0:01

The next few video vignettes will cover the

0:03

imaging appearance of hepatocellular carcinoma

0:06

within the liver, and we're going to use the

0:08

LI-RADS lexicon to describe some of

0:12

the liver lesions that we're going to see.

0:14

So before we jump right into LI-RADS,

0:16

I wanted to talk just very briefly about

0:19

hepatocellular carcinoma in general.

0:23

So hepatocellular carcinoma is the

0:25

most common primary hepatic malignancy.

0:29

It almost always occurs in patients who have

0:33

chronic liver disease, and by some estimates,

0:36

up to 70 to 90 percent will have cirrhosis,

0:40

and those patients will develop hepatocellular carcinoma.

0:43

We think that it develops in a stepwise

0:45

manner in that, in the setting of chronic liver

0:49

disease, you get these regenerating nodules,

0:52

they're also known as cirrhotic nodules.

0:55

And then one of these undergoes

0:56

some degree of differentiation to

0:58

become a low-grade dysplastic nodule.

1:02

This then can undergo further differentiation

1:05

to become a high-grade dysplastic nodule.

1:08

And over time, this can then develop

1:12

into hepatocellular carcinoma.

1:15

Now, the smaller the lesion is at diagnosis,

1:18

the better chance we have of survival

1:21

treating it.

1:22

And therein lies the impetus for a very

1:24

robust image-based screening and surveillance

1:26

programs in patients who are at risk

1:28

for developing hepatocellular carcinoma.

1:31

So we do screening in these patients

1:33

with MRI, with CT, with ultrasound.

1:37

A lot of that is dependent

1:38

upon the institution itself.

1:40

But the key imaging feature that

1:43

we're looking for on MR imaging is

1:47

arterial phase hyperenhancement.

1:49

This is essential.

1:50

We will not call a lesion

1:52

hepatocellular carcinoma unless it

1:53

has arterial phase hyperenhancement.

1:56

But having arterial phase

1:57

hyperenhancement is not sufficient.

2:00

In addition to this, it needs to have, depending

2:02

on the size of the lesion, some other imaging

2:04

features, and those include what we call

2:07

washout, pseudocapsule, or interval growth.

2:14

Now, when we talk about interval growth,

2:15

we're talking about greater than or equal

2:17

to 50 percent in a study that is within

2:22

or equal to six months of the prior exam.

2:25

Now, over the past decade or so, a

2:27

multidisciplinary team of experts has come

2:30

together and really formed a comprehensive

2:33

system which allows for better standardization

2:35

of the terminology, technique, and

2:38

interpretation of liver lesions in patients

2:40

who are at risk for hepatocellular carcinoma.

2:43

Now, this system is called LI-RADS; it stands

2:45

for Liver Imaging Reporting and Data System.

2:49

And we're going to cover some aspects of

2:51

LI-RADS in the following videos, but for a

2:53

more comprehensive look at this, there's a

2:56

free resource that is given out by the

2:59

ACR; it's accessible on their website that I

3:01

highly recommend you look at and go through

3:04

to better understand how to use

3:05

this lexicon when describing liver lesions.

3:08

The first thing that's important

3:09

to know is when to use LI-RADS.

3:12

There are specific criteria for this.

3:14

It is used only in adult patients, so

3:18

18 years of age or older.

3:21

Patients who are adults and have

3:25

cirrhosis or chronic hepatitis B infection,

3:30

or a history of prior HCC.

3:35

The only caveat

3:36

with patients who have cirrhosis is

3:38

that it excludes certain etiologies of

3:40

cirrhosis, including congenital hepatic

3:43

fibrosis or vascular disorders such as

3:47

hereditary hemorrhagic telangiectasia,

3:51

portal vein thrombosis,

3:52

and Budd-Chiari syndrome.

4:02

Anything else?

4:03

Besides the congenital hepatic fibrosis or

4:05

vascular etiologies, the atherosclerosis,

4:07

we can apply the LYRADS lexicon.

4:09

Now LYRADS, uh, separates liver lesions into

4:12

multiple groups or categories, and for the

4:15

purposes of this discussion, I'm going to sort

4:18

of separate them into three clusters of groups.

