22 Localization After Positive Biopsy

Clinical Vignettes in Prostate MRI

Now we're going to have a session on clinical vignettes in prostate MRI which will include myself, Jeff Weinreb and Dan Margolis.

And the first vignette, and these are basically case presentations, concerns, localization after a positive biopsy.

So this first case is a 65-year-old man with a serum PSA of two point four with Gleason six in the right peripheral zone on a truss biopsy.

And this is the he was referred to make sure that he was eligible for active surveillance.

And so this original MRI shows a lesion on the left side that was evidently missed on the standard biopsy.

Okay, withhold judgment on this until you see all the case.

There's some low signal on the ADC map and some enhancement after intravenous contrast.

And so this was biopsied and was confirmed to be a low grade cancer on the well, actually, the results of the biopsy were unchanged so on.

He was, it was agreed that he could go on active surveillance.

And so that one year later, you can still see a lesion, perhaps even bigger on the T two.

But importantly on the ADC map, there's an absence of a lesion, although there's still some enhancement here.

So now you might be thinking about something like prostatitis, because if you were just reading this scan for the first time, according to PI-RADS rules, this would be a either a one or a two, certainly not anything that you would recommend biopsy on notwithstanding these positive findings.

So on the third year of follow up, his PSA has actually declined a little bit.

The T two is completely normal, as is the ADC and the DCE.

So this is really a resolving area of prostatitis most likely, or with a microscopic focus of cancer somewhere in there.

And the point is that we need to keep following these patients and sometimes the lesions will resolve.

So this is a case.

One is basically tumor findings that recede over time, leaving a more normal looking scan.

Second Case: Stable Low-Grade Cancer

The second case is pretty much similar to the first in history.

A low grade cancer detected on a truss biopsy.

And these are the images from the original biopsy.

It shows a this kind of wedge-shaped lesion in the anterior horn, which is a common area that we see represented on both the T two and the ADC map, and the lesion does enhance.

So a targeted biopsy of this was repeated essentially, and it was also a low grade cancer.

So we conducted a follow up on this, and there's really no change.

He was re-biopsied at one year, but now he's been on a less regular basis just being followed with MRI.

So in essence, this is a low grade tumor that remains stable on active surveillance.

Third Case: Growing Tumor on Active Surveillance

So here's the next case is a 61-year-old with a serum PSA in the threes, and again, low grade tumor on random biopsies.

Is this a candidate for active surveillance, is the major question that's being asked on the referral.

And there is in fact a lesion here in the right PZ, clearly positive on the ADC and enhances.

So, PI-RADS four lesion, we recommended biopsy, which was performed using a fusion biopsy, and it was a three plus four on the repeat biopsy.

Now, this is a little bit of the larger lesion.

It might even meet criteria for a significant lesion based on its volume, but the patient was really eager to stay on active surveillance.

So we conducted a follow-up on this patient, and here the T two demonstrates enlargement, but of course, we've seen that before.

But the ADC has also become more obvious, no change in the DCE.

So we advised to re-biopsy, which was performed, and this had upgraded to four plus four at this point, and the patient went on to definitive therapy, a radical prostatectomy.

So the point of this is also that once detected a low grade tumor, we can make a decision to put the patient on active surveillance according to the patient's wishes in some regard.

And then continue to follow and see if there's growth.

So this is a growing tumor on active surveillance.

Fourth Case: Higher-Grade Cancer Detected by Targeted Biopsy

The fourth case is a 68-year-old male with high PSA, also Gleason six sort of repetitive history.

It's this is in the left mid PZ on conventional biopsy.

And sure enough, in the left mid PZ, there's a low signal lesion adjacent to the capsule, low in signal on ADC, who we call this a PI-RADS four.

It enhances, but that doesn't change the score.

And we just put a needle right back into that area.

Notwithstanding that it was a six on the the original biopsy.

On the secondary biopsy. It was a Gleason four plus four, and the patient went on to therapy.

So one of the problems with transrectal ultrasound biopsy is that we don't really know what part of the lesion was biopsied.

It could have been from the edge or even in the periphery of this lesion.

