0:00

Okay, so now we're going to do a little bit more

0:03

of a deep dive into the prostate itself

0:05

and how we can apply anatomy to our descriptions

0:08

of the primary lesion,

0:09

but also considering some normal patterns

0:11

of uptake that we may see.

0:13

So we're revisiting this slide with the prostate anatomy

0:15

and I like it 'cause 'cause it's really nice and schematic.

0:18

And we're going to apply it to some imaging as well.

0:21

So again, like we saw this imaging at the very,

0:25

very beginning, but we're going to revisit,

0:27

so moving from the base of the prostate through to the apex

0:31

as an inverted kind of pyramid, um, with the bladder sitting

0:34

above it and the urethra coming through the middle.

0:37

So with coronal it's looking a bit more like a love heart

0:39

and depending on how you, you slice it through.

0:42

So basically we're gonna kind of move

0:45

through in our axial plane.

0:46

Um, and just having a look here at the seminal SQLs

0:48

that are marked there with the brown arrows coming down,

0:50

we can see the ureters diving into the back

0:52

of the prostate and the hop bladder.

0:54

And this is a patient with in the enlarged prostate.

0:57

And here coming over the top here is our anatomy

0:59

and this corresponds to one.

1:01

So we're really looking through the base

1:02

of the prostate here with the urethra

1:06

with the hot urine coming through the bottom.

1:08

And we'll just take that away.

1:10

You can see just a little bit of radio

1:11

urine there sitting in the middle.

1:12

So coming down to position two,

1:14

we're getting towards the mid gland,

1:16

sorry we're scrolling up but now we're scrolling down, um,

1:19

coming in here and we're gonna superimpose it.

1:22

And so we've got more of

1:24

that anterior fibromuscular stroma which is devoid

1:26

of glandular tissue, um, with more

1:28

of the central gland coming through

1:30

and the yellow peripheral zone.

1:32

So next image here, we're moving more towards the apex

1:36

scrolling down and here we are seeing

1:39

that the rectum is indenting kind of more of the back.

1:41

We've got that indentation there.

1:43

Um, and the urethra is looking more kind of central,

1:45

still have that um, anterior fibromuscular s stroma

1:48

and the central gland with the peripheral zone

1:50

and then coming down towards the apex

1:54

in our last image coming down

1:58

there towards the apex

2:00

of the prostate in the lower pelvis here.

2:03

So you can see that as we scroll

2:04

through the different contributions

2:06

between the central gland, the peripheral zone

2:07

and the anterior fibromuscular stroma changes,

2:09

but we've gotta be wary of that position of the e urethra.

2:12

That said, you know, patients often don't read the textbook

2:15

so we just have to kind of take these anatomy with a grain

2:17

of salt and also think about how treatments

2:20

and other bystander pathologies such

2:22

as benign prostatic hypertrophy can impact our anatomy.

2:26

That said, there's a few structures we also have

2:28

to keep in mind and that includes the seminal vesicles which

2:31

we have indicated with this animation here.

2:34

So they come and insert at the posterior aspect

2:36

of the prostate

2:37

and here we are scrolling up again coming through

2:39

because invasion of the seminal

2:41

vesicles is really important.

2:42

It will upstage the patient

2:43

and if we can see

2:44

that there's abnormal uptake within these structures,

2:46

it can be really important for our referrers in terms

2:49

of their decision making for our patients.

2:52

So by assessing uptake in the prostate, I tend

2:55

to rely on visual inspection, but there are methods

2:57

and scores that you can use

2:58

and one of the more common ones is the primary score,

3:01

which very proudly has been developed here in Australia.

3:04

And our, we're going to be referencing a great paper which

3:06

is primary author is from one of the local Sydney hospitals.

3:09

So for my reporting

3:11

however I tend to go with visual inspection.

3:13

I'm looking for areas of focal increased uptake

3:15

and then correlate that with multiparametric MRI,

3:18

if I do have those results available.

