0:01

The second group of sequences to look at when evaluating

0:03

lesions on liver MRI are the T2-weighted sequences.

0:07

Now, these are extremely important because in my own

0:10

experience, I can probably make an assessment of whether

0:14

an indeterminate liver lesion is something I need to worry

0:16

about or not need to worry about in about 70 percent of

0:19

cases based on the T2-weighted imaging sequences alone.

0:22

The first set of T2-weighted sequences that we get

0:25

are performed using single-shot spin-echo techniques.

0:28

We can see them performed in the axial plane over here.

0:31

And the coronal plane over here.

0:33

And the advantage of using this technique

0:35

is it allows rapid acquisition of images.

0:38

From a practical perspective, because you

0:40

can obtain these images very rapidly, you can

0:42

perform these images using a single breath hold.

0:45

However, if the patient is unable to hold

0:47

their breath, you can use respiratory gating,

0:49

where images are obtained at end expiration.

0:53

Another advantage of this sequence is

0:55

that it is less susceptible to artifact

0:57

from coils and clips within the abdomen.

1:00

Now, we do these in the axial and coronal plane, and

1:03

we add the coronal plane as it allows us a different

1:06

plane in which to look at the liver pathology.

1:08

I use this sequence as a general anatomic

1:10

overview of the abdomen and of the liver itself.

1:14

On it, we can see that the liver signal is

1:16

very homogeneous, and it is slightly more

1:19

hypointense with respect to the spleen.

1:22

Because of the relatively low water content.

1:25

This sequence is excellent to look at liver lesions

1:27

that contain lots of water content or long T2 signals

1:30

such as cysts or hemangiomas, but I would say overall,

1:35

the soft tissue contrast is relatively poor compared

1:37

to other T2-weighted sequences that we can do.

1:40

While you can perform this with fat saturation, we

1:43

typically perform these without fat saturation as

1:45

done over here because having fat saturation with

1:49

the sequence tends to obscure the liver margins.

1:51

So overall, this is a great sequence that can be

1:53

obtained rapidly, allowing for a good anatomic

1:56

overview of the abdomen and of the liver, but I

1:59

don't use it exclusively to investigate the actual

2:02

T2 signal of any indeterminate liver lesion.

2:05

For that, we obtain a different T2-weighted sequence.