Obviously they got part of it, but they didn't get all of it.

And that's just one of the problems with a blind biopsy is that you don't know where you're aiming.

So the guided biopsy is very helpful.

This would've been a mistake to have the patient on active surveillance based on this finding.

So this is a prostate cancer that's higher in grade than it looks on MRI.

And the targeted biopsy reveals a high grade disease in a small tumor.

Fifth Case: Extensive Higher-Grade Tumor

So I think this is the final case that I'm going to show.

It's a patient who's 66 and slightly elevated. PSA, he had a Gleason three plus four tumor on a conventional biopsy.

And again, the thought was, could we perhaps put this patient on active surveillance based on these preliminary results?

MRI shows a large lesion greater than 1.5 centimeters with a long surface abutting the capsule which has been associated with microscopic EPE.

And sure enough, it's very positive in the on the ADC map and on the DCE clearly positive.

So already we're at a PI-RADS five.

And so really, even though this was three plus four on randoms, again, maybe a sampling problem on rebiopsy getting a better sample, there were elements of Gleason four plus five.

And clearly that dramatically changes the situation for this man.

And so the debate was whether he was actually a surgical candidate or a radiation candidate, and he eventually had surgery after the two sides duked it out, and the patient decided.

And so far as I know he's doing well.

So this is just an example of a much higher grade tumor than was suspected by the original biopsy, and much more extensive than would be suggested by the random biopsy.

And again, just reiterates the point that targeted biopsies are in many cases superior to random biopsies for all the reasons we've discussed.

Okay, well, so those are the cases that I have.

So I'd next like to have Jeff come up to the podium and discuss some of his cases.

Jeff Weinreb's Cases

So I'm also gonna show you a few cases each with a little lesson in them.

And this, all the images I'm gonna show you were all obtained with a surface phased array coil, not an endo rectal coil.

And then at the end of this, I'm gonna talk a little bit more about some of the issues with endo rectal coils that we discussed yesterday.

First Case: 73-Year-Old with Suspicious Biopsy

So this first patient is 73 years old and a PSA of over eight.

And the biopsy was suspicious for cancer.

So this biopsy was done not at our institution.

I don't have the biopsy results, but this is what we get.

So if they're done at our place, we know the biopsy results.

If they're not often, we don't actually have the biopsy results.

And so what we were told is that suspicious for cancer, but not diagnostic, not exactly sure what that means, but probably means it was a not a Gleason seven.

And the MRI was performed six months later.

And what it shows you here is an abnormality on all of our different techniques, but because this is in the transition zone, we'll map it out on the transition zone, and then we'll use our PI-RADS criteria for assessing it.

And this would be a peripheral zone DWI PI-RADS four because it's very dark on the the ADC, and very bright on the high B value image.

And then we'll assess it regardless of the fact that it's abnormal on the other techniques, because of the abnormality on DWI, it's gonna be a four.

And the results that we got back from the MR fusion biopsy was that it was negative in the right posterior lateral PZ.

So this area was actually targeted, and there were a whole bunch of biopsies there, and it came back normal tissue.

And on review, you know, you say, this can't be normal tissue.

Okay? I don't, you know, perhaps it's not a cancer, although it sure looks like a cancer, but it can't be normal tissue.

And on review, with the path with the urologist and the pathologist, the urologist who did the fusion biopsy probably missed it because of misregistration, because the ultra between the ultrasound and the MR.

So you see these kinds of things.

Now in all the cases where we're doing these fusion biopsies, we're also still doing systematic or systemic biopsies to learn.

And also because in the literature and in our own experience, there are not more than occasional cases where the targeted biopsies some things not everything is targeted, and a clinically significant cancer is found on the systematic biopsy.

Ideally we'd like to obviate the systematic biopsy, but at least right now in our situation, we're doing both.

And in this case, there was a Gleason four plus four or eight in the left medial base on the systematic biopsy.

And even in retrospect, not shown here, we couldn't find anything on the MR that correlated with that.

So we do get these kinds of cases.

