0:01

Let's take a look at this 72-year-old man with

0:04

a PSA of 6.44 and a prior biopsy that was negative.

0:08

No evidence of cancer.

0:10

You've got a fast spin echo two-dimensional

0:14

T2 in the axial projection, in the

0:16

sagittal projection on your left,

0:18

and in the coronal projection on your right.

0:21

Let's chat about BPH.

0:23

You know, there are several criteria that have

0:25

been proposed, but when you're measuring using

0:28

one of the techniques that we've described

0:29

in the past, including length times width

0:33

times height, uh, times a certain constant,

0:37

then 25 cc's is the number, that is the

0:40

cut-off number that you're going to use.

0:42

If you want to learn more about measuring,

0:43

go to, uh, our earlier vignettes on BPH.

0:47

Now the overall gland size then is

0:50

the major criteria that we use on MRI.

0:52

So 27 cc's, 30 cc's, mildly enlarged,

0:56

80 cc's, moderately to markedly enlarged.

1:00

So we would measure this and apply the

1:02

constant to it and give you a number.

1:05

I'm not going to do that right now

1:06

because that's just a mechanical maneuver.

1:09

And then things like histology,

1:11

stromal, uh, or epithelial hyperplasia.

1:14

The lobar classification of BPH comes

1:18

into the subsegmental, uh, division

1:22

of the different types of BPH.

1:24

Now usually there's stromal and epithelial

1:27

hyperplasia, but there's also another factor.

1:29

There's muscular dynamic contraction, which

1:32

further inhibits the patient's ability to urinate.

1:35

So let's look at BPH from

1:37

the standpoint of anatomy.

1:39

And I like to look at that in the

1:41

sagittal projection, believe it or not.

1:43

Even though a lot of the PI-RADS

1:45

designations are made off the axial.

1:48

Now we're right smack dab in the midline.

1:51

There are four lobar types of BPH.

1:54

Type 1.

1:55

The enlargement of the anterior

1:57

pushes the urethra posterior.

1:59

That is clearly not happening here.

2:01

What's happening is the central zone

2:03

of the central gland, in the TZ region,

2:07

or the posterosuperior quadrant in the

2:09

sagittal projection of the prostate

2:12

is enlarged, pushing the urethra down.

2:15

And forward.

2:17

Type three is when they're balanced.

2:19

This is as big as that, and

2:21

the urethra doesn't move.

2:23

And type four would be pedunculated or lobulated

2:26

extension into or invaginating the urethra.

2:30

Often very difficult to see unless you

2:32

have high-resolution imaging, so this

2:35

would be an example of a type two.

2:38

Now, in the axial projection,

2:39

that's a little harder to discern.

2:41

You might be tipped off to the fact that it's

2:43

the CZ or central zone or posterior gland that's

2:47

markedly hypertrophied because there's so much

2:50

enlargement as you go up to the prostate base.

2:53

Now within the prostate are these well

2:57

defined, hyperintense nodules that have

3:00

this acinar or glandular look to them.

3:02

They'll be hypovascular, so that's a good thing.

3:06

They'll show up very bright on the B0 image, but

3:08

as you increase the B value, they'll dissipate.

3:12

Which is also a good thing, so

3:13

a sign that they are not cancer.

3:15

And you'll also have some solid gray

3:17

nodules, like this one right here.

3:19

And they'll also be well marginated.

3:21

You don't want to see anything that is smushy or

3:24

gray or charcoal like that erases this lobular,

3:29

um, uh, nodular anatomy within the gland, and

3:31

you certainly don't want to see anything that

3:33

crosses the surgical capsule, which is right

3:36

here, going into the peripheral zone, or crossing

3:40

the anatomic capsule, which is right here.

3:44

So in the coronal projection, this type

3:47

2 BPH, because it's posterior superior,

3:50

really presses up on the bladder, and

3:53

occasionally, it'll look a little bit

3:55

like a piece of broccoli or cauliflower.

3:58

It'll have segments that extend off, they're

4:00

a little bit pedunculated, into the bladder.

4:03

And when that happens, the necks of these

4:06

pedunculated areas of BPH can get trapped within

4:09

the bladder and cause problems of their own.

4:13

So this is a patient that demonstrates

4:15

really profound um, elevation of the

4:17

bladder with marked trigonal thinning right

4:20

here, which is part of this form of BPH.

4:23

Now when you look at the diffusion

4:25

weighted images and BPH, you should not see

4:29

anything that progressively gets brighter.

4:31

So here's a low B value, B0.

4:34

Let's blow it up for you.

4:36

And then let's take something really high.

4:39

This is a 1,500 B value.

4:42

Let's blow that up.

4:43

And I could look at the ones in between.

4:45

And you would see that the bright areas,

4:48

let's take a bright area if we can find one.

4:50

Can't really find a good one here.

4:52

But the bright areas like this one.

4:55

There's one, and it dissipates progressively

4:57

as the B value goes up, and that's to

4:59

be expected because it's not a cancer.

5:02

And then we've got some intervening B

5:04

values, and we'll inspect them serially,

5:06

from B0 to 400 to 800 to 1500, and so on.

5:11

Let's take a quick look at

5:13

the contrast enhancement.

5:15

We've got both dynamic contrast

5:17

enhancement here, and uh, actually

5:21

that is not it, that's the B value.

5:23

Thank you.

5:24

But, uh, it's a nice illustration,

5:25

actually, of what happens to the high

5:28

signal areas as the B value goes up.

5:31

They get lower.

5:32

Let's see if we can find a dynamic contrast

5:34

enhanced MRI that's a little bit better to see.

5:38

Um, I have a delayed one right here.

5:43

Actually, here's my dynamic.

5:45

So here's my dynamic contrast-enhanced MRI.

5:49

And you can see the gland

5:50

pretty much uniformly enhances.

5:52

The brighter areas remain cold, as

5:54

we discussed a little bit before.

5:55

So this is my dynamic, not my delayed.

5:58

And just to get you oriented,

6:00

each one of these is a phase.

6:02

So, mask, 10 seconds, 20 seconds,

6:06

30 seconds, 40 seconds, 50 seconds.

6:09

Progressive wash in, nothing sticks

6:12

out by its own, 60, 70, 80, and so on.

6:15

And you can create as many phases as you want.

6:18

This is D.C.

6:19

6:22

And then finally, the last part

6:23

of the exam is the ADC map.

6:26

Here we are with our ADC map looking for

6:28

areas of overwhelming low signal intensity

6:32

within the peripheral zone, especially also

6:35

in the central zone, although this criteria

6:37

more important in the peripheral zone.

6:39

And we don't see anything in the

6:41

peripheral zone of the prostate.

6:43

Yes, that's a little fibrous

6:45

dot, but it didn't enhance.

6:47

And it didn't show any high signal

6:49

characteristics on diffusion-weighted imaging.

6:52

It is to be ignored.

6:53

And you can get those from biopsy, from

6:55

old blood, from fibrous tissue, from

6:57

it being very firm and desmoplastic.

7:00

But it's tiny.

7:01

And generally our detection for

7:03

prostate cancer is at about 2 to 3

7:05

millimeters is our lower threshold.

7:07

So this is an example of a PI-RADS, uh, of a PI

7:11

RADS 2, which we'll discuss a little bit later on.

7:14

But it's an example of a BPH low bar type 2 BPH.

7:20

Let's move on, shall we?