Liver Transplant Imaging, Dr. Mahan Mathur (9-29-22)
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Today we're honored to welcome Dr. Mahan Mathur
0:46
for a lecture on liver transplant imaging.
0:49
Dr. Mathur is an Associate Professor at the
0:51
Division of Body Imaging and is the Vice Chair
0:53
of Education in the Department of Radiology and
0:55
Biomedical Imaging at Yale School of Medicine.
0:58
He has also been awarded four times
1:00
the Yale Radiology Teacher of the Year.
1:03
At the end of the lecture, join Dr. Mathur
1:05
in a Q&A session where he will address
1:06
any questions you may have on today's topic.
1:09
Please remember to use the Q&A feature
1:11
to submit your questions so we can get to
1:12
as many as we can before our time is up.
1:14
With that being said, we are
1:16
ready to begin today's lecture.
1:17
Dr. Mathur, please take it from here.
1:20
You know, it's truly, um, an honor to be back here.
1:20
38 00:01:23,235 --> 00:01:26,535 Uh, I remember when, um, we first, you first
1:26
started doing these, uh, noon lectures.
1:28
I, I was, uh, perhaps amongst the first to give it,
1:31
and it's, it's been, um, it's been a pandemic since.
1:34
And, uh, it's really a delight to be here.
1:36
And as I'm going through the participant list, um,
1:38
as everyone's logged on, I see some familiar names.
1:41
And so, uh, to all of you, welcome, and
1:43
to those of you who I have a personal
1:45
connection with, uh, thank you for being here.
1:47
Uh, today I wanted to talk about, uh, a
1:50
topic which, uh, uh, is really dear to
1:52
my heart — imaging of liver transplants.
1:54
And, you know, one of the reasons that I,
1:57
I, I like this topic, um, is, is really
2:00
because when I was a trainee at Yale, I was...
2:03
I, I don't know about the rest of you, but I
2:05
was so scared of anything transplant-related.
2:07
You know, transplants was not something I, I
2:10
suppose I learned a lot about in medical school.
2:12
Um, I didn't, uh, uh, really know a lot of, um... I
2:18
didn't see a lot of transplants in my clerkships.
2:20
Uh, you know, it just wasn't a big thing for me.
2:21
So here I am as a resident now, um, particularly
2:25
on night float rotations where you're, you know,
2:27
don't have a lot of support and you're faced with a
2:29
fresh transplant out of the operating room, and you
2:32
have to look at it and you have to evaluate it, and
2:35
you have to make sure that everything looks okay.
2:38
Um, and obviously there's a, there's a whole team
2:40
that's taking care of these patients, but, you
2:42
know, so many of them rely on your interpretation.
2:44
And so you have some backup with attendings.
2:47
Um, attendings have all sorts of expertise, but, um...
2:51
Some may be comfortable in transplant, some may not.
2:53
And so I really took it upon myself.
2:55
You know, for a long time I thought I
2:56
would stay away from transplant imaging,
2:58
but you can't stay away for that long.
3:00
And so I had an opportunity to, to really dive
3:02
deep into it and, and learn a little bit about it,
3:04
and, um, came up with a lecture as a result of it.
3:06
So I'm really proud that I feel better
3:08
about transplant imaging and I'm, I'm
3:09
happy that you can all join me today.
3:12
And so I have two objectives for, uh, this session.
3:14
It's quite simple, you know, and, and I think that's
3:16
one of the things once I started learning about the
3:18
transplant imaging is just to keep things simple.
3:20
Um, and you know, the first, uh, I don't know
3:23
if it's gonna be a 50/50 split, but the first
3:25
portion of this talk will talk about the normal
3:28
living imaging appearance of transplants.
3:29
We're gonna focus a lot on ultrasound today.
3:31
There will be some CTs, I think
3:33
a few MRs here and there.
3:34
But a lot of this will focus on ultrasound,
3:36
'cause it's really the mainstay of how we, um,
3:38
uh, you know, evaluate liver transplants.
3:41
And then once we've done that, uh, we'll go through
3:43
the imaging appearance of common complications.
3:46
I'm sure you know, we have an
3:46
audience now of about 80-odd people.
3:49
Uh, and it's an international audience.
3:52
You've seen it all, right?
3:53
Our collective, um, experience has seen it all.
3:56
And, um, you may have some, uh, fantastic rare
3:58
examples of things and, and I'd love to, uh, have
4:01
you share your experience, uh, with everyone.
4:03
But I'll be going through some common
4:04
complications so that we can all get those, right?
4:07
Um, and those are the things that you're
4:08
probably gonna see more often than not.
4:12
I have a few unknown cases, uh, to start
4:14
with just to kind of whet your appetite for
4:15
some of the stuff that we're gonna cover.
4:18
And, uh, here's case number one.
4:19
You can use the, uh, chat feature if there
4:22
is, or you can just put something in the Q&A.
4:24
It's fine, um, to just see what you think.
4:26
And so here, you know, this is a post-transplant
4:27
patient and, um, you know, have some arrow pointed
4:31
to, uh, something here on this coronal MRCP image.
4:34
So what do you think is going on in
4:35
this post-liver transplant patient?
4:37
Um, there is also these T1-weighted
4:40
images, axial and a coronal reconstruction's
4:43
a little bit, uh, choppy over here.
4:45
Um, but there's a T1 hyperintense,
4:47
kind of a linear focus over here as well.
4:50
And what do you think that is, particularly
4:51
in the context of what we're, what I'm
4:53
trying to show you on the, um, MRCP images.
4:58
So that'll be, uh, the first case.
4:59
We'll revisit these at the end and, and throughout
5:01
the talk as well, so we can think about that.
5:07
And so we have one participant, so maybe
5:09
you're right, we'll get back to that.
5:12
This is another case, uh, multimodality,
5:15
um, a true liver transplant ultrasound.
5:17
I forget how far out the patient was
5:19
from their transplant, but it was a
5:20
couple of weeks, couple of months.
5:21
So, uh, you know, um, not a fresh
5:24
post-op transplant with Porta hepatis.
5:27
Um, something going on there.
5:29
Maybe the CT helps you a little bit more
5:32
in terms of defining where it is and
5:35
then a, a single shot from a PET/CT.
5:38
Maybe that gives you the clue. What do you think
5:39
is going on in this patient who's post-transplant?
5:45
We'll revisit that in a few slides.
5:48
Here, I got some, uh, nice Doppler images for you.
5:50
This is a, a patient who is, um, uh, out of the
5:53
operating room who's, uh, being evaluated, uh,
5:56
to make sure everything is working properly.
5:58
Post-transplant, we're sort of going in the hepatic
6:01
artery area and we see some flow in a structure here.
6:06
We're trying to find the hepatic artery.
6:07
Do we see hepatic artery flow?
6:08
Do we not?
6:09
We're looking at another area
6:10
of the right hepatic artery.
6:11
Do we see hepatic artery flow?
6:12
Do we not?
6:14
What do we think is going on?
6:15
What, uh, potential complication are
6:17
we worried about in this instance?
6:24
And finally, uh, I think this may be the
6:25
final case before we get into the talk.
6:28
Uh, lots of images here, so we'll give
6:30
you some time to just look at it and,
6:32
and take it in — a color Doppler image
6:34
of the, um, left hepatic lobe, kind of a nice, uh,
6:38
fun structure perhaps we're seeing there. And then we
6:40
interrogate certain regions of that structure, that
6:43
rounded portion. What is that sort of showing you?
6:48
We're interrogating another portion
6:50
that's, uh, associated with that structure.
6:52
What is that showing you?
6:54
And then a third structure associated
6:56
with that, uh, rounded structure.
6:57
What is that showing you?
6:58
Can you put it together?
6:59
Can you come up with a diagnosis?
7:01
If you can, you're well ahead of the
7:04
game. And if, uh, you can't or you're
7:08
struggling, well, we're gonna learn together.
7:11
Okay.
7:12
And, you know, a lot of the times, uh, maybe
7:15
it's just me, I don't know, but I, I like
7:17
to sort of frame, um, learning, I suppose,
7:19
around, uh, a little bit of background.
7:21
I sort of, perhaps gives me, um, has
7:23
happened prior to this moment where
7:25
I'm sort of approaching this concept.
7:26
And, um, one of the things I'd like to, um, pose
7:29
to the group — my internet connection said it was
7:32
unstable, but I'm hoping you can hear me now — but
7:34
one of the reasons that one of the questions I'd
7:35
like to pose to the group: is anybody in the group,
7:37
and you can use their chat box, uh, know when the
7:39
first liver transplant was done, around what time?
7:44
Are we dealing with something
7:45
that's been around forever?
7:46
Are we dealing with a sort of a recent
7:49
science, you know, within medicine?
7:50
Are we dealing with something
7:51
that's sort of in between?
7:52
Anybody have any ideas?
7:52
I had no clue.
7:53
I mean, I had to research all this
7:54
stuff, so anyone have any idea?
7:56
Um, carry the guess in the chat box.
8:00
I... yeah, I like it.
8:02
I like two for the 1960s.
8:04
Perfect.
8:04
You guys are spot on.
8:06
So you know your history.
8:07
And so it was actually 1963 and it was done
8:09
at University of Colorado by, um, uh, a
8:12
celebrated physician now, Dr. Thomas Starzl.
8:14
And, um, he had done a bunch of
8:16
liver transplants around that time.
8:18
I believe it was about four or five.
8:20
Uh, these were the first patients
8:22
who got these liver transplants.
8:23
Now, unfortunately, um, uh, as you may
8:26
be able to, as you can maybe imagine,
8:28
those patients didn't do very well.
8:31
They didn't last very long.