Second Case: 58-Year-Old with Family History and High PSA

Here's a 58-year-old who's got a strong family history and a high PSA of 32.

And on physical exam, there's a hard and derated nodule in the left lateral base to mid gland.

And then the you notice I called this a TRUS rather than a TRUSS.

TRUS sounds just like it's more anachronistic, which is probably what's happening with it.

But so on the ultrasound guided biopsy, there was a Gleason, and we're just doing this to stage it and also see what else is going on.

And there's the big nodule in the back here.

And again, it's very abnormal and all of the different techniques, and it measures 1.9 centimeter.

We map it out into the peripheral zone, and we call it a PI-RADS five.

And also commented when this was read the comment here is that there's a smooth bulge with the capsule tumor interface greater than a centimeter.

So they the report said that they suspect extra prostatic extension and patient ended up getting a radical prostatectomy, despite the fact that the radiologist said that they suspect extra prostatic extension.

This turned out to be a Gleason nine.

It was 40% of the gland was involved, and we certainly don't see that much of the gland involved here.

And there was no extra prostatic extension, but there was bilateral tumor, which we just don't see here.

So we do get this discord sometimes between what we see on the MR and what we see at pathology and this whole issue of extra prostatic extension.

In my own experience, unless I see gross extracapsular extension, I'm really very careful about calling it because I think we can be wrong as much as right.

And as you heard earlier, sometimes prevent people from getting a prostatectomy based on erroneous findings on the MR.

Third Case: Endo Rectal Coil Comparison

And this last case I'm gonna show you is just to illustrate some of the things we talked about with the endo rectal coil.

So here's a MR done without an endo rectal coil, and this was done at three T and what you can see here, is that a good, there's a lot of distortion back here because there's gas in the rectum, and here's the same patient same day with an endo rectal coil, and the peripheral zone miraculously reappears.

Okay? And that's because the endo rectal coil displaced the air away from it and got the coil up right near the prostate.

So this is a slide that I prepared this slide close to 20 years ago, and it hasn't really changed that much.

This whole issue of endo rectal coil is, there are advantages and disadvantages.

The main advantage, the advantage is increased signal to noise in the posterior part of the prostate, and it also displaces air.

But there are a lot of disadvantages to it, which is why there's been a trend away from using it.

The other thing, but I what I will tell you is that in patients who are large, and we have a lot of large people, you know, and most places in the United States, there's a lot of large people, there's just you're just not gonna get good images without an endo rectal coil.

'cause these surface coils just are not gonna get signal from that gland right in the middle.

And the same thing in my experience is with patients with small prostates, even if they're quote unquote normal size without an endo rectal coil, you don't get great signal to noise.

And we don't have great criteria other than we look at the patient and we say, if they're really big, you know, we're gonna have to use an endorectal coil.

So here's a patient done a three T on two different magnets, two different times.

So it's not a controlled experiment, but using this, just to illustrate to you, again, I actually showed this to you yesterday.

Here's a three T scan with no endo rectal coil, and look at the distortion here from gas.

And here's a 1.5 T scan with an endo rectal coil.

And it's just a better scan.

You can see the whole prostate, but it sometimes works the other way.

Here's a patient who had a three T scan with an endo rectal coil, and there was a little air in the balloon.

And with the endo rectal coil, you do get distortion of the gland.

And there is some artifact here without the endo rectal coil actually got a better scan in this patient.

And maybe it's 'cause the endo rectal coil wasn't positioned well in March.

I informally poll the members of the steering committee of the of PI-RADS about whether or not they're using endo rectal coils and which scanners they're using.

And here's the results.

And you can see, you know, as a group, we're all over the place.

And some people, as you've heard, are using endo rectal coils only for staging and the surface or phased array coils when it's not a staging exam.

You know, to me, that doesn't make a lot of sense because whenever we're doing an MR we're also staging, I you know, at least we are, when we're looking for, when we're doing detection, we're also staging.

Then you have, you know, places where they have multiple machines, and on some they're using an endo rectal coil and others they're not using an endo rectal coil.

And of course, at Yale, we can't make up our minds.

So we you know, we we sort of know.

