gauss, 200 gauss, other gauss lines labeled that are appropriate to bring things closer to the magnet. I just wanted to bring that up because this is not your normal suite. Also, in the course of after us doing this, there's a nice task group that's come out from the AAPM that goes through a lot of the events for doing MR-guided brachy procedures and addresses safety concerns. So there's now a document to refer to if you're interested in doing this at your hospital. That being said, for us, the key preparations when we're developing this, or any procedure to be quite honest that we're gonna do in the MRI, is to go through and identify what is the workflow for that procedure, what has to happen, and in what arena is that gonna happen? Is this happening in the magnet arena where we have hazards, or is it happening outside that area where there's less hazard? And then what are the needs that are gonna happen in each one of those? That's gonna drive the need for the equipment. Am I gonna have to have equipment that's MR-safe, MR-conditional? If I have things that are not MR-safe, MR-unsafe, they're gonna have to be out in the fringe field or in an area where I can control them, or tether them, like the ultrasound unit. In some cases, like the patient board that we put on top of the MRI, which is MR-conditional, there's parts that were not MR-conditional, so we had to take those out and replace them with things from the machine shop. And I also gotta tell you that there is a, there's something that's non-ferromagnetic, huge conductor, just bolting things down that cause amazing artifacts from the conductivity, that had to get pulled off of that table too. But anyway, so you have to modify everything. And so here you see like a tray with our MR-conditional devices, and those sorts of things. So that next thing that's gonna drive is gonna be your personnel. You need to identify the teams that must be in the room. Not the teams that could be in the room, should hang out in the room, just who has to be there, who's going to participate, where they're going to be, how they fit into the workflow, and make sure they're all MR-trained and screened. And then the big one, MR-training and screening's not enough. You don't want someone that doesn't understand what you're doing in the MR environment to walk into one of these procedures and then just do their job. They need to be trained on these procedures. They need to know what everyone's doing, and be in communication with everyone else. That's a big deal. Typical team for this one. The last one I wanted to bring up is doing dry runs. Usually when you're in intraoperative or interventional procedures, these are complex procedures, you immediately go through to find what are the holes in my procedure by going through and doing a dry run. In our particular case, we actually used a volunteer for the dry runs so we can optimize our imaging at the same time. That's where we found out that there's problems with the table that we're putting them on. The table raises the patient off the spine coil, had to compensate for that. We had a conductor that causes artifacts, had to compensate for that. So dry runs are extremely important to get you to the first day of procedure. Which brings us to the case. So we had a 65-year-old female. This is after they've already had their external beam radiation, and we brought them in, and we did the ultrasound guided placement out in the fringe field. Four additional interstitial titanium needles were placed. Then we moved the patient in for an MRI. First thing we see, or the tech saw, observant tech, on the localizer was, that shouldn't be there, that's a big susceptibility artifact where I expect to see a tiny little titanium needle. So scan stopped immediately. They go in to check the patient. Pull the patient out, start to raise the blanket that covers the patient's pelvis, and an obturator comes flying out and hits the side of the bore of the magnet. Everybody's shocked. How did that get there? So they brought the patient all the way out into the fringe field, removed the rest of the obturators, patient was not harmed, staff was not harmed, shaken, not stirred, and then they go through and basically complete the rest of the procedure. So our problem here, just like from the last talk, was this is an event. How did this happen with all the things we put in place? And so we're gonna go through. Continuous quality improvement dictates that we take events like these and we figure out what went wrong. We refine our procedures and we continuously learn from them. If we hide them or try and make them go away, they're just gonna happen again and possibly be worse the next time around. So never, ever do that. So the day prior, we're looking at our debrief what happened. The day prior, procedure workflow, let everybody know what's going on, who's going to be there, the technologist checks to make sure that people are gonna be there are actually supposed to be there and appropriately trained to be there. Then they bring the equipment down to the MR suite and the tech wands it and checks it out. When I say wand, in this case, they're using a hand magnet. Headlamp sutures identified as ferromagnetic, separated from the rest of the equipment. They also knew that those were gonna be ferromagnetic, so there's a little bit of prior knowledge on that. Day of our procedure, there's this huge delay. They actually had a scheduling issue with anesthesiology. Patient shows up extremely late. By that time, half of the staff had to be traded out for lunch for other staff. Now the tech is preoccupied going through and re-screening people on the fly as they arrive in the suite. Distraction is not a good thing in one of these procedures, they're complex. Patient arrives, screen prepped, put on the table. They do a timeout. After the timeout, while the patient's in there, the equipment gets screened again to be brought into zone four, actually the fringe field, in order to be put in. They pass through the ferromagnetic detector, no alarm set off. After placement of the device, the patient and table are prepared for MRI. During MRI, the artifacts noticed. That's what happened. So discussion of findings. We had a screening failure of the equipment. Your Swiss cheese, each layer of redundancy is extremely important. We don't want ferromagnetic objects in there, but if they do get in there, we wanna make sure they get screened multiple times so we catch them. That happened, and we still ran into a problem. What happened in this case? We have a tray, and unbeknownst to me, they had started doing the magnet