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PI-RADS 4/5

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Let's take a look at a 56-year-old male

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with an elevated PSA and a negative biopsy.

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This is a tremendous indication for MRI

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when you're not in the low-tier group.

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In other words, when the PSA is rising

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at a rate that's disconcerting, maybe a 50%

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rise or a doubling in one year,

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or the PSA is hovering around 10 or greater.

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And then your suspicion is pretty

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high because the likelihood of cancer

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is almost 50%, which is pretty good.

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And the possibility of extension outside the

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gland when you're, uh, you with a total PSA over

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10 is also 50%, maybe even a little higher.

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So here you've got to go for something

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and MRI is just perfect because

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you can find aggressive cancers.

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So we've got an axial T2-weighted image

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on the left, and immediately we see several

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abnormalities in the peripheral zone.

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In the right PZP, the posterior aspect of the

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peripheral zone is an area of hypointensity.

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And there is a question as to whether it has

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fuzzed out and produced an ill-defined capsule.

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Here is the anatomic capsule.

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It's a line, it's a line, it's a line.

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Now it's an interface, because it

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has an opacity on one side, and we've

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completely lost that crisp line.

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So we're suspicious of capsular invasion, not just

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because we lost the line, but look at the bulging.

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And look at the asymmetry of the

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little speckled tissues on either side.

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Nice and speckled and bright, a little

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less so, and they're pushed away.

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Another sign: bulging and asymmetry

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of the neurovascular bundle, along

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with this broad area of contact, all

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suggestive of capsular involvement.

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Also, asymmetry.

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of the pericapsular prostatic fat.

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Another very important sign of capsular invasion.

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Now here is a fat suppression one.

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And while I like this to look internally

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at the gland because it makes the whites

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whiter and the darks darker, you can

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see the edge of the tumor very nicely.

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It does hamper substantially your

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ability to see transcapsular extension.

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Now this was done with 3D technique for mapping.

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This is 2D technique over here.

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Now what's the major criteria for

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peripheral zone abnormalities?

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It's actually not the T2-weighted

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image even though it's pretty.

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It's actually not the 3D fat suppression

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T2 image even though it's pretty.

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It's the diffusion image with a high B value.

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How high?

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Well, 1200 is the absolute floor.

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But I like them around 1400 or 1600.

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And the thing that's going to limit your ability

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to get into these high B values is the efficiency

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and strength of the gradient on your MRI.

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So this is a B1600, and right there

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we've got diffusion restriction.

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And the intensity that you

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see on diffusion restriction.

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And the degree of low signal on the

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accompanying ADC map has a lot to do

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with the aggressiveness of the cancer.

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So, extremes of hyperintensity.

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Extremes of parametric hyperintensity.

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Velocity restriction on the ADC map

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means you've got a higher Gleason score,

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which takes you into a poorer prognostic

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cavity, a poorer prognosis overall.

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So now let's look at the ADC map.

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I'm going to blow it up a little bit.

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The ADC map, a parametric map of

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velocities, more sensitive by the

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way than the diffusion image itself.

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It's a calculated image made on the basis of

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multiple diffusion images. Shows our area of

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velocity decrease or diffusion restriction as low.

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So it's high on diffusion,

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it's low on the ADC map.

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Now let me just take you through

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a series of diffusion images.

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Here's the low B-value image.

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We'll go right to our spot.

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And the low B-value image is nothing more

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than a very fast echoplanar T2-weighted image.

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So it looks a lot like the regular T2 image.

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Let's take the next B-value up, say 50.

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Still pretty low.

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And the next B-value up, kind

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of an intermediate B-value.

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It's getting a little bit less dark, and the

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tissues around it are getting a little less white.

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Now let's go to a B-value of 1200.

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It's getting brighter, the surrounding

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normal prostate is getting darker.

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Let's go to a B-value of 1600.

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It's pretty bright, and the

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surrounding tissue is darker.

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So you see how you take these series

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of B-value diffusion images

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in which you crank up the volume.

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You crank up the intensity of the diffusion

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gradients, and you invert the signal.

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The signal goes from dark to bright

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on the high B-value images, and

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the rest of the prostate drops out.

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Now, we measure this in the axial

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projection, and the measurement,

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we'll measure it for you right now.

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The measurement here was about a

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centimeter or less, 9 millimeters.

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So that would make it a PIRADS 4.

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We'll look at it in another projection.

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Let's do that.

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Let's pull down the sagittal.

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And there is our lesion in the back.

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It may be a little longer

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than we thought previously.

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Let's look at the length.

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So if it exceeds 1.5,

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it's 1.2.

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131 00:05:32,650 --> 00:05:35,489 So it's still in the PI-RADS 4 category.

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But we're not done yet.

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Let's look at the coronal projection.

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So let's pull that down and go right to our spot.

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And perhaps it's a little bigger.

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So it's a little hard to measure the upper part.

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You know, are we seeing some

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fibrosis there, or is that tumor?

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This is clearly tumor.

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So if we measure it from here

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to here, it's gonna be 1.44,

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that'd make it a PI-RADS 4.

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If we measure it from here to here,

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as the original reader did, you'll

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see that in the report, then that's 1.7,

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that would make it a PI-RADS 5.

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In my opinion, it probably stops a

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little bit lower, like right there, and

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this is just fibrous tissue over here.

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So that would categorize it as a PI-RADS 4.

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So you see the designation between

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a 4 and a 5 is pretty simple.

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If you're over 1.5,

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it's a PI-RADS 5.

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If you're under 1.5,

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it's a PI-RADS 4.

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And if it's 1.5,

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then you might want to use some of the other

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parameters and kind of split the difference

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to decide which direction you're going to go in.

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Critical finding in this case, suspicion for

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transcapsular microinvasion on the right side.

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Let's finish the case off with

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the dynamic contrast-enhanced MRI.

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Let's pull it down.

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So what you're looking at

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now is each anatomic locus.

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Let's go to the site of the

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tumor, which is right here.

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And we'll start off with the mask.

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So this would be before the contrast arrives.

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Okay.

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Here we are at 7 to 10 seconds.

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A little bit of hypervascularity, not a lot.

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Now we're at 14 seconds.

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Now we're at 21 seconds.

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And it starts to blend in

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with the rest of the prostate.

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So it's not that vascular initially,

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but it is washing out, isn't it?

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It's getting a little bit darker as time goes on.

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So it has a tumor-like curve,

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even though the peak of it is not that high.

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So if we were to draw the curve,

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then it would look something like this.

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Typically, the tumor curves will be really high,

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for the aggressive tumors and then have a washout.

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In the prostate, they're not as consistently

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as high as we see in the breast.

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So you might have something that

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looks a little bit like this,

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and then kind of a more gradual washout.

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And that would be the curve

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of this area right here.

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So in summary, this would be a PI-RADS 4/5,

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depending upon what size criteria

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you use with microcapsular invasion suspected

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in the posterolateral right side, PZP area.

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And PZL2, posterolateral.

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Let's move on, shall we?

Report

Editorial Note

Faculty

Stephen J Pomeranz, MD

Chief Medical Officer, ProScan Imaging. Founder, MRI Online

ProScan Imaging

John F. Feller, MD

Chief Medical Officer, HALO Diagnostics. Medical Director & Founder, Desert Medical Imaging. Chief of Radiology, American Medical Center, Shanghai, China.

HALO Diagnostics

Tags

Prostate/seminal vesicles

Neoplastic

MRI

Genitourinary (GU)

Body

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