0:00

Let's take this 66-year-old man with PSA

0:05

of 12.27, prior negative biopsy,

0:08

and no history of carcinoma.

0:12

He has had a physical examination that is

0:14

positive for a nodule and is symptomatic.

0:18

We have an axial T2 fast spin echo

0:20

image, and the purpose of this case is

0:23

to introduce you to the basic analysis

0:26

of a high-grade cancer and a stager.

0:28

So staging is key.

0:32

And we're going to stage

0:33

according to the T-stage system.

0:35

So we're going to have a T-stage,

0:37

an N-stage, and an M-stage.

0:40

So let's begin with our cancer, which is

0:43

solid, intermediate in signal intensity, and

0:47

has transgressed key anatomic boundaries.

0:49

It has violated the surgical capsule.

0:53

The surgical capsule is really a

0:54

pseudocapsule between the central

0:57

TZ gland and the peripheral gland.

0:59

Here it's intact.

1:00

Here it's violated.

1:02

The cancer has violated the anatomic capsule.

1:05

There's the intact left anatomic capsule.

1:08

There is the transgressed anatomic capsule.

1:10

Let's scroll it.

1:11

Let's go up and down.

1:13

And this lesion has gone all the way

1:15

from the apex, low in the prostate,

1:18

to the base, high in the prostate.

1:21

In fact, it's gone into the base and

1:23

involved the right seminal vesicle.

1:27

Now as one ages, the seminal vesicle, which

1:29

is normally hyperintense, becomes more hypointense

1:32

due to desiccation of secretions and

1:36

sometimes the simple mere fact of obstruction

1:39

can produce desiccation of the seminal vesicle.

1:42

But we still see its glandular

1:45

acinar appearance or architecture.

1:49

On the right side that architecture is lost.

1:55

continuous with the rest of the mass.

1:59

Now let's look at the dynamic contrast

2:02

enhanced MRI, which is purely a supplement.

2:06

Because any DCE MRI can still

2:10

qualify you for a PI-RADS 4 or 5.

2:13

This one happens to be a hypervascular

2:16

lesion, which is a poor prognostic sign.

2:19

And let's get right into the center of the tumor.

2:21

So here's the center of the tumor.

2:22

And let's go to a mask.

2:25

And now let's follow the contrast.

2:28

Contrast has not arrived yet.

2:30

Contrast has arrived.

2:32

The right gland

2:33

is brighter than the left gland.

2:35

So if we look at the curve of the normal

2:38

gland, it would look something like this:

2:41

Pretty quick arrival, and then as time

2:43

goes on, we'll see it keeps going up.

2:47

Whereas the right gland, the tumor enhancement

2:51

on DCE MRI, is going to look something like this:

2:54

It's going to rise very quickly, as it does right

2:56

here, and then as we follow it, it's going to

2:59

come down and eventually they'll meet so that

3:03

as you get deeper into the time activity curve,

3:06

they're going to become equal in enhancement.

3:09

So let's do that.

3:10

Let's keep following them.

3:12

Let's take away our curves.

3:14

This is getting less bright.

3:15

This is getting more bright.

3:17

This is getting less bright.

3:18

That's getting more bright. This is getting

3:20

less, that's getting more, and they are equal.

3:24

That is typical of a tumor curve on the

3:27

right and a non-tumor curve on the left.

3:33

Now let's go to our diffusion portion of the exam.

3:38

We've got a diffusion image in the lower right

3:40

hand corner showing the scope of the cancer.

3:48

And very hyperintense.

3:50

If we go to an earlier image with a

3:53

B value of 0 or 500 or 700 or 800, this

3:57

area is not going to be as bright.

3:58

But as the B value goes up, this gets brighter.

4:02

I'm going to illustrate that for you in a second.

4:05

Interestingly, this portion of the tumor, the

4:09

brightest portion of the diffusion restriction

4:12

in the anteroapical region, was a Gleason 9.

4:17

This portion, brighter near the

4:18

base and the back, Gleason 9.

4:22

The rest of it, Gleason 7.

4:25

This is proven on TRUS, on transrectal

4:29

ultrasound biopsy imaging with MR as a map.

4:35

The ADC parametric map, which is

4:38

a map of velocities, shows the

4:40

restricted velocity of the main tumor.

4:43

The greater the degree of restriction we

4:45

know correlates with the Gleason grade.

4:49

So the lower the velocity, the darker

4:52

the signal, the higher the grade.

4:55

And that correlates very nicely with

4:57

what we saw on diffusion imaging as well.

4:59

So this area back here that's a

5:00

little bit blacker, Gleason 9.

5:03

These areas that are a

5:04

little bit grayer, Gleason 7.

5:06

And the apical region that we

5:08

saw correlated with a Gleason 9.

