0:01

So the following is a patient with

0:02

cirrhosis who presents for screening

0:04

for hepatocellular carcinoma.

0:06

So over here we'll start off by pulling

0:08

up, uh, some of the T1 post-contrast images

0:11

and we'll focus on this lesion over here.

0:13

So here we have a T1-weighted FATSAT

0:16

post-contrast in the arterial phase,

0:19

and this one's similar except we've

0:20

imaged in the portal venous phase.

0:22

And I wanted to use this case to

0:24

showcase what, you know, a LI-RADS

0:26

1 or 2 lesion could look like.

0:29

Many of the LI-RADS 1 or 2 lesions, we've

0:31

already covered in the benign liver mass talk.

0:34

And, you know, they include

0:34

things like cysts and hemangiomas.

0:37

However, this lesion was not

0:38

specifically covered in that talk.

0:40

And it's something we see quite

0:41

often in patients who have cirrhosis.

0:44

So let's look at some of

0:44

the imaging features of it.

0:46

We can see that it's located in the right

0:47

hepatic lobe, probably segment 7 over here.

0:51

And it has, overall, a

0:52

very wedge-shaped look to it.

0:54

Right?

0:55

Straight borders, wedge shape

0:56

at the periphery of the liver.

0:58

It demonstrates arterial hyper-

1:00

enhancement, but on the portal venous

1:02

phase, we really don't see anything.

1:04

It becomes isointense with

1:06

respect to the liver parenchyma.

1:07

Very difficult to see what it is over there.

1:09

And so this combination of this lesion that has

1:12

a relatively geographic distribution, almost

1:15

looks like a little bit of a triangle, very

1:16

sharp linear borders, enhances in the arterial

1:20

phase, you don't see it, is characteristic

1:23

of something called a Transient Hepatic

1:25

Intensity Difference, or a THID for short.

1:30

And this is thought to occur in portions of

1:33

the liver that have relatively poor portal

1:35

flow because of portal hypertension,

1:38

due to liver nodular regeneration.

1:40

So those areas with poor portal

1:42

flow will then compensate and have

1:45

increased arterial hyperenhancement.

1:47

As a result, you see them as these bright

1:50

lesions, relatively geographic in appearance,

1:53

as I said, with sharp and linear borders.

1:58

And, uh, you know, depending on

2:00

your degree of confidence, you

2:02

may call this a LI-RADS 1 lesion.

2:05

You don't need to worry about it.

2:06

You could even call it a

2:06

LI-RADS 2 lesion, potentially.

2:09

Small chance of malignancy, but regardless

2:11

of whether you call it LI-RADS 1 or 2, you

2:13

know, this is the sort of patient you need.

2:14

Who doesn't need specific follow-up

2:16

for this and can return to screening

2:19

back in six months from now.