0:00

I've got a 78-year-old man with an

0:04

elevated PSA that has remained stable at

0:07

around 11, 11 and a half for 6 months.

0:13

He had a negative guided biopsy in June of

0:18

2014 using ultrasound and now undergoes MRI.

0:25

His PSA density is 0.10 nanograms per mL per cc.

0:31

So, a pretty low PSA density.

0:35

So a lot of the signs point to benignity

0:39

or something that is non-aggressive.

0:42

So okay, that's fair.

0:43

We're going to integrate all that information

0:46

into our compendium of visual knowledge.

0:49

And I'm going to scroll around here a little bit.

0:51

And there is a beautiful demarcation

0:53

between the peripheral zone and the central

0:57

zone with the false surgical capsule.

1:01

There are some scant areas of linearity.

1:04

You're going to see that a lot.

1:06

Some of these are septa, sometimes

1:08

they represent prostatitis.

1:10

And remember, prostatitis can give you

1:12

hypervascularity, usually with a wash

1:15

in, but occasionally with a washout.

1:17

But prostatitis does not diffusion restrict.

1:21

In fact, it does the opposite.

1:23

So the diffusion image is extremely helpful in the

1:25

peripheral zone when you're worried about these areas

1:29

of wedge-shaped, non-mass-like, peripheral low signals.

1:34

Another teaching point.

1:36

There's quite a bit of heterogeneity

1:38

in the transitional zone.

1:41

This is the diffusion image, B-value 1600.

1:45

A little bit of diffusion restriction here and there,

1:49

and some crescentric ill-defined low signal on

1:53

the T2-weighted image with absolutely no diffusion

1:58

restriction correlate, and the ADC map was negative.

2:02

Beware of overcalling TZ tumors

2:05

unless they're very far in the front.

2:07

And they diffusion-restrict,

2:09

and they have size to them.

2:11

Teasy abnormalities are all over the place.

2:14

They tend to be benign or low grade, and you

2:17

should always look for an excuse not to call them.

2:21

So everything is just hunky-dory here, right?

2:24

All the signs point to non-

2:28

aggressive lesions in the prostate.

2:30

Well, let's keep going, shall we?

2:32

Let's go up high to the seminal vesicles.

2:35

We're oriented.

2:36

Now let's go down low.

2:38

Let's go.

2:39

And as we go down low, oh my goodness, we see a

2:43

mass that is quite different than any other mass.

2:47

In fact, that mass may even

2:49

extend in front of the urethra.

2:52

It's certainly behind the urethra, and it

2:55

demonstrates focal diffusion restriction.

2:59

Not only is it focal, it's pronounced.

3:02

It's intense.

3:04

And there's still a little bit of it over here.

3:05

Maybe it's not as intense, but it's present.

3:09

So we've got a periurethral tumor

3:12

in the apex of the prostate.

3:15

Completely unexpected, and completely counterintuitive.

3:19

So here, you know, our Likert system of

3:23

integration isn't all that helpful, because the

3:28

paraclinical criteria point away from tumor, but

3:32

the visual criteria heavily, strongly support

3:36

the diagnosis of tumor, and we're not done yet.

3:39

Look at our coronals.

3:40

Here's our urethra.

3:42

Look at that periurethral growth of our nodular grain.

3:49

Now let's go to the ADC map.

3:52

Let's go right down to that spot down low and see

3:55

if it is commensurate with the diffusion restriction

4:00

area that's bright, it should be dark, and it is.

4:04

There's a little bit of dark signal

4:05

in front of the urethra as well.

4:08

So everything fits absolutely perfectly.

4:13

So a couple points to be made here.

4:16

First, the paraclinical is important, but it shouldn't

4:22

completely override profound abnormalities on the MRI.

4:27

Second, we said that TZ lesions

4:31

have to be viewed with caution.

4:33

Look for any excuse you possibly can not to call them.

4:38

Another aspect of TZ lesions that I want to,

4:41

I want to pull out here for a moment, is that

4:43

sometimes the TZ will extrude into the PZ.

4:48

Not in this case.

4:50

But, you'll have nodules that are well

4:52

circumscribed, they'll either be gray or very

4:54

bright and they'll pop on into the peripheral zone.

4:59

And this can be a little bit problematic,

5:02

but they won't demonstrate the other typical

5:05

features that support the diagnosis of cancer.

5:09

And we already gave you another important pearl, which

5:13

is that hypervascular lesions in the peripheral zone

5:16

They tend not to wash out, but they can, but they do

5:22

not diffusion restrict unless you have an abscess.

5:26

Now abscesses do diffusion restrict,

5:29

but you should be all over that for

5:31

other reasons, including the clinical.

5:34

The patient's sick, they have fever,

5:36

the lesions are round, they have a

5:38

capsule, and they diffusion restrict.