0:02

Hello and welcome to Noon Conference hosted by MRI.

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Online, in response to the changes happening around

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the world right now and the shutdown of in-

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person events, we have decided to provide free

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Noon Conferences to all radiologists worldwide.

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Today, we are joined by Dr. Amir Barani.

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Dr. Barani is an Associate Professor of Radiology

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and Director of CT at Northwestern University.

0:26

He is an active member of several scientific

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committees and also a member of the editorial

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boards of major radiology journals, with a special

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interest in the topic of organ transplantation.

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A reminder that there will be a Q&A session

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at the end of the lecture, so please use the

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Q&A feature to ask your questions, and we will

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get to as many as we can before our time is up.

0:48

That being said, thank you all for joining us today.

0:50

Dr. Barani, I'll let you take it from here.

0:53

Okay.

0:53

Can you hear me now?

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Yep.

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Coming through loud and clear.

0:56

Thank you.

0:57

Well, thank you very much for the nice introduction.

0:59

It's my pleasure to be presenting today on this platform.

1:03

As mentioned, I'm the Associate Professor

1:06

of Radiology at Northwestern University.

1:08

Today, I'm going to discuss the topic

1:11

of imaging evaluation of living liver donors.

1:16

These are my disclosures.

1:18

So today, we start by talking

1:21

about the background of liver transplantation

1:24

with a special focus on the living donor technique.

1:28

We're going to go over the surgical techniques,

1:30

the parts that are relevant to our talk

1:32

and to radiology.

1:35

And we'll talk about the protocols.

1:38

In the second half of the talk, we're going

1:40

to discuss the hepatic and vascular biliary

1:43

variations, which are relevant to this topic,

1:46

and at the end, we'll discuss the report.

1:50

I'd like to give a tribute to

1:52

Dr. Thomas Starzl, an extraordinary surgeon and an

1:55

excellent human being with whom I had the pleasure

1:58

of working, and who was the father of liver transplantation.

2:01

He's the first person.

2:02

A person who did deliver transplantation

2:04

successfully established the first transplant

2:07

program and had a crucial role in, uh, the idea

2:10

of living liver donor, uh, transplantation.

2:15

Uh, liver transplantation has been on the rise over the past, um,

2:18

two, three decades; more and more centers are doing it.

2:21

The problem

2:22

is the shortage of, uh, organs.

2:26

Uh, nowadays there's an epidemic of NASH and NAFLD.

2:30

So there are more cases of chronic liver

2:31

disease worldwide, uh, because of improvements in

2:34

healthcare; uh, more cases are getting to a stage

2:38

that they require liver transplantation also.

2:42

The indications and criteria for liver

2:45

transplantation have been expanding.

2:46

Many indications, which used to be contraindications

2:50

10 years ago, 15 years ago, nowadays there are

2:53

uh, they're considered an exception, such as

2:56

cholangiocarcinoma or cases with multiple tumors.

3:00

Uh, the issue is that the supply of the deceased donor

3:04

pool has been fairly stable over the past few years.

3:07

So we have this continued mismatch and

3:10

increasing gap in the demand and supply.

3:13

So one of the solutions that came to mind about

3:16

20-something years ago is about using the living

3:19

donors as a solution, and that's why more

3:22

and more centers are doing this type of surgery.

3:25

Right now, it's still less than 5 percent of

3:28

the total liver transplantations performed in

3:30

the United States, but more and more centers are

3:33

doing it to solve the issue of the shortage of organs.

3:42

So what's the purpose of the imaging

3:43

evaluation in the living donors?

3:47

I can divide this into two different

3:49

topics or two different components.

3:51

One is to look for the eligibility of the donor and

3:54

selection of the donors because some of the donors might be

3:58

decided not to be good candidates, and they will be excluded.

4:00

And there are certain patients

4:02

that have more than one donor.

4:04

So it also helps us to find the best

4:07

donor, which is suited for that surgery.

4:10

Uh, all of these candidates, potential donors go

4:13

through exhaustive preoperative workup, which

4:16

includes physical examination, psychological

4:19

workup, socioeconomic workup, and imaging workup.

4:22

And imaging workup is undoubtedly one of the

4:25

major components of the preoperative workup.

4:27

So, in terms of eligibility, uh, the areas that

4:32

are concerned will be assessment of the liver size, in

4:35

particular, the size of the liver, which will be remaining

4:38

after the hepatectomy, assessment of liver health.

4:41

Looking for unknown diffuse or focal liver pathologies.

4:45

And this is of importance both for the donor

4:48

and the recipient because we don't want

4:50

to give a diseased liver to a recipient.

4:53

Also, if the donor has some underlying liver

4:57

injury or liver abnormalities, they're at higher

4:59

risk of having complications after hepatectomy.

5:02

Also, it's a good chance to look for incidental

5:04

significant extrahepatic pathologies, although those

5:07

are fairly uncommon because most of the donors tend to

5:10

be healthier individuals and they've been pretty vetted.

5:14

Before coming to imaging.

5:16

The second purpose of imaging, which is perhaps of

5:20

more importance, uh, will be preparation for

5:23

surgery, giving a roadmap to the surgeons, because

5:27

the procedure could be done in multiple different ways

5:29

and the plane of resection could be very different.

5:33

So that really helps the surgeon

5:34

to know what approach is the best.

5:37

Uh, for that individual.

5:38

Also, some centers that might have less experience,

5:41

so they might not do surgery if they foresee

5:45

multiple issues, requirement for multiple anastomoses,

5:48

which increases the risk of complications.

5:52

As far as the assessment of size, uh, future remnant

5:55

liver, or FRL, is the volume of the liver,

5:59

or percentage of the liver, which will be remaining,

6:02

in the body of the donor after the surgery.

6:06

And a small FRL increases the risk of post

6:09

hepatectomy complications, especially post

6:11

hepatectomy liver failure.

6:14

Um, so the goal is to make sure that after

6:17

hepatectomy, the donor has at least 30

6:20

percent of his initial total liver volume.

6:23

And that's one of the reasons that liver segmentation

6:26

and volume calculation is a very important

6:29

component of the imaging workup in these patients.

6:33

Um, assessment of possible incidental

6:35

diffuse or focal liver pathologies.

6:37

Obviously, more and more patients have NASH

6:40

and NAFLD nowadays without knowing it, because

6:42

of the increase in this epidemic across the world.

6:46

Um, steatosis is fairly common and it's

6:49

been shown that it is an independent risk

6:52

factor for post hepatectomy complications.

6:54

So that's another role of imaging to look

6:56

for steatosis and potentially to grade it.

7:00

Most centers don't do transplantation or

7:03

they don't consider the donor to be a donor

7:07

if there's anything more than mild degrees of steatosis.

7:12

And screening for incidental pathologies,

7:14

again, these are fairly uncommon.

7:16

Because of our selection bias, most of these

7:18

candidates are younger and relatively healthier.

7:21

But there are cases of incidental malignancy,

7:25

incidental vascular pathologies that might be pertinent.

7:29

This is a case of a young female who is being

7:32

evaluated to be a potential liver donor.

7:35

And you see classic findings of fibromuscular

7:38

dysplasia, uh, beading appearance in the

7:40

middle segment of the right renal artery.

7:42

You can see it on axial, coronal,

7:47

And this is an important finding because, as we know,

7:50

although an imaging might be a segmental focal finding,

7:54

but in many cases it could be a diffuse abnormality.

7:57

So there is a chance that this individual's hepatic arteries

8:01

are also affected by the disease that could affect the

8:06

outcome of the transplant if she happens to be a donor.

