0:02

Hello and welcome to Noon conferences hosted by M R I online response to changes

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happening around the world right now and the shutting down of in-person events.

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We've decided to provide free daily noon conferences to all radiologists

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worldwide. Today we're joined by Dr. Sylvia Chang. Dr.

0:16

Chang is a radiologist at Vancouver General Hospital and Associate Professor at

0:21

the University of British Columbia.

0:23

She's the Abdominal Imaging Fellowship director and she's also the co-chair of

0:26

the Society of Abdominal Radiology Prostate Disease Focus Panel. Quick reminder,

0:31

there'll be time at the end of the hour for our q and a session,

0:34

so please use the q and a feature to ask your questions and we'll get to as many

0:37

as we can before our time up. That being said,

0:40

thank you so much for joining us today, Dr. Chang.

0:42

I'll let you take it from here.

0:44

Great, thank you. Um, good afternoon and, uh,

0:48

good morning to some of you,

0:49

depending where you're in the world or maybe even goodnight and good early

0:52

morning. Um, yeah. First I wanna thank, uh, Dr.

0:55

Collins for the invitation and, um,

1:00

congratulate her on a great successful educational online program.

1:04

And I thank the online support team for making this all possible.

1:08

So I'm going to speak on prostate m r i.

1:13

Pearls to no and pitfalls to avoid.

1:15

I have no disclosures and as most of us know,

1:19

prostate cancer is the most common malignancy in North American men.

1:23

And second most common, uh, cause of death in North American men.

1:27

And in the last, I would say 10 to 15 years,

1:30

technical advances have been made to help improve the diagnosis of prostate

1:34

cancer with the use of Multiparametric M R I. And with that,

1:39

that's really increased the availability and utilization for multiparametric

1:43

prostate M r i to, um, its original indication,

1:46

which was for local staging determining if a tumor was T two

1:51

or perhaps beyond the prostate capsule T three.

1:55

It's also now involves various indications as listed here. Uh,

1:59

prostate m r I is used now for a detection of clinically significant cancer

2:04

for prostate cancer localization to further characterize the lesion for risk

2:08

stratification and to monitor treatment and guide the various treatments that

2:12

are out there, including the new focal therapies.

2:16

So with this increased utilization, it has, uh,

2:19

led to development of prostate guidelines. Uh, rads known as, uh,

2:23

prostate imaging, um, recording in, uh, data system.

2:26

And this was first introduced, uh, by, uh,

2:29

the E S U R in 2012 in European radiology

2:34

was, you know, widely accepted with the revisions in 2016,

2:39

known as version PI rads. Two and a more recent, um, revision, um,

2:44

updated as version 2.1 last year.

2:48

And these guidelines helped to categorize prostate lesions seen on M R I to the

2:53

likelihood of it being clinically significant rads,

2:56

one being very low rads two,

2:59

low risk of clinically significant cancer resi would be intermediate risk

3:03

RADS four high risk and RADS five very high risk.

3:07

So as we all realize the demands for prostate M r I

3:12

certainly has increased with recent studies showing that M r I does benefit in

3:17

the diagnostic pathway where M R I performed before the template biopsy can be

3:22

useful in directing targeted biopsies to pick up more clinically significant

3:26

cancers and decrease the detection of clinically insignificant cancers.

3:30

And some men even avoid prostate biopsy.

3:32

So with this increase utilizing of prostate cancer or prostate M r I, um,

3:38

there are more people learning and training to read these prostate MRIs.

3:42

And with the PI ides guidelines,

3:44

they've been very helpful in helping to streamline and standardize in

3:48

acquisition interpretation and reporting.

3:50

There's still some issues to kind of be aware of and you can encounter pitfalls

3:55

and mimics a prostate cancer. And, uh,

3:58

I've broken 'em down into technical factors,

4:00

normal anatomical structures that can mimic prostate cancer and benign disease

4:05

processes that can mimic prostate cancer.

4:07

So I'm gonna show you some examples of this and also provide some,

4:11

some pearls to help distinguish, uh, these pitfalls from prostate cancer.

4:17

So in terms of normal anatomical structures,

4:19

I will go over the structures that pertain to the normal anatomy of the prostate

4:24

gland itself, which is the normal central zone, the capsule and, uh,

4:28

fascia insertion site where focal thickens at the midline posterior peripheral

4:32

zone thickening of the surgical capsule, also known as acetyl capsule, uh,

4:37

the prominent anterior fibromuscular str and also go over structures adjacent to

4:42

the prostate gland that mimic prostate cancer.

4:44

And that is the prominent neurovascular bundle and the perio prostatic plexus

4:50

entrance, benign proce, uh, processes that can mimic prostate cancer.

4:54

These include the stromal E P H nodule or the hypertrophic nodule within

4:59

the peripheral zone hemorrhage within the prostate gland, chronic prostatitis,

5:05

and as well as granulomatous prostatitis.

5:09

So we'll just review anatomy of the protag gland before we begin with some of

5:13

the pitfalls. Uh,

5:14

here's axial images on the top and chromal images on the bottom on two different

5:18

patients. The peripheral zone, as you can see here, is usually bright on T two.

5:24

On the left is nice and homogeneous. In many cases.

5:27

You may get this heterogeneous appearance, um, on the top, uh,

5:31

right image here. And then you also have the peripheral zone and the coronal,

5:35

uh, plane as well.

5:36

So that's the peripheral zone where most of the cancers do occur about 70% of

5:40

the time.

5:41

Then you have the transition zone where approximately 20% of the cancers occur.

5:45

This can be a tough area to identify, uh, for prostate cancer. As you can see,

5:49

it does have a bit of a heterogeneous appearance at times.

5:51

Some describe it as organized chaos containing, uh, B P H nodules,

5:56

a couple of other zones to be aware of,

5:58

and they can be pitfalls of prostate cancer,

5:59

as I'll show you later in examples is a central zone and that is situated

6:04

in between the peripheral zone and the transition zone seen in the cornal

6:09

plane's at the level of the base has kind of a triangular shape.

6:12

And the anfa muscular stroma is fibrous tissue that is situated in the

6:17

anterior aspect of the gland and anterior to the transition zone.