And yes, it here's a 57-year-old who had a high PSA and this is great.

I told you yesterday, the PSA was down to two decimals.

Now we're getting in some of these cases with three decimals.

I I still can't quite figure this one out.

Anyway, it was a negative biopsy three years ago.

Here's the MRI, and it's pretty awful.

I mean, you really can't read this because of the distortion back there.

And this is one of those examples where this was done with the body coil.

You can see this gas there.

A enema was done with a Foley catheter, and it's better, I wouldn't say it's perfect, but it certainly improved matters.

Okay? So I mentioned this yesterday.

The way we we are doing these cases, we wanna do them without an endorectal coil if we can.

So we have the patient do a fleet enema at home.

Before they come to us, we discuss with them that we may need an endo rectal coil.

And frankly, if they're a big patient, we're gonna just tell 'em we're using an endo rectal coil.

And they're they're they're pretty much fine with it.

We tell the patient to evacuate and expel gas right before they get on the scanner.

The exams, if we're not using an endo rectal coil, we have to monitor the exams because we have to see if there's gas in the rectum and the quality of the images.

So we get our scouts, and first thing we look at is gas and the rectum.

If there is gas, we ask the patient to expel, and then we may do a enema.

The first series of images we acquire are the diffusion weighted images.

And we do that because those are the low signal to noise images.

Those are the ones that are more prone to artifacts, and they're the most crucial part of the examination.

And if they're good, we're home free most of the time.

If they're not good, then we may try again to remove gas, or we may at that point just bite the bullet and use it in the endo rectal coil.

Okay? So in our experience, we have to use the endo rectal coil about 10 to 20% of the time using this process.

It's not ideal.

It does take up more time because and somebody's got to monitor it.

But I will tell you that the results that we have with using, not using an endo rectal coil are very comparable to what has been published by multiple teams in the literature in terms of the incremental value of targeted MR ultrasound fusion biopsies.

And finally, this slide is drives a lot of radiologists crazy, but whether we like it or not in this country we are moving towards patients making decisions.

And most patients, if you can't tell them a compelling reason for using an endo rectal coil will prefer not to use an endo rectal coil.

And so in a lot of places, this is not a decision put in the hands of the patients in our place.

We sort of tell them the pluses and minuses and we'll and that we're gonna try to do it without an endo rectal coil, but if we have to use it, we will.

And most of the time, they're okay with that. Thank you.

Dan Margolis: Localization After Positive Biopsy

I'm just gonna wrap up with a few more examples, and if we have time, I'll process a case live.

So I'm gonna talk about localization after positive biopsy.

I think it's useful to go over one last time the appearance of prostate cancer on MRI on T2 weighted imaging.

So again, we're looking for a mass like low signal without corresponding hemorrhage.

And you want to very carefully evaluate the prostate capsule and the seminal vesicles.

And you want to determine whether or not the neurovascular bundles, which are these little dots at the recto prostatic angle whether or not they are involved.

So the signs of extracapsular extension, again if you see an obvious mass extending beyond the prostate, that makes it fairly easy.

And then the other things that you want to look for are whether or not there are signs of minimal or maybe microscopic extracapsular extension.

This includes bulging or a broad base of contact with the capsule or blurring or irregularity.

And again, you want to carefully evaluate the neurovascular bundle.

So I'm going to continue with some examples.

Example of Aggressive Anterior Cancer

Here's an example of aggressive anterior cancer.

So this is a 59-year-old man, PSA 4.3.

A number of the core biopsies were positive for three plus three disease.

So because of the volume the patient was recommended for surgery.

You can see here we do have an endo rectal coil.

The vertical arrow shows the level of the rectal prostatic angle.

The horizontal arrow shows a a mass like low signal focus which is in the anterior prostate.

And then the posterior peripheral gland has fairly normal signal.

There was corresponding restricted diffusion abnormal spectroscopic imaging and increased perfusion.

And the final path in this case was organ confined.

But higher grade then was initially suspected.

This is one of the cases where the gentleman was initially considered for a non nerve sparing surgery on the left because of how many cores were positive, and he was allowed to go to nerve sparing surgery based on the MRI findings.

