0:00

So this next patient is a 29-year-old female who's pregnant

0:04

and has shortness of breath for which a CT scan of the

0:07

chest utilizing a pulmonary embolism protocol was performed.

0:11

We'll scroll down through these images, I'm not going to

0:13

focus on findings in the chest, but as it turns out, we

0:17

image a little bit of the upper abdomen here, and we see a

0:21

rather large mass in the right hepatic lobe, maybe some rim

0:23

enhancement surrounding it, it looks like it has internal

0:26

complexity to it, and for this reason, an MRI was performed.

0:30

So, here we have MRI of this

0:33

patient to evaluate this liver mass.

0:36

Because the patient is pregnant, could not

0:38

give contrast and we had to do sort of an

0:40

abbreviated sequence for a variety of lesions.

0:43

But we're going to start off with our T2-weighted imaging

0:45

sequences to look at this indeterminate liver mass.

0:49

And on it, we can see a rather large

0:51

mass in the right hepatic lobe.

0:53

On the T2-weighted images performed without

0:55

fat saturation, we can see that this

0:57

lesion has a very interesting appearance.

1:00

So, pretty well-defined.

1:03

Internally, has what I would say is mostly intermediate T2

1:07

signals seen throughout most of it over here, for example.

1:11

There are discrete clusters of more hyperintense

1:14

T2 signal seen along the periphery of this mass.

1:18

On the T2 Turbo spin echo fat-saturated imaging

1:22

sequence, these findings are redemonstrated,

1:24

where we have, uh, sort of intermediate signals

1:26

centrally, and more discrete T2 signals.

1:29

Areas of hyperintense T2 signal

1:31

along the periphery of this lesion.

1:33

Also noted is a very, very discreet T2 hypo

1:37

intense rim that surrounds the majority of

1:40

this mass, or in fact, all of this mass.

1:43

It becomes an important imaging finding in this patient.

1:45

So, we didn't do a lot more sequences for this

1:47

patient, certainly did not give intravenous contrast.

1:51

This imaging appearance is quite characteristic of a

1:54

particular type of abscess that can inflict the liver.

1:57

This is known as an echinococcal abscess, and this

2:00

is a manifestation of hepatic hydatid disease.

2:05

Now, this results from infection of, uh, certain tapeworms.

2:09

You have the Echinococcus granulosus,

2:11

which is the most common one, and you have

2:14

the multilocularis, which is less common.

2:18

This tends to be a little bit

2:19

more aggressive in its appearance.

2:21

This tends to have an imaging appearance that's

2:23

quite characteristic of what we're seeing over here.

2:26

This finding is endemic in certain parts

2:28

of the world, such as the Middle East, the

2:30

Mediterranean region, Australia, New Zealand.

2:32

So if you see a patient with a mass that looks like

2:34

this, who either are from one of those countries or visit

2:38

one of those countries, you've got to be worried about.

2:40

And underlying echinococcal abscess.

2:42

Humans are the intermediate host.

2:44

Humans ingest the larvae into the GI tract and then

2:47

these get transferred to the liver via the portal vein

2:49

or through other vessels to the systemic circulation.

2:53

Initially, often patients are asymptomatic.

2:57

As this increases in size, you can get pain.

3:00

And one of the other complications

3:01

that can occur is rupture.

3:03

Now these can rupture internally, not

3:06

affecting the outer portion of the cyst.

3:08

It can rupture into the biliary tree.

3:11

And it can also rupture into the peritoneal cavity.

3:15

And particularly when the latter

3:16

occurs, you're at risk for anaphylaxis.

3:20

So that's something that you need

3:22

to watch out for in these patients.

3:24

The imaging appearance, as I said, is quite characteristic.

3:27

Well, you'll have a dominant cystic mass with

3:29

a very discrete T2 hypointense rim, as can

3:34

be seen on, uh, the, um, fat-saturated image.

3:38

And at the periphery of this, you're going to see

3:40

multiple, multiple, what we call daughter cysts.

3:46

And so that's what we're seeing along the

3:47

periphery of this, uh, mass over here.

3:50

Um, and this finding is characteristic

3:52

of an echinococcal abscess.