0:01

MRI BI-RADS is really fundamental

0:03

to our interpretation of breast MRI.

0:06

This is the Breast Imaging Reporting and Data

0:09

System, which was developed by the American

0:11

College of Radiology and developed to improve

0:14

consistency in interpretation and reporting.

0:17

It covers all of breast imaging, including

0:19

mammography, ultrasound, and MRI, and provides

0:23

standard descriptors for lesions, which we

0:26

refer to as the BI-RADS lexicon, and those

0:29

are the words that we use in our reports

0:31

and when we're talking about these cases.

0:34

And it provides a format for reporting.

0:37

We're using the fifth edition of the BI-

0:39

RADS Atlas, which was published in 2013.

0:43

Typically, the Atlas had been updated every five

0:46

years, so we were expecting an update in 2018.

0:50

But I think there was so much going on in breast

0:52

imaging at that time that it took a little bit

0:54

longer for the new edition to be published.

0:58

And I know it's, it's in the

1:00

works, but it's not available yet.

1:04

The first thing that we want to look at

1:06

under the MRI BI-RADS lexicon is the amount

1:10

of fibroglandular tissue, and this roughly

1:14

parallels breast tissue density, but we

1:17

don't refer to it as density on an MRI exam.

1:20

That would be an X-ray term.

1:24

So the amount of fibroglandular tissue

1:26

can be described as almost entirely fat.

1:29

Scattered fibroglandular tissue,

1:31

heterogeneous fibroglandular tissue,

1:34

and extreme fibroglandular tissue.

1:37

And we evaluate this on the

1:38

T1 non-fat saturated sequence.

1:43

Just for comparison, this is the

1:45

spectrum of what we can see on

1:48

mammography for breast density.

1:50

On the left side of your screen, there's

1:52

a patient whose breast tissue might

1:53

be described as almost entirely fatty.

1:56

And then on the right-hand side of the screen,

1:59

the breast tissue is extremely dense, so

2:01

there is a spectrum, a range of breast tissue

2:04

densities, and there's a similar range of

2:07

fibroglandular tissue that we see on breast MRI.

2:11

This is an example of a patient who would

2:13

be described as almost entirely fat.

2:15

We saw from our previous images of the

2:20

breast imaging protocol that on the T1

2:23

weighted non-fat saturated sequence, fat

2:26

is going to be bright signal intensity, so

2:28

we see a lot of high signal intensity fat.

2:31

Here on this image, scattered

2:34

fibroglandular tissue.

2:36

There's a little bit more of that low signal

2:40

intensity breast tissue, but still quite a

2:43

bit of the high signal intensity fatty tissue.

2:47

Heterogeneous fibroglandular tissue,

2:49

really just getting into the tissue.

2:51

That's a little bit more fibroglandular as we

2:54

go through this spectrum, but this would be

2:57

described as heterogeneous, a lot more tissue

3:01

and a little bit less of the fatty tissue.

3:04

And then extreme fibroglandular tissue,

3:06

there's really quite a lot of that low

3:09

signal intensity breast tissue, a little

3:11

bit less fatty tissue in this patient.