0:00

Okay, let's take a look at this 60

0:01

year-old man with a serum PSA of 6.5,

0:04

who previously, years past,

0:09

had a negative biopsy for cancer.

0:13

And he is undergoing serial

0:15

evaluation and surveillance.

0:18

So here is his Axial 2D Fast spin echo.

0:23

And I'd like you to kind of follow

0:25

along in the middle and on the right.

0:27

I'm going to make the right

0:28

side a little bit bigger.

0:30

So that you can see where you are.

0:31

So this is your coronal, this is your

0:33

sagittal, this is your axial, all 2D FSE.

0:38

Let's see where we are.

0:39

We're up near the base.

0:41

So, at the base, we're gonna see

0:45

mostly transitional and central zone

0:50

tissue or central region tissue.

0:52

So let's, let's draw that out for you.

0:55

We've got this area right here,

1:00

which is composed of the TZ and CZ.

1:05

The CZ is kind of this tissue in the back, and

1:09

the slightly more hyperintense tissue around

1:11

the edges, and maybe a little bit around the

1:13

back, is going to be the peripheral zone.

1:16

So let's draw over the peripheral zone.

1:20

And then the peripheral zone is going to

1:21

have a PZA, a PZP, for posterior, and a PZM.

1:29

Thanks for watching!

1:30

And there's a lot less peripheral

1:31

zone when you're up at the base.

1:32

In fact, near the back, there's

1:34

hardly any peripheral zone.

1:36

So in earnest, the central zone,

1:38

which is kind of hard to see in this

1:39

axial, is back a little further.

1:43

The urethra is also hard to see, but you can

1:45

cross-reference it in the sagittal by just

1:47

putting a dot right there at the bladder opening.

1:53

right at the base for the urethra.

1:56

In fact, when we're up really high

1:57

now, you see almost no peripheral zone.

2:00

This is all central region portion of the gland.

2:05

You see a little bit of the urethra

2:07

and the periurethral tissues.

2:09

So central region consists of

2:10

central zone and transitional zone.

2:14

Now let's work our way down.

2:17

We're at the base.

2:18

We pick up a little bit of

2:19

peripheral zone here and here.

2:20

Mostly central zone and transitional zone.

2:24

Periurethral tissues.

2:26

Let's keep going down.

2:28

Now we're picking up the anterior fibromuscular

2:29

stroma, this darker lentiform area, a little

2:34

bit easier to see on the right than on the left.

2:38

Let's take it away, and now let's put it back.

2:43

I'm going to put it back with a different

2:44

color, I like to put the

2:46

anterior fibromuscular stroma in red.

2:50

And let's take a look at the central TZ.

2:59

And then this patient's peripheral region, not

3:02

as hyperintense as you would usually expect.

3:05

We're gonna see how that plays into our PI

3:07

RADS grading, but let's, let's color over it.

3:10

So, we're gonna color over it right now.

3:13

Gonna make that blue.

3:15

Now as we go more inferior on the sagittal and

3:17

the coronal, things are gonna start to look

3:20

a little bit different, because we're gonna

3:22

start to pick up a little more peripheral zone.

3:24

So let's do that.

3:25

Let's go down a bit, a few slices.

3:27

And we have picked up, indeed,

3:29

a lot more peripheral zone.

3:30

Here it is.

3:31

I'm going to draw over it in blue.

3:36

There's the anatomic capsule.

3:39

This is the surgical capsule.

3:42

And everything in between, PZ, or peripheral zone.

3:46

PZA, PZP, PZM.

3:50

And central region of the prostate.

3:53

And there's a little bit more of our

3:55

lentiform anterior fibromuscular stroma.

3:58

Comes a little bit more off to the left side.

4:02

So everything that is uncolored

4:03

is central region of the prostate.

4:07

It's not unusual to not be able to

4:10

see the urethra, which is going to

4:12

make an angled turn for the anterior.

4:16

So it's probably right there, and the

4:18

tissue behind it is the verumontanum.

4:22

Let's keep going, shall we?

4:24

And I refer you to the anatomic vignette

4:25

if you want to know more about the anatomy.

