Computed Tomography Cerebral Perfusion Analysis (CTP) Open Public Meeting - July 16, 2020

Last Updated Aug 11 , 2020

Computed Tomography Cerebral Perfusion Analysis (CTP) Open Public Meeting Transcript - July 16, 2020

Jocelyn Fernandez:
Good afternoon, and welcome, members of the public to the Open Meeting for the proposed LCD Computed Tomography Cerebral Perfusion Analysis, LCD number DL 38709, for Jurisdiction E, and DL 38700 for Jurisdiction F.

The meeting will be recorded. The audio recording and written transcript will be posted on our website following today's meeting.

All lines are currently being muted by our system and will remain muted throughout the meeting. Only registered commenters will be allowed to comment during today's meeting. For the commenters: Each of you are being allotted 10 minutes to make comments. Your line will be opened when it is your turn to speak. Make sure you are not on mute within your system, or we will not be able to hear your comments. You should be prepared to begin presenting immediately when called upon and will hear the moderator’s voice when one minute remains. By signing in today, you are giving consent to the use of your recorded voice and your comments. Please be mindful of sharing any personal health information in your verbal comments. We ask that any comments made today also be submitted in writing. While only registered speakers will be commenting today, anyone in attendance may submit written comments. I will now turn this meeting over to Dr. Janet Lawrence.

Dr. Janet Lawrence:
Good afternoon, everyone. And, again, welcome to our Open Meeting for CT Cerebral Perfusion Analysis, also known as CTP. We appreciate your participation in our efforts.

This LCD is a collaborative MAC effort to better define the coverage of this technology that is used to define patient most likely to benefit from endovascular mechanical thrombectomy outside of the usual intervention window, which is about six hours post onset of neurological symptoms.

And this allows for a better selection of the patient who might be expected to benefit from having an intervention and gives them a treatment option up to 24 hours after the event. So, with that brief introduction, I'll turn things back over to Jocelyn.

Jocelyn Fernandez:
Thank you, Dr. Lawrence.

Our first commenter is Dr. Greg Albers. Dr Albers, your line is open.

Dr. Albers:
Thank you very much. I really appreciate the invitation to participate today. I'm the director of the Stroke Center at Stanford University and I was also the principal investigator of the Defuse trials, which were NIH studies that looked at imaging for selecting patients for reperfusion therapies. In particular, Defuse 3 of the most recent Defuse trial was one of the two pivotal trials that led to the clearance of thrombectomy out into the late window, extending out to 24 hours, as you mentioned. Was also involved in some of the early window trials, which used CT perfusion to select patients for thrombectomy within the first six hours of symptom onset. These includes includes Swift Prime and Extend-IA and although the early window is not the focus of today's meeting, I wanted to make it clear that CT perfusion was also incredibly pivotal, and leading to the approvals of the thrombectomy for the six hour treatment window. In particular, of the five landmark trials that looked at six hour thrombectomy in 2015, the two that had the largest treatment effects and the largest rate of good outcome, were those that selected patients with CT perfusion. So, CT perfusion gives you the opportunity to identify which patients have salvageable tissue, and which patients don’t.

In the six hour window, the majority of patients have salvageable tissue, so the recommendations and guidelines don't require CT perfusion, but it can also be quite useful in that time window, because, not only does it tell you who has salvageable tissue, but it clarifies who's having a stroke, and who is not having a stroke. Because sometimes, that can be a confusing issue. So, getting that information upfront can be extremely useful.

The other thing to comment about in ordering CT perfusion is that it most advanced stroke centers these days, the way to treat patients most efficiently is to take the patient immediately from the ambulance into the scanner. At that time, when the patient is first getting into the scanner, in general, there is limited information about the exact time of onset, so we don't always know if we're within six hours, or beyond six hours. So, many stroke centers order what's called the Stroke CT Protocol, which gives you the basic non contrast CT, CT perfusion and a CT angiogram. That information can be gathered very quickly if it's done altogether.

