0:01

So this next patient is a 20-year-old

0:02

gentleman who had biliary ductal

0:05

dilatation that was found on ultrasound and

0:09

they wanted to understand the etiology of it.

0:12

So they got an MRI for further evaluation.

0:16

They also got an MRCP and I want to

0:18

start off by showing you the MRCP images and what

0:22

do we see here as we zoom up on these images?

0:24

Marked biliary ductal dilatation.

0:27

Intracardiac ducts are dilated right and left.

0:30

As they join to form the common

0:31

hepatic duct, that's dilated.

0:33

And then as you come more inferiorly,

0:35

there is a cutoff, right?

0:37

And beyond this, we're really not seeing

0:39

the bile duct very well, certainly don't

0:40

see the common bile duct very well.

0:42

And so what's going on in this instance?

0:45

I'm going to show you the coronal T2-weighted

0:47

image, and hopefully that'll shed some

0:50

light on what's happening over here.

0:54

And so the first thing you notice is that

0:55

this gallbladder is quite distended.

0:58

If you measure from here to here, certainly it's

0:59

going to be more than four centimeters and lengthwise

1:01

it's going to be more than seven centimeters.

1:03

So we have a distended gallbladder.

1:05

As we scroll through some of the other

1:07

images, we can see that there's some

1:08

gallstones that are located within it.

1:10

And you know, this image, this sort of case also

1:13

nicely showcases some of the anatomy that we

1:14

spoke to about the gallbladder fundus, the body,

1:17

the infundibulum, that tapered segment, and then

1:19

the neck over here, and then the cystic duct.

1:22

This comes out here.

1:26

Wraps around here.

1:28

So from this point to this point to this

1:31

point over here and finally over here.

1:34

We see a filling defect.

1:37

Alright, so that's going to be a stone that's sort

1:38

of lodged in the cystic duct, but what's interesting

1:42

about the location where this is lodged is

1:45

that part of it is in the cystic duct.

1:48

Part of it is also lodged inside the junction of the

1:51

cystic duct and the common hepatic duct over here.

1:55

So it's at this unique location that's resulting

1:59

in both cystic duct and gallbladder distention and

2:02

also distention of the intrahepatic bile ducts in

2:05

the common hepatic duct, right?

2:08

So you can see that over here.

2:10

Let's follow this upwards.

2:11

That's all common hepatic duct and the

2:13

intrahepatic bile ducts.

2:15

Follow this cystic duct.

2:17

You can see how it's all connected to

2:19

the gallbladder that's also distended.

2:21

We can see these findings nicely

2:23

on the axial T2 images as well.

2:25

Non-fat saturated bile ducts,

2:27

intrahepatic bile ducts are dilated.

2:28

Common hepatic duct is dilated.

2:30

You can see that stone that's lodged resulting

2:32

in the intrahepatic ductal dilatation.

2:35

You can see the cystic duct over here.

2:37

It's also obstructed and resulting in marked

2:41

distention of the gallbladder, and so this sort

2:44

of unique location of cystic duct obstruction, which

2:49

also results in common hepatic duct obstruction, is known

2:53

as Mirizzi syndrome.

2:57

And what it is, is essentially obstruction of the common

2:59

hepatic duct due to a gallstone that's impacted either

3:03

within the cystic duct or within that infundibular

3:05

portion of the bile duct, of the gallbladder rather,

3:08

and that obstruction may be due to mass effect,

3:13

by the stone itself, as can be seen in this instance.

3:16

Or over time, there may be an inflammatory

3:18

stricture that develops as a result of the

3:20

irritation of that stone in this location,

3:22

resulting in that bile duct dilatation.

3:25

And on imaging, in particular, in ERCPs, when

3:27

you look at it, it results in a very smooth,

3:29

extrinsic compression of the common hepatic duct.

3:33

And one of the reasons that this is important

3:35

to know about is that if you just saw this, I

3:37

think a lot of people may be potentially

3:39

worried about a neoplasm or a stricture

3:42

of sorts that's causing ductal dilatation.

3:45

But having looked at the complete set of images, you

3:47

realize that it's just a stone that happens to be

3:49

lodged at that location that results in both common

3:53

hepatic and intrahepatic ductal dilatation, as well

3:57

as in this instance of a marked gallbladder distension.