8:32
And it wasn't, you know, the autopsies, you know,
8:34
rejection or any of that sort of stuff that we look
8:37
at now that, um, was causing those livers to fail.
8:41
It was stuff like infections, pulmonary
8:44
emboli — it was those sorts of things.
8:45
The stuff that we now know, um, how to, um, you
8:50
know, minimize complications related to those things.
8:52
Those are the sorts of things that, uh, were
8:55
resulting in these transplants being, um...
8:58
Relatively unsuccessful. Now, uh, there were
9:01
a few other transplants done, uh, elsewhere,
9:04
um, in, uh, in a few places in between.
9:07
But, uh, they were also not very successful.
9:09
And they put a moratorium — sort of
9:10
a stop — on all transplants.
9:12
So about 1967, and that's when, um, if you
9:15
look at, um, some of the history behind this
9:18
stuff, uh, that was when the first so-called
9:20
successful liver transplant was performed.
9:22
And we defined success in this context
9:24
as survival for greater than one year.
9:27
And as it would be, uh, it happened to be in
9:30
a little small girl, Julie Rodriguez, who had a
9:32
primary liver cancer, um, isolated to the liver.
9:36
No other surgical options.
9:38
They did a transplant. She did pretty well.
9:40
She, she lived for, um, over a year, uh, until
9:43
the disease spread to, um, other organs and,
9:47
um, um, and, and then wasn't able to make it.
9:50
But that was a huge stepping point into, uh, what,
9:53
uh, could be done, um, in terms of liver transplants.
9:57
Now here are some indications for liver transplants.
9:59
You know, there's a whole laundry
10:01
list of them if you look at it.
10:02
Big picture stuff — acute liver failure,
10:04
also chronic liver failure. But not just,
10:07
you know, that itself is not enough.
10:08
Chronic liver failure — it's
10:09
complications related to that.
10:11
Complications of cirrhosis, um,
10:13
that are not fixable, essentially.
10:15
So ascites.
10:16
Um, obviously HCC, and there are criteria
10:18
that we use in order to allocate who
10:20
gets a transplant, who doesn't get a
10:21
transplant — encephalopathy, etc.
10:24
Metabolic conditions, um, as well, that, uh,
10:27
are eligible for patients who can, uh, to
10:30
get liver transplants, and other, uh, systemic
10:32
complications of liver disease that's sort
10:34
of outside of just the liver, and some of the
10:36
other complications that we mentioned over here.
10:39
And with that there's obviously,
10:40
um, lots of contraindications.
10:42
And I don't always commit these to memory.
10:43
I mean, as a, as a radiologist, um, I think
10:46
our primary role, um, and if you know,
10:48
is to really look at these transplants,
10:51
image them, make sure we get that correct.
10:53
And once we've mastered that, you know, we
10:54
can add all these steps into our knowledge.
10:56
At least I can't keep everything straight.
10:58
There's so much to know.
10:59
But, you know, the basic idea here is if the
11:01
patient's very sick — uncontrolled sepsis, has
11:04
widespread, uh, metastatic disease — you know,
11:07
these patients are not gonna get transplants.
11:09
MELD scores, uh, of less than 15 —
11:11
this is what MELD stands for as well —
11:13
you know, the idea here is that, um, you know, the
11:16
relatively, um, uh, more healthy the patient is with
11:21
their, you know, with, with chronic liver disease,
11:22
the less likely they're gonna get transplant.
11:24
The ones who will get the transplants are
11:25
the ones who have liver disease and who
11:27
are also are, are not doing very well.
11:30
Um, I also find this always very interesting,
11:32
lack of adequate social support system.
11:35
And I'm not sure how it's run at, uh, your
11:37
respective centers, but at our center, when, um,
11:40
whenever we, uh, decide, uh, uh, to allocate a
11:45
living donor, so a donor who's completely healthy,
11:48
who, um, altruistically has decided to give up a
11:52
portion of the liver to a family or a friend or
11:54
a loved one, there's a whole meeting that takes
11:57
place and a radiologist attends that meeting.
11:59
We go over the anatomy of the, of the living donor.
12:02
Uh, there are hepatologists, GI docs, or psychologists.
12:05
It's a whole interdisciplinary
12:06
team that gets together.
12:07
And we talk about the adequate social support
12:10
system, both for the donor who's giving up the liver.
12:12
Uh, will they be okay postoperatively? Will they have
12:14
the support they need? And also for the recipient.
12:16
Are they ready to receive a liver?
12:18
You know, um, are they ready, uh, to, uh, to get that?
12:21
And are they sort of, um, in a, in a space
12:24
where they have the support they need in order
12:25
to take care of them, uh, with that transplant?
12:28
So I always find that always a very
12:29
fascinating part of the discussion.
12:30
Something that ordinarily, as a
12:32
radiologist, I'm not very privy to.
12:36
And so transplant started 1960s, successful in
12:40
1967. They started doing more — the one-year survival
12:43
not very great, about 25%.
12:45
We've come a long way since then.
12:46
You'll see all sorts of different numbers.
12:48
The point here is that, um, generally the
12:51
one-year, five-year, and ten-year survival
12:53
has, uh, is, is markedly improved.
12:56
And, and we would expect it to be so with different
12:58
immunosuppression regimens, with different medical
13:00
care, with our understanding of how to, um, you know,
13:03
treat these patients who have these transplants,
13:05
how to treat those transplants in general.
13:08
Um, the living donors.
13:09
So those, uh, patients who get transplants from, you
13:12
know, healthy patients who are giving up a portion
13:15
of their liver, they tend to have a better one-year,
13:18
five-year, and ten-year survival. Deceased donors —
13:20
not that far behind — but also do
13:21
great, uh, but also do pretty good.
13:23
And I just show this slide to show that we've come
13:25
a long way and, uh, we should all be proud of that.
13:27
We can always do better.
13:28
Um, but we've come a long way.
13:31
If you look at data from the last year,
13:32
this is in the U.S., uh, about 9,000 living and
13:36
deceased donor transplants were performed.
13:40
Vast majority are from the deceased donors, so
13:42
we don't have a lot from living donors, but,
13:44
um, a vast majority are from deceased donors.
13:47
Um, still a heck of a lot of
13:49
patients on the waiting list.
13:50
And so we can't really keep up with the
13:52
need for, uh, for these liver transplants.
13:55
And it just sort of hammers into me the need for,
13:59
um, us as radiologists to make sure that when
14:02
we see a transplant, uh, you know, we have to
14:05
make sure that we take care of it because there
14:08
are, so they're relatively scarce, uh, even now.
14:11
And, uh, the way we can take care of it, um,
14:13
from a diagnostic perspective is to identify
14:16
complications early, be confident or, um,
14:19
you know, know what the next step should be.
14:21
And so that's where sort of I
14:22
think our expertise can come in.
14:24
Um, and so hopefully we'll get, sort of
14:26
understand that more as we go through this talk.
14:30
So normal hepatic triad —
14:33
that was the first objective.
14:33
So let's dive into a normal — is there
14:35
three vascular anastomoses that are made?
14:39
The hepatic artery — the wrist donor to
14:41
the hepatic artery of the recipient.
14:43
Similarly, portal vein to portal vein,
14:45
and finally the hepatic vein to IVC.
14:48
Now the portal vein to portal vein is usually an
14:50
end-to-end anastomosis that's made. Hepatic artery —
14:53
there's all sorts of variability
14:55
in how that anastomosis is made.
14:56
I'm not gonna get into the details of
14:58
that, but suffice it to say that, um,
15:00
you could potentially have an end-to-end.
15:01
You could have the deceased donor’s, um, sort
15:05
of hepatic arteries taken along the celiac
15:07
artery and that celiac artery is anastomosed
15:10
to the recipient’s, uh, hepatic arteries.
15:12
So there are all sorts of sort of
15:13
configurations that can take place.
15:15
Um, oftentimes we — it's difficult to view
15:18
the anastomosis on ultrasound imaging.
15:20
Um, and so we're sort of seeing.
15:22
What's going on inside the liver and maybe
15:23
inferring what could be happening at the
15:25
anastomosis, uh, based on the waveforms.
15:27
Um, and then of course the hepatic vein and IVC.
15:30
And you know, I've had this slide ever since I've
15:32
made this talk, but I almost feel it's, uh, it's
15:34
futile because I always talk about how we used to
15:37
do IVC, uh, graft interpositions where you take
15:40
the, um, uh, donor liver with a portion of the
15:43
supra and infrahepatic IVC and you anastomose it
15:45
to the recipient's supra and infrahepatic IVC.
15:48
But as far as I can tell, um, with very
15:51
few exceptions, we don't do this anymore.
15:53
And so it's more important to sort of, um,
15:56
uh, you know, learn that this piggyback
15:59
technique is the one that's most often used.
16:00
And where you have the liver
16:02
that's taken along the donor.
16:03
IVC, the suprahepatic IVC is anastomosed to, uh, the
16:07
don—uh, the recipient hepatic venous confluence.
16:10
And the donor IVC here is sort of tied off.
16:13
And, uh, you may ask yourself, you know,
16:15
with it being tied off over here, does
16:18
it potentially fill with thrombus and, uh...
16:22
Sometimes it can. I've seen one example of that.
16:24
But oftentimes you have flow from the caudate
16:26
lobe, uh, that sort of allows flow, um,
16:29
uh, allows, uh, thrombus not to form — that
16:32
there's persistent flow in that region.
16:36
Finally, there's one nonvascular anastomosis.
16:38
So three vascular anastomoses...
16:40
I don't know if this is coming up right.
16:41
Three vascular anastomoses and
16:44
one nonvascular anastomosis.
16:44
And that's the common B duct, as you can imagine.