8:13

The second and perhaps more important purpose

8:16

of imaging is for surgical planning and roadmap.

8:19

Uh, and it provides information to make the

8:22

decision on the candidacy of that donor and also about the

8:26

type of hepatectomy, uh, which could be affected by the

8:30

presence of vascular anatomical variants.

8:37

So a little bit of background about surgical anatomy.

8:40

So the plan of resection, uh, in adults, it's

8:44

either right hepatectomy or left hepatectomy.

8:46

The left lateral segmentectomy is usually done for

8:48

the pediatric population, which is not the focus of the talk today.

8:53

Technically speaking, the surgeons prefer to do

8:56

right hepatectomy, and by right hepatectomy, which is

8:59

classic planar resection, they resect the liver about

9:04

a centimeter posterior to the middle hepatic vein.

9:07

So this is the middle hepatic vein,

9:08

planar resection will be here.

9:10

Thank you. The right lobe will come out and will

9:12

be used as a graft, and the remaining will stay.

9:16

So, the right hepatic vein comes

9:18

out, the middle and left remain in.

9:20

And the post-surgical anatomy, in the recipient,

9:23

as you can see, there is one outflow, uh,

9:25

typically, which is the right hepatic vein.

9:28

This is the right portal vein of the donor, usually in

9:31

anastomosis, the main, uh, portal vein of the recipient.

9:36

And you usually have, ideally, one biliary anastomosis.

9:39

If this is the right hepatic duct of the donor, in

9:42

this case, it's done as a biliary enteric anastomosis,

9:46

or called a choledochojejunostomy, although in some

9:48

centers it might do duct-to-duct anastomosis.

9:55

Planar resection for left hepatectomy is a little bit more variant.

9:59

So, um, again, the preference is to do right hepatectomy,

10:02

to use the right lobe, but in some cases, it's not feasible,

10:07

most of the time it's because of the presence of biliary or

10:11

vascular anomalies that make right hepatectomy unfavorable.

10:16

In order to do left hepatectomy, the planar

10:18

resection varies between different surgeons.

10:20

Many surgeons use exactly the same plane, so the

10:23

left lobe will be the allograft, both the middle and

10:26

left hepatic lobes come out as part of the graft.

10:29

Uh, whereas some other surgeons prefer to resect

10:33

anterior to the middle hepatic vein in order to,

10:37

uh, preserve the middle hepatic vein for the donor

10:40

and to minimize the risk of congestion of the allograft.

10:43

So this is one of the areas that you have to communicate

10:46

with the surgeons, be familiar with their approach.

10:50

In this case of doing a resection anterior to

10:53

the middle hepatic vein, uh, the left lobe is

10:57

used as the graft, and as shown here, you have

11:00

one outflow, which is the left hepatic vein.

11:03

You have the left hepatic artery, anastomosis

11:05

usually to the main hepatic artery.

11:08

The left portal vein, anastomosis to the

11:11

main, uh, portal vein of the recipient.

11:14

And again, in this case, you have one biliary

11:16

enteric anastomosis, but, uh, in certain, uh,

11:20

institutions, they use duct-to-duct anastomosis.

11:25

So we talked about the goals of imaging.

11:27

We need to use modalities that, uh, allow us,

11:30

uh, to evaluate the liver parenchyma adequately,

11:33

especially to be able to look for steatosis.

11:36

Uh, we should be able to evaluate the hepatic

11:39

vasculature, especially arteries, very well.

11:41

We should be able to evaluate the biliary tree.

11:44

And also, um, uh, we are looking for extrahepatic findings.

11:48

Again, this is unlikely.

11:50

Finding in these modalities, uh, in this indication.

11:53

There are different imaging protocols,

11:55

uh, among different institutions.

11:57

Um, the current modalities available, uh, to

12:01

help us to fulfill these goals are CT, MRI, MR

12:05

cholangiography or MRC, which could be with or

12:08

without contrast, and we'll talk about it later.

12:11

Historically, they've been using intraoperative cholangiography

12:14

and ERCP for evaluation of bile ducts.

12:18

But there's a trend of not using it because

12:21

of the invasiveness of those procedures.

12:23

So there are very, very few certain cases that

12:26

uh, they just use it during the surgery,

12:29

um, just to confirm a finding which is

12:31

already known based on preoperative imaging.

12:34

Uh, so our main focus will be on non-invasive

12:37

modalities, which will be CT, cholangiogram.

12:41

And different institutions are using different combinations.

12:44

Uh, there are very, very few institutions

12:46

that do everything based on MRI.

12:48

So they have one sub shop.

12:50

Everything is done by MRI, uh, but most

12:53

institutions are doing a combination of CT and MRI.

12:56

Uh, a paper published two years ago with

13:00

Dr. Eck, um, at AJR, they surveyed, uh,

13:04

about 20 transplant centers in North America.

13:07

And at that time, all those centers which were

13:10

questioned, they were using a combination of CT and MRI

13:13

for preoperative evaluation of these patients.

13:17

As we all know, there are some advantages and

13:19

disadvantages for each of these modalities.

13:21

Um, CT is the best for evaluation of the arteries.

13:25

Also, it usually provides better coverage, so perhaps

13:28

better for findings, uh, extrahepatic findings.

13:32

MRI is the best for liver parenchyma, and cholangiography

13:36

is the best for evaluation of the biliary tree.

13:38

And we will go over these, uh, one by one.

13:44

Uh, CT examination usually is

13:46

done as a multiphasic protocol.

13:50

Non-contrast phase was traditionally

13:52

used for evaluation of steatosis.

13:55

Although, since most centers are doing a combination

13:58

of CT and MRI, non-contrast is optional at this point,

14:01

just because you have MRI, which is a way more efficient

14:05

and potent modality for evaluation of steatosis.

14:08

But we want to make sure that we have good arterial phase,

14:11

which is early for optimum assessment of the arteries.

14:15

Also, we have a venous phase,

14:17

usually a little bit more delayed.

14:19

Uh, it's not the typical portal venous phase.

14:21

We want to make sure that we

14:22

have opacification of hepatic veins.

14:25

Um, so different institutions might do this with a delay

14:27

of, uh, somewhere around 80 to 100 seconds.

14:31

Uh, and that's for assessment of the parenchyma and

14:33

also for assessment of portal veins and hepatic veins.

14:37

Obviously, you want to have, uh, adequate

14:39

technique in terms of, um, collimation.

14:42

Uh, and pitch to make sure that the spatial resolution,

14:46

especially for arteries, is as high as possible.

14:50

As we mentioned before, post-processing

14:52

is an important, uh, component.

14:54

Uh, so we always include multiplanar reformats,

14:58

uh, in terms of, uh, coronals and sagittals

15:02

to provide better views.

15:04

But on top of it, volume-rendered images also

15:07

provide more information to the surgeons.

15:10

Also, liver volumes could be, uh, easily applied

15:14

to CT because of its isotropic, um, nature.

15:18

It gives us very accurate assessment

15:20

of the volumes as shown here.

15:22

So, the major advantage will be highest

15:25

resolution for evaluation of the arteries.

15:27

It's less prone to artifacts and motion,

15:29

so it's a more consistent modality

15:31

across different centers.

15:33

Um, so there's a better chance that if it's done

15:36

on different scanners or different centers,

15:38

the image qualities are adequate and similar.

15:42

The main limitation would be it's completely unable

15:45

to evaluate biliary anatomy in this population.

15:48

Also, it tends to have lower contrast resolution

15:51

for assessment of hepatic veins because, as I

15:54

mentioned, we usually wait a little bit longer

15:56

to have, uh, opacification of hepatic veins,

15:59

but by that time, the contrast between the

16:01

hepatic veins and background liver is not perfect.

