0:01

So this patient's a 60-year-old gentleman,

0:04

history of sepsis, got an MRI of the

0:07

abdomen to evaluate the etiology of this.

0:10

I'm going to start off by looking

0:11

at the axial and coronal T2 images.

0:16

As we scroll down the axial images,

0:17

we're starting to see ductal dilatation

0:19

in the left hepatic lobe, ductal

0:22

dilatation in the right hepatic lobe.

0:25

As they get to their confluence,

0:28

there is abrupt narrowing.

0:30

And we also notice, we may not notice in

0:32

our first scroll, but in our second, third,

0:36

fourth scrolls, we may notice that there is

0:37

in fact thickening right at that confluence.

0:41

Look at the soft tissue that is

0:42

narrowing that confluence, the

0:46

right and left hepatic bile ducts.

0:48

So dilated bile ducts, soft tissue

0:51

thickening right at their confluence.

0:53

And as we go downwards, the extrahepatic

0:55

biliary tree is relatively normal in its limits.

0:59

This relationship is nicely seen

1:00

on the coronal weighted images.

1:02

as well, where you have dilated

1:04

left hepatic ducts, dilated right

1:05

hepatic ducts, right where they join.

1:08

There is some narrowing at that biliary

1:11

confluence right over there, and the

1:13

extrahepatic biliary tree is within normal limits.

1:16

We can again see this very beautifully

1:17

on the ERCP images, where the intrahepatic

1:21

bile ducts are dilated, the extrahepatic

1:24

biliary tree is within normal limits.

1:25

And there's certainly a segment

1:27

here where you don't see the bile

1:28

ducts because they're narrowed.

1:30

When we look at our post-contrast

1:32

sequences, start off with the

1:33

pre-contrast axial T1 fat sat images.

1:37

You notice that there is some

1:39

soft tissue thickening here.

1:41

It just looks way too thick

1:43

prior to even giving contrast.

1:46

When we give contrast in the arterial phase,

1:50

you can see again that there is some hyper

1:52

enhancement of that biliary confluence where

1:56

the right and left hepatic ducts meet, look

1:58

way thicker, enhance way more than it should.

2:01

I'm going to put the arterial phase on the side.

2:04

And the next thing I'm going to do is go

2:05

all the way to the most delayed phases

2:07

I have in the post-contrast images.

2:10

Okay.

2:10

to show you what happens.

2:12

So this is where that thickening is.

2:14

This is sort of where we saw that

2:15

soft tissue in the T2 images.

2:19

We look at our delayed equilibrium phase

2:21

images, you can see that area enhancing as well.

2:25

But I want you to note what happens in that

2:28

there is more enhancement on this delayed phase.

2:31

This area here, that thickening, that

2:33

enhancement looks brighter on this

2:34

image than it does on this image.

2:37

So in some sense, there's more progressive

2:39

and brighter enhancement associated with a

2:41

soft tissue mass at the biliary confluence.

2:44

Putting everything together, this is very,

2:47

very concerning for a malignancy, and

2:48

specifically for a cholangiocarcinoma.

2:52

Now, cholangiocarcinoma is a malignancy

2:56

that arises from the bile ducts.

2:58

These are most commonly adenocarcinomas.

3:02

They tend to occur in the sixth to

3:04

seventh decades of life and slightly,

3:06

slightly more common in males.

3:08

Now they can occur anywhere in the biliary

3:10

tree, but we generally organize them,

3:13

at least their imaging appearance, into

3:14

three categories based on their location.

3:17

And I'm going to show you examples

3:18

of all those three categories.

3:21

The first category is what we're seeing here,

3:23

this hilar or perihilar cholangiocarcinoma.

3:26

It's the most common location.

3:29

When we see cholangiocarcinomas, and it's

3:30

really centered at the confluence of both

3:33

the right and left intrahepatic ducts, we've

3:36

also known as a Klatskin tumor. So that's

3:38

how you may have heard of it as well, and

3:41

essentially results in intrahepatic ductal

3:44

dilatation, which we can see over here, without

3:46

dilatation of the extrahepatic biliary tree.

3:49

Now, it's often a very ill-defined mass,

3:52

but one of the key imaging features of

3:55

cholangiocarcinoma, one that is manifested

3:57

in this case, is that the enhancement will

4:00

be more apparent on the more delayed images.

4:03

And that's thought to be because this is

4:04

the type of tumor that is very fibrous

4:07

and also elicits a desmoplastic reaction.

4:10

And any tumor that does that tends

4:12

to enhance a little bit brighter

4:14

on the more delayed phase images.

4:16

One of the things that you need to know

4:18

about specifically these hilar or perihilar

4:21

cholangiocarcinomas is that there is

4:22

something called a Bismuth-Corlette

4:24

classification system of how we describe

4:27

these when they are in this particular

4:29

location, and it's important only because

4:32

it has implications for surgical management.

4:35

Now, this is certainly something you can look

4:37

up if your surgeons require you to mention

4:40

it, but suffice it to say is that what you

4:43

really need to describe is a couple of things.

4:46

If you see a tumor that's located in that hilar

4:49

region, something you're worried about

4:50

a cholangiocarcinoma, you need to mention

4:54

whether it involves the biliary confluence

4:57

or it doesn't involve the biliary confluence.

4:59

If it doesn't involve the biliary confluence,

5:01

you need to tell them what the distance

5:03

to the biliary confluence is, and if it does

5:05

involve the biliary confluence, you need

5:07

to mention whether it involves the right

5:09

hepatic duct, the left hepatic duct,

5:12

or does it involve both hepatic ducts?

5:15

If you see this instance, this, we

5:16

have a cholangiocarcinoma that does

5:18

involve the biliary confluence.

5:19

It does go upwards to involve

5:21

the right hepatic duct here.

5:23

It also goes upwards to involve a small

5:25

portion of the left hepatic duct over here.

5:27

And so this is a nice example of a

5:29

cholangiocarcinoma located in the most common

5:33

location where it likes to occur, that is

5:35

at the hilar, perihilar region of the liver.