0:00

This is a 76-year-old who has an elevated PSA.

0:05

The PSA density is well below

0:08

the critical cutoff of 0.2.

0:11

5 00:00:11,240 --> 00:00:16,208 It's actually 0.102 nanograms per ml per cc.

0:16

7 00:00:17,229 --> 00:00:19,869 And the patient has a lesion that was

0:19

originally, right here, called a PIRADS 5.

0:25

So we've got an axial 2D fast spin echo in

0:28

which there's a discrete Peripheral zone region,

0:33

TZ region, round, dark, mass-like nodule.

0:39

Look at how less conspicuous the edges

0:42

are of the lesion, even though these are

0:45

one-millimeter, three-dimensional images.

0:49

The T2 contrast, in other words,

0:52

look how blurred the edges are.

0:54

The T2 contrast, typically of 3D

0:57

imaging, is not as crisp as 2D imaging.

1:01

Whereas the spatial detail is higher.

1:04

So I just, I just brought that up to

1:06

show the difference between these two.

1:08

Because as you're going to

1:09

see, this is not a cancer.

1:12

This is not a PIRADS 5.

1:15

Let's go over here to the ADC map.

1:19

Where the supposed cancer has

1:24

pronounced diffusion restriction, right?

1:28

Wrong.

1:29

That is not that.

1:32

That is next to the rectum.

1:35

That isn't even in the prostate gland.

1:38

That's in the prostate gland.

1:41

This tremendous disparity between the size of

1:45

this lesion on the T2 set of images and the

1:50

ADC map tells you that something is amiss.

1:54

And, in fact, you're looking

1:55

at something other than.

1:58

A solid mass.

1:59

It's too black.

2:00

The signal is almost lossless.

2:03

What gives you lossless signal?

2:06

Flow, air, siderosis.

2:15

So any one of those would be

2:16

possible on initial inspection.

2:19

Now this one's going to be blood products or

2:22

siderotic material because there's very slight

2:25

hyperintensity on the T1-weighted image.

2:29

We're at very dense calcium,

2:31

it would be darker here.

2:34

So this siderotic phenomenon or paramagnetic

2:38

effect is known as the T2 blackout effect.

2:43

Now you would not expect to see diffusion

2:46

restriction on the high B-value diffusion image.

2:50

So let's blow it up.

2:52

No, that is not the lesion right there.

2:55

That is not the lesion.

2:57

The area of interest is over here.

2:59

There's nothing there.

3:01

That's in the TZ.

3:03

That's over here.

3:05

That's just the TZ nodule in the back.

3:08

We know the TZ nodules are difficult.

3:11

They restrict all the time.

3:13

We use their encapsulation.

3:15

We use the presence of microcysts like

3:18

this to decide that they're not cancers.

3:21

We use the position.

3:23

For instance, most TZ cancers

3:24

are all the way in the front.

3:26

You're going to see a dime a dozen of these.

3:29

That doesn't correspond to that.

3:33

If we were to produce the

3:36

DCE MRI, it wouldn't enhance.

3:39

Let's do it.

3:40

Let's go to the DCE MRI,

3:43

and go right to that spot.

3:45

And if we're correct, let's

3:46

put our cursor on it, in fact.

3:48

Let's get our little cursor here.

3:50

Let's go right on our, on our blackout sign area.

3:56

Well, I don't think we get there, but right there.

3:59

It's dark.

4:00

Here we go.

4:02

There's nothing enhancing there.

4:04

What is enhancing is a little bit of that

4:06

TZ more anterior, which is quite common.

4:09

A nondescript area of enhancement, not

4:11

much different than that, or that, or that.

4:15

So this is an example of the T2 blackout effect.

4:18

Lesions with very short T2 or T2* effects,

4:23

siderotic effects, paramagnetic effects,

4:26

create this blackout phenomenon on T2.

4:30

On ADC mapping, you can see some

4:33

decrease in signal, but it's not

4:35

the same size as that seen on T2.

4:39

And frequently, the diffusion

4:40

weighted image is completely normal.

4:44

You can also see, remember, lossless-type

4:46

signal in the prostate gland from calcium,

4:51

from fast flow, and even from acute blood you

4:55

can get very, very black signal intensities

4:58

as well as air, which fortunately is uncommon.