16:04

So sometimes, uh, it's suboptimal compared to MRI.

16:10

And MR angiography classically is

16:12

done, um, uh, by, um, two major sequences.

16:17

So these two sequences are, um, uh, heavily T2-weighted,

16:22

uh, T2-weighted images that show the biliary tree.

16:26

Um.

16:27

That 2D technique, uh, or thick slab,

16:30

it gives us an overview of the biliary

16:32

tree, usually done in multiple projections.

16:35

Uh, and, um, it's good to give us a good picture,

16:39

but it doesn't have the highest spatial resolution.

16:42

So, uh, if you have small branches, they might be

16:44

missed or not well, uh, represented on these images.

16:47

The 3D MRC, on the other hand, uh, gives us higher

16:51

signal-to-noise ratio and higher spatial resolution.

16:54

There are much thinner images and they should be

16:56

done by respiratory gating or navigator gating.

16:59

Because they take much longer

17:01

time because of the same reason.

17:03

They're more prone to motion artifacts because of the

17:08

longer acquisition time and need for respiratory navigation.

17:11

But if they're done properly, if you can see in this

17:14

case, uh, the maximum intensity projection, the method

17:18

based on the 3D, uh, gives you a better look

17:22

with higher spatial resolution compared to the 2D.

17:26

And in this case, um, this is a normal, uh, or a

17:29

conventional anatomy in a 42-year-old potential liver donor.

17:34

And you can see the right posterior, right anterior,

17:37

they form a short right hepatic duct, and you have the

17:41

left hepatic duct, forming the common hepatic duct.

17:43

The patient obviously had breast cancer,

17:45

prior cholecystectomy and the cystic duct remnant is here.

17:50

Um, there's another concept, it's called contrast

17:52

enhanced MRC, um, some, um, experts call it T1

17:57

weighted MRC, but the idea is that, uh, we are giving

18:00

hepatobiliary contrast, and hepatobiliary contrast

18:03

will be absorbed by hepatocytes through a specific, uh,

18:06

receptor, which is OATP1B3, and then they'll be excreted,

18:11

via a separate set of receptors into the bile duct.

18:14

So if you just wait to catch the hepatobiliary

18:16

phase, you're going to see the excretion

18:18

of the contrast into the biliary tree.

18:22

So now you have a contrast

18:23

enhanced look of the biliary tree.

18:26

Uh, currently there are two types of contrast

18:29

available that give us the hepatobiliary effects.

18:32

EOB (Eobist), or it's called Primovist in Europe,

18:37

and Multihance are two different types.

18:39

EOB is the preferred type because it has about 90 to

18:42

95 percent excretion via hepatocytes and biliary excretion.

18:48

And also the hepatobiliary phase is achieved much

18:51

faster, usually within 20 minutes, versus for

18:53

Multihance, which is only 50 percent hepatic excretion.

18:58

And it takes hours to achieve.

19:00

So, um, these are comparisons of two-dimensional

19:04

MRC, 3D MRC, and contrast-enhanced MRC.

19:06

Obviously, 2D and 3D are usually done in conjunction.

19:10

They're part of the regular, uh, unenhanced MRC.

19:14

As I mentioned, 3D MRC could be affected by motion.

19:17

So in certain patients, it might turn out

19:19

to be, uh, not diagnostic adequate.

19:22

In terms of spatial resolution, the contrast-enhanced

19:25

MRC has spatial resolution as good as 3D MRC.

19:31

Uh, one of the reasons is that,

19:32

uh, it's a T1-weighted sequence.

19:36

Um, so most of the time they're done by 3D acquisition.

19:39

So it's a very rapid acquisition that, uh, um,

19:43

gives you higher spatial resolution as it's

19:45

not affected by motion, and also it's a 3D

19:49

acquisition, so you can do a volumetric assessment.

19:53

The signal-to-noise ratio, for the same

19:56

reason, is higher in the contrast-enhanced MRC.

20:00

It's similar to 3D MRC, and acquisition time

20:03

is much shorter compared to the other ones.

20:08

This is an example of a 28-year-old potential living donor.

20:12

This is 2D MRC.

20:15

Again, the spatial resolution is, uh, slightly lower.

20:19

After that, we tried to do 3D MRC.

20:22

Um, and this is the MIP images.

20:24

The first attempt was unsuccessful

20:26

because you see the motion artifact.

20:28

The second attempt was successful

20:30

and you have good quality 3D MRC.

20:33

But as part of the protocol, we also did contrast

20:36

enhanced MRC, which shows the biliary tree very nicely.

20:39

Um, obviously that, it's not an apple-to-apple

20:42

comparison because these are MIP images.

20:44

It's not, uh, feasible to make MIP

20:47

images out of the contrast-enhanced MRC.

20:49

But if you just have the same section and compare them,

20:53

usually contrast-enhanced MRC gives you very good results.

20:56

So, in our experience, and also the paper by AJR,

21:05

most people believe that having this additional

21:09

sequence will increase the confidence of evaluation

21:12

of biliary anatomy, both confidence and also accuracy.

21:20

MRI, um, is, uh, the best modality for

21:25

evaluation of the liver parenchyma.

21:27

And if there happens to be a focal lesion,

21:30

obviously it is the best modality for characterization.

21:33

Um, uh, and as we discussed before, steatosis is one

21:37

of the common entities which impacts the outcome.

21:39

And it's very important that we are able to, uh,

21:43

evaluate it adequately and MRI is the best to go.

21:46

So, chemical shift imaging is, uh, normally

21:49

performed on all the protocols in many places.

21:52

That's all they rely on.

21:54

Uh, but in certain institutions, more advanced sequences,

21:57

such as proton density fat fraction, could be performed

22:00

to better quantitatively evaluate the degree of steatosis.

22:05

Also, there is potential to evaluate fibrosis using MR

22:08

elastography or looking at the iron deposition. These are

22:13

not universally done in all institutions, but depending

22:16

on the availability of those, um, hardware and software

22:20

on that specific scanner, they could also be incorporated.

22:24

Advantages of MRI include its ability to

22:27

provide comprehensive evaluation of parenchyma,

22:29

both for diffuse and focal entities.

22:33

It usually gives you the highest

22:34

contrast resolution for hepatic veins.

22:37

The limitations of MRI include MRA.

22:40

Um, typically, the quality of MR angiography

22:45

is lower compared to CTA in terms of spatial resolution.

22:49

It is prone to respiratory motion and

22:52

requires a lot more technical expertise.

22:54

So it should only be done in larger centers

22:57

with adequate expertise on this topic.

23:01

This is a case, um, this is a patient, uh, 32-year-old,

23:06

um, um, I think, uh, yeah, 30-year-old patient.

23:10

And, uh, during the workup on CT, and in

23:13

this, uh, example, we were doing CT and MR

23:16

at the same time, um, or in the same setting.

23:19

Uh, on CT, which was done first, there is a

23:22

lesion, there's hyperdense, subcapsular, there's

23:24

a duct of, um, punctate calcification next to it.

23:28

It was indeterminate by CT alone, but when

23:31

looking at the MRI, these are in-phase and

23:34

out-of-phase images from chemical shift imaging.

23:36

You see a drop in signal in the out-of-phase.

23:38

You also have the fat images

23:40

based on the Dixon-type sequence.

23:43

You see that there is fat in that area.

23:45

So based on the location and the fat content,

23:49

it was consistent with pseudolipoma of the

23:51

Glisson capsule, which is a benign entity.