A very inefficient way to do this evaluation, is to do one test at a time. Some primary hospitals will do this, primary stroke centers, or community center, as well. They'll do a CT scan, then they'll get the patient off the scanner. They'll think about what's going on. They'll decide if they need a CTA, then they'll move the patient back. They'll get the CTA, they'll get them off the scanner, and then they'll move them back again for the CT perfusion. This can take the imaging to 45 minutes or more, which is completely unacceptable, because, obviously, everybody knows that the sooner you can treat the patient the better.

What many comprehensive stroke centers do is they do it all together. So, 10 minutes worth of imaging, you get all the information. You can make the diagnosis of stroke definitively and you can make the best treatment decisions, whether you're in the early window or the later window.

So, let me now focus on the later time window. So, the two trials that led to the extension of the window out to 24 hours with the Defuse-3 trial from the NIH.

That was coordinated out of Stanford by our group and then the Dawn trial, which was a 24 hour window trial, that was coordinated by a group that makes one of these set retrievers called Stryker. Both of these trials relied very heavily on CT perfusion. In fact, 80% of the patients in each of the trials were enrolled by CT perfusion. The other 20% came in with MRI, typically with perfusion imaging, along with the MRI. So, by using these techniques, you could identify patients with a salvageable brain, and this led to huge treatment effects. In fact, paradoxically, the treatment effects in these late window trials that relied on perfusion imaging were larger than the treatment effects and the early window trials. And the reason for that is what I alluded to earlier, that in the early window about 20% of the patients will come in with a completed infarct. And if you don't do the CT perfusion, you don't know which the 20% are those patients do not benefit from from back to me. But in the late window, we excluded the patients who had completed infarct. And by the time you get to the late window, it's about 50% we have completed infarct. So, by focusing on the 50% of patients with salvageable tissue, we're able to achieve huge treatment effects with the number needed to treat of only two patients to reduce disability and this time window. So, this is an incredible opportunity to reduce disability and death by selecting patients with CT perfusion and treating them in the late time window.

But again, the issue of greatest concern for me today is the very important issue of being able to obtain all the imaging at once.

Whenever these patients come in, again, we don't always know the exact time, often, they're found down, sometimes their wake-up strokes, you don't know the time, and to do the images, one after another is highly inefficient. So, any requirement that would require earlier imaging for CT perfusion would would be a great disadvantage to patients. Again, just to summarize and conclude, that the standard approach that we and many, many other comprehensive centers, as well as primary centers use is if it appears from the paramedics that this is a patient with a large stroke, somebody who can't speak, they're paralyzed on one side. They're gonna go straight to the scanner. And by doing all the images together, we have the most comprehensive analysis of the patient. We can decide what the diagnosis is. And then make an appropriate treatment decision regarding thrombolysis or thrombectomy.

So, my my strong request is to, to please strongly consider the approval of CT perfusion without a requirement to do initial images first, that would substantially delay the definitive diagnosis. Thank you again for allowing me to participate in this call.

Jocelyn Fernandez:
Thank you, Dr. Albers, for your comments.

Our second commenter is Dr. Srinivas Peddi.

Dr. Peddi:
Can you hear me?

Jocelyn Fernandez:
Yes, I can.

Dr. Peddi:
First, thank you to Noridian for their work on CT Perfusion Reimbursement. I'm a private practice neuro radiologist in LA. I work at two hospitals. one is a Thrombectomy Stroke Center and the other is a Primary Stroke Center. CTP has been an important tool in our practice for many years. Our CTP usage is different from the proposed LCD. In many of the ways that Dr. Albers mentioned, first time is critical. Patients come into our hospitals with suspected strokes after being evaluated by EMS.

An ER document quickly examined the patient before they get stroke protocol imaging, which includes CTP. The stroke neurologist often is evaluating the patient in the CT scanner and sometimes even afterwards.