underneath the tray, a thick plastic tray, right? So they're relying on a weak object to kind of pull the magnet up. It'd have to be very ferromagnetic for that to happen. Normally in interventions, when we screen a tray, what we do is we take a chuck, right, so that we can maintain sterility, and we put it over everything, and we go over and look for anything that pulls up. If anything pulls up that we don't expect to pull up, that's a problem. Some things do pull up, and we know what they are, and we're using the procedure, that's okay, but anything unexpected, you gotta watch out for. So that is basically what killed us on this one, and we were also kind of disappointed the ferromagnetic detector didn't pick it up, but these were very small, and when you walk right through the center. So thinking about using a hand wand or using the device to screening by bringing the table closer to it was discussed as well. Mitigating issues, this was only the second patient on this protocol, and it had been a few months since the last patient because of a delay, and so the team could have used the refresh with the devices and things being used. The normal radiation oncology team was completely aware that the obturator was ferromagnetic. The problem is the MR technologist was not, and in this case, they didn't remove it. The reason why the MR technologist has never seen it before is when we've done this in the clinic, and they just come down for a MRI, the obturators are always removed, and when we did the first case, the obturator was removed because it's supposed to be. It's not safe, and so that caused some confusion, and they didn't see it. There's the procedure delay, confusion, and titanium needle packaging was not clear that the obturator was unsafe. So what'd we do to help improve our procedure? Change the screening procedure, and added basically that the dosimetrist is gonna break things down. They already know what's supposed to be taken out. Ferromagnetic things get packaged one way. Conditional things get packaged another way like the titanium needles. They get checked, and then they go to get sterile processing, and then they get tagged and checked again. When they come down to MRI, it's much less likely something's going to creep in. And then the MRI technologist is going to screen independently as always, but they're gonna screen it properly. They also added this procedure to a timeout so that we know that we actually did this properly and check it off the list. You also wanna basically have someone now that conducts equipment counts on the table. Remember, all this stuff is on the table. We're gonna move the patient between the procedures. What we didn't have was actually someone specifically doing the counting. They were just checking in their minds. So now we actually have a spotter, and that spotter's making sure that the checklist is being filled out at each arena as we move between the arenas. The procedure checklist was updated. Everyone was educated on it. The vendor was contacted regarding the needle MR safety just to complete the loop. Doubt they're gonna change the packaging, but they do know now. And there's an MRI safety sticker program so that basically if you're screened and ready to go in MRI, you got a sticker. Everybody can look at you and know you're there. We don't have to go to a database and manually check you up, which is a real problem when you're getting a lot of people in the room. Not normally a problem in a diagnostic room. So summary, interventional interoperative procedures can be complex in terms of MR safety. So you really need to have different layers of procedures. The redundancy is important. The Swiss cheese way of making sure that you do not have a pathway to an accident. Multiple teams to manage who do not normally work in MRI and may not be completely familiar. In this case, they didn't know about the obturator. Some equipments needed for the procedure may not be designed for use in the MRI environment. You have to accommodate for that. There can be multiple procedure arenas and patient transfers. Each one's an opportunity for an error and you have to make sure you're managing those properly. MR safety can be managed by having very rigid procedure guides that everyone's educated on. Your equipment lists, checklists for managing where everything is and when. The equipment handling should have a rigorous SOP behind it as far as management and screening. Personnel need to be trained in both MR safety and like I said, the procedure. They need to be trained on the procedure. Tracking and review of the MR and safety events and making sure you understand where the holes are and refining your procedures is a total part of quality improvement. Safety, whether it's safety or image quality, it's always the same story. Report the event, find out what went wrong and fix it. That's pretty much all I had to say.
Video Summary
The session discussed various aspects of MRI safety, particularly in relation to implanted devices and the procedural challenges in MR environments. It emphasized the importance of non-reimbursed MRI safety work, motivated by patient care rather than financial gain, engaging physicians, technologists, and physicists. One notable topic was about unusual device behavior at different magnetic strengths, exemplified by a situation where a 3 Tesla MRI was more compatible with a specific device than the expected 1.5 Tesla. The panel highlighted the critical role of screening, communication, and coordination in developing effective MRI safety protocols. These protocols involve engaging MR Safety Officers (MRSOs), managing communication between diverse stakeholders, and ensuring robust screening for implants.<br /><br />Speakers provided case studies illustrating challenges and solutions in MRI safety, including interpreting device manuals and crafting strategies to reduce specific absorption rates (SAR) to safe levels. They also discussed complex cases emphasizing multi-step processes for managing off-label scans and potential hazardous events, like projectile incidents in the MRI suite. Lessons learned from these incidents underscored the importance of rigorous procedure guides, comprehensive safety checks, and continual training and refinement of safety protocols to prevent recurrence. The session concluded on the importance of teamwork and systematic improvements to enhance MRI safety.
Keywords
MRI safety
implanted devices
3 Tesla
screening protocols
MR Safety Officers
specific absorption rate
projectile incidents
safety training
teamwork
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