4:21

The first one is going to include those studies,

4:24

those patients who have absolutely normal exams.

4:27

These are termed negative studies.

4:30

And these are patients who can then re-undergo

4:33

their surveillance study in six months' time.

4:36

Under this category, I'm also going to

4:38

include the LYRADS not categorizable, or NC.

4:44

These are patients who have studies that

4:46

are inadequate for interpretation due to

4:47

image emission or degradation, and for

4:49

these ones, you're going to have to get a

4:51

repeat exam in no later than three months'

4:54

time, and you may change the imaging

4:56

modality that you use in these instances.

4:58

Also, I'm going to include under the first

5:01

group is LI-RADS 1 lesions and LI-RADS 2 lesions.

5:06

Now, LI-RADS 1 lesions are lesions

5:08

that are definitely benign.

5:10

We're not worried about these at all.

5:11

The risk of developing hepatocellular

5:13

carcinoma is 0 percent risk.

5:16

These include lesions such as cysts

5:18

or hemangiomas, many of the liver

5:19

lesions that we've covered in the

5:21

benign liver talk in this case series.

5:23

LI-RADS 2 lesions are what

5:25

we call probably benign.

5:28

For practical purposes, these are

5:29

also going to be benign lesions.

5:31

The risk of HCC or hepatocellular

5:33

carcinoma in these is about 16%.

5:36

Both these sets of patients can return to

5:39

surveillance in six months' time if we identify

5:42

and classify the lesion as LI-RADS 1 or 2.

5:45

The next group that I'm going to talk

5:46

about, the other spectrum, are going

5:49

to be LI-RADS tumor in vein, TIV.

5:54

In this instance, you may or may not see a

5:56

liver lesion, but you unequivocally see tumor

5:59

thrombus inside one of the hepatic vessels.

6:03

Many of these patients will end up

6:04

having hepatocellular carcinoma, but not

6:07

all of them will necessarily have HCC.

6:10

And so, when you recognize this and

6:11

you don't see a liver lesion with

6:13

HCC features, often needs to go to

6:15

multidisciplinary conference, and this may

6:18

require biopsy to confirm the diagnosis.

6:21

The other lesion I'm going to put

6:21

in this category is LI-RADS MRLM.

6:25

These lesions are lesions that are

6:27

almost certainly going to be malignant,

6:30

but are less likely to be HCC.

6:32

The risk of HCC in these

6:34

patients is about 37 percent or so.

6:37

So in this category, we're going to

6:38

talk about things that are metastases,

6:41

angiocarcinoma, basically other malignant

6:43

lesions that can occur in the liver

6:45

that are not hepatocellular carcinomas.

6:48

That brings us to the category in

6:50

between over here that consists

6:52

of LI-RADS lesions 3, 4, and 5.

6:56

So we'll spend a little bit of time

6:57

talking about these lesions because

6:59

these are the ones where they may end

7:01

up becoming hepatocellular carcinoma.

7:03

So when we evaluate patients with HCC, and we've

7:06

sort of excluded categories 1 and 3 over

7:09

there, the first thing we need to look for is

7:11

the presence of arterial phase hyperenhancement.

7:15

So we look for arterial phase hyperenhancement.

7:17

Hyperenhancement, and specifically

7:19

we look for something that we call non-

7:21

RIM arterial phase hyperenhancement.

7:24

What that means is when you see a liver lesion

7:27

and it enhances in the arterial phase, it's

7:29

not the periphery of it that's enhancing,

7:32

but actually the internal content within

7:34

it that's getting brighter post-contrast.

7:36

So we look for non-RIM arterial

7:38

phase hyperenhancement.

7:40

We assess whether it's present or

7:42

absent. So in this case, we'll say no; in

7:44

this case, we'll say yes, it's present.

7:48

Then we look at the size of the

7:50

liver lesion itself in millimeters.

7:52

We break this up into several categories:

7:54

Is it less than 20 millimeters?

7:56

Is it greater than or equal to 20 millimeters?

7:58

Is it less than 10 millimeters?