4:28

Let's go down all the way to the apex.

4:31

We're in the apex of the gland.

4:34

We'll take two slices and

4:35

toggle them back and forth.

4:36

Well, let's take this one.

4:39

And we've got quite a bit of

4:40

peripheral zone present now.

4:41

Let's go back to our very beautiful blue

4:44

color, which I love, and let's demarcate

4:48

the central region of the prostate.

4:52

There's a little vessel right there,

4:53

or some area of hyperintensity.

4:55

I'm going to ignore it for right now.

4:58

There's the anatomic capsule of the prostate.

5:02

This is all peripheral zone.

5:05

Everything uncolored is central region of

5:09

the prostate, or TZ, transitional zone.

5:13

And we see a bit of fibromuscular

5:16

stroma, or anterior stroma.

5:18

Anteriorly.

5:20

And we're starting to see a

5:21

little urethral opening again.

5:24

So this would be the apex of the prostate.

5:27

So if we had a cancer, say, right here, we

5:32

would say it's in the apical right PZA, or

5:38

anterior aspect of the right peripheral zone.

5:44

And we would look to see if it grew

5:46

into the fibromuscular stroma, grew

5:48

in front of the fibromuscular stroma,

5:50

going into the preprostatic space of

5:52

Reteus, going through the capsule, etc.

5:57

If it was back here, it would be PZP.

5:59

If it was back here, it would be PZM.

6:02

On the other hand, if we had a central

6:04

zone abnormality on the T2-weighted

6:06

image that was decisive and worrisome,

6:09

it might look something like this.

6:11

Would look like charcoal smearing

6:13

away this architecture so that all you

6:16

see is a big gray blob that may even

6:18

cross over into the peripheral zone.

6:21

That would be a worrisome TZ abnormality.

6:25

But fortunately we don't have it.

6:27

So we work our way up and down.

6:29

We look at the anatomic capsule, we look

6:33

at the integrity of the surgical capsule,

6:35

between the central region and the

6:36

peripheral region of the prostate gland.

6:39

We look at the preprostatic fat.

6:42

We evaluate the seminal vesicles, the ejaculatory

6:46

ducts, the little bright thing right here.

6:48

And we look at the periprostatic fat on the T1

6:51

weighted image, which we'll show you in a moment.

6:55

The rectum has been evacuated.

6:56

There's virtually no air in it.

6:59

And that allows us to get

7:00

a high-quality axial image.

7:03

In the sagittal projection, we see the urethral

7:06

opening to help us identify the midline.

7:09

It goes back and then goes

7:11

forward as we come down.

7:16

little bit brighter than the rest of

7:18

the central region of the prostate.

7:21

Now this area here that's a little bit

7:23

dark, especially as we go off to the

7:25

side, I'm going to draw over it right

7:26

here, in the posterior superior quadrant.

7:29

Now I'll go off to the side and follow it.

7:32

That's the central zone of the prostate,

7:36

part of the central region of the prostate.

7:38

And we run into the seminal vesicle, which has

7:41

variable signal intensity because it's a gland.

7:44

So you may have in speciated secretions, darker,

7:46

or very hyper intense secretions, lighter.

7:50

And we go over to the other

7:51

side, same thing applies.

7:54

You see a little bit of glandularity, acinar

7:56

like character to the seminal vesicle, and

7:59

the posterior superior is the central region.

8:02

zone of the central region of the prostate.

8:06

Now how about the peripheral

8:07

region of the prostate?

8:08

That's a little bit tougher in this case.

8:10

Cause this patient has a slightly

8:11

hypo intense peripheral zone.

8:15

We see it as a J-shaped structure right here.

8:17

It's a little darker than usual.

8:20

But nevertheless, that is

8:22

not a criterion for cancer.

8:24

In fact, that's a scoring system

8:26

peripheral zone criteria 2.

8:30

Not a PI-RADS 2.

8:32

A scoring criteria 2.

8:34

For the peripheral zone.

8:36

What's the scoring criteria?

8:37

One, uniformly bright signal

8:40

intensity in the peripheral zone.