6:22

Moving on to technique, uh, technique is important. Uh, you want to get,

6:27

uh, a really good study, uh, so you can interpret, uh, if there's prostate uh,

6:32

cancer within, within that uh, study. And what you wanna do is optimize your,

6:37

make sure you have optimal B values and make sure you use a high B value.

6:41

In this example here we see a lesion in the, um, right mid gland,

6:46

lateral length, peripheral zone that is right on the B 1500.

6:50

And with RADS is recommended to use at least a high B value of 1400

6:55

and to acquire that separately or have it extrapolated from low and intermediate

7:00

B values. As you can see here, with the B value of 800,

7:04

you cannot see the lesion.

7:06

And if your can scanner is not capable of acquiring high B values,

7:10

you can then get extrapolated images.

7:12

So this is extrapolated image from the B 800 where you can actually see the

7:17

lesion showing, um, restricted diffusion.

7:21

So the point here is to make sure you do use a high B value in order to detect

7:25

ally significant prostate cancer. On the other hand,

7:29

you don't wanna use a b value that's too high that you cannot generate signal

7:33

and you'll miss clinically significant cancer. And this is a study done by, uh,

7:38

Dr. Andan,

7:39

where he used various B values on two different patients.

7:43

And you can see that you can see restricted diffusion on some of these images.

7:47

But as you get into really high B values, certainly at 4,000, 5,000,

7:52

you're not able to identify the lesion because you're not able to,

7:55

the mag is not able to generate enough signal in terms of optimal B values.

8:00

Certainly when you're using, um, three t m r i,

8:03

it's in the range of 1500 to 2,500.

8:09

And once you have realized your optimal B values,

8:12

the other thing to keep in mind is making sure that you actually have window

8:16

your a d C levels appropriately. If they're not window appropriately,

8:19

you could miss an area restricted diffusion as shown here.

8:22

Whereas when you do window it appropriately,

8:25

you can see a focal area restriction in terms of optimal,

8:29

um, levels and windows.

8:32

That will depend on the obviously scanner type.

8:36

And certainly for myself, I've found that 1400,

8:40

1400 works well for my scanner that I use.

8:44

The other, um,

8:46

issue that can also be a problem is, uh, rectal gas.

8:52

And this is a patient,

8:53

as you can see there is rectal gas and there is a lesion here in the right

8:58

midland peripheral zone. But what the rectal gas does,

9:01

it does show cause quite a bit of distortion on the D W I and a D C image.

9:06

And, um, also not only kind of distorts the anatomy in that, uh,

9:10

the AP distance looks shortened compared to T two,

9:14

but it does obscure the peripheral zone.

9:16

So this lesion that I just mentioned here in the right midland,

9:19

it's obscured you, you can't see it on the a d C map. So that's one of the,

9:24

um, challenges is, is the rectal gas. And this is the same patient,

9:29

just maybe a couple of slices lower towards the, the micala and apex level.

9:33

And you can see an area of hypo intensity in the posterior transition zone

9:38

abutting the ceal capsule, uh,

9:40

with the geometric anatomic distortion from the rectal gas,

9:44

the lesion looks like it's actually in the peripheral zone,

9:46

so you could actually potentially mismatch lesions or mis uh,

9:51

localized lesions. So just kind of be aware with the rectal gas. Um,

9:55

here's another patient. Uh, you can see low signal T two in the anterior,

10:00

um, peripheral zone here.

10:02

It's kind of gonna wraps around and there is some restricted diffusion,

10:06

not tear behind, maybe you know, a pyra three with just a very subtle contrast.

10:11

So, you know, uh, RADS four, it came back as three plus three.

10:15

He went on to active surveillance a year later on his followup M r i

10:20

lesion here is T two. Not as well seen on a more recent examination,

10:24

you can still see the restricted diffusion,

10:26

but as you can see the lesion with the gas causing distortion,

10:30

the lesion looks like potentially a different lesion.

10:32

'cause this looks like it's further back in the gland. So again,

10:35

another example how rectal gas can call you cause you geometric distortion.

10:39

It's important to look at prior, uh, studies and look at the, the T two.

10:44

So what about ways to mitigate rectal gas? Um, when they do have it,

10:49

um, certainly, uh, we ask, um, our techs are well aware of it,

10:53

and they do remind the patients when they arrive to make sure that the gas is

10:57

emptied and evacuated, uh,

10:59

before they change into their gown to get on the table on the scout image.

11:04

If there is still, um, gas in the rectum,

11:07

then the technologist asks the patient to basically empty the gas, uh,

11:11

there on the table. Uh, and then the, um,

11:14

then there's also the more active measure where someone would actually insert a

11:18

fully catheter and aspirate, uh, the gas out of the, uh, rectum.

11:22

And this is a case of, uh, what happened in this case. So this patient,

11:27

this is his third time coming for prostate m r i and all three times he

11:31

had rectal gas. Um,

11:33

so in this case a Foley catheter was inserted and, uh, to evacuate the gas.

11:39

So when the gas is present,

11:40

you can see how it does obscure the peripheral zone and cause quite a bit of

11:45

anatomic distortion. You see most of this peripheral zone here is obscured,

11:49

and when the gas is evacuated, you can see that,

11:53

you can see most of the proposal.

11:57

So absence of rectal gas is ideal for imaging,

12:00

but sometimes it can be problematic and, uh, should be evacuated.

12:07

This is another patient. Another way to to do it is, um,

12:11

here's a patient again with some rectal gas. Doesn't look like a lot on T two,

12:16

but, uh,

12:16

strikingly on the D W I and a d C does obscure a lot of the peripheral zone.

12:21

In this patient. What we did was we switched the phase, um, encoding.

12:26

So usually an abdominal imaging phase is default anterior to posterior because

12:30

that's, they're usually shorter distance to scan,

12:33

but in the prostate one it,

12:35

you can default it to left to right in, in that case.

12:39

And that's what we did with this patient. Uh,

12:42

right afterwards when we realized it was rectal gas,

12:45

we switched it from anterior posterior phase and coating to left to right.

12:49

I mean, it doesn't completely negate the gas here,

12:52

but certainly there is improvement.