16:46
So usually do, um, an end-to-end anastomosis
16:49
of the donor CBD with the recipient CBD.
16:52
Now, if for whatever reason the CBD is damaged
16:55
in the recipient — maybe that patient has a
16:57
history of sclerosing cholangitis or some
16:59
other disease that affects the bile duct —
17:01
uh, in those patients they can do a choledochojejunostomy,
17:04
where they take a loop of the recipient's jejunum
17:07
and they anastomose that to the bile duct over there.
17:09
And all these patients routinely
17:11
do a chole—uh, cholecystectomy.
17:13
So when you see them in the postoperative CT, the
17:16
recipient, uh, will not have the gallbladder.
17:21
So this is one of the first cases
17:22
I wanna share with the group.
17:23
This is from an ERCP.
17:24
So I'm not starting off with
17:26
ultrasound, starting off with an ERCP.
17:28
And we've, uh, of a patient who's had a
17:29
transplant and we've cannulated the CBD.
17:32
We've injected contrast.
17:33
We see contrast in this common B duct here,
17:37
contrast in the common bile duct there.
17:38
And there I see a little bit of narrowing here.
17:40
And so what do we do?
17:41
How do we interpret that?
17:42
And so one of the reasons I wanted to show this
17:45
upfront is that in terms of that bile anastomosis
17:48
that I just spoke about, understand that
17:51
at times there may be a mismatch
17:53
at the biliary anastomosis.
17:55
And the idea here is that, you know, if you're a,
17:58
um, a recipient and you need to—if I'm a recipient
18:01
getting a liver transplant, getting it from a
18:03
donor, the donor's anatomy — the diameter of the
18:06
CBD — may be a little bit different from my diameter.
18:08
So the anastomosis — there may be some natural sort
18:10
of mismatch in that size that may manifest, um,
18:15
at least on imaging as a potential stricture.
18:18
And so often that could be normal.
18:20
Uh, there can also be lots of different
18:22
configurations of how they anastomose the
18:24
bile ducts depending on, uh, what portion
18:26
of the liver they're giving up — whether it's
18:27
the whole liver or the right hepatic lobe.
18:30
And so we often don't need to worry 'cause we
18:32
know now that that may be an expected finding.
18:35
And so the next question would
18:36
be, of course, when do you worry?
18:39
Um, and that's tough.
18:40
I mean, but I would just use common sense over there.
18:43
If over time there's worsening ductal dilatation
18:45
well, then you can be assured that there's
18:47
probably some narrowing at that anastomosis.
18:50
Uh...
18:51
If there's a word to this narrowing is, um, uh, you
18:54
know, while there may be a mismatch, but maybe that
18:55
mismatch is actually contributing to, um, to, uh,
19:01
some of the, uh, worsening liver function tests.
19:05
And so this was the first case that I'd shown
19:07
the group, and I think somebody had answered
19:09
on the chat box and was absolutely correct.
19:10
And this was a patient who had had a liver transplant
19:13
a number of years back and was doing okay, except
19:16
was having now worsening liver function tests.
19:19
I mean, that's the history that we get.
19:20
Nothing more specific than that.
19:22
We have this, uh, nice MRCP image that really shows,
19:26
um, moderate intrahepatic biliary ductal dilatation.
19:29
Common bile duct looks pretty good, but look at
19:31
that anastomosis — looks quite narrow over there.
19:33
And so in this instance, given the new biliary
19:36
ductal dilatation, given the worsening LFTs, we
19:38
would definitely be worried about a stricture.
19:40
One of the other things that, um, I've come across — not
19:43
too often — but, um, in terms of biliary strictures that
19:46
could happen, particularly in transplant patients,
19:48
you can often get something called a biliary cast.
19:52
And this is, um, perhaps not the best
19:54
biliary cast in the world, although
19:55
this turned out to be biliary cast.
19:57
Uh, this T1 hyperintense structure
19:59
that's just above that anastomosis in the
20:02
bile duct — you can see how linear it is.
20:04
And all that is, is sort of the solidified, um, cast
20:08
really of bilirubin that just sort of forms, uh, as
20:11
a result of all the stasis due to that stricture.
20:13
And it sort of conforms to
20:15
the shape of the bile ducts.
20:17
And it has this, uh, characteristic T1
20:19
hyperintense appearance that's just sort of
20:21
branching, um, and, and, and sort of weaving
20:23
its way through, uh, through the bile ducts.
20:25
And, uh, that's something to look out for.
20:27
And I think if you see that, uh, as well,
20:29
that would suggest that there's some reason
20:31
for biliary stasis, and in the context of a
20:33
liver transplant, you know, stricture would
20:35
be something that, uh, you'd be worried about.
20:40
What about the hepatic arteries
20:41
and all the vessels in the liver?
20:43
Well, this is a nice example of a normal
20:44
hepatic artery — beautiful, sharp systolic
20:47
upstroke, flow throughout diastole as well.
20:51
If, uh, you look at the, um, peak systolic
20:53
velocities — generally if these liver
20:56
transplants are less than 200 — I don't
20:58
often like to remember specific velocities.
21:00
I find that it's always just relative to, uh,
21:03
what else is sort of going on in the body.
21:05
But generally, a peak systolic velocity of less than
21:07
200 is acceptable. Resistive indices, um, resistive
21:12
indices, uh, generally range from 0.5 to 0.8 and,
21:18
uh, we calculate that as peak systolic velocity minus
21:21
end diastolic velocity over peak systolic velocity.
21:24
Uh, and usually a number between 0.5 to 0.8 —
21:28
um, 0.8 being the top normal —
21:30
would, uh, would be acceptable.
21:33
Um, understanding that,
21:35
when you receive livers freshly postoperatively
21:38
out of the operating room, those resistive indices
21:41
may sometimes be at 0.8 or slightly higher.
21:44
And one of the reasons that can happen is because in
21:46
the postoperative state there's lots of liver edema.
21:49
And so there's sort of this natural
21:51
resistance to vascular flow.
21:53
Therefore, the resistive indices tend to go up.
21:55
And normally, you know, we image postoperatively — you
21:58
know, as they come out of the operating room, day one,
22:00
uh, and in the first three days. And over
22:02
that period of time, as that edema subsides,
22:05
that resistive index should sort of fall down
22:07
and come to that range between 0.5 to 0.8.
22:11
Um, the other thing to understand is that
22:13
sometimes, um, you come out of the operating
22:16
room and, and that's your resistive index —
22:17
it's 0.8 — and it never really normalizes.
22:20
And that may be an expected finding, particularly
22:23
if the recipient is receiving a liver transplant
22:27
from a donor who perhaps is a little bit older,
22:30
who's had potential, um, uh, more time in life, I
22:34
would say, to have, uh, insults done to the liver.
22:36
So you're basically receiving a liver
22:37
that may not be the perfect specimen.
22:40
Um, and also during the surgery, uh, if
22:43
there's long ischemic times, you know, you—
22:45
the recipient may be receiving a liver that has
22:47
been ever so slightly damaged in that context.
22:50
And so those recipients may
22:51
never have an RI that, uh, that goes
22:54
between that range and may live at 0.8.
22:57
I do see a question in the chat box, which I think I
22:59
might as well just answer 'cause we're on the topic.
23:01
Does mismatch between the donor and the
23:02
recipient diameters increase risk of stricture?
23:04
That's a great question.
23:05
If so, was a chole-docho-jejunostomy
23:07
done preemptively in certain cases?
23:08
You know, um, this is asked by, uh, by Steven.
23:11
You know, I, I actually don't know
23:12
the, the right answer to that.
23:14
Um, I would say that, uh, you know, we—
23:16
don't see a lot of—I, I don't think it—
23:18
that we don't see a lot of patients
23:21
who end up having these biliary strictures.
23:22
And it's possible that the, uh,
23:24
mismatch may contribute in a small way.
23:26
But, um, given the amount of patients who probably
23:29
have minor degrees of mismatch, you know, the majority
23:32
of those patients don't end up getting strictures.
23:34
And so, um, oftentimes, you know, sometimes
23:37
in the postoperative period, if they're
23:38
worried about that mismatch contributing to
23:40
it, they may put a biliary stent in place, and
23:42
maybe, uh, that sort of minimizes the risk.
23:44
But I don't know offhand, but I, my gut feeling
23:47
is I don't think that mismatch will, uh, greatly
23:49
contribute to the formation of strictures.
23:51
Thank you for that question.
23:54
So we'll move on, um, to the portal vein.
23:57
Right.
23:57
So the portal vein, uh, flow, as you
23:58
can see, is monophasic and there's
24:00
some degree of respiratory variation.
24:02
Flow is obviously towards the
24:04
liver parenchyma over here.
24:05
And, um, it turns out, like the bile
24:07
ducts, there may be a mismatch, uh, at the
24:10
portal vein anastomosis as well from time
24:12
to time, particularly in pediatric patients.
24:13
Now, this is not something that I see as often.
24:16
I would say that, um, at least in our practice,
24:18
we don't always, uh, visualize that anastomosis
24:21
perfectly well, but, uh, just know that it can happen.
24:25
And, uh, we'll talk a little bit about portal
24:27
vein stenosis and, um, and some of the criteria
24:30
that people have published to define that.
24:33
But understand that there may be a mismatch,
24:35
uh, issue at the portal vein, uh, anastomosis.
24:38
Oftentimes that doesn't turn out to be a
24:39
big issue for these transplant patients.
24:43
Last but not least, the hepatic veins, as
24:45
you can imagine, they have more pulsatile,
24:48
phasic waveforms, and those are really
24:50
reflecting the right atrial contractions.
24:52
And so we like it to be above and below the baseline.
24:55
We like it to be, um, phasic.