8:44

So let's draw over our peripheral zone.

8:46

Take whatever color we've got.

8:48

It's got this sort of J-shaped look.

8:50

And look how anterior it goes.

8:55

very slit-like in this projection.

8:58

I'll make it even a little smaller line.

9:01

This time I will make it, uh, I'll

9:04

make it pink just to stand out.

9:06

Is the anterior fibromuscular stroma.

9:10

And then everything in the

9:11

middle is going to be TZ.

9:16

Transitional zone.

9:17

So let's draw over the transitional zone.

9:19

Let's make it blue.

9:23

And we're off to the side now.

9:26

And we probably have a little bit of

9:29

CZ kind of encroaching on here and meeting the PZ.

9:32

That's a little better depicted in the coronal

9:34

projection as I'll show you in a moment.

9:37

Now one of the reasons why we're

9:38

showing this as a PI-RADS 1 is there's

9:41

very little heterogeneity within.

9:44

The transitional zone.

9:45

It's pretty hard to find a PI-RADS 1.

9:47

Because all adult males have some

9:49

degree of nodularity in their prostate.

9:53

In the TZ.

9:54

And those nodules can be very bright or very gray.

9:58

But they must be well encapsulated.

10:02

And we have just a little bit

10:03

of heterogeneity, but not much.

10:06

No encapsulated dominant nodules.

10:08

Oh, there's a little dot there.

10:09

Okay.

10:10

We'll write that off.

10:11

And the peripheral zone has no masses.

10:15

Granted, it is a little dark.

10:17

So that would give it a score of 2.

10:20

The transitional zone has

10:24

probably a score of 1 or 2.

10:26

It's a little bit, uh,

10:27

heterogeneous, but, but not much.

10:30

So I would give it a score of 1.

10:35

And then I would go over to my diffusion image to

10:39

check out the absence of any diffusion restriction

10:42

whatsoever to give this a PI-RADS score of 1.

10:45

Remember, the major criteria for the

10:48

central region, the T2 character.

10:51

No dominant nodules, no dominant masses,

10:54

no charcoal-like erosive, sorry, erasure

10:57

like masses that cross boundaries.

11:00

We don't have that.

11:01

Yeah, we have a couple of dots.

11:03

The major criteria for the peripheral

11:05

zone, no diffusion restriction.

11:09

And we're going to see, we don't

11:10

have any diffusion restriction.

11:12

So we have no major criteria met in either zone.

11:17

Let's go over and look at the coronal projection.

11:20

on the T2.

11:21

We're gonna start in the back.

11:24

In fact, all the way in

11:25

the back, out of the gland.

11:27

And out of the gland, we see the seminal vesicles.

11:31

They're a little tougher because

11:32

they're a little grayer than usual.

11:34

And then the vas deferens, with

11:37

the duct within the vas deferens.

11:39

And you have the ejaculatory

11:40

duct right here on the right.

11:43

So, we're in the back of the gland.

11:44

Now let's, sorry, we're behind the gland.

11:46

Let's go to the back of the gland.

11:48

The very back.

11:50

And we see two gray blobs that

11:52

kind of meet in the middle.

11:54

And there's a little fibromuscular septum right

11:57

here, which can sometimes masquerade as a mass.

12:00

You can sort of see a squiggly, dark

12:02

line right here on one side, and maybe

12:04

a squiggly, dark line on the other side.

12:06

I might even make it a little bigger for you.

12:13

almost exclusively transitional zone

12:16

and central zone tissue making up

12:18

the central region of the prostate.

12:20

So let's draw over with my

12:22

favorite central zone color, green.

12:27

The central zone on the right.

12:29

The central zone on the left.

12:32

This is probably a little

12:32

more central zone right here.

12:35

This is probably some volume averaging right here.

12:38

And then let's color in the, let's

12:41

color in the uh, transitional zone.

12:44

Let's make that kind of a lighter orange.

12:51

And then unfortunately, in this

12:53

particular person, there's not a lot of

12:55

discriminatory signal between the central

12:58

and peripheral zone in this projection.