Formulating the Report

And so here's how we would formulate this in a report.

In the finding section, you can decide whether or not you want a narrative or a formatted or standardized report.

And you want to if it's a staging study, you want to mention whether or not there is a distant extra prostatic disease, a regional disease.

You want to let the surgeon know the size of the prostate.

They generally prefer measurements in grams.

As you know, a gram of water is one cc.

So it's a fairly simple conversion and how much prostatic hyperplasia there is.

And then you want to identify any suspicious areas.

You also want to talk about whether or not there might be a median lobe hypertrophy or a bladder neck invasion, things that might also alter the surgery.

So we talk about the location.

So this is left anterior peripheral mid gland.

And this would also correspond to our diagrammatic localization tool, which unfortunately my software doesn't let me insert into reports the size of the lesion.

You can either give the long axis or we're recommending consideration for inclusion of long and short or even a volumetric assessment.

But usually you want to include the long axis.

You want to mention the relationship to the capsule.

This is of primary importance for surgical or radiation planning.

And then you want to describe the characteristics.

So in this case homogeneous hyperintense mass less than 1.5 centimeters.

So T two score of 4.5 diffusion, focal markedly hyperintense on ADC hyperintense on DWI, but again, less than 1.5 centimeters and not clearly invasive.

So again, 4.5 perfusion was abnormal.

Spectroscopy was abnormal.

And again, because this is a peripheral gland, it's the anterior horn of the peripheral gland lesion.

We use the diffusion as a primary determinant.

We also mention the appearance of the seminal vesicles and neurovascular bundles.

We generally like to report out the technical quality.

This helps give our referrers a sense of our diagnostic confidence.

And then you want to identify where the lesion is and whether or not it's organ confined or not.

Case Not Organ Confined: Seminal Vesicle Invasion

And that brings us to what about cases that aren't organ confined?

So this is another 53-year-old man, a little bit higher PSA with relatively small volume disease on the biopsies.

So three plus or equal six, and only two of six cores.

And so there was a consideration at the time whether or not this man might be appropriate for active surveillance.

So on the coronal T2 weighted imaging, we see a low signal mass in the right seminal vesicles.

We see abnormal enhancement.

This is a simple subtraction map and restricted diffusion.

You can see that the ADC is very low.

And incidentally, there's a utricle cyst.

Please keep in mind, the utricle cysts arise at the level of the verumontanum at the level of the basis would be a mullerian duct cyst which is not all that important for surgical planning, but the surgeons like to know that we're looking at the images.

And so the final Gleason score was upstage.

But he was found to have seminal vesicle invasion.

Now you may wonder, well, how do we know this?

If he's got seminal vesicle invasion, that's generally referral for radiation therapy.

This guy really wanted surgery, so it's nice for us because we have the confirmation.

Also, you notice I'm not giving an overall PI-RADS assessment, and that's because the seminal vesicles are neither peripheral nor transition zone.

Another Example of Seminal Vesicle Invasion

Another example of seminal vesicle invasion ill-defined T2 hypo intensity at the left base.

So you can see here there's a little bit of low signal at the base and then it extends into the seminal vesicle.

So here, the seminal vesicles on the coronal T2 and axial T2.

And on the perfusion map, we see perfusion corresponding to the seminal vesicles.

Basically, the seminal vesicles should only show very minimal perfusion of the wall, of the seminal vesicles.

You should never normally see any perfusion within the center of the seminal vesicles.

If you do, that's a strong suggestion that there's seminal vesicle invasion.

And then of course, there's also restricted diffusion.

Example of Anterior Peripheral Horn Disease

Here's another example of anterior peripheral horn disease.

And so the anterior horn of the peripheral gland is a common area where cancer's high because it's not in the normal biopsy zone.

So this is another relatively young man 52-year-old PSA, just below four two of five biopsies on the right were Gleason three plus three.

So here on the right we can see that there's low signal.

It does have restricted diffusion on the ADC map, so very dark on the ADC, it was bright on the DWI.