24:57
When they start to fall flat, we start to worry.
24:59
We start to worry that either there's a blockage
25:02
between where we're interrogating and the
25:04
heart. That blockage could be inside the vein,
25:07
yeah,
25:07
thrombus, or could be outside pushing in.
25:10
Right?
25:10
And so those are the sort of things that
25:11
we worry about if we see a flat waveform.
25:16
Like showing this case as well.
25:18
Um, couple of grayscale images of this patient.
25:21
Um, I don't know if it was this case, but I
25:23
definitely remember seeing one case at least where,
25:25
um, one of our amazing technologists showed us a
25:27
case post-op liver and said, oh, there's a small
25:29
collection at the, um, at sort of the porta hepatis,
25:31
uh, you know, sort of the medial aspect of the liver.
25:34
Um, and what that person was seeing was actually, um—
25:40
the recipient and the, and the donor
25:42
IVC sort of caught side by side.
25:45
You can see here, you may mistake this for a
25:46
collection, but if you sort of scroll through it,
25:48
this indeed is just the, um, uh, donor IVC
25:53
that's about to anastomose with the recipient IVC.
25:55
You can see all the hepatic veins, uh, of the—
25:57
sorry, the, the donor hepatic veins coming in,
25:59
here, going into the donor IVC and anastomosing and
26:02
that piggyback technique here to that recipient IVC.
26:05
This is a beautiful image from, uh, something
26:07
that we published that shows the same thing.
26:09
This is the recipient IVC here, that's that
26:11
donor IVC, that beautiful piggyback anastomosis,
26:13
again, caught sort of that transverse plane.
26:15
And if you're sort of unaware of, um, that, uh,
26:19
that that's how they generally anastomose
26:22
the, uh, IVCs, it's possible you mistake it for
26:25
a small collection. Wouldn't be the biggest thing
26:27
in the world 'cause it's a very small collection.
26:28
But it's important to know
26:30
what these things look like.
26:33
And so here's a, just a summary slide.
26:35
I want sort of everyone to be on the same page as
26:37
we then dive deeper into some of the complications.
26:39
This is what a beautiful—
26:40
hepatic artery would look like.
26:41
The peak systolic flow is less
26:42
than 200, RI's about 0.5 to 0.8.
26:45
We like to have sharp systolic upstrokes
26:47
and nice flow throughout diastole.
26:49
We have portal veins that are monophasic,
26:52
with some degree of respiratory—
26:53
variation going towards the liver.
26:55
We have phasic hepatic, uh, vein waveforms
26:59
that reflect the right atrial contractions.
27:01
And of course, if we're so lucky enough to see
27:03
beautiful images of the recipient and donor
27:04
IVC, let's not mistake them for any small
27:07
collections that form in the postoperative period.
27:12
That's normal.
27:14
Let's dive deeper into some common complications.
27:17
And so, um, many of you in the call, I'm sure
27:20
do liver transplants, and I'm not sure how you
27:22
approach. It'd be fascinating to learn about that.
27:24
Um, one approach that's worked well
27:26
for me is just to sort of divide into
27:27
nonvascular and vascular complications.
27:30
Um, the nonvascular are looking for collections.
27:32
Collections can be outside of that liver.
27:34
They can be inside the liver.
27:36
And masses.
27:37
And I would say that when you look at a, you know,
27:39
uh, a liver transplant case, you could probably
27:41
exclude the nonvascular complications pretty quickly.
27:45
I mean, we're just looking at the grayscale images
27:46
essentially and making sure there's nothing that
27:49
we're seeing that's inside or outside the liver.
27:52
Um, you know, and so you can
27:53
probably exclude that very quickly.
27:55
Looking at the vascular complications,
27:56
that takes a little bit more time.
27:58
And we are, um, I would say very reliant at our
28:00
place on our excellent, uh, technologists who do a
28:02
wonderful job and are really trained to do this well.
28:05
Um, we're looking at the hepatic artery,
28:07
portal vein, and the hepatic vein.
28:09
And each of these can, they come
28:10
narrowed or stenosed, or they can have
28:12
thrombus inside the vessel and thrombus.
28:15
Okay.
28:15
And so we'll look at examples for, for
28:17
most of these, uh, in the next couple of
28:18
slides. And then post-biopsy complications.
28:21
Not sure one wants to put that in, but, uh, because
28:24
they often involve vessels, I'll just, uh, you know,
28:26
sort of put them into the vascular complications.
28:28
We don't see these that often, or at least,
28:30
um, uh, we don't, we may see them from time to
28:33
time, but their significance is usually not
28:35
as much, especially with the arteriovenous fistulas.
28:37
We often see them, um, uh, post
28:39
biopsies. And the pseudoaneurysms,
28:42
uh, we don't see them too often, but, uh, we
28:44
may, um, we may, uh, need to, uh, treat it,
28:48
particularly if it gets on the, on the bigger side.
28:53
So here are some collections for the group, right?
28:57
Grayscale images.
28:58
They all look a little bit different.
28:59
They all look a little bit complex.
29:01
This is the perihepatic recess, a little bit
29:02
echogenic, curvilinear. Uh, this here,
29:05
septated, some thick septations here.
29:08
Maybe some septations. Looks very loculated over here.
29:11
And so the question really is, what collection
29:13
is what? You know, what do these represent?
29:16
And, uh, uh, you know, I don't imagine
29:19
anyone in the group, or at least I wouldn't
29:20
be able to tell you what they meant.
29:21
So it's sort of a rhetorical question.
29:23
Um, the point here is that
29:24
they're all complex collections.
29:25
And so at least when I speak to my trainees, I find
29:28
that when they start out, there's this need for them—
29:30
and maybe I was the same way—to really,
29:33
with a hundred percent degree of certainty, be
29:35
able to know exactly what that collection was.
29:38
And I think it's always good
29:39
to strive for that, right?
29:41
'Cause you wanna challenge yourself.
29:42
You wanna be better than you know all the
29:43
time and make sure you're really
29:45
good and you know what you're saying.
29:47
However, don't be too hard on yourself.
29:49
Um, it's tough to tell apart collections.
29:52
And so I don't, uh, go outta my way to really
29:54
try to figure out what collection is what.
29:56
I know that in post-op livers you're
29:58
dealing with hematomas potentially, you're
30:00
potentially dealing with bilomas as well.
30:03
Hey, you may just have some ascites, some
30:04
fluid there that's a little bit loculated.
30:07
Potentially could have an abscess as well.
30:08
So those are probably the things you're dealing with.
30:11
Maybe there's some clues that can allow you
30:12
to be specific, but I don't, um, you know,
30:15
I don't lose too much sleep over that when I
30:17
sort of look at these cases. The teaching point
30:20
from my perspective—nicely, we follow it.
30:23
So now you have day one ultrasound,
30:24
you know, there's a collection, and, um—
30:29
Internet was a little unstable there,
30:30
so I'm just gonna say that again.
30:31
So day one, you see one collection, and
30:33
then see if the next day is it bigger,
30:34
smaller, does it look different, right?
30:36
So that's the other thing.
30:38
And perhaps the other fourth important thing for—
30:41
ultrasound is you can use it to guide intervention.
30:43
'Cause if you need to know what something
30:44
is, you need to get rid of that collection.
30:45
You're gonna have to put a needle
30:46
in it and aspirate it out, right?
30:48
And so that's also sort of, um, the big,
30:51
uh, use of ultrasound in that setting.
30:58
And, um, here we have, uh, another collection
31:01
that, uh, looks a little bit more complex
31:04
and over time you can see that it decreases.
31:06
And, uh, this was just, uh, a hematoma
31:09
that, uh, just resolved over time.
31:10
You know, it kind of looks like
31:12
a hematoma over here potentially.
31:13
Um, again, if you're not really sure what
31:15
it is, you could suggest it's a hematoma, and
31:17
see that over time it's sort of decreasing.
31:19
Um, uh, and that's actually probably the most
31:22
important value of ultrasound in this setting
31:24
is to see it and make sure that it's going away.
31:27
Let's see.
31:27
I saw something in the chat about HIDA.
31:29
Yeah, so I think, um, I suppose the question is,
31:32
is, is there a utility of HIDA scan in order to
31:34
figure out what these complex collections are?
31:36
And you're absolutely right, you can use
31:38
HIDA scans when you're worried about
31:39
biliary leaks and potential bilomas.
31:42
And so, um, with that in mind, I'm gonna show you
31:45
this case of a patient who had a liver transplant.
31:48
Um, geez, there's a lot of fluid in the abdomen.
31:51
I mean, I don't know about you, but I
31:52
don't see this much fluid in the abdomen.
31:54
I'm just showing you the coronals.
31:55
If you saw the axials, you know, most of
31:57
this body’s peritoneal cavity was filled
31:59
with fluid. It was suspicious for a leak.
32:01
Um, we actually ended up doing an ERCP and you can see
32:04
a nice, beautiful, uh, biliary leak in this instance.
32:06
And so this stent was placed,
32:08
and this resolved over time.
32:09
HIDA scan would be useful.
32:11
I find that, and, and I don't know what it's like
32:12
for the rest of the group here, but I find that, um—
32:16
we just, we're tending to use HIDA scans
32:18
a little bit less. And it may be more
32:19
about availability and, and how long our
32:22
providers are willing to wait for HIDA scans.
32:24
Um, oftentimes I find that, uh, when
32:27
we're worried about a potential biliary
32:28
leak, there's one of two ways things go.
32:32
Sometimes they'll go to MRI and they use Eovist, and
32:35
they see if there's a leak through that way.
32:37
Eovist being this hepatobiliary agent that
32:39
gets excreted through the bile ducts.