23:58

The topic will be what type of contrast agent to

24:01

use for MRI, extracellular versus hepatobiliary.

24:04

Extracellular agents are more commonly used and the

24:08

reason is that they provide better quality arterial phase

24:13

than using hepatobiliary agents, especially

24:16

when CTA is not done as part of the workup.

24:19

You really rely on your MRI for having good MR

24:22

angiography, and extracellular agents typically give

24:25

you much better quality than hepatobiliary agents.

24:28

Um, the issue with the lower quality of

24:31

angiography, uh, or arterial phase, uh, hepatobiliary

24:35

agents is due to three different categories.

24:37

Um, these agents tend to have higher relaxivity.

24:40

Um, so because of that, uh, the dose is half of the

24:44

extracellular agents, so lower dose, lower injection time.

24:47

So you have a smaller window and smaller peak.

24:51

Uh, so it's harder to catch a perfect arterial time.

24:54

Um, this type of contrast is more

24:56

prone to cause truncation artifacts.

24:59

And there's also an entity called

25:01

Transient Severe Motion, or TSM.

25:04

It's been reported around 8 percent in

25:06

multiple series, mostly in the United States.

25:08

So that means that about 8 percent or so

25:11

of patients, right after injection of the

25:14

hepatobiliary agent, experience this transient motion.

25:17

Uh, dyspnea and motion, and because of the motion, uh,

25:21

usually the arterial phase will be very low quality.

25:26

Uh, there are, however, new promising sequences.

25:29

There are, um, uh, several new sequences that, by subsampling

25:33

technique, result in faster acquisition, and by

25:37

doing that, you can decrease the acquisition time and

25:40

hopefully, uh, capture more than one arterial phase,

25:44

uh, and they can increase the signal-to-noise ratio.

25:50

These are two examples of two different patients.

25:52

On top, the patient received a hepatobiliary agent.

25:56

Right after injection of 10 cc of DTPA, the patient

26:01

experienced transient severe dyspnea and motion.

26:04

You can see the motion and your arterial

26:06

phase is technically non-diagnostic.

26:08

And the sequence after that, when we

26:11

captured, it was already in the venous phase.

26:14

So you're out of the window to capture the arterial phase.

26:18

And this is a CT on the same patient,

26:20

the same day, for comparison.

26:23

The bottom row is a different patient.

26:25

Again, it was used, um, it was performed

26:29

using, um, uh, EOB-DTPA or Eovist after 10 cc.

26:34

But in this case, we used one of the

26:36

newer sequences, which is called DISCO.

26:38

It's based on differential subsampling.

26:40

So, because of the faster acquisition

26:42

time, you have faster results.

26:44

Three, uh, chances to capture arterial phase.

26:47

So the first one, second one, and third one.

26:50

And if you happen to have some degradation

26:53

here, like there's some motion, you still

26:55

have two more chances to capture that.

26:57

So that's one of the solutions that more

27:00

institutions are using to optimize their MRA.

27:03

Um, again, in this case, you have the, um, CT

27:07

for comparison, and you see the classic course

27:09

of the replaced or accessory right

27:12

hepatic artery posterior to the portal vein.

27:20

Another solution, um, um, to overcome the

27:24

limitations of hepatobiliary agents for

27:27

MR angiography is using double agents.

27:29

This is off-label.

27:31

Very, very few institutions are doing this,

27:33

using this approach.

27:34

And in this approach, uh, you're doing

27:37

your, uh, non-contrast MR cholangiography.

27:40

You're using extracellular agent to, uh, obtain

27:43

your arterial phase and post-contrast phases.

27:46

Right after that, you inject a second

27:48

dose, this time with a hepatobiliary agent.

27:50

And 20 minutes later, uh, you're achieving your

27:54

delayed hepatobiliary phase using, uh, Eovist.

27:57

So basically, this is double agent:

27:58

one sitting, one examination, uh, but two injections

28:03

at two different points, uh, to basically take advantage

28:06

of the advantages of both extracellular and hepatobiliary agents.

28:11

In this case, you see very nice anatomy, both

28:14

in the regular MRC, on the contrast MR MRC,

28:18

and also you have very, very good quality MRA.

28:25

For the second part of this talk, we'll focus on,

28:28

uh, conventional and variant vascular and biliary

28:31

anatomies of the liver, um, mostly focusing on the

28:34

ones that are pertinent to this type of surgery.

28:37

Uh, biliary anatomies, uh, variant anatomies of the biliary

28:42

tree are very common, and they're actually the most

28:44

important, um, uh, uh, category in terms of causing

28:48

issues for the surgeons and complications down the road.

28:52

Most of these variants affect the right lobe branch.

28:57

There are different classification schemes.

29:01

In my opinion, it's best to just describe it

29:04

rather than using the number of classifications,

29:07

because some of the variations are not even described

29:12

in the common classification system.

29:14

As an example, this is based on one of the series

29:16

and the distribution of variants they have.

29:19

Uh, the conventional pattern is you have

29:21

a right posterior duct and right anterior.

29:24

They join together to form a single right hepatic duct.

29:27

You also have a left hepatic duct, which also

29:29

has two branches to the medial lateral segment.

29:32

And these together form the common hepatic duct.

29:35

Um, the common variations will be the right

29:37

anterior has separate drainage, so it's

29:40

slightly aberrant and lower down it drains.

29:43

Um, the other one will be the near trifurcation, so, um,

29:47

we have a very short or non-existent right hepatic duct.

29:51

The other will be the right posterior branch.

29:53

Instead of joining the right anterior,

29:55

it goes and drains into the left hepatic.

29:57

Um, another variation will be a variant drainage

30:00

of right posterior and the other subtypes.

30:04

And many of these variants, in cases of right hepatectomy,

30:07

they might dictate having two biliary anastomoses.

30:10

So that's why it's very important

30:12

for surgeons to know beforehand

30:14

and be prepared for that, uh, uh, approach.

30:18

As an example of the conventional branching pattern, as we

30:20

discussed, this is the right posterior and right anterior together.

30:24

They form the right hepatic duct.

30:26

You have the left; this is completely, uh, conventional.

30:30

And, uh, this is a 3D, uh, MIP image.

30:33

It's from the 3D MRC.

30:35

This is, um, uh, MIP from the

30:37

post-contrast hepatic phase MRC.

30:40

This patient underwent right hepatectomy.

30:42

Uh, you see the clips after right hepatectomy.

30:45

This is the intraoperative cholangiography

30:47

to make sure there's no leak.

30:49

This shows the common hepatic and left hepatic duct.

30:52

And this is the plane of resection.

30:54

On the right side, you're

30:56

seeing the graft in the recipient

30:58

a few days after.

31:00

And you see the, um, right hepatic duct, the branches,

31:04

and this is the anastomosis to a loop of jejunum.

31:06

So this particular patient had a biliary-enteric anastomosis.

31:14

Other types of pertinent variant

31:16

anatomies that could affect the surgery:

31:19

as shown before, this is a right

31:21

posterior draining into the left hepatic.

31:24

So, in cases of right hepatectomy, the surgeons will end

31:28

up having two, um, different, uh, bile ducts to anastomose.

31:33

Similarly, here, you have a right anterior, uh,

31:36

branch with an aberrant course coming all the way down.

31:40

Again, this requires anastomosis.

31:43

This is a case of near trifurcation.

31:46

Uh, again, a similar concept.

31:48

And in this case, you have the right posterior

31:51

coming all the way down and draining

31:53

into the cystic duct or near the cystic duct.

31:59

As I mentioned before, there are some

32:01

cases that have more complex, uh, anatomy.