We have one CTP capable CT scanner at each hospital, which, I think, is a common situation. And patients are often pulled off of our CT scanners when a code stroke patient comes in. It would use up a lot of critical time to do a CTA course, wait for the interpretation, and then bring the patient back for CTP.

I've spoken with several practices, both large and small, and all are doing CTP at the time of presentation.

So, therefore, my first request is that you consider modifying the LCD so that CTP can be done at the presentation in the 6 to 24 hour window.

My second request is on using CTP in the first six hours. Many of the trials treated patients with M2 occlusions. These patients can have large profusion defects. M2 occlusions are more easily seen with CTP with CPA. One statement in the LCD note that CTP had similar accuracy to CTA.

I'm not sure that that's correct. It was based on a meta-analysis done outside the US, published in a lesser known journal, reference 18, where more than half of the included trials are performed before 2010. In the trials since 2010, CTP was much more accurate. The newer trials also included the largest dataset in the meta-analysis, which was from Bruce Campbell's Group or world renowned and let the Extend-IA and Extend-TPA trials and found a large difference in sensitivity of CTP over CTA.

Their trial was also the newest study in the meta-analysis.

For that reason, I would put more weight on their conclusion that CTP has much better sensitivity than CTA, then on a meta-analysis, which included some very old airdrop.

So, my second request is that CTP be covered at presentation in the first six hours, in addition to the 6 to 24-hour window. A) because it's hard to get the age of a stroke correctly, especially in the early part of the assessment, as previously mentioned, when, usually, imaging is being done and B) it helps pickup strokes, which would otherwise, would have been missed by CTA alone. Thank you very much for your time.

Jocelyn Fernandez:
Thank you, Dr. Peddi for your comment.

Our third commentor is Dr. Mark Alson. Dr. Alson, your line is open.

Dr. Alson:
Thank you. Can you hear me OK?

Jocelyn Fernandez:
Yes, I can.

Dr. Alson:
Fantastic. So, thank you for having me. And thank you to Noridian and all the workgroup other MACs that are working on this. Again, my name is Mark Alson. I'm the CAC rep from California, and I have another hat, which I'm going to talk to more today, and that is besides being a physician, I'm also a Radiology Certified Coder. I have the initials RCC after my name. And the reason that's important what I'd like to talk about is not just the LCD, but the coverage article that goes with it. And at least in JE that's coverage article, DA 58225. The reason I'm talking about this is that every LCD as you know has a coverage article that says, what ICD-10 codes are covered. And that's very, very important here in stroke imaging.

If you look at the codes that are listed in that companion article, those are all codes for basically positive infarct due to a thrombis or occlusion either in one of the carotid arteries or in the middle cerebral artery.

The problem with that code list, that ICD 10 kit list, all the codes that are there now are entirely reasonable and should be there. But the problem is, as mentioned by our first speaker, Dr. Albers, you often don't know exactly what's going on other than the fact that the patients having an acute stroke based on the fact that the EMTs have said, this patient has got acute stroke symptoms, we’re taking the patient right to the scanner. This is something they call a code stroke. It's got different names in different institutions. But basically, the patient is having signs and symptoms of stroke.

Those can be things like facial weakness or aphasia or slurred speech, or altered mental status or diplopia, or hemiplegia, any of those stroke symptoms, those codes all need to be in the companion article. Excuse me, because it doesn't do any good to have just the infarction codes, if, let's say this turns out to be a TIA and not an infarct. Let's say the person is having a stroke symptoms and it turns out it's not a stroke. Well right now, there's no way for coders to code for that. Coders have to code for the symptoms of the patient in the absence of a finding or, let's say, the coder or the study, the CTP finds an infarct in the anterior cerebral circulation. Well, that's not on this list. So, if we find an answer infarct in the ACA distribution or the Vertebrobasilar distribution, those aren't covered as it stands now. And so my plea is that we have a much more robust list of ICD 10 codes in the companion article. And yes, we will be submitting a proposed list in writing of additional ICD 10 codes that we feel are reasonable and necessary for this. That is all I have. I'll leave my extra time to the future presenters. Thank you very much.

