0:00

So far we've spent quite a bit of time

0:02

talking about hepatocellular carcinomas

0:05

and LI-RADS, and I think that's appropriate.

0:07

Because when you look at primary malignant

0:09

liver lesions, the vast majority of

0:12

them will be hepatocellular carcinomas.

0:15

Over the next case and the last few cases,

0:17

I want to shift gears to talk about a

0:19

few other malignant lesions that you can

0:21

see in the liver, one of which is common,

0:25

while the other group are very, very

0:28

common and arguably even more common.

0:30

than hepatocellular carcinomas.

0:33

So we'll go on to these images.

0:34

We have two patients with the same diagnosis,

0:37

um, and we'll talk a little bit about

0:38

diagnoses once I describe the findings.

0:41

So neither of these patients has

0:43

history of cirrhosis or chronic liver

0:46

disease, but they have liver masses.

0:48

First patient has a mass in the hepatic lobe.

0:52

I'm just going to scroll through

0:53

it to start with and then show

0:54

you some sample snapshots of it.

0:57

So this is a T2-weighted image with fat

1:00

saturation, and we can see in the lateral left

1:05

hepatic lobe, the signal is hyperintense,

1:10

T2 hyperintense. This portion of the liver is

1:12

abnormal, while the remaining portion of the

1:15

liver over here has a relatively normal signal.

1:19

And if we look with a very discerning eye, we

1:21

can see that amidst this area of abnormality,

1:23

there are some bright tubular structures, and these

1:26

are going to turn out to be dilated bile ducts.

1:29

So let's see what this looks like

1:30

on our in and out-of-phase images.

1:32

Here we have the T1 out-of-phase image.

1:35

Here we have the T1 in-phase image.

1:38

And if we actually look at the

1:40

liver that's not diseased, i.e.,

1:42

most of the right hepatic lobe,

1:44

we can see that it actually loses signal

1:47

on the out-of-phase image when you

1:49

compare it to the in-phase image.

1:51

And both of these, of course,

1:53

are being compared to the spleen over here.

1:54

So it becomes as dark as the spleen,

1:57

if not darker, on the out-of-phase

1:58

image, while on the in-phase image

2:00

it appears brighter than the spleen.

2:01

So that tells us that a lot

2:03

of this liver is steatotic.

2:05

And as a result of that, it can trick

2:07

our eye into thinking that maybe the

2:09

out-of-phase and in-phase appearance

2:11

of this lesion as well looks different.

2:12

But if you actually look at it and measure

2:15

region of interest over it, you'll see

2:17

that the signal actually doesn't change

2:19

between the out-of-phase and in-phase.

2:21

It remains T1 hypointense, and this lesion

2:25

does not contain any lipid within it.

2:28

If we go to our T1 Fatsat pre-contrast

2:32

images, again we can look at this lesion

2:34

that's essentially replacing the lateral

2:36

left hepatic lobe, and this has T1 hypointense

2:40

signal before giving contrast.

2:43

And after we have contrast,

2:45

observe the enhancement pattern

2:47

that we see with this lesion.

2:49

So here we have a T1 fat-saturated

2:51

post-contrast image.

2:53

We've done this in the arterial phase,

2:55

we have a portal venous phase here,

2:57

and here's our equilibrium phase.

2:59

Here's the lesion on each of these phases.

3:02

And so far, when we've looked at lesions,

3:05

and we've sort of classified them as

3:07

hepatocellular carcinomas, we've looked for

3:09

areas of arterial phase hyperenhancement.

3:12

But if we look at this lesion, certainly, on the

3:14

arterial phase, there is enhancement within it.

3:16

There is also enhancement on the

3:17

portal venous phase, and there is also

3:19

enhancement on the equilibrium phase.

3:21

And if you sort of look at the way this is

3:23

enhancing, it enhances more, or the most, on

3:27

the equilibrium phase, followed by the portal

3:29

venous phase, followed by the arterial phase.

3:31

And you can just look at aspects of the lesion.

3:33

Look at this aspect.

3:34

It enhances a little bit.

3:35

If it gets brighter over here,

3:37

it gets even brighter over here.

3:38

Look at this aspect.

3:39

It enhances a little bit.

3:41

It gets brighter over here, it gets

3:42

even brighter on this sequence.

3:44

So it's sort of heterogeneously

3:46

enhancing, and that enhancement is

3:48

sort of filling in as we go from the

3:50

arterial phase to the equilibrium phase.

