0:01

Let's look at the American College of Radiology's

0:03

PI-RADS assessment of the transition zone.

0:07

Now this is a great start.

0:09

It's not perfect, just like any grading system.

0:12

You're going to have to do a little bit of

0:14

creative thinking here, and I'm sure this

0:16

is going to be recast and developed as

0:18

time goes on, as will the peripheral zone.

0:21

We are leading with the T2 character on

0:26

a fast spin echo image, as opposed to the

0:28

peripheral zone, where the DWI was the trump card.

0:32

Here, the trump card, if you play bridge,

0:35

is the T2 morphology and character.

0:40

We're going to look at two easy

0:42

categories, the 1 and the 5.

0:46

The 1, homogeneous intermediate signal

0:50

intensity in the transitional zone,

0:52

TZ, or central region of the prostate.

0:56

Doesn't matter what the diffusion character is.

0:59

Or the DCE, Contrast Enhanced MRI is.

1:04

Then we've got a 5.

1:06

In a PI-RADS 5, the T2 score

1:10

corresponds to a greater than

1:13

1.5 centimeter area.

1:15

We'll call this the central

1:16

region or TZ of the prostate.

1:18

We have this very charcoal-like smearing

1:20

effect that may cross boundaries.

1:22

It may cross capsules.

1:23

It may invade the neurovascular bundle.

1:27

And it's.

1:28

Equal to or really greater than 1.5 cm

1:31

in size, usually close to 2 cm in size.

1:35

It doesn't matter what the diffusion character

1:38

or the DCE-MRI shows in these two circumstances.

1:44

So a 1. A 4 is also easy.

1:47

A 4 is the same as a 5,

1:49

except the lesion is just simply smaller.

1:52

It's equal to, but really under,

1:54

1.5 centimeters in size, with that

1:57

charcoal-like, erasure-like, smearing

2:00

phenomenon crossing boundaries.

2:04

How about a 2?

2:05

A 2 is pretty easy.

2:07

A 2 is simply, within the prostate gland,

2:12

you have well-encapsulated nodularity.

2:16

Now those nodules, it is said, are gray or

2:18

intermediate, but in my experience, those nodules

2:21

can be heterogeneous or even very, very bright.

2:26

If it's a very bright nodule, they don't enhance.

2:30

So that's a, that's another helpful

2:32

little tool that's not really listed here.

2:34

Bright nodules are almost always cold.

2:39

If you start to see a bright nodule that's bigger

2:42

and irregular and it enhances or has some nodular

2:44

enhancement, you may have to worry about the rare,

2:47

mucinous tumor.

2:48

However, that's really exceptional.

2:51

So well-defined nodules in the TZ or

2:54

central region of the prostate with any

2:57

diffusion character, with any DCE MRI,

3:01

with the exception that I just mentioned.

3:03

You know, early enhancement associated

3:05

with a bright nodule, got to worry a

3:07

little bit, but typically bright nodules

3:09

and gray nodules encapsulation is key.

3:13

So that leads us to the toughy.

3:14

Now, in a, in a PI-RADS 3, the T2 criteria is

3:23

heterogeneous signal intensity, ill-defined

3:26

margins, doesn't cross boundaries like the

3:29

surgical or anatomic capsule, and it basically

3:33

doesn't fit into a 2, a 1, a 4, or a 5.

3:37

So if you have this scenario now,

3:40

the diffusion-weighted criteria kick in.

3:44

If the diffusion-weighted

3:45

criteria are a 5, in other words.

3:50

There is a greater than 1.5 cm

3:51

area of diffusion restriction that is bright

3:59

as you go up with the B value and is dark on the

4:03

ADC map and is well-defined and very hypo intense,

4:07

then this tweener scenario now becomes a PI-RADS 4.

4:13

If the diffusion characteristics are more

4:15

mild, then you're at a PI-RADS three.

4:19

So now you're probably thinking to yourself.

4:21

Well, what if the DWI scoring is a four?

4:24

That's a tough scenario.

4:27

Now, even though the ACR lists DCE-MRI as any,

4:32

this is a scenario where I rely personally

4:35

more heavily on the DCE-MRI characteristics.

4:39

If this scenario is cold, then I'm

4:43

very comfortable calling it a three.

4:46

If this scenario is mildly enhancing

4:48

with a progressive rise,

4:50

I'm comfortable calling it a PI-RADS 3.

4:53

However, if it's very hyperintense early on,

4:56

I usually move it up a bit to a PI-RADS 4,

5:00

or I survey it much more carefully or more aggressively

5:03

in reading this scenario with early enhancement.

5:08

But otherwise, the enhancement is

5:10

not that reliable in the central

5:12

region or TZ of the prostate gland.

5:15

So that's a summary of the TZ or central

5:19

region of the prostate gland as it relates

5:21

to synthesizing the different parameters,

5:24

noting that the T2 is dominant and trumps

5:28

some of these other criteria in most cases.