0:01

62-year-old with a rising PSA to 4.

0:04

We have our images, and I have an axial T2.

0:08

The ADC map rendered at 1400 by 1400, an interpolated

0:13

high B value with B equals 1600. And here I have

0:17

a sagittal T2 that I'll sometimes slip in, uh,

0:21

arterial phase from the post-contrast dynamic series.

0:23

You can see the arteries are bright, but the

0:25

draining veins are not, so it is an arterial phase.

0:29

Okay, so we start at the peripheral zone,

0:31

and on both T2 and ADC, the peripheral zone

0:34

looks to be high signal, which is normal.

0:37

So we go to the bottom of the gland, come back here.

0:43

And one thing we note is way at the bottom

0:45

of the gland, there's some distortion on

0:47

the ADC map, and there's some low signal.

0:50

It's hard to know if that low signal

0:51

is real or if there's a lesion there.

0:53

And this is from a small amount of air in the rectum.

0:56

So one of the limitations,

1:00

3T is susceptibility from air in the rectum.

1:02

And this is mitigated by giving, you know,

1:05

antispasmodics, such as Buscopan or glucagon,

1:09

making sure the patient has a good enema prep.

1:11

Uh, but the best way to do this really is to use

1:14

advanced diffusion techniques like a multi-shot

1:16

diffusion, uh, that keeps the echo train short, keeps

1:20

the TE short, uh, and reduces the distortion.

1:24

So you get here and, you know, is this artifact,

1:26

you know, it's dark on the ADC map, it's the

1:30

only place that's bright on the high B-value image.

1:33

Maybe there's something there on the axial

1:35

image, but it's not very, um, um, distinct.

1:38

So remember, we image T2 in all three planes,

1:41

and I've pretty much just been showing you the axial

1:44

planes, but you gotta look at all the planes.

1:47

And that, that went in the wrong window here.

1:49

Let me put that one there, put the axial back here.

1:52

Well, if you look down here In this left

1:57

base, sorry, left apex, look, there is a

2:01

well-defined low signal T2 lesion there.

2:04

So, the fact that there's actually something

2:06

there on T2 is going to make me think

2:08

that the diffusion image is accurate.

2:11

Now, it won't let me show you what the

2:13

ADC value is, but it was in the 500s.

2:15

So I've got a focal well-defined area of low ADC in

2:19

the 500s, well below the 1000 threshold that I use.

2:23

Alright, it measures less than 1.5 centimeters.

2:25

2:26

I don't see an extracapsular spread.

2:28

Uh, that makes it a PI-RADS 4 lesion.

2:32

That's what we call it.

2:32

It was biopsied, and we got

2:34

Gleason 4 plus 4 disease in it.

2:36

Let's keep going, because there's some other areas

2:39

of subtle diffusion abnormality on the ADC map.

2:43

So there's a region right here,

2:45

and this corresponds to a T2 finding.

2:49

Now it's dark on the ADC map.

2:51

The ADC value measured above 1000.

2:53

It's not bright on the high B-value,

2:57

so we're looking at a PI-RADS 3 score for the

3:00

diffusion because it's a focal well-defined

3:03

abnormality on one of these two, but not on both.

3:07

And then it becomes very important to look at

3:09

the post-contrast images, because something

3:12

with a PI-RADS score of 3 on the diffusion gets

3:16

bumped to a 4 if there's focal enhancement.

3:19

So if we look at this area,

3:21

let's find it again right here.

3:23

There is some focal enhancement.

3:25

So this is a PI-RADS three elevated to a PI-RADS four,

3:29

which in my opinion is like the worst part of PI-RADS

3:33

because it's done because there's a small number of

3:37

these that will turn out to be significant cancer. But

3:39

not very many and you don't want to miss them. But you

3:42

know that most of these that you biopsy are gonna turn

3:44

out to be negative. And then you do unnecessary biopsies

3:48

and you don't want to call them. But you know that some

3:50

of them are gonna be positive and it's in the life.

3:52

It's in the lexicon, so they're PI-RADS for us.

3:54

This was biopsied and it was benign tissue.

3:58

And then the other area is right here,

4:02

which, you know, it's hard to see on the ADC

4:05

map, but maybe you see it first on the

4:07

T2 weighted image as a little low signal nodule.

4:11

It does have a focal area of decreased diffusion.

4:15

The ADC value is well above a thousand.

4:17

It's not present on the high B value image.

4:20

That makes it a PI-RADS 3.

4:24

It does focally enhance, that makes it a 4.

4:27

This was biopsy, it also was benign tissue.

4:30

So, one of the approaches is, you look for

4:33

something abnormal on the diffusion, and if it's

4:36

abnormal on both the ADC map and the high B value,

4:39

it's going to be either a PI-RADS 4 or 5 based

4:42

on size or presence of extracapsular disease.

4:45

It's pretty uncommon to have a tumor that's dark on

4:48

the ADC map and is not dark on the T2, but it happens.

4:51

Now, conversely, if I see something dark on the T2,

4:55

then I go and I make sure that I check the ADC map.

4:57

And by coming at it from both ways,

4:59

you make sure you don't miss anything.

5:01

And in this case, there are two such

5:03

findings that are dark on the T2, dark

5:06

on one of the two diffusion techniques.

5:09

That gives you a PI-RADS 3, and then they enhance, and

5:12

now it's a 4, and you biopsy them, and enough of them

5:18

will be positive that it's worth doing the biopsy.

5:21

According to the literature, I

5:23

don't feel very good about it.

5:26

Let's go to the rest of the study.

5:27

So you have the transition zone, which has no

5:30

focal areas that are concerning for neoplasm.

5:32

Again, here's a nice example

5:34

of thickened anterior stroma.

5:36

It's where there's no peripheral zone.

5:38

It's usually bilateral, and it will interdigitate

5:43

between nodules in the midline.

5:46

Again, on the arterial phase,

5:47

there's no enhancement in this area.

5:49

So this case is, A, a nice example of how

5:52

some air in the rectum can cause warping.

5:55

It's a nice example of how to approach things

5:57

that you see on T2 but maybe don't, sorry,

6:00

things that you see on T2 in the ADC map,

6:03

but are very subtle on diffusion, but they

6:04

enhance, and that can kick them from a 3 to a 4.

6:07

And it's another nice example of anterior stroma.