32:41
That sometimes works. Sometimes that even
32:43
doesn't work, and you don't quite see,
32:44
um, enough of the agent coming out to, to,
32:47
you know, definitively say there's a leak.
32:49
Oftentimes the workflow may also be that
32:51
they just sort of aspirate some of the fluid.
32:53
They see there's biliary content in
32:54
it, and they go straight to ERCP.
32:57
I think there's a role for HIDA scans.
32:58
I just find that in our, in our particular
33:00
setting, we're tending to use them less,
33:02
and I'm not really sure if that's, um, uh, a
33:04
throughput thing or an availability thing.
33:09
Here we have another grayscale image
33:11
of an intrahepatic collection.
33:13
Um, and just like extrahepatic collections, you know,
33:15
it's gonna be difficult to figure out what these
33:16
intrahepatic collections are, but maybe, maybe we
33:19
can figure out what this one is and why is that?
33:21
Looks a little bit complex, but
33:23
it has these echogenic foci in it.
33:25
A little bit of dirty shadowing here.
33:27
And so if I saw this, I'd be
33:29
definitely worried about an abscess.
33:31
Um, and you know, the teaching point again
33:33
here is that oftentimes the intrahepatic
33:37
collections, like the extrahepatic collections,
33:39
have a non-specific appearance,
33:40
it's gonna be difficult.
33:42
Look at the clinical history, that's gonna be your—
33:43
your friend to, to sort of, uh, sort this out.
33:46
Certainly.
33:47
Um, if something looks like an abscess, you know,
33:49
somebody has fever, you see this sort of complex
33:51
collection with foci and dirty shadowing like
33:53
this, you're gonna be worried about an abscess.
33:55
And then of course, if you see hepatic
33:56
abscess in the liver transplant patient,
33:58
what are you gonna be worried about?
33:59
Yeah, you can be worried about the hepatic arteries,
34:01
and we're gonna come to that in a little bit
34:02
and show you some examples of what, um, abnormal
34:06
hepatic arteries look like in this setting.
34:08
Just another example here just to sort of drill in
34:10
the point—uh, complex, uh, collection but hypoechoic,
34:13
I'm not sure how much liquid fluid it has in it, maybe
34:15
a developing abscess. A little flag on, uh, at this
34:18
point. Echogenic foci, a little dirty shadowing,
34:21
uh, and certainly, uh, an infected collection, abscess
34:24
over here in this patient who is post-liver transplant.
34:29
This was our, uh, second unknown case of a
34:32
patient who had come in, um, sometime out
34:34
now after their liver transplant who had
34:37
this, uh, gray scale image of the port hetus.
34:39
And, you know, the vessel a
34:40
little bit tortuous over here.
34:41
I want you to ignore that, but, uh, you
34:44
eagle eyes may see that, you know, there's a
34:46
little bit tifying hypo coic structure here.
34:48
Um, maybe it's a collection, maybe it's a mass.
34:50
Hard to know.
34:52
Um, not sure if the CT scan helps.
34:54
Uh, certainly I think confirms that there's
34:56
something going on in the Port of Heus.
34:58
Looks, uh, hypo attenuating has
35:00
somewhat ill-defined features.
35:02
Um, patient ended up getting a, a PET scan and,
35:06
uh, their discrete masses or their ftg avid.
35:10
This, as you can imagine with biopsy and Eastern, had
35:13
to be post transplant lymphoproliferative disorder.
35:17
Alright.
35:18
PTLD.
35:18
We can see that, um, from time to time.
35:21
I haven't seen too many, too many cases,
35:23
but uh, you know, do have to think about it.
35:25
And it almost comes to a point, you know, where if
35:28
there is a transplant patient with, it's a renal
35:30
trans liver transplant, any transplant patient,
35:31
and I see a new mass in that patient, the first
35:34
thing my head goes to is, could this be PTLD?
35:37
Alright.
35:37
That's sort of always there in the back of
35:38
my mind when I'm approaching any transplant
35:40
patient because I always find I forget about it.
35:42
So I need to somehow drill that in.
35:43
If I see a transplant patient somewhere in my head,
35:46
I need to think, could anything that I see a mass,
35:48
especially if it's mass, like, could that be PTLD?
35:51
As I said, we don't see it that often
35:53
and the time presentation is variable.
35:55
You can see it as soon as one month.
35:56
You can see it after several years.
35:58
Generally, the later on the patients present,
36:00
particularly after one year prognostically
36:03
for whatever reason, they tend to do poorer.
36:05
Um, it's thought to be related to an Epstein
36:07
bar virus related proliferation of B cells.
36:10
And, um, in some sense, um, if it's easier for
36:14
the group to remember this, whatever lymphoma
36:16
can look like in the body, PTLD can look like.
36:19
So it can manifest as a single hepatic
36:21
mass, multiple masses, and have a
36:23
more diffuse infiltrative appearance.
36:25
Um, in this case, like this case can have a massive
36:28
sort of encases the vessels and the common biotech.
36:31
Um, much like what lymphoma can do, it's very
36:34
important, however, to biopsy the tissue.
36:38
Um, you know, there's a whole spectrum of
36:41
histology you can see in PTLD from, um, sort of.
36:45
You're run of the mill, I suppose, PTLD to
36:47
Frank Lymphoma, treatments of which differ.
36:50
And so the point here is if you
36:51
see something that looks like PTLD,
36:52
certainly, uh, mention it in your report.
36:55
However, it needs a needle.
36:56
Need histology, need to have tissue.
36:58
And that will help you triage the treatment,
37:00
whether you just have to decrease the
37:01
immunosuppression in broad terms or whether you
37:03
have to give systemic therapy to treat the tumor.
37:08
Now here was the case where I kind of went down
37:10
the tube, um, and it was a lesson, a simple
37:12
lesson that, uh, I just hadn't really thought of.
37:15
'cause I was so fixated on PTLD all the time.
37:18
This is a patient in 20, uh, 2014 who had
37:21
a liver transplant, had an MR just, and
37:23
uh, the reason for the liver transplant
37:25
I believe was hepatocellular carcinoma.
37:27
So they were just looking to see whether
37:28
the, uh, transplanted liver was doing okay.
37:30
And, um, we thought it was doing okay.
37:32
In retrospect, maybe there's a few notes,
37:34
but you know, I. Nothing to worry about, uh,
37:37
objectively so far over time, as you can see,
37:39
these nodes have enlarged, particularly this,
37:41
um, uh, portal cable node here quite big.
37:44
And then this node over here just se uh, anterior
37:47
to the inferior cava, also quite big over there.
37:49
And so I read the case in 2016, saw this adenopathy
37:52
sort of, uh, not quite porta habitus, but near it,
37:56
growing over time in a post-transplant patient.
37:59
What did my mind go to?
38:00
This is PTLD.
38:02
Great.
38:03
The biopsy of it.
38:04
This turned out to be recurrent HCC.
38:08
And so, you know, a simple lesson that I learned
38:10
is that, uh, there are liver, you know, there
38:13
are a lot of transplants, patients who have
38:15
transplants because they have a primary HCC,
38:18
and, uh, whereas we always hope that that HCC
38:22
does not recur again, it can, it can recur.
38:25
And so as much as you wanna think about PTLD, if the
38:28
patient has had a history of a primary neoplasm, um.
38:31
And you see disease in the, in the new transplanted
38:34
liver or post-transplant, always also think,
38:37
could this be recurrence of that original disease?
38:41
And so that's what I have for nonvascular stuff, you
38:43
know, really, um, looking at collections, whether
38:46
they're inside or outside the liver, knowing that
38:48
with very few exceptions, it's gonna be difficult
38:50
to be specific, but you're using the ultrasound and
38:52
you're imaging to follow them, to make sure they're
38:54
getting smaller, to perhaps use them as a means to,
38:57
um, uh, aspirate them and diagnose what they are.
39:00
And then masses.
39:01
And when you think about mass, I think of PTLD,
39:03
but always remember, could there be recurrence
39:05
of any primary neoplasm that the patient has.
39:08
So now let's dive deep into
39:09
the vascular complications.
39:12
This was a, um, I think it's, I call it a special
39:16
case — they're all special cases — but I, you know, I
39:18
remember, uh, as a newer faculty, I was, uh.
39:22
Had some experience with transplants
39:24
and, and I had seen a lot of transplants
39:26
that were all within the range of normal.
39:28
And this, I distinctly remember as being one
39:30
of my first patients who had a complication
39:33
that I called, asked faculty prospectively.
39:36
Um, and it gave me a lot of confidence
39:38
and I wanted to share with the group.
39:40
Um, and so, uh, this is a patient who,
39:42
um, was not doing well post-transplant.
39:45
I forget how long they were out, but they were
39:46
out at least, uh, it was not a fresh transplant,
39:48
maybe a couple of years they were out.
39:50
And let's look at their intrahepatic
39:51
vessels at the right hepatic artery.
39:54
Doesn't look—
39:55
really good.
39:56
It doesn't look like what we want to be normal.
39:59
Um, there's a delayed upstroke.
40:00
We don't have that nice, nice sharp upstroke.
40:02
This is a delayed upstroke.
40:04
Um, there is a relatively
40:06
diminished peak systolic velocity.
40:08
Thirty-three is on the lower end.
40:10
I didn't define a lower end, but
40:12
most of the transplants we were seeing
40:14
were, uh, were much higher than that.
40:16
And look at the diastolic flow.
40:18
Um, lots of diastolic flow, but as a
40:20
result, look at the resistive index of 0.33.
40:23
So really, um, you know, the resistive
40:26
indices are a lot lower than that.
40:28
0.5 minimal threshold —
40:29
that's in the right hepatic artery.
40:31
Left hepatic artery shows similar findings.
