0:00

Challenge number five, the disappearing lesion.

0:04

So this is a lesion like the one I just showed you.

0:07

So these are patients who have a lesion

0:09

that shows on the diagnostic study,

0:11

but when you come to biopsy it,

0:13

you can't find a target to biopsy.

0:14

And this is always a little anxiety provoking, both

0:17

for the patients and for the radiologist when this happens,

0:21

because you wonder if it's there

0:23

and you're just not seeing it

0:24

and you don't wanna miss a cancer, et cetera, et cetera.

0:27

One thing that's really important in this case is you need

0:30

to warn the patients this might happen

0:31

at the time of consent.

0:33

Um, it happens I would say in about 10%

0:37

of our cases, roughly.

0:39

Um, so it's not an insignificant risk as such.

0:42

Um, I tell patients sometimes these things don't light up

0:45

when we come to biopsy them.

0:47

If we don't see it, then we can't biopsy it.

0:50

Um, I explain to them we would be doing a follow-up scan in

0:54

that situation, um,

0:56

but that if we stop the study in the middle, that's why.

0:59

And they just need to know that it's,

1:00

it makes it much less distressing for them.

1:02

And a surprise, the first thing you need

1:05

to do if you don't see the lesion is make sure

1:07

that there has been an adequate contrast injection.

1:10

If the contrast hasn't got into that patient,

1:12

if it's all infiltrated into their arm,

1:14

you ain't gonna see that lesion.

1:16

So look at the heart, look at the blood vessels, make sure

1:20

that you have contrast on the post gadolinium image.

1:25

The next thing that can happen, I'm gonna show a diagram

1:27

for this in a minute, is the breast can be over compressed

1:30

if you squeeze that breast too firmly.

1:33

You want it firm enough to be able to fixate it,

1:36

but not enough so that you're basically stopping the blood

1:38

or the contrast coming in.

1:41

If you think that it is over compressed,

1:43

get the technologist to release

1:45

the compression a little bit.

1:46

You know, you assuming you have adequate contrast in there,

1:49

and then take another scan.

1:52

Sometimes it just needs an, uh, an extra couple of images

1:55

to do and some subtractions to be able to see the lesion.

1:58

And I will always take some additional imaging further out

2:01

and see whether it turns up the more

2:03

progressive type of flow.

2:05

Um, generally speaking, the coils that you are using

2:09

for the biopsies do not have as many channels,

2:11

so they're not as high quality, high resolution

2:15

as the regular diagnostic coils.

2:17

So, and the breast is more compressed,

2:19

it's positioned differently

2:21

and it can be quite challenging sometimes to just sort

2:23

of work out the anatomy.

2:25

Um, I, my rule of thumb is if I see anything that lights up,

2:31

it enhances in the place where I was concerned

2:33

that corresponds to the lesion, I will biopsy it.

2:37

I do not say, well, you know, it's not enhancing as much

2:40

as it did on the diagnostic study.

2:41

Let's leave it alone because, um,

2:44

it often does not enhance as well.

2:46

And then finally, if none of these things work,

2:48

you're gonna stop the exam, reassure the patient,

2:51

but you should repeat that exam in three to six months.

2:54

Um, studies have shown in this situation

2:56

that there is a five to 10% false negative

2:58

Rate. For

2:59

whatever reason it didn't enhance on

3:01

that study, but it is a real lesion.

3:04

So how do we know if a breast is over compressed?

3:07

Well, um, don't laugh. Well, you can't laugh.

3:10

Um, but this is how I do it.

3:12

So this is how you test stake by feeling it.

3:16

So how tense at stake feels, how dense

3:19

that stake feels is how well done it is.

3:22

And you position your hand, like here,

3:24

you're pressing on your thena eminence,

3:26

and you move your thumb across various fingers.

3:28

And as you move it from the first finger over

3:32

to the fifth finger, it's an in your,

3:35

you'll notice your thena, eminence

3:36

and I, I know that you're all trying it at home right now,

3:40

um, will go from being, uh, medium rare to well done.

3:43

Well, we want the breast to be medium rare.

3:46

So after the technologist has positioned the patient,

3:51

I will stick my finger through the grid, obviously with no,

3:54

um, cleaning up done at that point before we start the scan.

3:57

And I will prod her breast to see if it feels medium rare.

4:01

If it feels well done, it's too tight.

4:03

If it feels rare, then that breast is, is not tight enough.

4:06

That grid is not tight enough on the breast,

4:08

and the breast is going to move

4:09

and push away from me when I try and biopsy.