32:04

Again, it doesn't fit into any of

32:06

the, um, described classifications.

32:09

So the best way would be just to describe

32:11

and also review with your surgeon.

32:13

So this is a very complex, um, um, variant anatomy.

32:18

And in these cases,

32:19

the contrast-enhanced MRC will be very, very handy

32:22

to increase confidence and accuracy.

32:25

In this case, you have a left lateral segment

32:27

branch of the hepatic duct, left hepatic duct.

32:30

The medial branch of the left hepatic duct has

32:33

separate drainage here, close to the confluence.

32:36

The right posterior is going to the

32:38

left, and you have a right anterior here.

32:41

And you also see that on the axial images.

32:46

Hepatic arterial anatomy is the second most, uh, important

32:49

category, uh, again, really affecting the outcome.

32:52

Um, uh, the overall prevalence is 25 to 50.

32:57

Uh, so you can actually divide the arterial

33:00

anatomy into two different categories:

33:02

the extrahepatic arteries and intrahepatic arteries.

33:05

So in terms of the extrahepatic anatomy, which is

33:09

also very similar to the concept for whole liver

33:12

transplantation, uh, we basically talk about the presence

33:16

or absence of accessory or replaced hepatic arteries.

33:20

Conventionally, you have the celiac artery coming,

33:23

giving rise to a common hepatic artery.

33:25

After the takeoff of the GDA, you have a single proper

33:29

hepatic artery, which divides into the right and left

33:31

hepatic arteries, uh, in order to, um, supply the liver.

33:36

Uh, in variant anatomies, you have an accessory

33:39

or replaced artery supplying the left or right.

33:43

This is a case of accessory left hepatic

33:46

artery coming off of the left gastric artery.

33:49

A case of an accessory right

33:51

hepatic artery coming out of the SMA.

33:53

So it's very important to describe these.

33:56

But the thing that is unique for this type of

33:59

transplantation is the arterial anatomy inside

34:04

the liver, because in cases of whole liver, we

34:06

don't care about the branching pattern inside the

34:09

liver, because the whole liver will be explanted.

34:12

But in this case, uh, the planned resection is

34:15

really, uh, uh, might affect, uh, the arteries.

34:19

Uh, so if you look here, um, this

34:21

is a conventional branching pattern.

34:23

This is the main hepatic artery.

34:25

You have a right hepatic artery and a left hepatic artery.

34:28

And conventionally, this branch to segment 4, or the medial

34:31

segment, is arising from the left hepatic artery.

34:34

But there are variations where this branch might

34:37

come off, uh, the right hepatic artery or close by.

34:41

So, for example, if you look at this case,

34:43

you have a segment 4, segmental branch of the

34:45

segment 4, which is part of the left lobe,

34:48

arising from the right hepatic artery.

34:50

And during the right hepatectomy,

34:53

this artery will be taken out.

34:54

So, uh, the result will be ischemia and

34:58

complications in segment 4 of the donor.

35:01

So, it's very important to communicate these

35:03

beforehand, as that affects the planned resection.

35:05

They may decide to do a left hepatectomy

35:07

instead, or they may try to resect

35:11

superior to this, uh, origin of this

35:13

artery to, to save that artery, uh, or

35:17

perform some angio, um, uh, or reconstruction.

35:21

Um, some examples: uh, this patient has a replaced

35:27

right hepatic artery, this is the SMA, so the right

35:30

hepatic artery is arising from the, um, uh, SMA.

35:35

And it's called replaced because there's

35:37

no other branch going to the right lobe.

35:39

So the sole supplier of the right lobe is

35:42

this artery, which is coming off the SMA.

35:44

Also, the segment 4 branch in this case is coming off

35:48

of the left hepatic artery, which is conventional.

35:50

So all in all, this is a very, um, this is also a

35:53

preferred anatomy for the surgeons because

35:55

there's one right hepatic artery; they can just cut

35:57

it, and they have, um, a lot of space to work with.

36:04

Another example of accessory right hepatic artery,

36:06

so this one is arising from the SMA, but you also

36:09

have other branches from your proper hepatic artery.

36:12

So that's why it's called an accessory

36:14

right hepatic vein, um, versus replaced.

36:18

And this patient or this candidate has both, both a replaced

36:22

right hepatic artery and an accessory left hepatic artery.

36:28

And other examples.

36:30

This patient, um, has a near trifurcation

36:33

of the common hepatic artery.

36:35

So you have a common hepatic, GDA,

36:37

right hepatic artery, left hepatic.

36:39

So there's no, uh, proper hepatic artery.

36:42

But this is not relevant, uh, to this surgery.

36:44

So it's not causing any issues because

36:46

you still have one right hepatic artery.

36:49

Uh, and also, uh, showing that the branch to the

36:53

segment 4 is arising from the left hepatic artery.

36:56

So again, this is a very favorable anatomy

36:59

in terms of arterial configuration.

37:03

Uh, versus this case, in this case, uh, you

37:05

see the fissure for ligamentum of Teres.

37:08

So this is segment 4, this is the lateral segment.

37:10

So this part of the liver is stained, um, for the donor.

37:15

And you see that the supplier of the segment

37:17

4 is arising from the right hepatic artery.

37:20

So if the surgeons don't know beforehand and

37:23

they resect here, uh, the segment 4 will be

37:27

uh, compromised in terms of arterial supply.

37:31

Again, same, same case on the coronal aspect.

37:34

So this is the schematic of this type of

37:36

anatomy where the segment 4 branch is arising.

37:39

From the right hepatic artery.

37:40

In another case, we have two branches, so segment 4, both

37:46

from the right and left hepatic artery.

37:48

Again, it's very, very important to detect

37:50

these and communicate these with the surgeons.

37:53

And this is a topic that is fairly

37:55

unique for this type of transplantation.

38:00

As far as the hepatic venous anatomy, uh, uh, there are

38:04

about 30 percent prevalence, uh, but the main ones that are

38:08

important are the presence of the, um, accessory right hepatic

38:13

vein, and also the big territorial, um, branches.

38:17

So, the common or conventional pattern is having one

38:21

right hepatic vein, middle, and left hepatic vein.

38:23

They typically, um, go together,

38:26

having a very short common trunk.

38:28

And as we mentioned before, in the case of right hepatectomy,

38:31

both the middle and left, uh, stay in the donor's body.

38:36

So when you have a large, uh, accessory right hepatic

38:39

vein, the surgeon should know beforehand and they should

38:42

decide whether to, um, cut it and, uh, ligate it, but

38:47

then the patient will be at risk of, um, congestion of

38:50

that segment of the liver or reconstruct it using a graft.

38:55

Uh, and obviously knowing is very important

38:57

because if they're not aware of the presence

39:00

of that vein, there's a risk of, uh, bleeding.

39:03

Um, so anytime we see this type of accessory, inferior

39:07

orthopedic vein, you like to describe, uh, different

39:11

surgeons might use different numbers, but, uh,

39:13

most institutions use, uh, anything more than four

39:17

millimeters or five millimeters in diameter as significant.

39:20

And those are the ones that need to be

39:21

reconstructed for adequate drainage of that

39:24

segment of the liver, which is usually segment six.

39:28

And also, it's recommended to communicate the distance

39:31

between these two because they can decide if it's going to

39:34

have, uh, two anastomoses or have a large Krell's patch.

39:38

To include both of them, um, for, for anastomoses.

39:42

The other entity which is important to recognize and

39:46

communicate would be having large, um, uh, venous branches.

39:51

So segment five and eight, in many cases,

39:54

they'll be drained into the right hepatic vein.