40:33
Delayed upstroke and, uh,
40:36
reduced resistive index.
40:38
Now when we see that inside the
40:40
liver, what are we worried about?
40:43
Right?
40:44
We're worried that something on some level
40:47
upstream from where we're interrogating.
40:50
Is narrowed.
40:52
And so you just work your way through the liver
40:53
and you try to find out where that narrowing is.
40:55
And so we work our way to about this point
40:57
here, which, um, is sort of the proper hepatic
41:00
artery at the porta hepatis, and perhaps less of
41:03
that, uh, delayed upstroke, but still there.
41:05
Um, peak systolic flow a little bit higher,
41:08
but, uh, the stohn also on the lower end.
41:10
So, um, we haven't quite localized where
41:14
that region of potential narrowing is.
41:16
'Cause at that region of narrowing, what we're
41:17
expecting to see is velocity that jumps really high.
41:22
And so we're not quite there
41:23
yet, but this is about as far as we
41:25
can take it from the ultrasound case.
41:26
You look at this, your interpretation should be,
41:29
I see, um, you know, these waveforms — we're gonna
41:32
talk about in a few minutes what we call them.
41:35
And I'm worried about the, uh, images from
41:36
that, and look at that right over there.
41:39
Beautiful.
41:40
Beautiful.
41:42
A beautiful narrowing of the, uh, uh,
41:45
of the, uh, proper hepatic artery.
41:48
And this was confirmed on, uh,
41:49
angiographic imaging as well.
41:51
Uh, this was angioplasty.
41:53
The patient did very well after this,
41:54
with velocities that, uh, normalized.
41:58
And so this is hepatic artery stenosis.
42:00
And these are the key findings that we're gonna
42:02
look for in all our patients post-transplant.
42:04
For hepatic artery stenosis, we're gonna
42:06
look for that slow upstroke, not, you
42:09
know, normally, as you can see here, sharp
42:11
systolic upstroke, much more slow upstroke.
42:13
And that's our tardus waveform that we see with
42:16
diminished amplitude of the peak systolic velocity.
42:20
That parvus, so that tardus-parvus waveforms.
42:23
And when we see that, it indicates
42:26
there's a proximal stenosis somewhere.
42:28
If you're able to find that proximal
42:29
stenosis, you're gonna see real elevated
42:32
velocities here with color aliasing as well.
42:35
Uh.
42:36
We find that, you know, it's usually so proximal
42:39
that it's difficult to interrogate that area, but if
42:41
you do find it, then that's what you're gonna see.
42:43
And as it turns out, with, uh, with tardus-parvus
42:46
waveforms, they'll be most pronounced
42:48
the further you get from the stenosis, right?
42:52
So if you see, uh, if you interrogate the leg
42:55
region of the liver right over here, well that
42:57
tardus-parvus waveform will be more pronounced
42:59
than if you interrogate it over here, than
43:01
if you interrogate it over here, et cetera.
43:05
And so this is a paper, it's
43:06
an older paper now, but, uh.
43:09
Geez.
43:09
It's a, it's a very good paper from, uh, RadioGraphics
43:11
that really shows you hepatic artery waveforms.
43:14
And, um, I always reference it whenever I get,
43:17
um, stuck on, uh, on any sort of waveforms.
43:20
Um, you know, I find, and I'm not sure
43:22
how people do it at their institutions, at
43:23
our institu— I find we use very subjective
43:25
evidence generally for tardus-parvus waveform.
43:27
We just look at 'em, we say, you know what?
43:28
Th—that just that upstroke
43:30
is not as nice as we need.
43:31
That velocity is not as high as we'd like.
43:33
So it's sort of approaching the
43:34
tardus-parvus waveforms.
43:36
But I personally am not, uh,
43:38
a big fan of subjectivity.
43:39
'Cause I think it just confuses things.
43:41
Um, and so I always have these objective criteria
43:43
sort of in the back of my head, and there are
43:45
objective criteria that have been published
43:47
that, uh, talk about acceleration times and
43:49
that time to peak, um, suggesting, uh, that, uh,
43:53
parvus, uh, that tardus waveform as well.
43:59
Here's another nice example
44:00
of, uh, of a hepatic artery
44:02
stenosis.
44:03
Again, just interrogating really the proper
44:04
hepatic artery, seeing diminished amplitudes,
44:07
delayed upstrokes, angiogram shows
44:09
beautiful narrowing, much like our other case.
44:12
Uh, and this is just showing
44:13
you what normal looks like.
44:14
And I always find it useful, at least in this context
44:16
of giving talks, to have a normal, just to show you
44:19
how different it is from what normal looks like.
44:24
So that's hepatic artery stenosis.
44:27
What about hepatic artery thrombosis?
44:30
Well, we don't like—he, we
44:30
don't like any complication.
44:31
We certainly don't like hepatic artery thrombosis.
44:34
It's quite a significant complication.
44:36
And one of the things that, uh, you know,
44:39
I'll talk about at this juncture is I
44:41
think it's useful is that oftentimes, uh.
44:46
You know, you evaluate liver transplants fresh out
44:48
of the operating room, and, uh, you get them—the
44:51
sonographers imaging them, and they come to you
44:54
and say, you know, I can't find the hepatic artery.
44:57
It's very difficult for me to find it.
44:59
And so in your head, what you're thinking
45:01
is, is it difficult to find it because
45:04
you're in the postoperative state?
45:05
Maybe it's a little bit of bowel
45:06
gas that's obscuring things.
45:08
But also in the postoperative states,
45:09
you can have vasospasm of vessels,
45:10
and so you don't see them too well.
45:12
They're really, really tiny in that state.
45:14
There's lots of edema.
45:15
You know, things are not
45:15
really, uh, optimal for imaging.
45:18
So that's one option.
45:19
Or the other option is, is the hepatic artery
45:22
thrombosed? Is it just not there anymore?
45:24
And you have to sort of decide that in that
45:26
moment, because if the hepatic artery is thrombotic,
45:30
they need to go back and do something
45:31
about it, because it can be quite significant.
45:33
But if it's just postoperative stuff and
45:35
vasospasm, well, then you can say, fine.
45:37
You know, we can, uh, we can wait.
45:39
And so one of the things that we do at our
45:41
institution, um, is we use a vasodilator, or
45:43
Nifedipine, and that, uh, so we're sort of trying
45:47
to differentiate between those two options.
45:49
We ask the referring team to give this vasodilator
45:54
and we image typically about 30 minutes after.
45:56
So we sort of time it with, uh, the
45:58
administration of this, uh, of this medicine.
46:00
It's a calcium channel blocker, and we see if
46:02
we can see the hepatic arteries. And if we can
46:04
see it post vasodilation, we are reassured
46:07
that the, the, the reason we couldn't see it at
46:10
first was just because of postoperative state.
46:12
Uh, and then we just follow them and, and
46:14
hopefully over time things open up nicely
46:16
as the postoperative changes subside.
46:18
But if we don't see it post...
46:22
Then we may need to do something about it.
46:23
So I'll just give you an example.
46:24
This is not quite us not seeing the
46:26
hepatic artery, but post-op, you can
46:27
see there's hardly any diastolic flow.
46:29
Not an ideal state for this liver.
46:31
Uh, but post, uh, vasodilation, you
46:32
can see beautiful diastolic flow.
46:34
And so a lot of this in this context is probably
46:36
due to edema in the postoperative setting.
46:40
But I wanna show you this case, which is unknown case
46:42
number three, I believe, where we got this patient
46:46
outta the operating room. We're
46:48
interrogating the hepatic artery.
46:49
This is the portal vein. Looks pretty good on
46:52
color imaging, and as we're interrogating, we
46:54
can catch a little bit of the portal vein, but
46:55
we're trying to find that hepatic artery in the
46:58
porta hepatis adjacent to it. Not having luck,
47:01
not on the color imaging, not on the Doppler.
47:03
Spectral Doppler imaging, not seeing
47:04
that beautiful hepatic artery waveform.
47:07
Then we go to the liver.
47:08
Can we find any hepatic artery waveforms?
47:10
There, not really. You know, no sharp
47:13
systolic upstroke, no good diastolic flow.
47:14
There's nothing that we can confidently say,
47:16
"This is the hepatic artery."
47:18
So what's our next step?
47:20
We're gonna give Nifedipine. We gave Nifedipine.
47:24
No luck over here.
47:26
Can't see it on the power images.
47:28
We do spectral, uh, waveforms as well.
47:31
I couldn't see it.
47:32
Uh, maybe somebody here can see it, but
47:34
I, I certainly couldn't see anything.
47:35
And if I can't confidently see it,
47:36
what am I gonna tell my providers?
47:38
Listen, we're worried about hepatic artery
47:39
thrombosis, so they have a couple of options.
47:43
I mean, they can certainly take them back,
47:44
but oftentimes, uh, we try to expedite a CTA.
47:47
They really wanna see what they're, you
47:48
know, everything before they go back in.
47:50
And, uh, you can actually see very nicely.
47:52
So the coronal CTA, this is the hepatic artery
47:54
coming out, completely thrombosed from here on.
47:57
And there's a thrombus here on the, um, axial images,
48:02
hepatic artery coming out here, a little bit of flow.
48:03
And then you can see it up to
48:06
about here, then past here.
48:09
Abrupt cutoff, and there's a defect of thrombus there.
48:13
And so this was truly hepatic artery thrombosis.
48:15
We don't see it that often.
48:16
Uh, you can look up the literature for
48:17
how often it occurs, et cetera, but
48:19
um, we're always on the lookout for it.
48:22
And why are we on the lookout for it?
48:24
Well, I'm sure as many people on the call know, hepatic
48:27
arteries are what's feeding the biliary system.