12:54

You can see most of the peripheral and you can identify this area that

12:58

demonstrates some, um, low signal on a d c correlating to the TT findings,

13:03

which you cannot see when there was rectal gas. Okay, so, uh,

13:08

basically limiting the rectal gas or maybe, um,

13:12

switching the phase and coating could help, uh, with that challenge. So, uh,

13:16

moving on to anatomical structures that can mimic prostate cancer.

13:21

This is a patient, uh,

13:22

who has an area of low signal in the right base here,

13:27

denoted by the arrow. It looks like it's in the peripheral zone.

13:30

You can see the pseudo capsule here.

13:33

It doesn't show strong restricted diffusion on the D W I.

13:36

It doesn't restrict at all really.

13:38

And on a d c it does demonstrate some low signal and does not, um,

13:43

show, um, contemporaneous enhancement or, or hyper enhancement.

13:47

If you look carefully in the coronal images here it is, but if you scroll,

13:51

you realize that actually there is another lesion on the other side that's

13:54

similar. So one of the, um, you know,

13:59

I guess, um, pearls i I use is anytime you see a lesion on an axial plane,

14:04

I always look at an orthogonal plane,

14:05

a sagal coronal plane to see potentially could this be a normal anatomic

14:10

structure? And that's what this is, this is normal central zone,

14:14

and this is a common pitfall, uh,

14:16

because it can look quite focal in the axial plane and it can look like it's

14:20

restricting, but,

14:21

but you don't really see it in restricting that high on the D W I.

14:25

So that's something to look out for. And uh, as mentioned earlier,

14:29

it's normal anatomic structure situated between the peripheral zone and the

14:32

transition zone. At the level of the base,

14:34

it surrounds ejaculatory ducts On T two,

14:37

it is hyperintense and that's why it can mimic tumor.

14:40

It's decreased signal on a D c, again, that's why it can mimic tumor.

14:43

But some tips to kind of keep in mind to distinguish it from prostate cancer is

14:47

it is symmetric. Look on the coronal plane.

14:50

It's centered as mentioned in the midlines surrounding the ejaculatory ducts on

14:55

the axial plane. It can have a, uh,

14:57

dumbbell shape appearance on the axial plane on cron.

15:00

Some have described it looking like a mustache,

15:02

or in this case a triangular or inverted teardrop shape,

15:07

and it doesn't show rapid enhancement or washout.

15:13

In contrast to this case is a central zone prostate cancer.

15:17

So if you look at the T two image,

15:19

you can see that it doesn't really look all that much different from the other

15:23

case. It, it shows low signal on T two,

15:26

it's just more prominent on this side compared to the other side on coronal.

15:30

Again, it looks bulkier here. If you look at the D W I,

15:34

it does show restriction compared to the other case. And again, it's,

15:39

it's hypertensin, E D C, but it's quite hypervascular.

15:43

So a central zone shouldn't be hypervascular. And if it is hypervascular,

15:47

it does raise a suspicion that, that this could be central zone prostate cancer.

15:52

Of course,

15:52

the clues you have when you're interpreting these cases is to have the P S A and

15:56

to have the p s A trend because in central zone cancers,

15:59

they are more aggressive. They have a high Gleason score and are prone to,

16:04

uh,

16:05

exert extra prosthetic extension and invade the seminal physical and higher

16:09

level of recurrence. So this ended up being a central zone prostate cancer.

16:14

So when there's hyper enhancement and a definite restriction, think of, uh,

16:18

cancer rather than just normal central zone.

16:22

The other anatomical structure that can mimic cancer is where the prostate

16:26

capsule and the les fascia insert together at

16:31

the posterior peripheral zone at the midline.

16:34

And there it can cause focal thickening and mimic prostate cancer.

16:37

It will be depicted as an area of low T two signal and looks like it will show

16:42

restricted diffusion in that it is dark on a d c but not strikingly bright on D

16:47

W I. And that's one of the,

16:49

the features is that it doesn't really strong show, really strong, um,

16:54

restricted diffusion.

16:56

The other clue is that it's the typical location is at the midline,

16:59

and more importantly is it doesn't exert mass effect. As you can see here,

17:03

it does show a concave contour and also it

17:08

usually shows type one or type two enhancement. It doesn't show washout.

17:13

So those are the clues that it is, uh,

17:15

the capsule and fascia insertion and not prostate cancer.

17:19

This is another case, as you can see,

17:22

it can be quite conspicuous if you look at it,

17:24

it does look a bit rounded and nodular, but if you look carefully,

17:28

you realize it's in the typical midline location. It has concave,

17:32

um, borders posteriorly,

17:35

and usually it's kind of inferiorly located just below the central zone here on

17:39

the chrono plane. Again, it can be low signal on E D C,

17:43

but usually not, you know,

17:45

strikingly restricting on the D W I and enhancement. It just,

17:49

just can show a slow delayed enhancement curve as shown here.

17:53

So there's no washout,

17:55

and both of those lesions were biopsy proven benign lesions.

17:59

Another anatomical structure that can mimic prostate cancer is the thickened

18:03

surgical capsule, also known as the Ceal capsule.

18:07

And this consists of fibrous and muscular tissue between the transition and the

18:11

purple zone. It is known as a surgical capsule because urologists, uh,

18:16

recognizes as a surgical landmark when they do their, um,

18:21

transurethral prostatic resection. When they see this structure,

18:24

they know they've made it to the, um, outer edge of the transition zone.

18:28

And they know that going beyond this landmark will enter the peripheral zone

18:34

in men as they, uh, um, get older. Um, they, the,

18:38

some men will develop hypertrophy and, uh,

18:41

the hypertrophy can cause the theory is perhaps irritation of the pseudo capsule

18:45

causing it to fo thicken and it can mimic a prostate cancer

18:50

as it will be demonstrated. Its hyperintense on T two as shown here.

18:55

Low signal on the a d C map

18:59

clues that it's a pseudo capsule and not a tumor. It's its location,

19:03

it's centered with the pseudo capsule should be. And on the chrono plane, again,

19:08

looking at, uh, orthogonal planes on Cornal plane, it has a band like stic, uh,

19:13

shape following the, uh, contour of the SAL capsule.

19:17

And it doesn't enhance, it's, it's, it's fibrous tissues,

19:20

so it does not cause a hyper enhancement.

