0:00

Let's take this 66-year-old man with a PSA of 6.55,

0:05

positive physical examination, and

0:09

utilize this to drive home three points.

0:12

PI-RADS grading, T staging,

0:16

and capsular involvement.

0:19

So let's start with PI-RADS grading.

0:22

This is a basic PI-RADS

0:23

grading case of a PI-RADS 5.

0:26

There is a mass, some portions of it nodular,

0:30

some ill-defined, infiltrating the entire left

0:35

portion of the gland without crossing the midline.

0:39

The mass, as we'll see in a moment, meets

0:42

major peripheral zone criteria, which is

0:46

diffusion restriction, heavy diffusion

0:48

restriction, at the locus of the mass.

0:53

The T2 criteria are more important in the TZ

0:56

central region, the diffusion criteria more

0:59

important in the PZ peripheral region.

1:03

The fact that the mass is greater than 1.5

1:06

centimeters in size makes it a PI-RADS 5.

1:08

1.5 and under would make it a PI-RADS 4.

1:10

5 and under would make it a PI-RADS 4.

1:16

Now let's take issue number two, the T stage.

1:20

The T stage reflects the

1:23

size, extent, and magnitude.

1:26

Non-local, as well as local extent of the mass.

1:31

So, do we have a mass that

1:34

extends out of the prostate?

1:36

That's probably one of the most

1:38

important T stage criteria.

1:42

So, what would be a T2?

1:44

A T2 would be a tumor involving

1:47

one half of one lobe or less.

1:50

A T2B would be a tumor involving more than

1:53

one half of one lobe, but not both sides.

1:57

A T2C would be involvement of both sides.

2:02

A T3 would be involvement of the prostate capsule.

2:07

And a T3B would be involvement

2:10

of the seminal vesicle.

2:12

So let's take a look at our seminal vesicles.

2:14

We saw in a companion case that we had

2:18

a desiccated seminal vesicle on the

2:20

left and an invaded one on the right.

2:21

Here we've got normal seminal vesicles.

2:24

With a typical glandular secretory acinar pattern.

2:30

And in fact, we see some proteinaceous

2:33

material that is layering dependently.

2:35

These are normal seminal vesicle glands.

2:38

There is no seminal vesicle involvement.

2:41

What about T3A?

2:43

Is there capsular involvement?

2:45

And the answer is yes.

2:47

There is likely capsular involvement.

2:51

And what do we use to make that determination?

2:55

That there is capsular contact

2:57

for at least two centimeters.

3:00

Not only is there capsular contact for at

3:02

least two centimeters, but if we blow up

3:04

our coronal projection, and this is why

3:07

we look in every projection, we've got

3:09

capsule, anatomic capsule, anatomic capsule

3:13

violated, transgressed by this tissue.

3:16

Not quite as easy to see in the

3:18

sagittal projection, but suggestive.

3:21

So, you should suggest that there is capsular

3:24

invasion, that this is a T3B abnormality.

3:30

Now what about regional nodes?

3:32

If regional nodes are not

3:33

assessed, then we say NX.

3:36

If regional nodes are positive, then

3:40

we'd say that there is an N1 abnormality.

3:45

And that's a pathologic designation, but if

3:47

we are confident that we have regional nodal

3:49

involvement on MRI, we'd say MR suggestive of N1.

3:53

A T3a N1 abnormality if nodes were present.

3:59

If nodes are not present, then we'd say N0 by MRI.

4:04

So you have NX, not assessed.

4:06

N0, not involved.

4:08

N1, regional nodes involved.

4:11

What about distant metastases?

4:14

Distant metastases, M0, no distant mets.

4:18

M1, M1A, non-regional lymph nodes,

4:25

M1B, bony metastases, and M1C, other

4:29

sites with or without bone involvement.

4:33

In this case, we did not have evidence

4:35

of distant metastases, so we would have

4:39

an M0, at least by MRI, not by pathology.

4:44

Now, let's turn our attention to the

4:46

major criteria for the peripheral zone,

4:49

which is the diffusion image, and see if

4:51

there is high signal intensity diffusion

4:53

restriction on the high B-value image.

4:57

And indeed, there is, in the

4:59

left portion of the gland.

5:01

And it's highly diffusion restricted.

5:04

It's very hyperintense, meaning it's

5:06

likely to be a Gleason 9, 8, or 7,

5:11

above a Gleason 6.

5:13

Let's put up the corresponding ADC map.

5:17

There should be low velocity pixel by pixel

5:21

illustrated by darker signal intensity

5:24

in the left hemigland and there is.

5:28

You can actually calculate these values and

5:30

the lower the velocity, the higher the Gleason

5:34

stage or Gleason histology is likely to be.

5:39

For our final act, let's

5:41

put up a B0 diffusion image.

5:46

The tumor is darker than the normal gland.

5:49

Now let's put up an intermediate B-value image.

5:54

The normal gland, still a little bright.

5:57

The tumor, still a little gray.

6:00

Let's take a higher B-value, say around 1200.

6:04

Now the tumor getting brighter,

6:06

the gland getting darker.

6:09

And then the B1600 value, the tumor is

6:12

brighter and the normal gland is darker.

6:14

So they invert.

6:16

When you're at a B-value of 0, in

6:19

other words a T2 image with echoplanar

6:21

technique, the tumor is solid and gray,

6:25

the normal peripheral zone is bright.

6:28

But as the B-value goes up, the tumor gets

6:31

brighter, the normal gland gets darker.

6:35

The brighter that gets, the

6:37

worse it is for the patient.

6:39

And the more likely the patient is to have

6:41

a histologic advanced Gleason stage.

6:44

So we've illustrated three key points.

6:47

An obvious left hemigland

6:50

not crossing the midline.

6:52

PI-RADS 5 lesion measured

6:56

length, width, and height.

6:59

I'm not going to measure it for you right now.

7:02

A suggestion on MRI of transcapsular extension.

7:06

We've illustrated the technique for T, T

7:10

stage grading, including nodes and metastases.

7:14

We stuck with the higher T-stage grades.

7:17

And then finally we gave you some

7:19

subtle and not so subtle criteria

7:22

for assessing capsular invasion.

7:24

Two centimeters of capsular

7:26

contact, bulging, bulging, bulging.

7:28

One I didn't describe, the facement

7:30

of the neurovascular bundle.

7:33

And then finally, directly seeing the anatomic

7:36

capsule, as we did in this case, transgressed.

7:40

This was also a hypervascular tumor on DCE MRI.

7:44

PI-RADS 5.