0:00

Let's take a look at a 56-year-old male

0:03

with an elevated PSA and a negative biopsy.

0:05

This is a tremendous indication for MRI

0:09

when you're not in the low-tier group.

0:11

In other words, when the PSA is rising

0:15

at a rate that's disconcerting, maybe a 50%

0:18

rise or a doubling in one year,

0:21

or the PSA is hovering around 10 or greater.

0:24

And then your suspicion is pretty

0:26

high because the likelihood of cancer

0:27

is almost 50%, which is pretty good.

0:29

And the possibility of extension outside the

0:31

gland when you're, uh, you with a total PSA over

0:34

10 is also 50%, maybe even a little higher.

0:39

So here you've got to go for something

0:41

and MRI is just perfect because

0:44

you can find aggressive cancers.

0:46

So we've got an axial T2-weighted image

0:48

on the left, and immediately we see several

0:52

abnormalities in the peripheral zone.

0:54

In the right PZP, the posterior aspect of the

0:58

peripheral zone is an area of hypointensity.

1:03

And there is a question as to whether it has

1:05

fuzzed out and produced an ill-defined capsule.

1:08

Here is the anatomic capsule.

1:10

It's a line, it's a line, it's a line.

1:12

Now it's an interface, because it

1:14

has an opacity on one side, and we've

1:17

completely lost that crisp line.

1:20

So we're suspicious of capsular invasion, not just

1:25

because we lost the line, but look at the bulging.

1:28

And look at the asymmetry of the

1:29

little speckled tissues on either side.

1:32

Nice and speckled and bright, a little

1:34

less so, and they're pushed away.

1:36

Another sign: bulging and asymmetry

1:39

of the neurovascular bundle, along

1:41

with this broad area of contact, all

1:44

suggestive of capsular involvement.

1:48

Also, asymmetry.

1:50

of the pericapsular prostatic fat.

1:52

Another very important sign of capsular invasion.

1:55

Now here is a fat suppression one.

1:57

And while I like this to look internally

1:59

at the gland because it makes the whites

2:01

whiter and the darks darker, you can

2:02

see the edge of the tumor very nicely.

2:04

It does hamper substantially your

2:07

ability to see transcapsular extension.

2:11

Now this was done with 3D technique for mapping.

2:13

This is 2D technique over here.

2:16

Now what's the major criteria for

2:19

peripheral zone abnormalities?

2:21

It's actually not the T2-weighted

2:23

image even though it's pretty.

2:24

It's actually not the 3D fat suppression

2:28

T2 image even though it's pretty.

2:29

It's the diffusion image with a high B value.

2:32

How high?

2:33

Well, 1200 is the absolute floor.

2:36

But I like them around 1400 or 1600.

2:39

And the thing that's going to limit your ability

2:42

to get into these high B values is the efficiency

2:45

and strength of the gradient on your MRI.

2:49

So this is a B1600, and right there

2:51

we've got diffusion restriction.

2:54

And the intensity that you

2:55

see on diffusion restriction.

2:57

And the degree of low signal on the

2:59

accompanying ADC map has a lot to do

3:03

with the aggressiveness of the cancer.

3:06

So, extremes of hyperintensity.

3:09

Extremes of parametric hyperintensity.

3:12

Velocity restriction on the ADC map

3:14

means you've got a higher Gleason score,

3:17

which takes you into a poorer prognostic

3:20

cavity, a poorer prognosis overall.

3:26

So now let's look at the ADC map.

3:29

I'm going to blow it up a little bit.

3:30

The ADC map, a parametric map of

3:32

velocities, more sensitive by the

3:34

way than the diffusion image itself.

3:37

It's a calculated image made on the basis of

3:40

multiple diffusion images. Shows our area of

3:44

velocity decrease or diffusion restriction as low.

3:48

So it's high on diffusion,

3:49

it's low on the ADC map.

3:51

Now let me just take you through

3:53

a series of diffusion images.

3:54

Here's the low B-value image.

3:57

We'll go right to our spot.

3:59

And the low B-value image is nothing more

4:01

than a very fast echoplanar T2-weighted image.

4:05

So it looks a lot like the regular T2 image.

4:09

Let's take the next B-value up, say 50.

4:12

Still pretty low.