3:53

In other words, it's brightest in the

3:55

equilibrium phase when compared to either

3:57

of the two other contrast-enhanced phases.

4:00

The other thing to look for in this patient

4:03

is, you know, I mentioned this patient does not

4:04

have a history of cirrhosis, should not have,

4:06

therefore, a nodule or liver contour, and yet.

4:09

If we look at aspects of the liver

4:10

contour, certainly along the right

4:12

aspect, it looks pretty smooth.

4:14

And most of the liver that's not diseased looks

4:16

pretty smooth, but look what happens here.

4:18

Diseased liver has capsular

4:20

retraction associated with it.

4:22

Tumor has a desmoplastic response, a fibrotic

4:26

response that's pulling the liver towards it.

4:28

You can see it over here as well.

4:29

So that's our first patient.

4:31

I want you to show you the second patient

4:32

and we'll sort of summarize the findings and

4:34

talk a little bit about what this lesion is.

4:36

Okay.

4:36

Thank you.

4:37

So this is our second patient, no history

4:39

of cirrhosis, has a liver lesion that

4:42

is certainly involving the medial aspect

4:45

of the left hepatic lobe and involving

4:47

probably segment 5 over here as well.

4:49

We can see this lesion.

4:51

This is on our T2-weighted sequence.

4:52

It has hyperintense signal

4:55

on the T2-weighted images.

4:56

It's not fluid bright, but certainly

4:57

looks intermediate signal, um, and very

5:00

similar to the spleen, if anything.

5:02

If you look at the border of the liver, it

5:03

looks very, very smooth here, and if you

5:05

go down, there is this capsular retraction,

5:08

again, seen associated with this lesion.

5:10

I'm not going to show you

5:11

the in and out of phase.

5:12

This lesion did not contain fat.

5:14

But what I will show you is

5:15

the post contrast images.

5:17

And in the post contrast images, we

5:19

see a pattern that is very similar

5:20

to the case that we just saw.

5:22

So this is T1 Fatsat, post contrast

5:25

arterial phase, portal venous phase.

5:28

Equilibrium phase, and we can see that

5:30

there is a very heterogeneous enhancement,

5:32

and the brightest amount of enhancement

5:34

is seen in the equilibrium phase.

5:36

See how much this area fills

5:37

in as compared to this.

5:39

So if we were to summarize this, uh, lesion,

5:41

either lesion that we've seen in either

5:43

of these, uh, two cases, we certainly

5:45

have, you know, a variably sized lesion.

5:48

It has intermediate to hyperintense T2 signal.

5:53

There is no fat within this lesion.

5:56

It is associated with capsular retraction.

6:01

When we give contrast, it has sort of centripetal

6:06

enhancement that's most on the delayed images.

6:10

Also, in the first case that I showed you, it

6:12

was associated with biliary ductal dilatation.

6:17

So when we see these findings, it is quite

6:20

characteristic of cholangiocarcinoma.

6:25

Thank you.

6:25

Now cholangiocarcinoma sort of comes

6:28

in different flavors and we can, uh,

6:30

qualify it by describing its location.

6:34

So if we draw sort of a, a liver, mini

6:36

liver over here, and these are the

6:39

bile ducts, cholangiocarcinomas can be

6:41

seen in the extrahepatic biliary tree,

6:44

so over here, so that's extrahepatic.

6:47

Oftentimes they're seen at the bifurcation

6:49

of the right and left bile ducts over

6:50

here, so that's what we call perihilar.

6:55

Tumors, also known as Klatskin tumors,

6:58

or they can be sort of intraductal.

7:01

And these are also known as

7:04

peripheral cholangiocarcinomas.

7:07

Intraductal peripheral cholangiocarcinoma,

7:08

which is just what this is.

7:09

And these tumors can also look

7:11

in a variety of different ways.

7:12

The cases that I presented here are

7:15

mass-forming in their shape, but they

7:18

can also be quite infiltrative and

7:20

just form along the ducts themselves.

7:23

Or they can manifest as polypoid

7:25

masses inside the ducts.

7:27

But often times we see them when

7:29

they're intraductal or peripherally

7:31

located, we see them as mass-forming.

7:33

And the key finding is that they have this

7:35

capsular retraction, they're desmoplastic

7:37

tumors, and this, uh, centripetal enhancement,

7:41

and most evident on delayed phase images.

7:44

And if we are suspecting a

7:46

cholangiocarcinoma, we often do ten

7:48

minute delayed post-contrast images.

7:50

Thank you very much.

7:51

Because that's when the

7:51

enhancement will be most apparent.