13:00

We're going to see it a little

13:01

better as we come forward.

13:03

Or a volume averaging a little bit

13:05

of the peripheral zone with the

13:06

central region of the prostate.

13:08

I'm gonna give it the color purple, but it would

13:10

be kind of down here if we could discriminate it.

13:14

Granted we can't, but we're gonna use

13:15

the other projections and keep going.

13:18

Life isn't perfect.

13:19

Get over it.

13:20

So here is the coronal.

13:23

Let's go forward now.

13:24

Now you can really discriminate

13:25

it on the very next cut.

13:28

So now we've got a better view of the CZ.

13:32

Make it green again.

13:34

CZ.

13:37

TZ,

13:42

this is going to be TZ in here, filling in.

13:47

And this is, this is kind of all

13:48

transitional zone right here.

13:51

we start to see very well.

13:52

Let's make that a nice color blue.

13:55

We've got quite a bit of peripheral zone now

13:57

coming into view, going all the way to the apex.

14:01

Now let's keep coming forward.

14:03

We're going to run into better discriminatory

14:05

character between the PZ and the

14:08

central region of the prostate gland.

14:10

This lighter area represents

14:12

the periurethral zone.

14:14

Within the central region of the

14:15

prostate, there's the urethra.

14:18

Let's keep going forward.

14:20

Same thing.

14:21

Central region of the prostate gland.

14:24

Peripheral region.

14:25

Much thinner now.

14:27

Coming forward.

14:28

Central region of the prostate.

14:31

A little bit of peripheral region.

14:33

Little harder to see.

14:34

There's a little more peripheral tissue.

14:36

I'm going to draw over it right here.

14:38

There.

14:39

And there.

14:41

And then we keep coming forward.

14:42

Now we're starting to get

14:43

out of the prostate gland.

14:45

We're in the fibromuscular stroma now,

14:47

which assumes a bit darker character.

14:50

The sagittal projection.

14:53

Let's stay in the midline.

14:55

We have a relatively homogeneous central

14:58

region, although some innate heterogeneity

15:01

is there because you have a central zone

15:04

and a transitional zone and a periurethral

15:06

zone, which is a little bit brighter.

15:09

But no dominant bright or gray nodules.

15:13

No erasure of the anatomy.

15:16

Posterosuperior, central

15:18

zone of the central region.

15:21

More in the middle, transitional

15:23

zone and periurethral zone.

15:25

And those would go off to the side.

15:28

So, we could go either way and

15:30

still this area would be TZ.

15:34

But as we go off to the side, now we start

15:36

to hit a lighter signal that makes a J shape.

15:39

As we pointed out earlier, there it is.

15:41

I'm going to take an even more peripheral cut

15:42

and I'm just going to color the PZ in for you.

15:45

This is all PZ right here.

15:50

This is PZ, peripheral zone.

15:53

This is PZA and apical too.

15:56

Anterior and low, apical.

16:00

This would be PZP and also closer to the base.

16:03

PZP, posterior and base.

16:07

And this is your central region which is

16:10

mostly now transitional zone off to the side.

16:19

no diffusion restriction in the peripheral zone.

16:23

Major criteria.

16:24

So let's go to the peripheral zone

16:27

and look at the diffusion image.

16:32

We're going to take each diffusion

16:33

image and the B value is going up.

16:35

We got a B value of 0 and then a B

16:38

value of 900 and then a B value of 1200.

16:44

Let's flatten it out so you can see it.

16:47

And if there was diffusion

16:49

restriction, when we get to, say, 1600.

16:53

You should be seeing a bright, nodular, mass

16:56

like area in the peripheral zone, if you did

17:01

not have a PI-RADS 1 and you had a PI-RADS 4 or 5.

17:04

We don't have that.

17:06

We don't have anything that is going

17:07

up in signal intensity as we go from

17:10

low to intermediate to high B values.

17:12

In fact, the signals are

17:14

almost uniformly going down.

17:17

What about our ADC map?

17:19

Do we have any dominant areas of low signal?

17:21

Let's check it out.

17:24

No, we don't.