4:14

And the next B-value up, kind

4:16

of an intermediate B-value.

4:17

It's getting a little bit less dark, and the

4:20

tissues around it are getting a little less white.

4:23

Now let's go to a B-value of 1200.

4:26

It's getting brighter, the surrounding

4:29

normal prostate is getting darker.

4:31

Let's go to a B-value of 1600.

4:33

It's pretty bright, and the

4:35

surrounding tissue is darker.

4:37

So you see how you take these series

4:39

of B-value diffusion images

4:41

in which you crank up the volume.

4:43

You crank up the intensity of the diffusion

4:46

gradients, and you invert the signal.

4:50

The signal goes from dark to bright

4:52

on the high B-value images, and

4:54

the rest of the prostate drops out.

4:58

Now, we measure this in the axial

5:00

projection, and the measurement,

5:03

we'll measure it for you right now.

5:04

The measurement here was about a

5:06

centimeter or less, 9 millimeters.

5:08

So that would make it a PIRADS 4.

5:12

We'll look at it in another projection.

5:13

Let's do that.

5:15

Let's pull down the sagittal.

5:19

And there is our lesion in the back.

5:22

It may be a little longer

5:24

than we thought previously.

5:25

Let's look at the length.

5:27

So if it exceeds 1.5,

5:30

it's 1.2.

5:31

131 00:05:32,650 --> 00:05:35,489 So it's still in the PI-RADS 4 category.

5:35

But we're not done yet.

5:37

Let's look at the coronal projection.

5:39

So let's pull that down and go right to our spot.

5:44

And perhaps it's a little bigger.

5:46

So it's a little hard to measure the upper part.

5:48

You know, are we seeing some

5:49

fibrosis there, or is that tumor?

5:51

This is clearly tumor.

5:53

So if we measure it from here

5:54

to here, it's gonna be 1.44,

5:57

that'd make it a PI-RADS 4.

5:59

If we measure it from here to here,

6:01

as the original reader did, you'll

6:03

see that in the report, then that's 1.7,

6:06

that would make it a PI-RADS 5.

6:09

In my opinion, it probably stops a

6:11

little bit lower, like right there, and

6:12

this is just fibrous tissue over here.

6:15

So that would categorize it as a PI-RADS 4.

6:18

So you see the designation between

6:19

a 4 and a 5 is pretty simple.

6:22

If you're over 1.5,

6:23

it's a PI-RADS 5.

6:25

If you're under 1.5,

6:26

it's a PI-RADS 4.

6:28

And if it's 1.5,

6:28

then you might want to use some of the other

6:31

parameters and kind of split the difference

6:33

to decide which direction you're going to go in.

6:36

Critical finding in this case, suspicion for

6:41

transcapsular microinvasion on the right side.

6:45

Let's finish the case off with

6:48

the dynamic contrast-enhanced MRI.

6:51

Let's pull it down.

6:53

So what you're looking at

6:54

now is each anatomic locus.

6:57

Let's go to the site of the

6:58

tumor, which is right here.

7:00

And we'll start off with the mask.

7:03

So this would be before the contrast arrives.

7:05

Okay.

7:06

Here we are at 7 to 10 seconds.

7:09

A little bit of hypervascularity, not a lot.

7:12

Now we're at 14 seconds.

7:15

Now we're at 21 seconds.

7:17

And it starts to blend in

7:18

with the rest of the prostate.

7:19

So it's not that vascular initially,

7:22

but it is washing out, isn't it?

7:24

It's getting a little bit darker as time goes on.

7:28

So it has a tumor-like curve,

7:31

even though the peak of it is not that high.

7:34

So if we were to draw the curve,

7:37

then it would look something like this.

7:40

Typically, the tumor curves will be really high,

7:45

for the aggressive tumors and then have a washout.

7:48

In the prostate, they're not as consistently

7:50

as high as we see in the breast.

7:52

So you might have something that

7:53

looks a little bit like this,

7:54

and then kind of a more gradual washout.

7:58

And that would be the curve

7:59

of this area right here.

8:01

So in summary, this would be a PI-RADS 4/5,

8:04

depending upon what size criteria

8:07

you use with microcapsular invasion suspected

8:10

in the posterolateral right side, PZP area.

8:14

And PZL2, posterolateral.

8:17

Let's move on, shall we?