7:59

Between 10 to 19 millimeters?

8:03

Or is it greater than or equal to 20 millimeters?

8:06

So we look for the presence of

8:08

non-RIM arterial hyperenhancement.

8:09

Is it present?

8:10

Is it absent?

8:11

What's the size of the lesion?

8:12

And then we look for our final

8:14

secondary imaging features:

8:16

Is there a presence of a pseudocapsule?

8:18

Is there a presence of washout?

8:19

And specifically, non-peripheral washout.

8:22

Means not the outside of it that's

8:24

washing out, but the inside of it.

8:26

Or is there interval growth?

8:28

As stipulated earlier.

8:30

If lesions have none of these features,

8:34

do they have one of these features?

8:35

Or do they have two of these features?

8:37

Now we can start to sort of fill in

8:39

our table and categorize these lesions.

8:42

If you have no arterial phase hyperenhancement,

8:44

you're going to have no secondary features,

8:46

doesn't matter what the size is,

8:49

you're going to qualify it as a LI-RADS 3.

8:52

Over here, if you have no arterial phase

8:54

hyperenhancement, it's less than 20 millimeters.

8:56

You have one of these three features over here,

8:59

it's going to qualify as a LI-RADS 3 still.

9:02

If you have two of those features,

9:03

it's going to bump it up to a 4.

9:05

Non-RIM arterial phase hyperenhancement,

9:07

more than 20 millimeters.

9:09

And it has one feature, or it has two features,

9:12

you're going to bump it up to a LI-RADS 4.

9:14

So, none of these will fall into the

9:16

category of LI-RADS 5, because in order

9:18

to call something a LI-RADS 5, you need

9:20

non-RIM arterial phase hyperenhancement.

9:23

So if we now fill in this portion of the

9:24

table, you have arterial phase hyperenhancement.

9:27

It's a small lesion, less than

9:28

10 millimeters, no secondary features.

9:30

This will be maintained at 3.

9:32

Arterial phase hyperenhancement, small

9:34

lesion, you have one feature or two features.

9:37

You're going to keep this as a 4

9:39

because of the small size.

9:41

If you go in that middle category, 10 to 19,

9:44

you have arterial phase hyperenhancement between

9:45

10 and 19 millimeters, no other features.

9:48

This is going to maintain a LI-RADS 3.

9:50

10 to 19 millimeters, and it has two features.

9:54

Well, that's going to be bumped up to a 5.

9:56

We'll fill in this box last.

9:58

Let's go to 20 millimeters, non-RIM

10:00

arterial phase hyperenhancement, more than

10:02

20 millimeters, no additional features.

10:04

We're going to keep it as a LI-RADS 4.

10:06

But, if it has one or more features,

10:08

it's going to bump it up to a 5.

10:10

Final thing I'll draw over here is that if it's

10:13

a lesion between ten and nineteen millimeters

10:15

with arterial phase hyperenhancement,

10:18

and it has one of these three features, it

10:20

could either be a LI-RADS 4 or a 5,

10:23

depending on which of these features it has.

10:26

If the feature is a pseudocapsule,

10:28

we're going to call it a 4.

10:29

If the feature is non-peripheral

10:31

washout or interval growth, we're

10:33

going to bump it up to a 5.

10:35

And, as a result of sort of qualifying these

10:37

things, what they really mean from a practical

10:39

perspective is a LI-RADS 3 lesion will have

10:41

about a 37 percent chance of malignancy.

10:44

If you call it a LI-RADS 3, you'll do a

10:46

surveillance study in 3 to 6 months' time.

10:49

A LI-RADS 4 lesion, chance of malignancy

10:52

is going to go up to about 74%.

10:54

And this may require discussion

10:57

at a multidisciplinary tumor board,

10:58

may require biopsy.

11:01

Whereas, finally, a LI-RADS 5 lesion,

11:02

you're going to be about 95 percent

11:04

sure that it's going to be an HCC.

11:07

No need to biopsy this lesion.

11:09

Next step here is you discuss it in

11:11

a multidisciplinary conference to

11:13

discuss management of the lesion.

11:16

What do we do next and how do we treat it?