It does have abnormal perfusion.

And if you look very carefully, you can see that the peak to the left of midline is higher than the peak at midline.

So there's elevated choline.

Now here's the surgical pathology.

And you can see that there's a very large abnormality here somewhat larger than we would expect based on the T two or even the diffusion or perfusion appearance.

So this was three plus four.

Again, upstaging is not uncommon at surgery there was also a very small three plus three tumor somewhere in here possibly.

And the margins were negative.

So because we were able to identify the tumor the surgeon was able to resect completely.

And as you sort of wonder if somewhere in this low signal in the anterior fibromuscular stroma this little thing is hiding, but it's three plus three disease, and we often don't pick that up, although I'm gonna show you an example where we sort of do.

Small Volume Aggressive Disease

So another example, small volume, aggressive disease.

PSA almost doubles over about a year.

And only two of six biopsies were positive, but one of them was high grade.

And so the surgeon this was a very healthy gentleman and wanted to consider surgery.

So here we see the right medial apex.

So this is a coronal image, an axial T2 weighted image.

And you can see a low signal focus with highly restricted diffusion.

Again, this is the primary determinant in the peripheral zone.

There's abnormal perfusion.

And if you look very carefully, you can see this nice black line that defines the pseudocapsule of the prostate, and we lose it barely right here.

So we said that the margin was irregular which may suggest minimal extra prostatic extension.

I would encourage you to avoid the use of the terms focal and established, because these are pathologic terms that depend on the number of high power fields that are abnormal.

And it be it can be confusing when you're trying to correlate those two.

So we use minimal or gross to describe extra prostatic extension.

And sure enough, at surgery, this was a high grade lesion with focal extra prostatic extension.

The margins were negative.

And then there was a second tumor four plus three here.

Again, it's hard to see whether or not it it may be hidden by the anterior fibromuscular stroma.

So in this case, focal means only one high powered field.

So we were right, but probably based on luck.

Small Volume Low-Grade Disease

Another example, this is small volume, low grade disease.

So PSA 3.6 a number of the core biopsies were positive.

So on the right side, you can see that there's this sort of ill-defined low signal.

It doesn't abut the margin.

The ADC is a little bit restricted.

It does have a type three enhancement curve.

And at pathology there are two foci.

One that's probably this thing here, and one that's over here.

You can see they come much closer to the resection margin of the prostate.

They were both low grade disease and microscopically, they did not abut the capsule.

So you can sometimes see functional abnormalities with low grade disease.

But generally we do not.

Another Example of Low-Grade Disease

Another example of low grade disease.

So this gentleman, 54-year-old again PSA just under four five outta six biopsies were positive for low grade disease.

So on the T two, you can see that there are bilateral low signal areas.

They're not really mass like they're sort of diffuse.

So you might give this a PI-RADS two for T2 weighted characterization.

And then on the ADC, you can see here that the coil is buckling a little bit.

So my bad, I didn't check the coil to make certain it was distended well enough.

And this can confer a much higher degree of geometric distortion on your echo planar acquisitions that you use for diffusion weighted imaging, which makes it much harder to figure out what's going on close to the prostate capsule.

And we thought that there was maybe some abnormal perfusion.

This is a pretty K-trans map.

I'm not a big fan of the fuchsia though, but we can change that.

And then there was elevated choline.

So we figured, okay, so there's something abnormal here.

And here's what we see at surgical pathology.

It is all three plus three with a tertiary pattern, four, but only on the left.

So this here is a tumor, this here is a tumor, this here is a tumor, and this is false positive.

That's prostatitis or something else.

So low grade disease can be very difficult to discriminate from.

Prostatitis and low grade disease are often similar in appearance.

And it's important that our referrers understand that that can be a difficult discrimination to make.

Interestingly there was focal extra prostatic extension, which looking back, you know, the prostate capsule looks intact, but there is this broad base of contact here maybe we should have mentioned it.

And although three plus three disease almost never metastasizes, there are case reports in the literature, it can actually extend locally.

So it behaves a lot like basal cell.

But margins were negative fortunately.

Thank you very much.