19:25

Another normal anaco anatomical structure of the academic prostate cancer is

19:29

when the anterior muscular STR is prominent. As mentioned earlier,

19:34

it is situated anterior to the transition zone is composed of connective tissue

19:37

smooth and skeletal muscle.

19:40

It is low signal on T two as well as on a d c,

19:44

and that's why it can mimic tumor. But, um,

19:48

one of the features is that it's location. It's, it's basically anterior,

19:53

it has a symmetric appearance and it's low signal on d w i. It,

19:58

it doesn't restrict.

19:59

So the key distinguishing feature is that there's no restriction on on D W I and

20:04

also it doesn't show washout. It,

20:06

it shows kind of a type one progressive enhancement.

20:11

Here's an example of prominent anterior musculars stroma denoted by the green

20:15

arrow. We see, uh,

20:17

areas of T two hypo intensity on in the midline

20:21

extending into the apex is quite prominent in this, in this case it looks kind,

20:25

rounded and nodular. You can see on a d c map is correlating low signal.

20:31

And on the t w i there's no restriction at all and there's no, um,

20:36

hyper enhancement or, or out. So this isn't keeping with, uh,

20:40

a prominent anterior mus, uh, anterior fibromuscular stromer, uh,

20:44

and not to mis call it as tumor.

20:47

And there is also a pyres four cancer on here,

20:51

pys four lesion that, uh,

20:53

ended up being clinically significant cancer biopsied as, uh,

20:55

three plus four on T two. You can see it's, uh,

20:59

hyperintense here and it demonstrates strong restricted diffusion on

21:04

the D W I as well as a d c and hyper enhancement.

21:08

So this isn't keeping with the PIRES four lesion. So this example,

21:12

just showing how this is what a cancer looks like, it's very,

21:16

it's restricts strongly with hyper enhancement,

21:18

whereas an fibromuscular str cha mimic cancer, but makes sure,

21:23

but it doesn't, um, um, show strong restrict diffusion.

21:27

So it can show the T two and low a d C that can mimic cancer,

21:30

but it doesn't have the restricted diffusion D W I,

21:33

and that's one of the distinguishing features. Okay,

21:36

moving on to adjacent anatomical structures that can mimic prostate cancer.

21:40

And that's a prominent neurovascular bundle.

21:43

It has a rounded appearance on axial T two and on a d c it

21:48

demonstrates low signal and because of the some anatomic distortion,

21:52

it can look like it's actually within the peripheral zone rather than outside of

21:56

it, as shown here.

21:58

Distinguishing features is that it's situated at the five and seven o'clock

22:02

location and symmetries. There's usually the other,

22:05

another one on the other side. Again, look at orthogonal planes, uh,

22:10

because it will be displayed as a tubular structure as shown on the

22:15

coronal plane and will show delayed enhancement.

22:20

Another structure that can mimic prostate cancer is the periprosthetic plexus.

22:25

Again, it can look rounded on axial T two low signal on a D c,

22:30

and again,

22:30

with anatomic distortion can look like it's actually within the peripheral zone.

22:35

In this, uh, patient here,

22:37

there is actually a tumor in the anterior transition zone.

22:41

Here you can see it demonstrates restricted diffusion on a d,

22:45

C and D W I and enhancement. Um,

22:49

if you look on a d c,

22:51

it looks like perhaps there could be extension and extra capsular extension,

22:56

but if you look carefully,

22:57

it's actually the para prosthetic plexus here and it shows delayed

23:02

enhancement. The other side here,

23:04

it looks like potentially could have another focus here on the other side in the

23:09

prostate gland, but if you look more carefully,

23:11

it's actually the para prosthetic plexus and the can mimic, uh, prostate cancer.

23:16

So just be careful about structures adjacent to prostate gland or prostate

23:21

gland that can mimic prostate cancer. In terms of para prostatic plexus,

23:26

the location is typical.

23:27

They're usually situated either laterally adjacent to the prostate gland and

23:32

also anteriorly as shown here.

23:35

These vessels do communicate and eventually drain in the,

23:38

into the internal iliac vein. So imaging structures, imaging features, sorry,

23:43

uh, location again,

23:45

they can be symmetric tubular structure in the orthogonal plane and show delayed

23:50

enhancement. Okay, so moving on to benign,

23:55

um, entities that can mimic prostate cancer.

23:58

Stromal B P H nodule can mimic prostate cancer as they are displayed as low

24:03

signal intensity with low A d C and can show early

24:07

enhancement and washout. Uh, however, uh,

24:11

imaging features is that they are round and if you look more carefully,

24:15

the margins are fairly discreet compared to the, you know, the rads. Uh, four,

24:20

five or or three lesions were all circumscribed margins and they may not

24:25

restrict as, as low as, uh, clinically significant. Uh, cancer nodules,

24:32

this was biopsy proven to be, uh, benign, whereas, whereas,

24:37

um, STR nodules, uh, like in this case, uh, it,

24:42

it's not as obvious. It's kind of similar signal to the other side.

24:46

But what you can see on the D W I and A D C is that it

24:51

restricts strongly. Um, also shows contrast enhancement.

24:55

So in cases where you do see a ster nodule that restricts strongly,

24:59

then in that case it gets upgraded from a RADS two to a RADS three.

25:04

Uh, so if you do see potentially Strom neurologists that demonstrates strong

25:08

restricted defusion in that case,

25:09

then there's a chance they could have clinically, uh,

25:12

higher chance they could have clinically significant cancer and should be

25:15

upgraded to a RADS three. Uh, this patient went on to targeted biopsy,

25:19

which reviewed Gleason score of, uh, four plus three. Okay,

25:23

so going back, the stromal nodule will not have strong restricted, uh,

25:28

diffusion,

25:29

but if you have an atypical nodule that demonstrates strong restricted fusion

25:32

becomes a RADS three,

25:34

and the chance of that being clinically significant cancer is about

25:38

7.5%. In a recent, um,

25:41

online publication in A G r, uh, showed, that was the, uh, positive,

25:46

uh, rate in, in, in that, in that series. Okay, yeah,

25:51

so just a reminder, it was a t it was a, um, a score of two on T two,

25:56

but it demonstrated strong restricted diffusion. So it bumped it to a three.