48:30
And so if you damage the hepatic arteries, the
48:31
biliary system undergoes necrosis. You're gonna
48:33
get abscesses, you're gonna get bile leaks,
48:35
you're gonna get all sorts of stuff in the liver
48:37
associated with high mortality rates as well.
48:41
Here's another, uh, example of a case
48:43
that, that we saw a couple years back.
48:45
Somebody with fever, uh, had a CT scan,
48:47
saw these ill-defined collections.
48:49
They're certainly worrisome for, uh,
48:51
abscesses or bilomas or infected bilomas.
48:53
On the ultrasound, you can see if
48:54
the liquid component within them.
48:55
So we verified that on non-contrast and
48:58
ultrasound imaging on the ultrasound.
49:00
Then we get these, uh, spectral Doppler
49:02
images to look at the hepatic arteries.
49:03
What do we see in hepatic arteries?
49:05
Tardus-parvus waveforms, right?
49:06
And the, uh, proper hepatic artery
49:08
there in the right hepatic artery.
49:10
And so as we've, uh, gone through and we
49:11
see these waveforms, to us it means that
49:13
there is some hepatic artery stenosis.
49:16
So we got a CTA. This is the
49:19
hepatic artery coming out.
49:21
What's interesting is there's no stenosis here.
49:23
It's completely thrombosed.
49:25
And so then the question that sort of
49:27
arises in, in one's head is how is it that
49:29
the hepatic artery is completely thrombosed,
49:32
and yet we're seeing flow within the liver?
49:35
So how does that work?
49:37
This is a C-angio image that was
49:39
done showing you the splenic artery that
49:41
looks beautiful, but not the hepatic artery.
49:42
It's gone.
49:43
So we're not, uh, you know, that's
49:44
not some sort of weird artifact.
49:46
It's completely thrombosed.
49:48
And this was something that, um, this sort of case
49:51
taught me, uh, something that I had learned, I
49:52
think on some level intellectually, but this was a
49:54
real-life example of it, in that with hepatic artery
49:59
thrombosis, sometimes you can get collateral vessels
50:02
that form through the superior mesenteric artery,
50:04
through the pancreaticoduodenal arcade, that
50:06
come up and start to perfuse the liver. And those
50:09
vessels, those collaterals, when you, if you're
50:12
able to—if they form and you're able to interrogate
50:15
them—have these tardus-parvus waveforms. That's what
50:17
you're seeing over here, is those collateral vessels.
50:20
And so if you actually look at the
50:22
occluded hepatic artery, you don't see it.
50:24
But if you inject the SMA, you can see
50:26
these faint collateral vessels that are
50:28
sort of coming up, and that's what was being
50:29
interrogated with those tardus-parvus waveforms.
50:33
Here's another, uh, different example
50:35
of a patient who is post-transplant.
50:37
Get a color spectral Doppler image.
50:39
We see a trickle of flow in the main portal
50:41
vein, but not within most of it. All these
50:43
low-level echoes that are filling it out.
50:45
And so this is a classic example
50:47
of portal vein thrombosis.
50:49
And, uh, another example—I don't know if it's the
50:51
same patient—on CT, you can see a beautiful filling
50:53
defect inside, uh, this patient's, uh, portal vein.
50:56
And of course, uh, we're all gonna be,
50:58
uh, cognizant that clot can sometimes
51:01
be hypoechoic or even anechoic, right?
51:05
And so on, uh, color imaging, it may
51:07
just look like the vessel is "unquote"
51:09
patent, 'cause it looks anechoic.
51:11
But we're gonna interrogate it with color Doppler
51:13
imaging to make sure that, uh, there's indeed no
51:15
flow, as would be expected with a clot formation.
51:20
This is another interesting example
51:22
of a, of a very uncommon complication.
51:24
Um, portal vein about 43 centimeters per second.
51:29
Reasonably good, uh, waveforms.
51:32
And on the color image here, lots of aliasing and
51:35
turbulent flow as you sort of interrogate that area.
51:38
Look how far the velocities jump from like 40 to 232.
51:42
That's a huge jump.
51:45
And, uh, and so maybe something's going on there.
51:49
And so we ended up getting an MR in this patient.
51:51
And look what's going on. This is that portal
51:53
vein. That's about the 42 velocity that
51:54
you're seeing right at the porta hepatis.
51:56
There's this adenopathy that's, uh, quite
51:58
enlarged, squeezing that portal vein.
52:00
Look at that. That area we're
52:01
interrogating—that's that 232 area.
52:04
And so this was a true example
52:07
of, uh, of portal vein stenosis.
52:09
And, uh, again, we don't see this that often.
52:11
So I don't want you to leave this, um, session
52:14
thinking that, you know, you're gonna diagnose this,
52:16
but, um, just be on the lookout if you see this.
52:19
You know, real elevated velocities,
52:22
uh, over across the portal vein.
52:24
Um, I think there's one paper on this.
52:26
Maybe the group knows that there's more data, but
52:28
I only found, found one paper that suggested that
52:30
a, you know, portal vein velocity that, uh, is more
52:33
than 125, if it elevates and it's more than 125,
52:36
the ratio's three to one—that may
52:38
suggest that there's portal vein stenosis.
52:40
And so I would say that I keep those
52:42
numbers in the back of my head.
52:44
Um, I also understand that sometimes, uh, it
52:48
could be falsely positive because particularly
52:50
in pediatric patients, you get a mismatch between
52:52
the portal veins—just that one size is bigger
52:54
than the other—and you can get that artificial
52:56
sort of, uh, ratio elevation when there's no
52:59
real narrowing that's actually taking place.
53:04
Echogenic content in it.
53:05
There's a little flow, but it's, uh,
53:06
near-occlusive thrombus on a CT scan.
53:11
On the CT scan here, we can also
53:13
see there's flow in the right hepatic.
53:14
Uh, there's a thrombus, there's filling
53:15
effect in the right hepatic vein that's going
53:17
all the way up over here on the coronal CT.
53:20
And so not much different teaching points here.
53:22
You're gonna interrogate the veins.
53:23
You're gonna look for these low-level
53:25
echoes. Sometimes clot may be anechoic.
53:28
And make sure you do a Doppler analysis
53:29
to make sure there's no thrombus there.
53:32
Another example, a nice example of a right hepatic
53:36
thrombus going into the IVC in this instance,
53:38
and that CT correlate showing you beautiful
53:40
thrombus going into the IVC over here.
53:44
So as we wrap up, this was, I think, our, um, uh,
53:47
end last case that I'd shown. Lots of images here.
53:52
Color image showing rounded structure.
53:55
Lots of turbulence and color
53:57
aliasing and, and turbulent flow.
53:59
Uh, as we interrogate it on the spectral
54:01
Doppler image, quite high velocities.
54:03
There's a structure that's feeding it,
54:04
and a structure that's draining it.
54:06
As we interrogate the feeding structure, we're
54:08
seeing somewhat tardus-parvus waveforms, right?
54:11
Um, low velocities, delayed
54:13
upstrokes, high diastolic flow.
54:16
Look at the vein.
54:16
That's draining it—very, very pulsatile.
54:19
And this is about the best example of an
54:21
arteriovenous fistula that I've seen in the liver.
54:23
We probably see these, um, not uncommonly post
54:25
biopsies, but they're very small, not significant.
54:28
Um, you know, but this was a nice
54:30
example of how we can see it beautifully.
54:32
Uh, the feeding artery, the vein that's draining,
54:34
that's pulsatile, and the fistula that has aliasing
54:36
and high flow, um, that's, uh, within it.
54:41
This is another favorite case—a very somewhat basic
54:43
concept, but important to remember. Transplanted
54:45
liver, anechoic structure through transmission.
54:48
Uh, you know, easy to think,
54:49
this is a cyst.
54:50
We can call it cyst most of the time, except
54:52
for when we put color in it and we see
54:54
there's flow in it and almost a yin-yang sign.
54:58
And this turned out to be a
54:59
pseudoaneurysm post biopsy.
55:01
And so we can see that swirling
55:02
flow resulting in the yin-yang.
55:04
And, um, different treatment options exist for this,
55:07
depending on where it is, depending on how big it is.
55:09
I won't go through that right now.
55:11
But, uh, if you're so lucky enough as to
55:13
see the neck and you interrogate that,
55:15
you can see flow going above the baseline,
55:17
below the baseline, as flow is
55:18
going in and out of that aneurysm.
55:19
This is too beautiful,
55:20
an example not to share with the group of
55:22
a beautiful pseudoaneurysm that can also
55:24
be picked up on the CT scan over here.
55:28
So that's our vascular complications.
55:31
And as we wrap up, I'll talk a little
55:33
bit about what we've spoken about today.
55:34
We've talked about fluid collections, understanding
55:36
that imaging appearance is often non-specific,
55:38
but you're dealing with a few certain things, and
55:40
ultrasound is typically very useful to make sure
55:43
it's decreasing over time or potentially aspirated.
55:45
And there's some different imaging modalities you
55:47
can use to prove that there's a bile
55:50
leak. As we've talked about neoplasm, remember that
55:53
PTLD should always be in the back of your head, but
55:55
also, the patient has a history of a primary neoplasm,
55:57
they certainly may recur in the, uh, transplanted
56:00
liver or in and around the transplanted liver.
56:02
We talked about various stenosis and thrombosis
56:05
that can occur with the three vessels in
56:07
the, uh, transplant that we're worried about—
56:08
the hepatic artery, veins, and portal veins.
56:11
And we talked about post-biopsy complications,
56:14
um, as well as some Doppler principles that
56:16
I think we can use to sort of apply broadly
56:19
to much of ultrasound in order for us
56:21
to diagnose some of these complications.
