0:00

Let's take a 77-year-old man with a PSA

0:03

of 13.42, a negative biopsy in December of 2015,

0:09

and now we're two years later in 2017.

0:14

So he's obviously undergone MRI as part of a

0:17

surveillance program with a negative biopsy.

0:20

We've got axial T2, 2D fast

0:23

spin-echo imaging, 3 mm cuts.

0:25

We also have the 3D images as

0:27

well, and we may show those or not.

0:29

Let's scroll up to the base, seminal vesicles, and

0:33

vas deferens, let's scroll down towards the apex.

0:38

And when we get down low in the apex region, I'm sure

0:42

you all remember that the peripheral zone is going

0:44

to get bigger, so the prostate gland is going to

0:47

look like this, you're going to have a central region

0:49

that's here, a fibromuscular region that's here, and

0:54

the peripheral zone you're going to have the PZ here.

0:57

And the PZ is going to be divided up into

0:59

anterior and posterior, maybe a little

1:01

bit medial, so PZA, PZP, PZM, and so on.

1:06

So, in the back, in the region of the PZM and

1:10

PZP, say PZP right here, and PZM right here,

1:16

We've got a trapezoidal-shaped abnormality.

1:21

So let's look at it, and I'm going to call

1:23

right up the 1600 b-value diffusion image.

1:27

And there is a bright area corresponding to this area.

1:31

If we smoke them with our cursor,

1:33

they are in the exact same position.

1:35

There they are.

1:37

So what has happened here?

1:40

When we went from the b-value of zero, which I

1:42

haven't shown, to 400, to 800, to 1200, to 1600,

1:46

this area got brighter and brighter and brighter.

1:49

That's pretty self-explanatory.

1:51

If we correlated this area with

1:54

the ADC map, let's do that.

1:57

Let's look at the map.

1:58

That's the exact spot.

2:00

The diffusion is restricted, the velocity is low.

2:04

So this parametric map shows low signal intensity.

2:09

So we've got in the peripheral zone

2:11

major criteria for a PI-RADS 4 lesion.

2:15

In other words, focal diffusion restriction.

2:19

That is well-defined, that is mass-like, that

2:23

progressively and intensively increases in signal, and

2:26

is clear and sharp on the diffusion-weighted image.

2:30

And it is corresponding, maybe the images

2:33

are just slightly a little off, because

2:34

right there, that corresponds very nicely

2:37

to this locus and to this shape, and we also

2:40

have a second lesion on the opposite side.

2:44

Now that second lesion does not have a correlate on

2:46

the T2, it does have a correlate on the diffusion

2:49

image. It does have a correlate on the ADC map.

2:53

So that one is a little bit in question.

2:56

So let's check it out on the Contrast

2:59

Enhanced Dynamic MRI, or DCEMRI.

3:04

Well, first and foremost, our central lesion,

3:08

our lesion in the apical portion of the prostate,

3:11

so prostate apical mass, trapezoid-shaped.

3:15

We'll measure it.

3:16

It's under 1.

3:17

5 centimeters.

3:18

It involves more than 50%

3:21

of the right side of the peripheral zone.

3:24

So that automatically makes it a T2B lesion.

3:28

It looks like it crosses the midline

3:30

on Dynamic Contrast-Enhanced MRI.

3:32

Again, a T2B lesion.

3:35

It does not violate the capsule in any way.

3:39

And the other lesion that we saw did not enhance.

3:44

So, I kind of used that as a tiebreaker, but we'll

3:46

direct them to biopsy this lesion, although this

3:49

one would be categorized as a PI-RADS 3, because it

3:53

doesn't have a very good correlate on the ADC map.

3:56

It doesn't have a very good correlate

3:58

on the T2 in the peripheral zone.

4:02

This is gonna be a PI-RADS four.

4:04

Now it's a four for a number of reasons.

4:07

It's a four because there is a discreet abnormality

4:11

on the T2-weighted image in the peripheral zone

4:14

that correlates on DWI, which is the major criteria

4:18

focal markedly hyperintense on the ADC map.

4:22

Let's get the map down again,

4:24

so we have a nice correlation.

4:26

Vocally hypointense on the ADC map and markedly hyperintense

4:30

on the high B-value DWI but not greater than 1.

4:36

5 centimeters.

4:38

So our criteria is already met.

4:40

So the DCE MRI, which I pulled down, was just a helper.

4:44

It showed early enhancement in the

4:46

first 10 or 20 seconds after injection.

4:49

It showed some crossing of the midline.

4:52

It did not show the other accessory lesion.

4:56

So this is going to be a higher grade.

4:58

Gleason 7, 8, 9, or 10 cancer.

5:01

I don't know what this turned out to be pathologically,

5:05

but this would be categorized as a PI-RADS 3 because

5:10

it doesn't have a good correlate on the ADC map.

5:13

It does have some diffusion restriction.

5:16

It had nothing on the T2.

5:18

So it's got some mixed character to it.

5:20

So we have one PI-RADS 3 lesion.

5:22

We've got one PI-RADS 4 lesion that

5:24

meets all the criteria under 1.

5:26

4 centimeters in size.

5:28

Not crossing the anatomic capsule,

5:30

not invading the neurovascular bundle.

5:33

This would be an example of a right-sided PZA, PZP,

5:39

and M crossing the midline, T stage 2B, less than

5:46

1 centimeter in size, not crossing the capsule,

5:50

not invading the neurovascular bundle, PI-RADS.