0:01

So this patient is a 48-year-old female.

0:04

History, I think, was follow-up liver cyst,

0:07

but it had a sort of interesting finding

0:09

involving the bile ducts that I'll show you.

0:10

And so if we scroll through our axial

0:12

T2-weighted image, the intrapatic

0:14

biliary tree looks pretty good.

0:16

These ducts, you can see them, but if you were

0:18

to measure them, they're about two millimeters

0:19

or less, so that's within normal limits.

0:22

I'm going to zoom up on them, magnify on them

0:24

as well, a little bit as we scroll downwards.

0:27

Let's follow the extrapatic bile ducts.

0:29

This is the common hepatic duct, a

0:30

common bile duct coming downwards.

0:32

And we notice that right around

0:34

here, there's just this little

0:36

outpouching that's associated with it.

0:38

And then it continues normally right over there.

0:42

So scroll upwards again, focus

0:44

on this little outpouching that's

0:47

associated with the common bile duct.

0:51

I think it's nicely seen on

0:52

this coronal image as well.

0:54

This is the, um, common bile duct here,

0:57

little outpouching, and you can follow

1:00

the rest of it very nicely over here.

1:03

And so this is unusual; we don't often see these

1:05

little outpouchings associated with the biliary

1:08

tree, but this is a nice example of a type 2

1:13

choledochal cyst, which is a true diverticulum

1:18

involving the extrahepatic biliary tree.

1:22

Right, so we talked a little bit in an

1:24

earlier case about choledochal cysts, which are

1:26

congenital cystic dilatations of the bile ducts.

1:29

There are different types.

1:31

Type 1 is the most common.

1:33

We have fusiform or cystic

1:34

dilatation of the extrahepatic bile ducts.

1:37

Type 2 is very uncommon.

1:38

Don't see a lot of cases, but it really is

1:40

just a little outpouching, focal outpouching.

1:42

It looks like a diverticulum

1:44

off the extrahepatic biliary tree.

1:46

There's a type 3 as well.

1:48

I don't have an example of this to

1:49

show you during this master course.

1:51

I'm going to talk about it here.

1:52

And a type 3 is what we call a choledochal

1:55

cyst, where the dilated segment of the

1:57

bile duct occurs right at the distal

2:02

most portion of the common bile duct

2:04

as it's sort of entering the duodenum.

2:06

So it's sort of a dilated segment

2:08

in the intraduodenal portion

2:10

of the extrahepatic biliary tree.

2:12

There's a type 4 as well, which was

2:14

shown in another case, but this was a

2:16

nice example of a type 2 choledochal cyst.