56:25
These were unknown cases.
56:26
This was a biliary stricture—
56:27
post-transplant patient with a small cast.
56:30
This was a biopsy-proven case of PTLD,
56:33
hepatic artery thrombosis in this patient.
56:36
And of course, arteriovenous fistula.
56:40
Some references here.
56:43
And I wanna thank all of you, um, for your attention.
56:45
I'm gonna stick around a little bit.
56:47
I can, I can certainly stick around a
56:48
little bit more after one, um, to engage
56:50
in any conversation, dialogue, questions.
56:52
I know people have been asking a few in the
56:53
chat and, uh, I think there's maybe another
56:56
Q and A in the box, but I really appreciate
56:57
your time today and thank you again.
57:05
So if you wanna go ahead and move to
57:06
that one question in the Q and A box.
57:08
Absolutely.
57:09
Yeah, that's a great question.
57:10
I saw that early on and I
57:11
was like, oh, I'm in trouble.
57:13
Uh, 'cause I don't know if I know the answer to this.
57:14
Um, I think it's a great question.
57:16
Any role of ultrasound elastography in liver
57:17
transplant, early detection of complication?
57:20
You know, we, um, uh—
57:23
I'm sure there's a role.
57:24
I mean, I think that, um, intellectually
57:27
speaking, there must be, uh, a role
57:30
of at least evaluating liver stiffness and, and
57:34
maybe there's a correlation between the liver
57:36
stiffness and potential complication developing.
57:38
I just don't know all the data on ultrasound
57:40
elastography in that patient population.
57:41
So I don't know if I'm well-educated to answer that.
57:43
What I will say is that our own transplant
57:45
practice—and we actually do quite a few
57:47
transplants at Yale—we haven't used it yet.
57:50
It doesn't mean that it's not useful.
57:52
It doesn't mean that, uh—
57:54
other places aren't using it.
57:55
But, um, what it may mean is
57:57
that it's not mainstream yet.
57:59
Uh, and when things aren't mainstream, it
58:01
may be because it's not quite found its niche
58:03
yet for that particular—I don't know if it
58:05
really helps with thrombus in the portal vein.
58:07
Uh, as your follow-up question, I think, you know,
58:09
our Doppler, uh, techniques are pretty good.
58:11
There may be, um, you know, there's probably
58:13
a role for ultrasound contrast agents
58:15
in that, but again, that's not something
58:17
that we use mainstream at our practice.
58:19
Uh, but I think these are great questions.
58:21
Um, and perhaps there is a role, but I, I
58:23
just don't know of it, uh, off the top of my head.
58:32
Thank you for—uh, it's
58:34
always, uh, nice to see people.
58:36
Um, it's always nice, nice to read
58:39
all the, the messages in the chat box.
58:40
So, um, please know that it's appreciated.
58:42
Even when you say thank you.
58:43
It's, it's very appreciated.
58:51
That's a great post-surgical Doppler, ultra—
58:53
alias, need a difference in caliber of the portal.
58:54
And how long can it last?
58:56
Um, you know, uh, I've seen it last, uh—
59:01
it's probably variable.
59:02
I've seen certain cases where there is
59:04
sort of, um, that persistent finding over a
59:08
period of time and it just doesn't go away.
59:10
Um, and I think it's, it's a really good
59:13
and, and it's a sort of—and, and when we
59:16
interpret those cases, we again note it
59:18
as, uh, you know, difference in velocities
59:19
and, you know, elevated velocity at anastomosis.
59:22
Um, I think, you know, I, I'm almost reassured
59:24
as long as the liver transplant, um, is doing
59:27
okay, uh, and the patient is doing okay, I mean,
59:30
and their numbers are doing okay,
59:31
then I think most hepatologists and surgeons
59:35
will just let that aliasing be what it is—
59:37
just sort of that representing perhaps a
59:40
mismatch and won't do anything about it.
59:41
I think the minute that there's any
59:42
decompensation in the patient, they'll start to
59:45
look at that to see if there's any significance.
59:46
But I have seen it sort of just,
59:48
just last in patients. We keep on
59:50
reporting it, uh, on our patients,
59:52
um, uh, time after time.
59:58
And, uh, another question by one
60:00
of our colleagues—common syndrome.
60:02
Another great question, you know, um—
60:05
You know, you're asking tough questions to me.
60:06
I don't know the numbers.
60:08
Uh, I'll say that. I don't know.
60:10
I gotta tell you, I haven't seen a
60:11
lot of cases of Budd-Chiari, period.
60:13
Um, in my time as faculty, I—and I, and
60:16
I say this because I remember recently,
60:17
you know, we have a weekly body session
60:19
where we show all interesting cases.
60:20
And you know, in the last year, one of
60:22
my colleagues showed a case of Budd-Chiari.
60:24
And, uh, and that was like, wow.
60:25
Everyone was like, this is really cool.
60:27
We just, you know, I guess we
60:28
just don't see it as often.
60:29
And so I would say that, uh, in the
60:31
transplant patients that I've looked at,
60:32
I just haven't seen it, uh, that often.
60:34
Um, you know, you can certainly, uh,
60:37
get, uh, thrombus in those vessels.
60:39
That can happen, but it's very, very uncommon.
60:41
I just don't have a good number for you.
60:42
But, you know, we're always on the lookout for it,
60:44
because, um, you know, you never know when these
60:46
things can happen, and the minute you sort of,
60:48
uh, your shield goes down, your guard goes down,
60:50
is the minute that you're gonna miss it, right?
60:51
So, uh, but I would say it's very,
60:53
very uncommon from my experience.
61:05
Are there any changes in parenchymal echogenicity?
61:07
Just complicated.
61:07
That's a great question.
61:08
You know, I, it, it's really interesting, and I
61:10
don't know how it is in your practices, but I
61:12
find that, uh, I've sort of—this is nothing to do
61:16
with, um, this is not a reflection of anybody—but
61:19
I find that all the livers that I'm interpreting,
61:22
uh, are often annotated as being heterogeneous.
61:25
Uh, they're all heterogeneous architecture, hetero.
61:27
So I, I stopped almost understanding what normal
61:29
echogenicity and architecture of the liver is, and I
61:32
don't know if other people have that same practice.
61:34
Um, that being said, um, I, uh, whenever you see, um,
61:41
differences in echogenicity over a period of time,
61:43
particularly when things get more hypoechoic, um—
61:47
and when they look almost band-like or wedge-shaped,
61:49
I start to worry about ischemic changes in the liver.
61:53
And so we have seen cases where over monitoring
61:56
patients who are not doing well start to
61:57
develop almost band-like, wedge-shaped regions
62:00
of, um, uh, hypoechogenicity in the liver.
62:03
And that brings up the possibility of ischemia.
62:04
We follow it up with a CTA, because we're looking
62:07
particularly at hepatic arteries to see if they're patent,
62:10
and we're obviously looking at the
62:11
portal vein to see if it's patent.
62:12
So that's always, um, something that
62:14
can, uh, that, that, uh, we worry about.
62:17
So that's certainly one specific thing that I
62:19
can look for to, to tell you that something's
62:21
not going right in that liver. Role of, uh,
62:26
endoscopic ultrasound in early post-op period.
62:32
So that's an interesting question.
62:33
And so I'm assuming—so we, we, um, we often
62:38
use endoscopic ultrasound to look at potential—
62:43
maybe lesions in the stomach,
62:44
but more often in the pancreas.
62:46
I suppose your question is through the endoscopic
62:49
ultrasound, can we evaluate the liver parenchyma?
62:51
Is that what you're asking?
62:52
Um, is that—
62:58
Yeah, I got it.
62:59
Yeah.
63:00
Um, I find that we don't do that and I, I don't know
63:02
the role, uh, but I don't think it's mainstream.
63:04
I do know that, um, if there is something, uh,
63:07
perhaps a liver lesion or, um, that can't be
63:12
biopsied, or, uh, via conventional ultrasound or
63:16
CT techniques, which is really, really uncommon,
63:19
um, that's at least once I've seen endoscopic
63:22
ultrasound be used to do so, or at least we
63:24
suggested that was a possibility.
63:27
But I found, uh, that that's few and far between.
63:29
I think it's, it's certainly possible, but I think
63:31
that we have alternative techniques that are less
63:33
invasive, um, than endoscopic ultrasound that requires
63:37
the probe to be put down the GI tract that can—
63:40
more often than not, uh, figure out what's going
63:42
on and, and, and biopsy and answer the questions.
63:47
Um, one of my colleagues has
63:49
asked to send a case of syndrome.
63:51
I'm, uh, always happy to see any
63:53
cases, uh, if you want to send it.
63:54
So, um, I, uh, you know, if it's a
63:58
nice image or so, feel free to do so.
63:59
You have my email there, so I'm
64:00
always happy to, to, um, to see that.
64:03
Yeah, that'd be, that'd be, that'd be fine.
64:06
Okay.
64:06
I think that is all the questions we have.
64:09
All.
64:10
Thanks so much for that great talk, Dr. Mather.
64:12
I learned a lot, and thanks to all for your
64:13
participation in our noon conference. A reminder
64:16
that you can—thank you again—access the recording of
64:18
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64:20
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64:32
Be sure to join us next week on Thursday, October 6th,
64:35
at 12:00 PM Eastern Time for a lecture with Dr. Susie
64:37
Bash on AI applications in advanced neuroimaging.
64:41
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64:43
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64:45
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64:47
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64:49
Thanks again, and have a great day.
Mahan Mathur, MD
Associate Professor, Division of Body Imaging; Vice Chair of Education, Dept of Radiology and Biomedical Imaging
Yale School of Medicine
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