Jocelyn Fernandez:
Thank you, Dr. Alson for your comments.

Our fourth commenter is Dr. Max Wintermark.

Dr. Wintermark your line is open.

Dr. Wintermark:
Thank you. Can you hear me?

Jocelyn Fernandez:
I can hear you.

Dr. Wintermark:
So, thank you very much for allowing me, allowing me to comment on the Noridian LCD. I'm the Professor and Chief of Neuro Radiology at Stanford. I'm also the President of the American Society of Functional Neuroradiology and I'm the chair of the NIH Stroke Net Imaging working group. But a lot of my comments are going to be similar to those that my colleagues made earlier. I copied on this first slide, the current proposal for the, LCD, and I highlighted in yellow a couple of the elements that I would like to to discuss. Next slide, please.

So the the three issues I have with the LCDs as currently formulated are again listed here, and there's a small aspect of the acute ischemic stroke, and there is the causation by an occlusion in the proximal anterior circulation, and finally there is the time window, next slide.

So I'm going to start with the small aspect, next slide.

And I just wanted to remind that in those clinical trials that were discussed earlier, including Defuse-3 and Dr. Albers, being the PI of that trial and Dawn, the infarcts that [inaudible] strokes that were treated were not necessarily small. Basically, as you can see, the core could be up to 70 CC, which is not small, which is actually, it could be bigger, but it's, it's definitely not small like a [inaudible] infarct which is typically a couple of millimeter large and also, you must not forget that [inaudible], so that a viable tissue that is suffering the penumbra, that the CTP's identifying. And I took here, an example, and, as you can see, sometimes the whole area that is ischemic can be, can be very large, can represent a third, or even more of the brain. And so next slide, please. My first recommendation would be, and the same applies by the way, to Dawn the other pivotal trial. Next slide, please.

And so, my first recommendation would be to remove that small, because, again, you know, the patients who are typically treated paired, the recommendation of Defuse-3 and Dawn are not necessarily small, acute ischemic stroke. So that's my first recommendation. Next slide, please.

Then I want to comment on a point that has already been made by a couple of the previous speakers and it's about the proximal anterior circulation. And next slide, please.

And what I wanted to remind here is that in both Defuse 3 and Dawn, the patient got their CTP first that then allowed to figure out what where the infarct was located, but that's not something that is easy to do, prior to the imaging being done because there are a lot of confusing factor. And so, to perform the CTP only in those patients who would have an Anterior infarct is almost impossible because it's not until you have done it that, you know, where the infarct is located. And the next two slides, basically, again, remind you what I just mentioned, is that in the design of Defuse 3 and Dawn. Next slide, please. Again, the imaging was obtained first. And then after that, they were able to determine where the infarct was located. So that's what Dawn did. Next slide.

So again, as you can see here, you know, I cannot point, but in the middle column, you see that the imaging was done which allowed to determine where the infarct was located and then only the patients were randomized, but it's not a goal that they could make prior to performing the CTP and next slide.

And the same applies basically to Defuse. You can also see that the imaging was obtained first prior to randomization, because, again, we felt the imgaing is hard to determine where the stroke is located. Next slide.

And again, the same thing. Next slide.

And here, I thought, I would also report that interesting article that shows that again, you know, it's very difficult just based on those clinical symptoms to determine, you know, if it's a stroke or not. Because there are many mimicking condition. And it's particularly difficult to determine where the infarct is located just based on the clinical symptoms. And if you read the conclusion of that article, that's exactly what it says that basically if you just rely on the clinical symptoms to differentiate the posterior versus an anterior circulation infarct. You would be wrong in a very large number of, for a very large number of patient, it's really the neuroimaging, including the CTP that allows you to make that distinction. So, next slide. So, that leads to my second recommendation, which is that instead of indicating that CTP's only indicated in patients with proximal anterior circulation occlusion that it would be recommended in any patients suspected of acute ischemic stroke.

