0:01

So here we have a patient.

0:02

History, uh, is elevated lipase.

0:04

She's a lady in her fifties.

0:07

And so we're getting an MRI without

0:08

intravenous contrast and an MRCP sequence

0:11

added onto it in order to evaluate

0:13

the etiology of the elevated lipase.

0:15

And presumably they're looking for

0:16

choledocholithiasis in this instance.

0:19

And so as we scroll on in our T2

0:20

weighted sequence, we can see that

0:23

the intrapathic biliary tree is

0:24

larger than what we would expect

0:26

in this patient.

0:27

So probably something's happening.

0:29

So we'll have to evaluate it further.

0:31

The common bile duct also looks quite large.

0:34

And as we scroll all the way down, we can see

0:36

that the common bile duct is on the bigger side.

0:39

It does taper as we go downwards.

0:41

You can see the caliber of this sort of circle

0:44

getting a little bit smaller, smaller, smaller,

0:46

as it goes all the way down to the ampulla.

0:49

So let me sort of zoom in on this, and

0:51

you know, if you've gone through the other

0:52

cases, you're reasonably familiar with

0:55

what choledocholithiasis looks like, which

0:57

is a T2 hypointense filling defect, right?

1:01

And when we say hypointense, we're

1:02

really looking at something that looks

1:04

as dark as this sort of signal, or this

1:05

sort of signal, or this sort of signal.

1:07

We don't see anything like that

1:09

inside the common bile duct in

1:11

this instance, all the way through.

1:13

Now you can certainly verify that before

1:15

we draw that conclusion on other sequences

1:17

here, we have a coronal T2-aided sequence.

1:20

Now there's not a lot of motion on this study.

1:21

This patient tolerated the MRI quite well.

1:23

You can see here, um, the common hepatic and

1:26

common bile duct is dilated, tapers nicely

1:29

as we get to the ampulla, but certainly no T2

1:32

hypointense filling defects are seen within it.

1:35

Again, findings, uh, you can look at

1:38

the MRCP sequence, another fairly good

1:40

sequence, just a little bit of motion,

1:42

but as you scroll through it, really no

1:45

choledocholithiasis that we can identify.

1:48

Now, remember, we may potentially miss tiny,

1:50

tiny stones, so it is possible that the

1:51

patient has a tiny stone or maybe passed a

1:54

recent stone that we're not seeing, but the

1:57

reason that I wanted to show you this case is

2:00

for this finding within the common bile duct.

2:03

If you look at it, say, on this slice

2:05

over here, you do notice that

2:07

the inside of the common bile

2:09

duct is not particularly clean, right?

2:12

This is what bile looks like.

2:14

It's fairly T2 hyperintense.

2:16

Look at it more posteriorly.

2:18

There is a signal alteration there that looks a

2:20

little bit more hypointense than clean bile, right?

2:25

It's not as dark as what a stone would look

2:27

like, but it's a little bit darker than bile.

2:29

And if you kind of look upwards here,

2:30

again, there's a little bit of a layering

2:33

effect where there's some semblance of

2:35

a straight line, even, that separates bile

2:37

that's relatively clean, superior to it,

2:41

and stuff that's relatively hypointense

2:43

inferior to it.

2:45

We also have these oblique T2-weighted

2:47

images where we have angled, we're angling

2:50

with respect to the bile duct as well.

2:52

And I just wanted to show this to

2:53

you because some of that layering

2:55

becomes more apparent right over here.

2:58

If we were to window this, we can see

3:00

that over here, it looks relatively clean

3:02

and over here, more dependently, there's

3:05

a layering effect right over here as

3:07

well, where it's relatively hypointense.

3:11

So this finding is highly suggestive of the

3:14

presence of sludge inside the common bile duct.

3:18

And in fact, if we look at the

3:19

adjacent gallbladder, we can see some

3:21

sludge layering within it as well.

3:22

So some of the sludge may have sort of

3:24

transferred over to the common bile duct.

3:27

And, you know, we can often see this

3:29

in the gallbladder, as I mentioned,

3:30

but I just wanted to show you an

3:31

example of what that could look like

3:33

within the common bile duct.

3:35

And much like stones, sludge can also cause

3:39

relative stasis of the biliary tree where

3:42

the bile is just not emptying very nicely.

3:44

You can see it over here as well.

3:46

And so this patient had an ERCP and indeed

3:49

they removed some sludge and a few tiny,

3:51

tiny debris from the bile ducts themselves.