39:57

So after a hepatectomy, these will have adequate

40:00

drainage through the right hepatic vein.

40:02

But in a certain number of patients or candidates,

40:05

uh, these branches drain into the middle hepatic vein.

40:09

And as remember, the middle hepatic

40:11

vein is going to stay in the donor.

40:13

And this will be the planar resection.

40:15

So now you're left with this vein,

40:18

um, which needs to be taken care of.

40:20

So if it's unknown and it's caught,

40:22

obviously, it causes bleeding.

40:24

And if it's ligated, then that part of

40:26

the liver will be at risk of congestion.

40:28

So most surgeons decide, based on the size, to reconstruct

40:32

them, using some interposition grafts.

40:36

To be able to adequately drain those segments.

40:40

So again, wanna recognize the large segmental veins of

40:45

segment five and eight, uh, draining into the middle

40:48

hepatic vein and communicate them with the surgeon.

40:51

Um, an example of conventional

40:54

pattern: a right, middle, and left.

40:57

You have a very short common trunk between the middle and

41:00

left, which is a very common, um, anatomy in this patient.

41:05

You're seeing two right hepatic veins.

41:07

This is the actual one, and you have

41:09

a second one, which is fairly large.

41:11

So this patient, after the surgery, uh, the

41:15

graft had, um, a jump graft, or interposition

41:18

graft, to drain this one to the IVC.

41:24

And the other candidate, there are

41:26

actually two of those accessory ones.

41:28

So this is the actual right hepatic vein.

41:30

You have one accessory and two accessories, and both of

41:33

them are rather large, so they need to be taken care of

41:36

to, uh, ensure there's adequate

41:40

drainage of those segments of the liver.

41:42

Uh, just an example, just to show you that, uh,

41:45

hepatic veins on CT sometimes are hard to appreciate

41:48

because of the issue with contrast resolution.

41:50

I mean, you do see them, but, um, you can imagine

41:53

for smaller ones, it might sometimes be harder.

41:55

So that's why MRI is actually better for hepatic

41:59

veins, because you have multiple sequences to show you,

41:02

um, them, um, uh, better, with better contrast resolution.

42:05

These are FSSP, Fiesta in this case,

42:08

and you see the veins very well.

42:10

This is one of them, this is the other one.

42:12

And this is the hepatobiliary phase, 20-minute

42:15

delay, and all the vessels will be dark.

42:17

So again, you have, uh, pretty good

42:19

contrast resolution of dark vessels.

42:23

Uh, against the background, um, enhanced liver.

42:29

This is an example of a large segment 8 tributary

42:33

vein, which is going to the middle hepatic vein.

42:36

This is the planar resection.

42:38

Again, um, if, uh, this is ligated, this

42:41

segment of the liver will be congested.

42:43

So in this case, you're going to use an

42:45

interposition jump graft to adequately

42:48

drain this into the IVC of the recipient.

42:54

The last entity will be the portal venous anatomy.

42:57

Uh, usually they're less common; the variations are common,

43:00

but, um, usually, they don't affect, uh, the type of surgery.

43:04

They're not as common as the biliary and arterial

43:07

ones, in terms of affecting the, uh, surgical approach.

43:10

Um, the, um, the most common pattern or

43:13

conventional will be having a main portal vein bifurcate

43:16

to the right, left, and each of them will further

43:19

bifurcate into the, uh, two, um, additional branches.

43:26

This is a conventional right and left.

43:28

You have one main and dividing at the level of the hilum.

43:35

In this case, it's a very short right

43:37

portal vein or almost near trifurcation.

43:40

So you have a portal vein and at

43:42

the same area you have the left.

43:44

You have the anterior branch of

43:46

right and posterior branch of right.

43:48

So in these cases, the surgeon might decide to do

43:51

a venoplasty, um, to make sure that, um, the

43:55

anatomy for the residual liver for the donor

43:58

is adequate.

43:59

Another example showing the comparison between CT and MRI.

44:03

This is the venous phase CT.

44:05

I had to use MIP to show the entire venous anatomy

44:08

here, so some of the degraded quality is because of

44:12

using MIP, but there's some inherent issues with the

44:15

contrast resolution on CT because we have to wait a

44:18

little longer to have hepatic venous capacitation.

44:21

In comparison, same patient, venous-wise.

44:25

and we're using hepatobiliary phase and you have

44:27

excellent contrast resolution between the dark

44:30

vessels and the background hyperintense liver.

44:35

Another example of variant, uh, portal venous anatomy,

44:39

in this case, the right portal vein, the posterior branch

44:42

of it, has low variant drainage into the portal vein.

44:46

So in this case, for right hepatectomy, again, they might

44:49

cut the veins at two different sides and they have to

44:51

do some, uh, back benching and back-table venoplasty.

44:55

So again, very important to

44:56

communicate these with our surgeons.

45:01

Uh, as far as the reporting, uh, the reports

45:03

should be pertinent, uh, to the point and

45:06

detailed about the pertinent anatomies.

45:09

Uh, the ones that, uh, we talk about are very important

45:12

to be very detailed about the biliary anatomy.

45:15

If you see anything, uh, non-

45:17

conventional, just be very descriptive.

45:19

Obviously, we have some, uh, uh, uh, reformats in

45:23

NPR to provide more information to the surgeons.

45:27

Uh, very important to look for intra-

45:29

and extrapodic arterial anatomy.

45:32

And in the intrahepatic part, very

45:34

important to recognize segment 4 branch.

45:37

And, uh, to report if it's arising from the left or right.

45:41

If it's not conventional, again, be very descriptive.

45:44

And similar, um, um, concept for

45:47

the portal vein and hepatic veins.

45:49

Uh, portal vein, uh, the relevant portal vein,

45:52

um, varying anatomies are uncommon.

45:55

But in terms of biliary and arteries, they're

45:58

very common and they're usually associated.

45:00

People who have, um, um, variant biliary anatomy

46:04

most likely will also have variant arterial anatomy.

46:08

And it's very important to have a multidisciplinary approach.

46:10

So, um, uh, should be engaged, uh, with the

46:15

transplant surgeons and the pathologists.

46:17

Make sure that we are providing

46:19

all the information they need.

46:21

We have to make sure we are familiar with

46:23

their surgical approaches, with their criteria.

46:25

And, uh, we provide, uh, whatever they need.

46:28

Uh, information they need to make a decision.

46:32

And there are different approaches.

46:34

Some institutions, I know that all these cases are reviewed.

46:37

by surgeons with, uh, usually one

46:39

or two designated radiologists.

46:41

So each of them, for every case, they sit down

46:43

together, review everything, uh, in, uh, some

46:46

institutions that might have some scoring sheet to

46:49

predict the complexity of the, uh, operation based

46:53

on the number and type of the, uh, variations.

46:57

Uh, in some other institutions, perhaps, since they're doing

47:00

more and they have more experience, the surgeons might rely

47:04

on, uh, reports and also looking at the, um, at the, uh,

47:08

immediate studies themselves, but it's very important to

47:11

be engaged and offer them, if they need to have, um, sit down

47:16

one-to-one review of this case, because these are one of

47:19

the few scenarios that everything, if something goes wrong,

47:23

two people will be hurt, both the donor and the recipient.

47:27

Uh, there's also potential for using a templated report

47:30

to make sure that all the pertinent information is looked

47:33

at, and that will ensure better inter-reader consistency.

47:37

This is an example of a template report that, uh,

47:42

basically, like, has bullet points to talk about

47:44

the diffuse liver disease, focal lesions, and

47:47

anatomic variations of the liver, very uncommon.

