0:00

Other technical problems, um, include, uh, breast

0:04

that does not compress to a satisfactory amount.

0:08

Targets that are deep, closer to the chest wall,

0:11

and then patients who have decreased mobility

0:15

or who have back or neck problems.

0:18

So let's talk about the thin breast.

0:22

What are the technical requirements for performing a, uh,

0:25

mammographic guided core biopsy?

0:28

Well, in the standard approach

0:29

where the needle is perpendicular to the plane

0:32

of compression, all of this would need

0:35

to be under the skin.

0:38

Okay, so we have the tip or the dead space,

0:41

and then the trough, the notch,

0:43

the tissue acquisition chamber, all of that needs

0:47

to be within the breast.

0:49

So the breast thickness

0:51

is really dependent upon the needle that you're using.

0:54

You need to add up the dimension of the trough

0:57

and the tip to know approximately the BRE minimal breast

1:00

thickness, um, that you can use with that particular device.

1:06

So here's a schematic of different types of needles,

1:10

and this is what I just described to you

1:12

as the standard needle, eight millimeter

1:15

dead space at the tip and a trough of two centimeters.

1:20

So we think approximately three centimeter thickness

1:23

to be able to proceed with a standard approach for

1:27

that particular patient using that particular needle.

1:31

Some manufacturers and facilities will have a petite needle.

1:36

In this case, the tip is the same eight millimeter.

1:40

The trough is only 12 millimeter, so that a breast

1:43

that compresses closer

1:44

to two centimeters still could undergo stereotactic core

1:48

biopsy or tomosynthesis guided core biopsy.

1:51

Furthermore, there may be an option for a blunt tip,

1:54

petite needle where the tip is only four millimeter.

1:57

The trough is again, 12 millimeter.

1:59

And so now we're down to one

2:02

and a half centimeters Approximately

2:05

manufacturers have now developed another approach

2:09

to address the issue of a thin breast.

2:11

Rather than changing the length of the trough

2:15

or the dimension of the dead space

2:17

or tip at the end, there's something called the

2:20

lateral arm approach.

2:22

In this case, the needle is advanced parallel

2:27

to the plane of compression.

2:28

So typically we are perpendicular, as I mentioned,

2:31

and there is a hole, a window in this compression paddle,

2:35

and the needle is approaching the breast in this direction.

2:39

Again, Val, along the Z axis here,

2:44

because the needle is parallel to the plane of compression,

2:48

you can be successful in targeting this patient.

2:52

Even if the breast thickness is minimal,

2:54

you don't need a lot of space between the paddle

2:57

and the detector in order to get

2:58

The needle in there.

3:01

It is easier to see the needle in the

3:03

breast adjacent to the target.

3:05

I'll show you an example

3:07

and this may, uh, decrease the accordion effect.

3:11

I personally have found this a little bit of a challenge,

3:13

uh, in a very thin breast only

3:15

because I can't get my hand in there.

3:18

I have to get close enough to the breast

3:19

to clean off the skin and anesthetize.

3:22

And sometimes I've just found it a challenge.

3:25

I ask the technologist to try to place the edge

3:28

of the breast as close as possible to the edge

3:31

of the paddle, still

3:32

with obtaining satisfactory compression.

3:36

Here's an example of a lateral arm approach done at our

3:40

institution, a screening mammogram

3:43

and a patient with dense breasts.

3:44

And there are very faint new calcifications here.

3:49

As I mentioned, these are new.

3:52

They were evaluated with diagnostic imaging.

3:55

Uh, here's an MLV. Here's the CC magnification view.

3:58

These are very amorphous.

4:00

Uh, again, new calcifications

4:02

that are amorphous need to be biopsied.

4:05

So the patient was referred for, uh,

4:07

mammographic guided core biopsy.

4:09

They are at 12 o'clock, very superficial,

4:12

and the decision was made to use the lateral arm approach

4:15

because her compression, uh, was less than two centimeters.

4:20

So this is the, uh, scout image with the patient

4:25

compressed in an ml uh, plane.

4:29

Here's the upper breast, the inferior breast,

4:31

and our target calcifications.

4:36

The needle was placed from above.

4:37

Here's the pre-fire image

4:39

and you see the needle pointing to the target right here.

4:43

And then post-fire image with a two centimeter throw.

4:47

We see that the calcifications, the target are adjacent, uh,

4:51

to that trough.

4:53

Notice how easy it is

4:54

to see not just the needle trough but the target.

5:00

And this was this successful biopsy.

5:02

You can see lots of calcifications in different cores

5:05

here, here, here.

5:07

And this was DCIS.

5:10

Other challenges besides, uh, a thin breast would be targets

5:15

that are very close to the chest wall.

5:17

Uh, patients who may not be able to climb steps

5:20

to get onto the stereotactic core biopsy table.

5:24

Um, patients who cannot lie prone

5:27

and perhaps lack of physical space for a

5:31

prone biopsy table.

5:35

Here's what, uh, we have at our institution.

5:38

We have a room that is dedicated

5:40

to mammographic guided biopsies, uh,

5:43

with a lovely mural there for patients to look at.

5:45

And you see here with a patient lying prone, the back

5:49

of her breast is actually at the level of the table.

5:53

So if there is a target at the back

5:54

of the breast, there's no way

5:56

To get that within the imaging window.

6:00

Well, one option is to bring the arm through the hole

6:06

and rest the arm on a device that's attached to the table.

6:12

And you can get a little bit deeper with this

6:14

because the whole chest is going a little bit lower

6:16

so you can access a deeper target.

6:19

An upright unit though, is actually easier to obtain

6:24

a deep target.

6:25

I do not have this at my institution,

6:28

but I know that you can get deeper targets

6:30

because you don't have the thickness

6:32

of the table in the way.

6:34

Um, patients who cannot, like prone

6:37

also are better addressed with an upright stereo, uh, unit.

6:43

Also, these are add-on units,

6:45

so they don't require a dedicated room

6:48

and can be added on to one of your routine mammogram units.

6:53

Here's an example of the patient sitting in a chair

6:57

and the needle coming from above.

6:59

And sometimes the patients are actually

7:01

positioned in a decubitus fashion, so it's considered,

7:04

quote unquote an upright,

7:05

but patients may be actually lying on their side.

7:08

Again, you don't have the thickness of the table in the way.