0:00

So now we're gonna look at a different area,

0:02

a different clinical indication, which,

0:04

which is using contrast-enhanced mammography

0:06

to evaluate for neoadjuvant chemotherapy.

0:08

So this was a patient who had a grade three, um, HER2+

0:11

breast cancer and had a positive lymph node.

0:14

You can see the cancer marked by the thicker arrow

0:17

and the node, uh, marked by the longer, thinner arrow.

0:23

And so, this is an example where the contrast mammo was

0:26

used to see how the patient responded to treatment.

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So these are the recombined images initially

0:32

before treatment, which show you what

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you would expect — the cancer and the node.

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And this is what we see after treatment.

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So, um, the images in yellow are the pre-treatment

0:42

images, and the images with the white annotations are

0:45

post-treatment. And so on our low energy images, we can

0:49

see that it looks like there's improvement, but you

0:51

probably remember from other, uh, talks on neoadjuvant

0:56

therapy where typically we categorize things as:

1:00

total response, no response, and a partial

1:03

response, which has to be at least 30%.

1:05

And so the question is, where does this fall in?

1:07

Is this a partial response?

1:08

Is this a total response?

1:09

So we get our recombined images, which give us

1:12

a much better sense as to how this patient has

1:15

responded to the chemotherapeutic treatment.

1:21

So there was a meta-analysis in 2023 — so recent —

1:25

that showed that the sensitivity for, um,

1:28

evaluating neoadjuvant chemotherapy treatment

1:30

response was actually better for CEM over MRI.

1:33

And it showed that the specificity was

1:34

actually a little bit worse — 68% to MRI.

1:37

But they're always kind of balancing,

1:38

you know, these, these two imaging

1:39

exams are always kind of teetering.

1:41

Like one is a little bit better,

1:42

one is a little bit worse.

1:44

Um, Bernardi and colleagues in 2022 showed that

1:47

the CEM size measurements correlate highly with

1:49

the size measurements on MRI. And studies show

1:52

variable rates of over- and underestimates for

1:54

contrast mammo and MRI, but always very similar.

1:57

So it's hard to say,

1:58

do they overestimate it by a few millimeters?

2:00

Do they underestimate it by a few millimeters?

2:02

I don't know what the exact answer for

2:04

this is because the data is kind of,

2:06

like I said, very variable. But the take-home point

2:09

is that these two imaging exams are very similar,

2:12

and that we can use contrast-enhanced mammography

2:14

as an alternative to MRI for neoadjuvant and

2:16

chemotherapy treatment response, especially — for sure —

2:19

if you don't have MRI, for sure.

2:21

For sure.