26:03

Now B P H nodules can also occur in the peripheral zone as shown here.

26:07

They will be relatively low signal intensity compared to the surrounding

26:11

peripheral zone and will also be seen as low signal on a d c.

26:16

As we know with b h nodules,

26:18

they can show rapid enhancement with washouts so they can mimic prostate cancer.

26:24

Uh,

26:24

the distinguishing feature is that it's very well circumscribed and if you look

26:27

carefully just gonna zoomed up on the image,

26:31

it has a very well demarcated, um, low signal rim around it.

26:35

And in addition, it contains a full sci high signal within it.

26:40

So it looks like a B P H nodule. It just happens to be in the peripheral zone.

26:44

So this is a B H nodule and this is regarded and would be reported as a PI

26:49

RADS two. This is another BPH H nodule, again,

26:54

relatively low signal on T two, low signal on E D C.

26:58

It does show hyper enhancement

27:02

and also shows a restricted diffusion on D W I and it's well circumscribed

27:08

and shows high signal ForSight within it. So it does look like a b h nodule.

27:12

It looks like the transition zone, but it's out in the peripheral zone.

27:15

And just because it's intervening normal chronic mode doesn't mean it can't be a

27:19

BP nole. It can, um,

27:21

most of the ones you see looks like they might have been kind of rising from the

27:25

transition zone or maybe exophytic or some say,

27:28

extruded from the transition zone.

27:30

And you'll see a kg some the patient nodules that are separate,

27:34

separated with intervening tissue. And that can occur in the um,

27:39

literature. In the pathology literature, they have described that, uh,

27:43

b h nodules can arrive de novo within the proposed zone peripheral zone itself,

27:48

rather than extending from the transition zone.

27:52

Another entity that can, uh, mimic, uh,

27:55

prostate cancer is post biopsy hemorrhage.

27:57

It is demonstrated as low signal on T two and low signal on A D

28:02

C. However, some of the features is that it, um,

28:06

is high signal on T one. So look for the T one to see if there's any hemorrhage,

28:11

especially if patients have had prior, uh, biopsy and, uh,

28:16

appearances. They can have more of a geographic appearance as shown here.

28:21

Again, as mentioned, T one hypo intensity,

28:24

their restricted fusion is not as strong and subtraction imaging is important

28:30

'cause here it shows up,

28:30

there's no enhancement and that would be keeping with hemorrhage.

28:36

Moving on to prostatitis is commonly due to bacterial,

28:41

um, infection, whether it's acute or chronic,

28:44

and it's usually seen as low signal.

28:47

It can be focal in that case can mimic prostate cancer and sometimes it can be

28:51

diffuse. It'll also demonstrate restricted diffusion and also rapid,

28:56

um, uh, washing and wash out. So it can totally mimic prostate cancer.

29:01

But the morphology is helpful in this patient.

29:04

You can see that there is a large component that involves a peripheral zone,

29:07

but as you can see, there isn't any obvious mass effect. And, uh,

29:11

it does demonstrate restricted diffusion and certainly hyper enhancement.

29:17

But you'll realize that it does occur throughout the peripheral zone. And again,

29:21

um, the clues looking at the other planes. Um,

29:25

so if you look at the sagal plane in this patient,

29:27

you can see that the peripheral zone is diffusely involved,

29:30

but there is no mass effect at all.

29:32

You still see the normal shape of the peripheral zone. And more importantly,

29:36

when you compare to the contralateral normal appearing left peripheral zone,

29:40

this the effect that the low signal purple zone is actually atrophic in

29:44

comparison to the left side. So this is all in keeping with prostatitis,

29:49

which was called prospectively, that his P S A was so high,

29:52

he went to systematic biopsy and the results came back as prostatitis.

29:56

So imaging features, again, there's no counter to formulary,

30:00

there's no mass effect. Uh,

30:02

in some cases you may have the ill-defined streaky appearance,

30:04

which just gives you more confident diagnosis of prostatitis. As mentioned,

30:09

the D W I and a cmap, um, will show some restriction,

30:12

but maybe not as strong as a a clinically significant cancer.

30:16

The contrast enhancement actually may be symmetric,

30:19

even though if there's some asymmetry of the restricted defusion or the T two

30:24

appearance, uh, interesting,

30:26

sometimes a contrast enhancement will will look more symmetric.

30:31

This is another case of, uh, prostatitis,

30:34

and you can see that it does have a geographic appearance on T two,

30:39

albeit on a d c, maybe not as obvious,

30:41

but when you have geographic appearance on, uh, D W I and A D C,

30:46

then that's in keeping with, uh, pyres two. In keeping with prostatitis,

30:53

well, granulomatous prostatitis can also mimic prostate cancer. It is, uh,

30:57

epitheloid granulomas with inflammation. It can be idiopathic,

31:01

but can also be related to intra cycle, uh, treatment with B C G,

31:06

um, related to infection including TB as well as intervention, uh,

31:10

including T U R P. It's usually seen as hyperintense on T two,

31:15

which can be focal or diffuse and can demonstrate strong restricted

31:20

diffusion, which, uh, certainly in that case can mimic prostate cancer.

31:24

In terms of the imaging features, um, of course, history is, is is helpful if,

31:29

if the patient has a history of travi cycle B c G treatment,

31:32

then certainly consider this in the differential imaging. As mentioned,

31:36

it can be diffused for focal and in contrast enhancement when they, uh,

31:41

develop necrosis or Casey's necrosis. Uh,

31:44

there will be areas of non enhancement, uh, shown here.

31:51

And I'm just gonna finish with a few, uh,

31:53

kinda other entities that can mimic prostate cancer. This is not a common one,

31:58

but it's one I just wanted to show you here is MCO plaquea. Uh,

32:02

we're aware of this, but it doesn't commonly occur in the prostate gland. Uh,

32:06

we know it's a rare chronic inflammatory condition,

32:08

and ker has pathologically ous guttin bodies on T two,

32:13

it demonstrates T two hyperintensity with restricted diffusion and hyper

32:18

enhancement. Um, in this patient,

32:21

he did have a history of U T I. So, um,

32:25

so this ended up being, um, molecular plaquea. He did have prostate cancer.