5:12

Now, let's look at some of the other projections.

5:16

So let's take a look at the

5:17

coronal projection for a moment.

5:20

I'm just going to drop it in the left-hand corner

5:21

and keep my diffusion image up, because I promised

5:24

to show you the individual diffusion images.

5:26

And we have our best look at seminal

5:30

vesicle invasion on the right.

5:32

We have involvement of the base, the

5:35

mid, the apical, the lateral, and

5:38

mesial segments of the prostate gland.

5:41

If we were to localize this tumor axially, we'd

5:44

say that its epicenter is in PZP and PZM, with

5:48

extension into TZA and TZP from apex to base.

5:54

We'd say that the capsule is transgressed,

5:57

both laterally and posteriorly, and we'd

5:58

say that it's transgressed laterally.

6:00

With crossing of the right-sided

6:04

Denonvillier rectoprostatic fascia.

6:07

We would say, in the sagittal projection,

6:10

that the mass does not invade the preprostatic

6:13

space of Retzius, even though the Gleason 9

6:17

component was, in part, antero and apical.

6:22

We would say that the bladder base is not invaded.

6:26

We would say that the pelvic sidewall

6:28

in the coronal and axial, not shown right

6:30

now, is also not affixed by the mass.

6:35

Now let's return to our diffusion sequences.

6:39

So let me start with this one.

6:42

This would be a b value of zero.

6:44

Let's go to an intermediate b value.

6:47

Let's go to a higher b value.

6:49

And then let's go to the highest b value.

6:52

Now the things that cause diffusion

6:54

restriction, and you've heard this on multiple

6:56

vignettes, are viscosity, cellularity,

7:01

cell membrane interruption, and so on.

7:03

Cell death, cell necrosis.

7:07

The ones that apply here in prostate

7:10

cancer are desmoplasia, or firmness of the

7:13

lesion, and cellularity, or cell packing.

7:17

That can also occur, by the way, in the

7:18

bone marrow, as we'll see in a moment.

7:20

So now let's scroll.

7:21

Let's focus on our tumor.

7:22

I'm gonna make it a little bit bigger.

7:25

Let's focus on our tumor.

7:27

Keep focusing while I'm making it

7:28

bigger, and look what's happening.

7:30

Our tumor, as the B value goes

7:32

up, is getting a little brighter.

7:35

A lot brighter.

7:36

Brightest, as we go from B value

7:38

to 0, to 800, to 1,200, to 1,600.

7:43

And the areas with the highest signal

7:45

intensity have the highest Gleason scores.

7:47

But wait, there's more.

7:50

There's involvement of the pubis.

7:53

There was involvement of

7:54

other skeletal areas, too.

7:56

And just as you would with PET CT, you're

7:59

going to take each of these dots, and

8:02

correlate it with a morphologic image.

8:04

So you might pick up, say, the axial T2, for

8:08

instance, and then you would look to see if

8:10

those dots correspond to linear tubular vessels,

8:14

or whether they correspond to lymph nodes.

8:18

So in this particular example, the

8:20

patient did have positive lymph nodes.

8:23

There are a few of them that are, like this one,

8:25

very tiny, micrometastases, non-tubular, there it

8:28

is right there, and

8:33

It's there, it's there, it's gone.

8:37

There, there, gone.

8:39

So not a tube.

8:40

Whereas some of these are very

8:42

squiggly and wiggly like that.

8:44

That's obviously a vessel.

8:45

You don't even need the

8:46

anatomic image to prove that.

8:48

But you go back and forth like you would

8:50

with PET CT to decide what's anode, what's

8:54

round, what's gray, what's lost its fatty

8:57

hilum, and what is a tubular structure.

9:00

So in staging this lesion,

9:03

we've got a T three B lesion.

9:08

We've also got nodal metastases, so it'd be an

9:11

N1 for nodal metastases as opposed to an N zero.

9:15

And we've got an A, a metastatic lesion in the

9:19

bone, which would make it an M1 B for bone lesion.

9:23

So T three BN one regional nodes, M1 B for bone.

9:29

There's seminal vesicle invasion,

9:30

there's transcapsular extension.

9:32

We give the tumor volume.

9:34

We'd say the right

9:35

neurovascular bundle is invaded.

9:37

The right rectoprostatic fascia is invaded.

9:41

The lesion is not affixed to the pelvic sidewall.

9:44

There's bony metastases.

9:46

And there are regional nodes.

9:48

By the way, don't forget to

9:49

look at the rest of the scan.

9:51

Yes, you looked at the bones, but there

9:52

is an ileosois bursal cyst on the right.

9:55

And there are some other

9:56

additional minor findings.

9:58

That is an example of a PI-RADS 5

10:00

with T staging illustrated.