0:00

So this next patient is a 70-year-old gentleman

0:03

with a history of prostate cancer who had a

0:05

staging CT scan of the abdomen and pelvis.

0:08

As we scroll through the CT images and we

0:10

evaluate the liver, we note that there is

0:12

a hypodense mass in the left hepatic lobe.

0:15

We can see the mass over here.

0:17

And as such, it has indeterminate imaging features.

0:19

Some of the borders of it look a little bit ill-defined.

0:22

And so an MRI was requested in order to further evaluate

0:26

this to make sure that this does not represent a metastasis.

0:29

for your patience.

0:30

and that this was a benign entity.

0:32

So here we have our MRI examination of this patient, and

0:35

we'll start off by looking at the T2-weighted sequences.

0:38

We're going to scroll through these and go

0:40

to the approximate level of where we saw

0:43

the abnormality on the CT scan over here.

0:46

So here we have our T2-weighted imaging

0:48

sequence without fat saturation and our T2

0:52

turbo spin echo sequence with fat saturation.

0:55

We can see the liver lesion here in the left hepatic lobe.

0:58

It is slightly hyperintense on the T2-weighted images.

1:01

And when you do fat saturation, we notice that

1:03

the lesion is actually slightly hypointense on

1:06

these sequences, suggesting that whatever this

1:08

ends up being, that it contains some degree

1:11

of underlying lipid or fat content within it.

1:15

The next set of sequences that we're going to

1:16

look at are the T1 in and out-of-phase images.

1:19

We'll again scroll down to the abnormality.

1:22

Here we have the out-of-phase image.

1:24

Here we have the in-phase image.

1:27

Very tough to see this lesion on the in-phase image.

1:30

But, quite obvious in the out-of-phase

1:33

image, it looks like it loses signal, it's

1:35

T1 hypointense on the out-of-phase image.

1:38

This tells us that this lesion contains internal lipid, as

1:43

we had suspected from our T2-weighted sequences as well.

1:47

I want you to note one more thing

1:48

about this lesion, look at its borders.

1:52

lesions we've seen throughout these vignettes.

1:55

The borders are somewhat straight, and the overall shape is

1:58

a little bit geographic, almost looks a little bit like a

2:00

triangle, or a rectangle, or a quadrilateral of some sort.

2:05

So, there are some geographic borders associated with

2:09

this lipid-containing lesion in the left hepatic lobe.

2:13

Next up, we're going to look at our

2:14

T1 pre-contrast fat-saturated image.

2:17

So, on this image, we can see that the

2:19

lesion, once again, is T1 hypointense.

2:22

The borders are somewhat geographic in shape.

2:25

And we'll move on to our post-contrast imaging to see

2:28

what this does when we give, uh, contrast to this patient.

2:32

So, here we have post-contrast imaging.

2:35

We're going to scroll down to the, uh, same

2:36

location, and we can see that liver lesion over here.

2:41

And really, when you look at it on the arterial

2:42

portal venous equilibrium phase images, there's not a

2:45

whole lot of enhancement going on within this lesion.

2:48

It remains somewhat dark with respect to

2:50

the liver parenchyma in all the phases.

2:53

Here you can see it on the arterial phase.

2:55

Here you can see it on the portal venous phase.

2:57

And here is the equilibrium phase.

2:59

You can see this lesion again with the geographic borders.

3:02

We also notice that there are a few vessels that

3:05

are going through this lesion that are unperturbed.

3:08

They're not distorted or spread out.

3:10

They're just kind of going through this

3:11

lesion as if this lesion has real no mass

3:13

effect upon the adjacent vasculature.

3:17

So, these combination of findings, the lesion that

3:19

contains a lipid, the geographic borders, the fact

3:22

that it doesn't enhance, the vessels that are going

3:25

straight through without being splayed anywhere, are all

3:29

characteristic of focal fat deposition within the liver.

3:35

This is a very, very common finding.

3:38

The reason I wanted to talk about it is that if you're

3:41

not used to seeing it, you may mistake it for another

3:46

type of liver lesion that you may intervene on.

3:51

there's nothing that you really need to do about it.

3:54

It tends to have characteristic locations adjacent

3:57

to the falciform ligament, or the uh, fissure

4:01

for the ligamentum venosum, um, it tends to

4:04

be in the region of the porta hepatis, as well

4:07

as adjacent to the gallbladder fossa as well.