47:50

Uh, the volumes should be reported.

47:51

They're very, very important for assessment

47:54

of the FLR, future liver remnant, which is a

47:57

very important, uh, uh, indicator of the, uh,

48:01

post-hepatectomy liver failure in the donor.

48:05

And for each of the organs, arteries, ovaries, and

48:07

platelet veins, you want to have a detailed bullet

48:10

point about the, um, the pertinent information about.

48:13

So

48:15

in conclusion, um, radiologic evaluation is

48:19

an integral part of preoperative evaluation

48:22

of the candidates for liver donation.

48:26

And we as radiologists have to ensure that we're

48:29

providing the highest quality and comprehensive imaging

48:32

techniques with efficient protocols to provide all the

48:35

information necessary for the surgeons and the team.

48:39

And also, we ensure, uh, we recognize those pertinent

48:43

information and clearly communicate them to the team.

48:48

And in order to do that, we have to be very

48:51

familiar with the surgical techniques, and

48:53

those could be specific to your institution.

48:55

So it's very, very important to know exactly your

48:58

surgeons, what they do, how they do, and communicate.

49:02

And, uh, also, uh, post-processing is an integral part

49:05

of these studies, um, just to show the anatomy better,

49:09

but most importantly, importantly to make sure that we

49:12

have an accurate assessment of the volumes, an accurate

49:15

assessment of the future, uh, liver, um, uh, remnant.

49:20

Because in one of the papers, the most common

49:23

reason that a donor was excluded as being

49:26

a donor was anticipation of inadequate FLR.

49:31

So it's very important that that piece of

49:32

information is reliable and accurately done.

49:36

And with that, I conclude the session.

49:38

Thank you everyone for your attention.

49:40

Um, uh, I just want to acknowledge,

49:42

uh, uh, my colleagues,

49:44

Dr. Furlan, uh, from Radiology University of Pittsburgh,

49:47

Dr. Humar, uh, the transplant surgeon from Pittsburgh,

49:50

and the ACLRS group, uh, since we did a similar work

49:54

as a presentation on paper, uh, a few months ago.

49:57

And with that, I, uh, finish my

50:00

talk and, uh, I'll be available

50:03

for questions.

50:05

It does look like we have one question in the Q&A.

50:14

Uh, so it's a very good question about what is the

50:17

definition of myosteatosis for a living donor.

50:19

So, it's a little bit subjective.

50:21

It used to be, uh, based on surgery, um, journals

50:25

that, uh, if it was a myosteatosis that you can

50:28

detect based on MRI, but not based on non-contrast

50:31

CT, they basically considered that being a mild.

50:35

So something that really needed chemical shift imaging.

50:38

Nowadays, more places are doing more objective evaluations.

50:41

So if you have PDFF, protein density fat fraction,

50:45

so we use the thresholds described for that.

50:47

So it is less than, uh, is more than 6%, uh, more than 6.

50:51

2 percent is abnormal, uh, up to like almost 11, 12.

50:55

So if it's less than 11 percent, it is

50:57

mild and they're okay, um, to do it.

50:59

Uh, and some places also use just chemical shift

51:02

imaging and then use at the drop in signal.

51:06

Um, and 10% drop of signal.

51:08

They considered it, uh, more than mild.

51:10

So I think that area is a little bit of a

51:12

subjectivity, it's more of a, uh, based on,

51:16

uh, if you have PDFF, that's very clear cut.

51:19

So you just go by the numbers, but you don't have that.

51:22

It's a little bit of al based on your

51:24

subjective assessment of chemical of imaging

51:27

and whether you perceive that on, on IT.

51:33

Well, I think, um, we can give it a

51:35

couple more minutes if anybody else has.

51:39

Any questions they'd like to, uh, pose for Dr. Barani?

51:47

Uh, very good question in the role of contrasting has also,

51:50

um, I, um, I am not familiar, um, um, uh, to be honest, um,

51:58

um, it is very important, uh, in these cases to get, uh,

52:04

biliary information, um, so you do need, uh, uh, you do need

52:07

other modalities for biliary anatomy, uh, which will be MRI,

52:12

so you still need MRI, but you still need very, very good

52:15

look at the arteries, right, so I, I doubt that you can

52:19

a, uh, perfect look at small branches, like a segment four

52:23

branch with ultrasound, uh, with contrast neural ultrasound.

52:26

So in my opinion, um, CT and MRI are more potent modalities.

52:32

And even if you do contrast-enhanced ultrasound,

52:35

you still need those modalities for other reasons.

52:38

So I don't see that being a replacement

52:40

for other, um, for other modalities.

52:43

And again, this is a topic that you really

52:45

don't afford to miss anything because this is

52:48

something that could affect two individuals.

52:50

So we just want to make sure that you're providing the

52:54

best out there. And for that reason, I think contrast

52:57

enhanced ultrasound is not adequate to look for that

53:00

tiny segment four branch, uh, and also, as you know,

53:04

it's not perfect to look at the extrahepatic arterial

53:07

anatomy just because of issues with penetration. So,

53:10

uh, I would say that, me personally, I don't think

53:15

that this will be very beneficial in this setting.

53:23

Yeah, about the variants, I, to be honest,

53:25

um, they don't, the, the, the main thing

53:27

they care will be the planar resection.

53:30

Uh, so from the surgeon's mind, would be that, uh, within the

53:35

planar resection, if they are cutting any major thing,

53:38

so if they know that they're just going

53:39

to cut it, there's no major artery or big

53:42

vein traversing that plane, they're okay.

53:45

And then, um, they decide to do, uh, one

53:49

or multiple anastomoses for each of them.

53:51

And then also they care about the,

53:53

the, the volume of the remnant liver.

53:56

So, uh, most of these variations, uh, like a regular

54:00

lobe, um, they just do not affect the planar resection.

54:04

And also they consider the total volume and

54:07

remnant; they just care about the number of it.

54:09

So, uh, the short answer will be.

54:11

Uh, no, basically, they're not

54:13

pertinent for this type of surgery.

54:17

And I see, um, I'm not sure if I'm saying

54:19

your name, your last name correctly,

54:21

but Dr. Debner, um, if, I know you raised your

54:25

hand, but if you can direct your question

54:26

to the Q&A function, that would be great.

54:33

Give him a moment, see if he can,

54:34

uh, if he types his question up

54:46

It's a very good question.

54:48

Uh, the

54:51

Oh, you mean the recipient, is it recipient or donor?

54:54

Maybe I can add something else about this.

54:56

So it's a good excuse to talk about the

54:59

safety. So how about the donor safety?

55:01

So there are very few cases of death after hepatectomy

55:05

in the donors, but they're like a long time ago.

55:07

Uh, and both of them.

55:09

Yeah.

55:09

Thanks for the correction.

55:10

And, um, uh, those were like, because of

55:12

hepatic failures, but recently there were

55:15

zero reports of death in the United States.

55:18

There was, um, in 2012, a big multi-

55:21

institutional, uh, observational study.

55:23

They looked at 760 donors.

55:26

They, uh, followed them for 12 years, uh,

55:29

all from institutions in the United States.

55:31

And there was zero case of post-hepatectomy liver failure,

55:36

basically just because we were doing a much better

55:38

job in pre-op evaluation by imaging and estimation of

55:42

future liver remnant.

55:44

So the risk of hepatic failure was zero.

55:46

There were three cases of death.

55:49

One was due to sepsis, a post-operative

55:51

infection, and multi-organ failure.

