0:00

We're gonna move on to talking about challenges of CEM.

0:03

As I mentioned, you know, whenever we— we always

0:05

have to talk about the challenges, there's

0:07

always something that we need to discuss.

0:09

And the main challenge of contrast-enhanced mammo really

0:11

relates to contrast administration, as you would expect.

0:14

So there is a real risk of contrast-related events.

0:18

This includes what we used to call, uh, contrast-

0:21

induced nephropathy, and now it's called contrast-

0:24

associated or contrast-induced acute kidney injury.

0:28

Um, and it also includes extravasation

0:30

of the contrast material in the arm after

0:32

it's administered through the IV line.

0:34

Um, contrast-associated acute kidney injury,

0:37

or contrast-induced nephropathy, is not

0:39

really, um, it's not really a thing anymore,

0:43

um, or I should say people are questioning

0:46

whether it's really a thing anymore.

0:48

And so some institutions are actually not even

0:51

evaluating for underlying risk factors for

0:54

contrast, uh, for this contrast complication.

0:57

That being said, the ACR Contrast Manual still

1:01

treats it as an entity to be mindful of.

1:04

And so, you should talk to your individual

1:07

institution to see how they navigate this.

1:10

Do they test people's renal function before

1:13

doing, uh, before administering contrast?

1:15

Or you can always, um, you can always refer to

1:19

the ACR Contrast Manual for how to navigate this.

1:22

There's also a challenge of

1:24

contrast administration on workflow.

1:27

Again, we have to place an IV line.

1:29

We have to screen patients to make sure they

1:31

are not going to— they're not at increased

1:33

risk for developing a contrast reaction.

1:35

And so, um, that can impact the

1:38

workflow through the department.

1:41

Another challenge of contrast are, um, false positives.

1:45

So similar to MRI, areas that are benign

1:48

can take up the contrast material.

1:51

That's a challenge.

1:52

Contrast mammography,

1:54

when we look at it at the moment, it's really

1:55

just, is there contrast or is there no contrast?

1:58

We don't have all of the information that

2:01

we have with MRI, you know, T2 signal,

2:03

and maybe even diffusion-weighted sequences.

2:07

And so, there's the real possibility to just see abnormal

2:11

enhancement and to say, oh, this is concerning for

2:13

breast cancer, and we have to do something about it.

2:15

So there are false positives.

2:17

Let's look at an example of that.

2:19

This was a 56-year-old woman who had a history of

2:22

left breast cancer that was treated with wide excision

2:24

alone, and she had new right breast calcifications.

2:26

So you can see there's the surgical bed on the left.

2:29

I marked it.

2:31

That was where the wide excision was done.

2:33

And these are the new calcifications on the right.

2:34

These are— this is the image showing, you know, highly

2:37

polymorphic, uh, linear branching calcifications, BI-RADS 5.

2:41

So we are worried about these for sure.

2:44

These are the recombined images that

2:45

show that there's abnormal enhancement

2:48

associated with the new calcifications.

2:49

Not surprising because these were concerning.

2:52

They look like cancer, but what you'll also notice is

2:55

that there's a mass enhancement in the surgical bed.

2:59

And we saw this and we thought,

3:00

for sure this is gonna be a recurrence.

3:01

This patient didn't have radiation therapy.

3:03

It was only wide excision.

3:05

And so, um, we thought this was gonna be a recurrence.

3:07

We ended up having an MRI

3:09

because this was early on in our

3:11

implementation. We can see the same thing

3:13

on the right with those calcifications.

3:14

We had enhancement, and we also saw mass

3:16

enhancement in the surgical bed on the left.

3:18

And it turned out that this was not recurrence, 'cause

3:22

we did a biopsy, and we found that it was just

3:25

post-treatment change in the area of fat necrosis.

3:27

So this is an example of a false

3:29

positive on contrast mammo and MRI.

3:33

Another challenge of contrast mammo are false negatives.

3:36

Um.

3:38

False negatives happen because you have to remember that

3:41

a contrast mammogram is still just a mammogram, right?

3:44

We're still limited by what you can get on the detector.

3:48

So sometimes you can miss lesions that are in the deep

3:51

chest wall or in the medial breast, or certainly not

3:54

imaging the axilla, but that's not really the goal.

3:56

Another reason for false negative has to do with

4:00

BPE, which is, uh, background parenchymal enhancement.

4:04

So we know from MRI that

4:06

normal glandular tissue can take

4:07

up contrast to varying degrees.

4:10

Um, same thing happens on a contrast mammogram,

4:13

and you can see the image all the way on the

4:15

left is minimal background parenchymal enhancement,

4:18

where there's almost no uptake of the contrast

4:21

material as compared with marked background parenchymal

4:24

enhancement, which is quite a bit of contrast uptake.

4:28

So we have the same four categories

4:30

on contrast mammo as we do with MRI.

4:31

Minimal, mild, moderate, and marked.

4:34

And you can imagine that when you have marked,

4:37

a lot of background parenchymal enhancement, it might be

4:39

difficult to appreciate a solitary area of enhancement.

4:42

And so this can be a reason for false negative

4:45

on contrast-enhanced mammography.

4:49

Another challenge of contrast mammo, and this is

4:51

really more of an implementation challenge,

4:54

has to do with recombined-only findings.

4:56

We know from the literature that even if you see an

4:59

abnormality on recombined imaging only, even if it's

5:01

only one view, you have to take these seriously.

5:04

One of the studies that was put out by Kim

5:06

and colleagues showed that, um, foci, non-

5:09

mass enhancement, and mass enhancement had

5:11

positive predictive values of at least 6%, um,

5:15

all the way up to 40%.

5:17

So you have to address these if you see them.

5:19

And why that's an implementation challenge

5:22

is that what happens—

5:24

um, what do you do in these circumstances?

5:26

The first thing you do is you have to identify,

5:29

see if there's a low-energy correlate, because then maybe

5:31

you can do a stereo or tomosynthesis-guided biopsy.

5:35

Well, if you don't have that,

5:36

you can do, um, an ultrasound and see if you

5:39

have a target for ultrasound-guided core biopsy.

5:42

But if you don't have that, then what do you do?

5:43

So, um, we used to send these patients

5:46

to MRI to do an MRI biopsy.

5:48

Now, contrast-enhanced mammo biopsy —

5:50

you can do that, but you have to know

5:52

how you're gonna navigate these findings

5:54

once you implement contrast-enhanced

5:56

mammo, because it's a real thing.

5:57

It'll come up and you'd have to address the things.

6:00

At the very least, you would do a

6:01

follow-up, which is not recommended.