32:30

He had a template biopsy, uh, which showed cancer more so on the right side,

32:34

the left side of biopsies were negative,

32:37

so these imaging findings were discordant, uh, with the pathology.

32:41

So that's something to keep in mind, um, is to correlate with the,

32:44

with the pathology, uh, because it didn't make any sense, um,

32:49

that the biopsy were positive on the right and nothing was on the left.

32:53

And the patient really wanted, um, aggressive treatment. He went on to surgery.

32:57

So this is pathologically proven MCO plaquea. And, um,

33:02

in terms of considering history of U t I, interestingly, he did actually,

33:06

unfortunately,

33:07

was one of those men that did have a complication and actually did have post

33:10

biopsy sepsis requiring hospitalization at as a result of his prostate biopsy.

33:16

So, uh, something to think of about is, you know,

33:19

prior history of U T I and certainly if, um,

33:23

the biopsies don't, uh, correlate, uh, with imaging findings,

33:26

could this be an inflammatory process?

33:29

And in this case it was molecular plaquea. Uh,

33:33

IG four related prostatitis, uh, can also affect the prostate gland. It's rare.

33:37

Uh, as we know it's immuno co um, uh, G four related disease.

33:42

It is a multisystemic disorder, uh,

33:45

but as mentioned can affect affect the prostate gland. It, um, involves, uh,

33:50

lympho pla lymphocytic infiltration and fibrosis on,

33:55

uh, pathology imaging wise. Um, it is hard to distinguish. Uh,

34:00

it can look like your other types of prostatitis, uh,

34:04

low signal on T two can be diffused, which shape and can also show, uh,

34:09

enhancement. The clues here would be that perhaps the patient also has a G four,

34:14

um, um, involvement in other organ structures and, um,

34:19

a blood test showing that, uh, it's elevated.

34:24

Now what about this case? Um, just finishing with the last two cases here, uh,

34:27

you could see that's an area of low signal on TT T two.

34:31

If you look at it carefully, it's, it's very low signal, almost signal void.

34:35

Unfortunately, this patient had a left hip, uh, prosthesis,

34:39

which is why on the A D C, and I didn't show the D W I here. It's,

34:43

it's very suboptimal. In fact, the,

34:45

that left sided lesion is completely obscured by the artifact on T

34:50

one. Uh, it's subtle here, uh, based on the windowing,

34:53

but it's subtly T one hyperintense and on subtraction imaging,

34:58

it doesn't show enhancement.

34:59

So this is an infarct and it's infarct related to prostate artery embolization.

35:05

It's a new, uh, technique, an option, uh,

35:09

for treating benign prosthetic hypertrophy.

35:11

And M r I can be used to assess the prostate pre and post prostate

35:16

artery embolization. Uh, currently, uh,

35:19

there's no formal guidelines as to when and how often to perform the M r I post,

35:24

uh, prostate artery embolization. But, uh, certainly in the literature so far,

35:28

infarcts are very common and they occur in the transition zone.

35:33

So imaging features, they are hypo intense on T two.

35:37

Occasionally you can see hyperintense cy within it,

35:40

and it becomes iSense over time. So it does eventually resolve.

35:45

And similarly, on T one,

35:47

it'll be hyperintense on T one and becomes iSense over time.

35:52

In terms of d w i, it does demonstrate lower signal intensity compared to,

35:57

uh, pre, uh, prostate embolization imaging.

36:00

And also the A D C values tend to be higher when compared to the pre, uh,

36:05

post embolization findings. Other features is, I mean,

36:09

the key feature is obviously,

36:11

hopefully the pro value of a history that this procedure has, uh, taken place,

36:15

and there's no enhancement on the subtraction imaging. Um, if,

36:20

if this goes to subsequent imaging,

36:22

you'll see that it's starting to resolve over time.

36:26

You can get cystic transformation sometimes where it becomes T two hyperintense

36:30

and T one hyperintense, and over time the prostate volume decreases, uh,

36:35

of about 37% over 12 to 18 months.

36:41

Okay, so finishing with this last case, uh, 69 year old man,

36:45

P s A is very high, 120 and a very big gland,

36:50

a two 15 CCS prostate gland. You can see that it's causing retention.

36:55

He has a Foley catheter in situ. You, uh, very large gland. Uh,

36:59

the transition zone is just, uh, distorted. There's,

37:04

you know, it's protruding into the bladder. Um, so in this case it's,

37:09

you know, very, very unusual looking prostate gland. You wonder, you know,

37:13

you could see bits of the peripheral zone. It's, it's compressed by all this,

37:16

um, transition zone. And in terms of restricted diffusion,

37:21

there wasn't anything really struggling, strongly restricting.

37:26

Um, his P S A was so high,

37:28

he went to a systematic biopsy as there was nothing really, uh, to target, uh,

37:32

specifically. And the biopsy came back as a stromal tumor,

37:36

unknown malignant potential, which is known as stump. It is a rare,

37:41

um, atypical stromal perforation,

37:44

and it's distinct from prostate carcinoma.

37:48

It can affect the peripheral or transition zone or the entire gland.

37:52

Looks like in this case, involved mainly the transition zone. Uh,

37:55

in terms of symptoms, uh, most commonly, uh,

37:58

they present as lower urinary tract obstruction. Um,

38:01

elevated P S A and hematuria. Uh, the course is unpredictable,

38:04

which is why it's, uh, termed unknown malignant potential.

38:08

There are four subtypes, uh, pathologically,

38:10

they're known as the degenerative AIA hypocellular mixed and fall

38:16

subtype. And in this case, this patient had a combined subtype, uh,

38:19

degenerative AIA and hypercellular hyper cellularity.

38:24

So this brings, uh, in terms of, uh, stump features, um,

38:28

they're heterogeneous on T two. As you can see, uh,

38:30

areas of hyperintensity and cystic change, um,

38:33

in some areas that have low signal with low signal areas and bands,

38:38

as you can see it, this does,

38:39

can resemble CYS adenomas or mucinous type adenocarcinoma because of the T

38:44

two cystic appearances as well as sarcoma and, uh, cystic e p H.

38:51

So that brings me to the end of my lecture.

