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So this patient is a 60-year-old

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female, and the history provided

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is elevated liver function tests.

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LFTs are elevated.

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Um, wanted to get an MRI; sounds very reasonable.

0:12

So we do our MRI examination, and we're going

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to go through some sequences to see if we

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can figure out what's causing these problems.

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So here's our T2-weighted sequence,

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non-fat-saturated in the axial plane.

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And we see what probably amounts

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to a small liver cyst over there.

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We can ignore that for the moment.

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And as we go down, we already start to

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see that the bile ducts are dilated.

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Now remember, if you've gone through

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sort of the normal anatomy on these T2

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weighted sequences, you hardly ever get

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to see the intrahepatic bile ducts.

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They're so small, they should

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be less than two millimeters.

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So the fact that I'm seeing the bile

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ducts on my T2-weighted sequences

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here tells me that they’re dilated.

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Doesn't necessarily have to mean there’s

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some abnormality associated with it,

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but it does mean that they are dilated.

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So let’s figure out if we

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can see why they’re dilated.

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You can see here, very, very dilated.

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And again, this is the extrahepatic biliary tree.

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You can see the cystic duct

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over here on this image.

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We start to see a bit of a gallbladder.

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You can see some gallstones here,

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T2 hypointense filling defects.

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But let's ignore that again for the moment.

1:16

Let's focus right over here on

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the extrahepatic biliary tree.

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And already, the next slice downwards, you

1:24

can start to see a filling defect inside

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the common hepatic duct over here.

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At this point, it may even

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be the common bile duct.

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Certainly, as you go lower, it starts

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to become the common bile duct.

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Another filling defect here, another filling

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defect here, T2 hypointense, and quite a

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large one here within the common bile duct.

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Another one here.

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And we can go all the way downwards

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and see that it looks relatively clean.

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Let's look at the same findings, but just

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on a different plane, the coronal plane.

1:53

Again, we can see that the

1:54

intrahepatic tree is dilated.

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Both the right and left hepatic ducts,

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the common hepatic duct is dilated.

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As we go downwards, we can start to

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see that there are numerous filling

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defects inside the common bile duct.

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Various shapes, various sizes, all of them

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are T2 hypointense as we go downwards.

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And so these are going to be

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some filling defects here.

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We can look at the same thing on

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our T2 fat-saturated sequences.

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A little bit more motion here, but we can

2:18

certainly appreciate the filling defects.

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And notice how all these filling

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defects are dependent.

2:23

Right.

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So they're sort of going to the dependent

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portion over here, which is obviously posteriorly

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and they're lying down upon the dependent

2:30

portion of the bile duct for the most part.

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We can look at the same thing

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on our T1 pre-contrast image.

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And we notice that some of these

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filling defects, a lot of

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them really are T1 hyperintense.

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And in this instance, we did an MRCP.

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And so I just want to finish off the

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description by showing you the MRCP images,

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and the images came out reasonably well.

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You can see that the intrahepatic bile ducts are

2:59

dilated; the extrahepatic biliary tree is dilated.

3:01

You can start to see some filling

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defects inside the extrahepatic biliary tree.

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And this is sort of an MIP image showing

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at least one of those filling defects.

3:09

And so again, you know, this is not giving

3:11

me any extra information that I haven't

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gleaned from my other sequences, but, you

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know, nevertheless, this may be useful.

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And so what's going on here?

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You may have guessed it already.

3:20

This is an example of choledocholithiasis.

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Choledocholithiasis refers to the

3:25

presence of stones in the bile ducts.

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Oftentimes, we see it due to the passage of stones

3:32

from the gallbladder that escape and go into

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the extrahepatic biliary tree, but it's

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important to know that they can potentially

3:39

form in the absence of gallstones in the

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setting of biliary stasis for whatever reason.

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Oftentimes, patients may present with

3:47

biliary colic as a result of these stones.

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We also see patients who are relatively

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asymptomatic and just sort of present with

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incidentally noted choledocholithiasis.

3:58

Most times, if patients are suspecting

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choledocholithiasis, they will get an ultrasound,

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but oftentimes, the more distal aspects of the

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common bile duct are tough to see on ultrasound.

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And so an MRI is pretty rare

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often performed if the findings

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are unclear on ultrasound.

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Choledocholithiasis essentially

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looks very similar to this.

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They're dependent filling defects,

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with relatively geographic shapes, such as

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circles or small triangles.

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All of them will be T2 hypointense.

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Most times they're also T1 hypointense.

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In this case, these were T1 hyperintense,

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which you could see with pigmented stones.

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It's also important to understand that

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MRI is very good at detecting these, but

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occasionally, if they are very tiny stones,

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maybe two millimeters or even three millimeters

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or less, we may end up missing those stones.

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So sometimes we'll call it no choledocholithiasis

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and then an ERCP may reveal

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a few tiny stones that were missed.

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But MRI does fairly well for the most part

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in detecting choledocholithiasis, and this is a

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nice case of choledocholithiasis resulting in

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biliary ductal dilatation and presumably the

5:03

elevated liver function tests in this patient.