55:54

And two other ones, they were perhaps non-relevant

55:57

to the surgery because it was like almost two years

55:59

after. One was suicide, the other one was drug overdose.

56:03

Um, so the safety, there is risk, the

56:05

complication risk is there, is real, but it's low.

56:08

Uh, and most commonly, um, there are very mild

56:12

and self-limiting, um, right pleural effusion.

56:15

Uh, liver infection by Loma is rare, but

56:19

most of them could be taken care of fairly

56:22

simply, so the safety is pretty good.

56:24

But there's a risk.

56:26

And to answer your question, it

56:28

depends on different institutions.

56:30

So one of the institutions I, uh, used to work at before

56:35

as a routine, all of the donors would get a CT of the

56:38

abdomen without contrast three months to make sure

56:40

that the, uh, there's adequate regeneration of the liver.

56:44

And almost all of them, I have to say all of them,

56:47

had adequate regeneration, meaning that the retained

56:50

liver grew to be more than 80 percent of the initial

56:54

total liver, which is pretty, uh, uh, impressive.

56:58

But other institutions, they don't

57:00

do it unless there's a reason.

57:02

So they do not have a set protocol

57:04

for imaging of the donors.

57:05

But the other institution has.

57:07

So I think that's really, uh, based

57:09

on, um, uh, institutional preferences.

57:12

Uh, but overall, the complications, if

57:14

they happen, they're usually early post-op.

57:17

The most common significant one will be, uh, bile leak.

57:20

But they usually know because they leave

57:22

a drain, surgical drain after hepatectomy.

57:24

So clinically, it's suspected because the

57:27

patient has continuous bilious, uh, drain.

57:30

And then that will prompt imaging studies and workup.

57:33

So it's, it's, it's unlikely to see.

57:35

major significant complications down the road.

57:38

I mean, there are cases of hernia,

57:40

uh, but nothing, uh, major.

57:43

Because of that, many institutions opt not to do repeat

57:46

imaging or, or protocol imaging on these patients.

57:49

That's what is used to become functional.

57:52

So that's,

58:01

that's the question.

58:01

So that's

58:02

a very, um, top big topic.

58:04

So, uh, volume of veins, as I said, in

58:06

three months, they regrow adequately.

58:08

So most of the, uh, chemists I

58:11

noticed, uh, the future, uh, LR.

58:13

So, uh, right after hepatectomy, they're left

58:17

with about 40 percent of their initial liver.

58:20

And within three months, it doubles

58:22

in volume, and they are 80 to 90%.

58:24

So volume-wise, it grows back to normal very fast.

58:28

Function-wise, um, I'm not sure.

58:30

I mean, uh, there are no, uh, studies out there showing

58:33

that these donors have, uh, issues down the road.

58:36

Uh, but at the same time, it needs a big and high

58:40

power study to show if these are at increased

58:43

risk of having, say, like NASH or injuries.

58:46

Um, so there are some animal models, um,

58:49

Uh, working on this, and there are some, uh,

58:52

contradicting results, uh, but right now the

58:56

concept is that, um, the, the, the long-term, uh,

59:00

risk in terms of your hepatic

59:02

reserve is very low, if it exists.

59:05

Um,

59:10

sure.

59:11

I'll show you that, uh, one more time.

59:13

The report template that's actually, uh, it was with

59:16

some revision is one of our colleagues from Brazil.

59:19

Actually, they use this and we just, um, changed it

59:23

a little bit, but we just try to include all the

59:26

pertinent things, like which liver volumes to include.

59:30

Um, and the vasculature.

59:32

So feel free if you want to take a picture or save, uh,

59:35

but this is, but again, important to talk to your surgeons

59:40

because depending on, I know that there are still some

59:43

centers that do left lateral segmentectomy, even for adults.

59:47

Uh, so it's important to know, um, what the plan is, what

59:50

the surgical approach is and, uh, revise this accordingly.

59:55

Yeah.

59:55

And just so all attendees know this, um, this new conference

59:58

will be available on demand on MRIonline.com.

60:01

So if you want to get another look at the

60:04

template, um, it will be available on the website.

60:08

Another question is about, um,

60:10

what is the most common finding?

60:12

Uh, yeah.

60:13

Uh, so about 25 to 40 percent, roughly,

60:18

have been reported to have complications after surgery.

60:21

Thank you.

60:21

Uh, in the donors, but most of them

60:23

are very, very mild and self-limiting.

60:25

The most common two are, uh, red clorofusion,

60:28

infection number one, red clorofusion number

60:31

two, uh, but there are like, you know, uh,

60:34

rare cases of PEs, um, and severe sepsis.

60:38

The surgical complications, uh,

60:40

small hematomas could happen.

60:41

The biloma and bile leak is the most important one.

60:44

Uh, the number reported in one of the series

60:47

is around, uh, like, uh, single digit, like 6, 7%.

60:51

But many of them were self-limiting.

60:53

And the good news is that those are caught pretty early

60:56

because after hepatectomy, you have a surgical drain there.

60:59

So the surgeons notice that there's continuous

61:01

bilious drain and that prompts, uh, workup early.

61:04

So that prompts doing, um, uh, uh, imaging.

61:08

If we do imaging, usually we don't see a biloma

61:12

necessarily just because it's been drained.

61:14

Um, by the surgical drain, uh, uh, that's usually,

61:17

basically they, they, they presume there is a bile

61:20

leak, so the role of imaging is to show where it is.

61:23

Uh, so because of that, we prefer to do, um, M-R-I-M-R-C-P

61:27

with the use of a hepatobiliary agent, um, just to provide

61:31

both functional and anatomical information.

61:33

In certain cases, you might need to do nuclear

61:35

medicine, hepatobiliary scintigraphy, uh, but

61:39

that's usually in the rare cases that later on.

61:43

On imaging, you see that there's a collection either because

61:46

of hematoma or a biloma, which was not caught timely,

61:51

and they present with complications of the biloma, such

61:54

as superinfection, mass effect, and pain, but those are

61:57

really rare cases because the surgeons are getting much

62:00

better, and they have very, very vigorous post-op care.

62:05

To make sure there's no complications in this.

62:08

The other question is about thrombosis of the hepatic artery.

62:11

It's not common.

62:12

No, I mean, arterial complications

62:14

are common in the recipient, right?

62:16

Because you have a small artery.

62:18

So in the whole liver, you're working with

62:21

the main hepatic artery, which is much larger.

62:24

In this setting, you're working with one small right

62:28

hepatic artery, or if you're dealing with some, uh,

62:33

donor with varying anatomy, you might have two small

62:36

arteries, like right anterior and right posterior,

62:39

obviously the risk of complication will be higher.

62:41

And that's why some of the surgeons,

62:43

if they anticipate having two arterial

62:45

anastomoses, they might not even do that.

62:48

Um, but in the donor itself, the risk of

62:51

vascular complications is very, very low.

62:53

It's like almost non-reported.

63:00

All right.

63:00

Well, it looks like that is it for the questions.

63:02

Um, as we bring this to a close, I want to thank

63:04

Dr. Brownie for this lecture and thanks to all of the

63:07

attendees for participating in our noon conference.

63:09

Um, as I mentioned before, uh, this conference

63:12

will be available on demand on MRIonline.

63:16

com, in addition to all previous noon conferences.

63:18

And be sure to join us again on

63:20

Monday for a lecture from

63:21

Dr. Kimi Kondo on renal cryoablation.

63:26

All right, you can register for that at MRIonline.com

63:29

and follow us on social media at MRIonline

63:33

for updates and reminders on upcoming noon conferences.

63:36

Thanks again and have a great day.

63:38

Thank you.