38:53

So I've gone over some pitfalls and mimics of prostate cancer and some pearls to

38:58

help distinguish kind of, uh,

39:00

normal anatomic structures and benign processes that can differentiate from

39:05

prostate cancer. We've gone over technical factors,

39:06

so it's important to optimize your imaging. You can see how, um,

39:10

suboptimal imaging with D D W I can be quite cal,

39:13

challenging to interpret an anatomical structures to avoid and also did not

39:18

other d disease processes besides prostate cancer to to consider. Uh,

39:23

so just to conclude,

39:24

there are various entities that can mimic prostate cancer and multiparametric M

39:28

r I.

39:29

It's important to have an awareness of the imaging features as that is paramount

39:32

to make the correct diagnosis, avoid mis calling, um,

39:36

as that will optimize management of the patient and avoid unnecessary

39:40

intervention. Uh, with that,

39:43

I thank you for your attention and I'll open up

39:47

the screen to questions. Uh,

39:51

looks like I have four questions here.

39:57

Um, first question is,

39:59

does diffusion imaging help with diagnosis of prostatitis? Well,

40:04

what happens with prostatitis is it can cause restricted diffusion,

40:08

though they say in many cases it may not restrict as strongly as a

40:13

clinically significant cancer.

40:15

The clues of the prostatitis is the geographic shape of, um,

40:20

the abnormality, uh, shown in the two examples, there wasn't, um,

40:24

mass effect and it did have more of a geographic appearance.

40:29

So those are kind of the clues. Once you have a geographic appearance, um,

40:33

especially you see that on the D W I and a D c,

40:36

then you can call it a a pyres too.

40:39

You do have to be careful because the prostatitis that you see classically the

40:43

more in a radial shape.

40:45

So they'll extend from the pseudo capsule to the capsule.

40:48

But be careful when you have a geographic lesion that's subcapsular.

40:52

'cause sometimes those actually can be prostate cancer.

40:55

So just be careful if it's focally, really subcapsular. And again,

41:00

i I use all the data that's available.

41:01

It is important to have the P s a calculate the p a density.

41:05

If it's more than 0.15,

41:06

there is a higher risk of clinically significant cancers to look very carefully.

41:10

So look at all those factors. And if you know, the PS a a density is high,

41:15

the P s A is rising,

41:16

there's a good likelihood the patient's gonna go to systematic, uh,

41:20

biopsy anyways.

41:21

It may be well worth commenting that perhaps targeting that lesion as well,

41:24

especially if it's subcapsular. Um,

41:29

next question. Uh, besides the four sequences plus T t1,

41:33

do you use other fancy sequences such as spectroscopy? No, I,

41:38

I've had experience with spectroscopy, but I haven't used it. Um, I find it,

41:43

um, that, uh, I just follow the current pi rads, uh, version 2.1,

41:48

which is, uh, T two, uh,

41:51

in one other orthogonal plane.

41:53

But I do use it in all three planes because I find it very helpful to, again,

41:58

avoid pitfalls, identify pitfalls,

42:00

and to look at margins of the lesions because it could look slightly

42:05

blurry, questionably blurry on, say on a axial plane.

42:08

But in the coronal plane you'll see it's very well demarcated.

42:11

Or in the cornal plane, you realize, oh,

42:13

it is actually an exophytic B P H nodule.

42:16

So T two and three planes, you have to use D W i,

42:21

you have to use a, at least a high B value 1400.

42:24

You want to have that acquired separately or extrapolated from an intermediate

42:29

and low B value.

42:30

So your low intermediate B value should be acquired for your a d C map,

42:35

and you get a separate high B value for your D W I. Um,

42:39

and then in terms of contrast, um, that's also recommended by pyres,

42:44

so I don't use spectroscopy. So bottom line is T two, at least two planes.

42:47

I use three D W I with high B values, lower values for the a d C map.

42:52

And there's contrast. So I don't use spectroscopy, it's all in the pire. It's,

42:57

uh, it's all the details are also in the pires 2.1 version. Um,

43:02

it's question,

43:06

is there any other indication for M R I besides staging and follow-up

43:10

management? Most of the times it's now using for detection. Uh,

43:15

you know, is there a prostate cancer there? Um,

43:19

so it's using for detection, and if there is something suspicious, uh,

43:24

then it goes, usually goes on to targeted, uh, biopsy.

43:28

So certainly for that, like is there a cancer, um, high suspicion of cancer,

43:32

where is it, is it a situation that's gonna be easy to, um,

43:36

operate and the patient will able to go undergo nerve sparing surgery because if

43:41

it's location is away from the neurovascular bundle,

43:44

or is it a tumor that's in the apex and extending to the external sphincter,

43:48

that would make it tricky.

43:49

So it's also localizing where it is to a urologist in, in the best approach, uh,

43:54

for the, the surgery. Uh, in terms of monitoring, yes,

43:58

and then focal therapy's important as well as other patients. Um, you know,

44:02

there's various treatments out there, so MRI's also helpful in, um,

44:07

uh,

44:08

deciding patients for types of therapy and also for recurrence

44:13

and, uh, monitoring, um, post, uh, focal therapies. Uh,

44:17

so those are additional indications. Uh, for prostate. M r I,

44:24

uh,

44:27

can you constantly report prostate with a 1.5 magnet? Yes. Uh, I,

44:31

we've been doing that for, for, I don't know, maybe, uh, quite a few years.

44:35

Yeah, we are, we do quite well with, uh, 1.5, um,

44:40

and we do that without a coil as well. The images that I've showed you, um,

44:44

I think they're all 1.5. They're all our 1.5, uh, clinical cases.