Because, again, the CTP's going to help figure out, where the infarct is located and to confirm that you are dealing with a stroke.

Next slide.

And the last element is this time window aspect that was already mentioned by the number of the previous speakers. Next slide.

In the Swift Prime trial and the Extend-IA trials, again, CTP was used to treat patients within the first six hours with success. So that's the the reference for Swift Prime. And the next slide will be the reference for Extend-IA. So, again, CTP has been shown to be also helpful within the first six hours. And next slide.

And, again, as I mentioned by many of my colleagues who have spoken before, in terms of, you know, determining the appropriate patient management, you need the imaging, and it's most efficient to perform it all at once. Next slide.

One thing I wanted to remind you that time is brain. An old any delay, any delaying, incorporated, by waiting to do some imaging by doing just the non con and then thinking about it. And then, getting the CT perfusion done, results really in, in brain, being destroyed at the fast pace, And doctor Saver from UCLA made those calculations showing how much brain you lose in one minutes. And as you can see, those numbers are quite staggering. Next slide. I'd say it's very well known that the outcome of the patient decreases as time goes by, and so any effort, despite the time window, I've been extended, any effort needs to be made to treat them as quickly as possible.

Next slide. And so, as Bruce Campbell, kind of nicely summarized it, in terms of stroke imaging, it's important to do it right, the first time. And so, next slide, My practical recommendation would be not to limit the CT perfusion to 6 to 24 hours, but to have it recommended within the 0 to 24-hour time window. Next slide.

So, in summary, my recommendations would be, again, to recommend CTP for any patient suspected of any acute ischemic stroke within the 0 to 24 hour time window on my final slide. I tried to cut that back, you know, in the LCD for suggested coverage. So again, I think that was my last slide, is that correct?

Yes. So, thank you so much, again for allowing me to comment, and I'm very grateful to Noridian to consider CTP. I think that, as mentioned, by all, the other speakers, really told us to improve the outcome of those patients with stroke and so, it's, We're really moving in the right direction. Thank you.

Jocelyn Fernandez:
Thank you, Dr. Wintermark for your comment.

Our last commenter is Dr. Sammy Chu. Dr. Chu your line is open.

Dr. Sammy Chu:
Good afternoon everyone.

Thank you. Thank you. I'm glad you can hear me OK. I wanted to thank Noridian and the other Medicare contractors for considering coverage for CT cerebral perfusion.

I think it's a very important tool right now, with regards to the management and treatment of patients that present with acute stroke in the, in the time window, the first 24 hours. I really don't have very much to add to my previous speakers, but I think works, what I'll try to do is summarize what everyone has talked about and and and make recommendations really re-iterate what Dr. Wintermark says with regards to how we can improve the LCD. So, I want to thank Noridian very much for the opportunity to provide comments for their proposed LCD.

I think the overarching principle that we need to consider for this is that time is brain and in those in the first few hours and first day of someone who presents with acute infarct, those neurons or loss at a very fast rate and it's been shown time and time again that the success of.

The magic for acute stroke, it hinges on the fact that we try to do this as soon as possible.

So in tying in with Dr. Alson’s request, I think the important thing is we need to expand out the ICD 10 lists as much as we can to cover more symptoms and signs of the acute infarct.

Reason for that is is if a person presents in that early time window with any of any of the symptoms and signs of an infarct, they really need to get the imaging done. Whether it be CT, CTA, a CTP as soon as possible, right off the bat, so that all the information is laid out there for the clinicians, and to be able to make a decision as to whether thrombectomy makes, or would be helpful for the patient or not.