17:25

That's a dot.

17:26

Okay.

17:26

That is not an area of low

17:29

signal that meets criteria.

17:31

It's just a spot, another little spot.

17:34

And you get these little spots at areas

17:37

of, uh, signal decrease or signal poor

17:41

areas will show up as dark on the ADC map.

17:45

That can either be from fibrosis or

17:47

pixelation or a number of other causes

17:50

that we'll describe in the pitfall section.

17:52

But in order to have an ADC map abnormality,

17:55

I want it to be 3 to 5 millimeters or greater.

17:58

And we don't have that.

17:59

That's about a millimeter.

18:00

So, negative ADC map, negative

18:03

diffusion image for the peripheral zone.

18:06

We've already hit the major

18:07

criteria for the TZ, which is a T2.

18:12

No nodules, no masses, no erasure, no invasion.

18:16

So this qualifies as a PI-RADS.

18:21

What about the DCE MRI?

18:24

Let's see if we can find it.

18:28

We've got it right here.

18:30

So this would be your mask.

18:33

And on the right, I'm going

18:34

to put the subtraction.

18:36

So let's go through our mask,

18:38

see when the contrast arrives.

18:39

It has not arrived yet.

18:42

Let's keep looking.

18:43

Not arrived yet.

18:45

Not arrived yet.

18:47

It's arrived.

18:48

Contrast is there.

18:50

And we see symmetric central region, TZ area and

18:55

periurethral enhancement, which is quite common.

18:59

And that'll progressively wash in over time.

19:01

Let's keep looking at it.

19:03

Each one of these is between

19:04

7 and 12 seconds per run.

19:06

Let's keep looking.

19:07

So, another, let's say 10 seconds, so the

19:09

first one was at 10, this is at 20, now

19:13

we go to 30 seconds, and it progressively

19:16

gets brighter and brighter and brighter.

19:19

You can also subtract this information,

19:22

which is what was done on the right,

19:23

let's look at the subtraction.

19:25

You'll see that central periurethral

19:27

enhancement right there, and you'll see it

19:29

get brighter, the rest of the gland starts

19:33

to catch up, and brighter, and brighter.

19:38

It is very common to see

19:40

enhancement in the central region.

19:42

especially associated with BPH nodules.

19:45

It is less common to see it with BPH

19:47

nodules that are very bright on T2.

19:50

It is usually the solid, well

19:52

encapsulated ones that enhance.

19:54

So, this is normal periurethral zone in the

19:58

central region of the prostate enhancement.

20:00

It's absolutely and totally symmetric.

20:05

It does not, in any way, adversely affect your

20:08

criteria of a PI-RADS 1, um, uh, BPH nodule.

20:11

This is a PI-RADS 1.

20:13

One more caveat.

20:15

Let's bring down our last

20:16

sequence, the T1 basic spin echo.

20:20

And what are we using that for?

20:21

To look at the surrounding fatty tissues.

20:24

The pre-prostatic or retropubic space of Retzius.

20:29

To look at the rectoprostatic fat.

20:32

To look at the little dots surrounded

20:33

by fat, the neurovascular bundle.

20:36

To make sure the anatomic capsule

20:38

of the prostate is not violated.

20:40

To evaluate.

20:41

The presence or absence of lymphadenopathy,

20:44

of which there is none, and perhaps

20:46

to evaluate the skeleton to look for

20:48

hypointense sclerotic metastases.

20:53

The entirety of a study using 2D technique, a

20:57

PI-RADS 1, where you've seen DCE MRI for the

21:01

PZ, T2 for the TZ, you've gotten to look at

21:06

the ADC map, you've seen how we used the T1

21:10

weighted image to look at the surrounding fatty

21:12

tissues, and The dynamic contrast-enhanced MRI

21:17

showing physiologic normal anatomic enhancement.

21:21

We've showed you how to go back and forth and

21:23

evaluate the anatomy and the labeling and the

21:25

sagittal, the axial, and the coronal projection.

21:28

Let's move on and if you have time,

21:30

you might want to look at the 3D T2

21:34

presentation of this same protocol.