0:01

This next patient is a 42-year-old female with an

0:03

indeterminate liver mass seen on another imaging modality.

0:06

And, uh, the thought was that this could reflect

0:08

a hepatic adenoma or focal nodular hyperplasia.

0:11

So we did an MRI, and we used, um,

0:15

Eovist as our intravenous contrast agent.

0:17

And so, let's go ahead and evaluate

0:19

what this lesion looks like.

0:21

So we'll start off with our T2-weighted sequences.

0:24

As we scroll through it, you can see that there's

0:26

a, uh, sizable lesion in the right hepatic lobe.

0:29

On the T2-weighted images performed without

0:31

fat saturation, you can see it over here.

0:33

This is the T2-weighted TurboSpin echo

0:36

sequences performed with fat saturation.

0:38

The lesion is seen over here.

0:40

And, if you look at it, um, quite hyperintense signal

0:44

on the T2-weighted images seen on both sets of sequences.

0:48

Now, you notice that the signal is hyperintense,

0:50

but it's nowhere near as hyperintense as CSF.

0:53

So, this is not going to be something that I can

0:55

call immediately benign, like a sister hemangioma.

0:58

If anything, the signal looks almost similar to the spleen.

1:01

So, this is something that I really do need

1:03

to evaluate on the remaining sequences to

1:05

have a sense of what this is going to be.

1:08

One of the other teaching points that this case showcases is

1:12

The fact that the TurboSpin echo, uh, T2-weighted TurboSpin echo

1:15

fat-saturated sequences really do have better soft tissue

1:18

resolution compared to the, um, regular T2-weighted images.

1:22

And we can see that if we scroll through these images, there

1:24

are multiple liver lesions with imaging features that are

1:27

similar to the index lesion that we're going to talk about.

1:30

And these, for example, in the left hepatic loop

1:31

are much better seen on the fat-saturated image here

1:34

compared to, uh, the regular T2-weighted sequence.

1:38

The other thing I'll note is that there is a lesion

1:40

at the tip of the liver over here. Again, much better

1:42

seen on the TurboSpin echo T2-weighted fat-saturated

1:45

sequence compared to the regular T2-weighted sequence.

1:48

And I want you to note the T2 signal within

1:50

this; it's much brighter than the index

1:52

lesion or any of the other liver lesions here.

1:55

And so, this already, I can tell, is probably going to be

1:57

something benign and that I don't need to worry about.

1:59

Let's go back and evaluate our index lesion using

2:01

the T1 in and out of phase imaging sequences.

2:03

So here we have T1 in and out of phase.

2:07

We're going to look at our index lesion in

2:09

the right hepatic lobe, right over here.

2:11

T1 T5. Let's look at it first on the in-phase sequence.

2:15

Quite challenging to actually

2:16

see the borders of this lesion.

2:17

It's probably going to be this lesion over here.

2:19

Pretty iso intense with respect to the liver parenchyma.

2:22

Maybe some portions of it are minimally T1 hyper intense,

2:26

but overall pretty iso intense with respect to the liver.

2:29

What happens to this image on the out of phase image?

2:32

Let's have a look.

2:34

There are definite portions within

2:37

it that drop out and signal.

2:39

Look at the periphery of this lesion.

2:40

Looks much darker.

2:41

Look at this central portion of this lesion.

2:43

It looks much darker.

2:44

This lesion here looks much darker over here.

2:47

So there's very discrete components within this lesion

2:51

that lose signal on the out of phase image, and this

2:54

tells us that this mass contains microscopic lipid.

3:00

Based on this alone, my differential

3:02

diagnosis narrows quite a bit.

3:04

The common lesion in the liver that can contain

3:06

microscopic lipid include hepatic adenomas

3:10

and potentially hepatocellular carcinoma.

3:14

However, hepatocellular carcinomas, or HCC, are seen

3:18

in patients who have underlying cirrhosis typically.

3:21

This patient is an otherwise healthy 40-year-old female.

3:24

So already as I evaluate this on the remaining sequences,

3:28

I'm going to be thinking that the imaging features

3:30

are more likely going to reflect hepatic adenoma.

3:33

Let's see what it looks like on the remaining phases.

3:35

Prior to giving contrast, we have the

3:37

T1 fat-saturated pre-contrast sequence.

3:41

You can see the lesion over here.

3:43

Portions of it are probably iso intense with respect to the

3:46

liver parenchyma, maybe minimally hyperintense as well.

3:50

And there are portions within it that are discretely

3:53

hypointense, particularly this portion here.

3:55

And that tells us that this contains

3:58

microscopic lipid, as we previously discussed.

4:02

The next set of sequences are the

4:03

dynamic post-contrast sequences.

4:06

As we scroll down and evaluate this lesion.

4:09

We can see that it demonstrates

4:10

enhancement on the arterial phase image.

4:14

Homogeneous enhancement, particularly along the central

4:16

portion of this lesion; the periphery, not so much.

4:19

On the portal venous phase image, the

4:22

mass remains hyperintense with respect

4:24

to the liver parenchyma, suggesting that it

4:26

still has some degree of enhancement.

4:29

And certainly on the equilibrium phase, it looks similar,

4:31

it looks hyperintense with respect to the liver parenchyma.

4:35

So here we have a mildly T2 hyperintense mass.

4:39

That has microscopic lipid that enhances with the

4:42

imaging appearance pretty consistent from the arterial

4:44

to the portal venous of the equilibrium phase images.

4:47

If this is all we had, this would be very,

4:50

very suggestive of a hepatic adenoma.

4:53

Final thing we're going to look at is our post-contrast

4:56

phase at 20 minutes to see if this retains contrast

5:00

as would be expected for focal nodular hyperplasia.

5:03

Or if this does not contain contrast, it appears

5:05

as a black hole, as would be expected for adenoma.

5:09

And here it is, 20 minutes post-contrast image,

5:13

and we can see that the lesion is hypointense with

5:17

respect to the liver parenchyma, and this combination

5:20

of findings is compatible with a hepatic adenoma.

5:26

Now hepatic adenomas are benign neoplasms.

5:30

They're less common than FNH.

5:34

for certain complications, most notably bleeding.

5:40

And potentially malignant transformation to 8 CC

5:46

or hepatocellular carcinoma, though I would

5:50

say that cases of malignant transformation

5:54

are very, very rare, very few and far between.

5:56

Bleeding is the primary thing that we worry about.

6:00

Like athenasias, this tends to

6:01

happen in a similar age group.

6:03

Having young females taking oral contraceptive pills or

6:07

OCPs is a big risk factor for patients developing adenomas.

6:11

It can also occur in, uh, male patients who are

6:15

taking steroids, and it can occur in either females

6:19

or males if they have glycogen storage disease,

6:22

particularly type 1 type of glycogen storage disease.

6:26

There are a variety hepatic adenoma,

6:29

some of which have relevance for imaging.

6:31

Three most common ones that we

6:33

encounter are the inflammatory subtype,

6:35

this is the most common subtype of hepatic adenoma, and

6:37

this tends to have heterogeneous hyperintensity 2 signal.

6:41

We also have the HNF alpha mutated hepatic adenoma.

6:45

This is the one that's almost exclusively seen

6:47

in females and is a very, very strong association

6:51

with patients taking oral contraceptive pills.

6:53

This often also has lipid

6:55

deposition within the lesion itself.

6:58

And finally, there is the beta catenin

7:02

mutated hepatocellular adenomas,

7:05

and these are the ones that are more likely to

7:08

occur in male patients and have a theoretical

7:13

malignant transformation to hepatocellular carcinoma.