44:52

Uh, moving on endo rectal versus surface coil,

44:58

yes, uh,

45:00

it will depend on lots of factors and really comes down to

45:05

resources, workflow efficiency. Uh,

45:09

we stopped using the Endorectal coil. Uh,

45:13

we're happy with our images without Endorectal coil, though,

45:18

in terms of literature. Some will say it doesn't make a difference,

45:21

and some will say it does detect more cancers. Uh, we did our own trial, uh,

45:26

recently, um, when I spoke one of the re uh,

45:30

webinars and our paper was published also in a G R just in, uh,

45:35

July, we showed that the coil can pick up, um,

45:38

more clinically significant cancers. Uh,

45:41

a few of the three plus four tumors were missed, albeit low volume. Um,

45:46

so, and, and also in, in these cases, low, low volume,

45:49

three plus four in some instances, um, in some centers,

45:52

wonderful active surveillance. So with our coil,

45:55

we found there wasn't too much of a a difference,

45:59

so we decided not to use the coil. In terms of pys, again,

46:03

the PIRAD guidelines suggests that, um, I, it depends on again,

46:08

um, what the current, uh,

46:11

environment is in your situation in terms of resource availability,

46:14

because obviously, um, you do need, uh, resource, uh,

46:19

human resources to insert the coil, check the coil position. Uh,

46:23

there's also obviously funding to purchase the coil. Um,

46:27

and then more importantly, the patients do not, um, like the coil

46:34

even diffused or low grade may not show significant restrict how to differ.

46:38

Sometimes it can be hard if you don't have the geographic appearance. It,

46:43

it can be hard to, to distinguish it, but usually the morphology does help.

46:48

Uh, the fact that, uh, uh, you don't see, uh, mass effect as a geographic,

46:54

uh, shape

47:01

other than rectal in terms of technical factors. Um,

47:06

yeah, so it's mentioned, it's, it's the, it's a D W I that, that can, uh,

47:11

mimic prostate cancer. Uh, so that has to be optimized. Um,

47:16

recal gas is the, the big challenge as, as shown as well,

47:21

is just not, if you windowing inappropriately,

47:24

sometimes you can window so that it looks like there's more than one cancer if

47:29

there's only one cancer. So again, it has to do with, uh,

47:31

with the windowing levels, academic, uh, prostate cancer.

47:40

Um, any role of CT prostate cancer?

47:49

Well,

47:49

the role of CT currently is staging for intermediate to high

47:54

risk cancers.

47:58

Though there isn't a lot of work, uh,

48:01

with regards to dual energy ct, um,

48:05

perhaps using the vascularity might be helpful,

48:08

but there isn't a lot of information on that. Um,

48:12

there is work on ultrasound, you know, ultrasound elastography, uh,

48:17

time enhanced ultrasound, which is a,

48:18

a study that I'm currently involved in as well. Um,

48:21

so maybe in the future there might be more modalities at this time.

48:26

MRIs, the best non-invasive test to detect prostate cancer. Uh,

48:31

P M S A PET is also another internal alternative.

48:34

There's early studies showing that it, it may, uh, you know, um,

48:39

work just as well or perhaps better. I guess again, more,

48:43

more research needs to be done

48:47

for arteric, fibromuscular, str, should it be evaluated with DT device?

48:56

Um, so under fibromuscular str in terms of d w i,

49:01

it's, it's usually low signal. There's usually no restriction at all.

49:06

So in like the images I showed you, there wasn't anything, um,

49:10

really bright. Uh, so usually on the D W I itself,

49:14

it should be iso intense to, uh,

49:18

the rest of the gland. Um, so where, where,

49:22

it's similar to per peripheral on transitions.

49:24

So I find when you're at a high D w I value everything

49:29

you know, is usually low signal. And then you look for areas that, uh,

49:35

restrict. And then similarly for,

49:40

uh, central zone for D w I,

49:43

similar to what I'm looking for in the,

49:47

if I'm looking at the central zone and trying to decide whether I'm worried

49:50

about it or not, is um, how strongly it restricts.

49:55

Um, which can be difficult.

49:58

I agree when you're subjectively reviewing it because we're not like using a

50:03

d c thresholds, which may be more objective, but that's difficult 'cause of, um,

50:07

variability to cross platforms.

50:09

So what I look for in d i is is what I mean by restriction is to call it a

50:14

DWI four on d w i,

50:17

it should be the brightest lesion on that image.

50:21

And if it's not and I see other lesions that are similar, not that bright,

50:24

then I'm calling, call it a DWI three.

50:27

So it's not gonna be an outright restriction. And then on a d c,

50:32

it should be the darkest lesion on the image as well. So you,

50:36

if you have it both the brightest on D W I and the darkest on a D C,

50:41

then that's an outright strongly restricted lesion.

50:44

It gives you a score of of four.

50:46

So if I saw that in the transition zone, then I would be worried. Um,

50:51

I would look to see if it hyper enhances,

50:54

then I would then call it as suspicious. Again,

50:57

I do use all the clinical information that's given to me or I can access,

51:02

fortunately I do have, um, uh,

51:04

information system or imaging system that I can acquire the, um,

51:09

trends of, uh,

51:10

or obtain the trends in p s a levels to get a sense and calculate, uh,

51:15

p s a density to get a sense of how suspicious I am

51:24

Display the slides on all the mimics, you mean the list or the images?

51:30

Um, let's see.

51:34

I'm not sure which slide you mean,

51:36

if you mean more this or maybe at the beginning.

51:43

I guess this is a quick review going backwards,

51:48

so I hope I've answered all the questions. I think I did kind of go in order,

51:55

but I'm just gonna go back to maybe the first few slides, which kind of list,

51:58

uh, the entities.

52:04

So in terms of kind of benign processes, these are probably the,

52:08

the most common ones.

52:12

And then in terms of normal anatomic structures, um,

52:15

I would say central zone is a common pitfall that leads to, uh,

52:20

mis calling. Um,

52:24

I think it's not what you meant.

52:29

Oh, great. This is fine. So there's the list.

52:33

Any other questions? I think we just have a few minutes left.

52:42

Okay. Looks like that's all the questions. So as we bring this to a close,

52:45

I wanna thank you Dr. Chang for giving this lecture.

52:47

And thanks to all of you guys for participating in our noon conference.

52:51

Quick reminder, this conference will be available on demand on mri online.com.

52:55

In addition to all the previous noon conferences, tomorrow,

52:58

we're gonna be joined by Dr.

52:59

A Simian for a lecture on clinical I fundamentals and unexpected challenges,

53:05

registered mri online.com,

53:06

and follow us on social media at the MRI online for updates and reminders on

53:11

upcoming conferences. Thanks again and have a great day.

53:14

Thank you everyone.