So that's my first request. Second of all, I think because of what we've seen so far with regards to imaging, sorry, just hold on a sec. The other thing is, as Dr. Wintermark had explained with one of his slides, the presentation of a stroke is sometimes very difficult to realize whether they've had an infarct or not. A lot of the time delay with regards to getting thrombectomy done has to do with actually transport in a hospital.

So you can't have a patient coming back and forth to get say, for example, if they've had a CT and CTA component done, suddenly, they realize, Oh, wait a minute, they do have an occlusion in their M1 segment, then they have the patient come back for a CT perfusion study. So, it's much more beneficial for the patient, if we get all three imaging exams done right at the top, right at the very beginning.

Third point I want to mention is that, with regards to the ICD 10 lists, the only arteries are recovered were the M1 segment, or the first segment of the middle cerebral artery. And, of course, the internal carotid artery.

And there may not be, I think, there aren't any robust studies with regards to the other vessels. But I think because of the fact that we don't know right off the bat which arteries are involved, really need to try to get coverage with regards to occlusions, in terms of the anterior cerebral artery and also the posterior circulation, which involves the vertebral arteries and the basilar artery.

So I think it's important that we expand out the ICD 10 lists, and make sure that we get symptoms and signs covered, because oftentimes when people present right off the bat at the hospital, it's important that we get all the imaging studies done, and make sure all of those are covered. And I think that's very important.

All right, so as I, as I mentioned, that's pretty much all I need is, I have to say. But the important thing is, that, we want to try and make sure that we include more symptoms and signs, so that, when patients present, we know, we can make sure that the CT perfusion study is covered. So, I think we're making sure that the time window goes from 0 to 24 hours, as opposed to just limiting it to 6-24 hours is important. And, oftentimes, the time window may change too when a patient presents. Because you may think, Oh, they woke up with a stroke, last well known as, for example, at 12 hours, which is when they first went to sleep. But then, suddenly, you get more information later on from collaborating with a family member that says, Oh, they actually, no they actually were fine when they woke up and then it actually changed at the 5 or 6 hour mark.

So, I think it's important that we make sure we treat as many patients that need this treatment done on E thrombectomy. And most important thing is to try to expand out the criteria as opposed to just limiting it to 6-24 hour mark.

All right. That's all I need to have to say. Thank you very much for the opportunity to comment on your proposed LCD.

Dr. Lawrence:
Thank you, Dr. Chu and thank you all of our presenters, Dr. Albers, Dr. Peddi, Dr. Alson and Dr. Wintermark. We truly appreciate the well thought out well researched comments that you have made. And we will definitely give them consideration as we go forward to complete the LCD.

Again, I would like to remind all of you to submit your comments in writing, so that we can make sure that we give them, we get them exactly right, as you intended them. And, I'd also like to remind others on the call that the comment period for others to submit written comments go through August eighth.

And, with that, I will turn things back over to Jocelyn.

Jocelyn Fernandez:
Thank you, Dr. Lawrence. This concludes the presentation for today's meeting.

In closing, we would like to communicate the next steps in the policy development process.

The comment period for the proposed LCD will remain open until August eighth, 2020. As noted earlier, all comments to be considered by our medical Director for their proposed LCD must be submitted in writing. Written comments can be e-mailed to or mailed to the address on your screen.

Comment information for our proposed LCDs are located on our website at Upon review of the comments, are medical directors will either finalize or retire, the proposed LCD. Please monitor our website, or register for our Listserv notifications to be informed of actions that are taken on our proposed LCDs.

Dr. Lawrence, do you have any final comments?

Dr. Janet Lawrence:
No. I do not. Just again, thanks and as always, we appreciate your input into our LCD process because it is our desire to get these LCDs as right as possible, so that proper technology or procedures are being covered, and that we cover them for the appropriate indication. So thanks again.

Jocelyn Fernandez:
Thank you everyone. This concludes our meeting for today and have a wonderful day.


Last Updated Aug 11 , 2020