3:19

And for a lot of patients I do.

3:21

And now we're gonna look at the primary score.

3:23

So this is kind of the first slide

3:25

that's taken from the paper by Emmett Aal.

3:27

And Professor Emmett is working at St Vincent's Hospital in

3:30

Sydney and there's a lot of fantastic research for PSMA PET

3:33

and coming out of St.

3:35

Vincent's and also Peter Mac in Melbourne.

3:37

So here is the primary score

3:38

and essentially I really encourage you to look at the paper,

3:41

I've included it in our related readings.

3:43

Um, thinking about how the distribution

3:45

of uptake in the prostate can help us

3:47

to determine whether it may be benign

3:49

or potentially malignant.

3:51

Um, so these are the in blue here we're looking at the

3:54

benign patterns of uptake.

3:55

So score one, there's low grade ability only

3:57

and yeah, you want a little bit of

3:58

uptake through the prostate.

3:59

And then we score two diffuse transition zone.

4:01

So here's the transition zone, it's relatively symmetrical.

4:04

Um, you can see some mild uptake through that gland.

4:07

It can be asymmetrical and it can be variable

4:10

and then also um, CZ or central zones

4:12

and we can sometimes call this compressed central zone

4:15

and it can be a little bit focal.

4:16

So you've gotta be aware of this pattern in your

4:18

interpretation, um, and use this score to help.

4:22

Once we're starting to move more asymmetric

4:26

and particularly when you're getting focal intense uptake,

4:28

that's when we really start to worry.

4:30

So we score three focal transitional zone, um, uptake

4:33

and it's asymmetric.

4:34

You can see here that it's quite up there in terms

4:36

of SUV measurement and then focal peripheral zone.

4:38

And you'll notice that on this slide here,

4:41

there's on these benign patterns,

4:42

there is no uptake in the peripheral zone.

4:44

And we do know that peripheral zone uptake is concerning

4:47

because over 70% of the cancers do occur there.

4:50

So peripheral zone uptake score four, um,

4:53

focal up avidity involving the

4:54

peripheral margin of the prostate.

4:56

And then score five. And really we are looking

4:57

at SUV max greater than 12.

4:59

So really intense focal uptake

5:01

and a few of the cases we've already looked at, including

5:03

that textbook case had intense focal uptake.

5:05

So this is really, um, score five consistent

5:08

with prostate neoplasia.

5:10

So here we go On this scan here, this is an example

5:14

and apologies there are fiducial markers in situ.

5:16

This patient was planned for therapy,

5:17

but you can see mild, um, symmetrical uptake here, um, just

5:21

through this zone here that we've marked with the cal.

5:24

And this is kind of diffuse transition zone.

5:26

So we would've given this a primary score of two,

5:29

these focal uptake here in the central prostate.

5:31

But here having a look at this uptake here,

5:34

and this patient also has planned for radiotherapy, um,

5:36

there is focal intense uptake here

5:39

and that had an SUV max of greater than 12.

5:41

So we would easily score this, a primary score

5:43

of five, very suspicious.

5:45

And then here's something like this.

5:46

So focal peripheral zone uptake, query intense uptake.

5:49

So you may score this depending on the SUV here,

5:52

specific uptake value and we put a region

5:54

of interest on this in our um, PET software.

5:56

Um, you may give it a four or a five,

5:58

but just judging that visually,

6:00

I think we're gonna be hitting an CCB max

6:02

of greater than 12, so probably a five on this one.

6:05

So just a few slides to give us a bit of understanding

6:07

that uptake in the prostate can be variable,

6:09

it can be heterogeneous, particularly if they've had a

6:11

biopsy, there may be some inflammation.

6:13

So not every focus of uptake you see is cancer.

6:15

And we have to be mindful of the patterns

6:17

as we go towards our interpretation.

6:20

Now, let's now look at some cases.