GU Sonography of the Urinary Bladder, Scrotum & Prostate - SD

Ultrasound Evaluation of the Bladder, Scrotum, and Prostate

I'm Dr. Ethan Halburn from Thomas Jefferson University, where I'm a professor of ultrasound. And today I'll be speaking about ultrasound evaluation of the bladder of the scrotum and of the prostate.

We're gonna speak today about sonography of the urinary bladder, the scrotum, and the prostate, and we're gonna start off with the urinary bladder.

Normal Function and Capacity of the Urinary Bladder

As you probably know, the urinary bladder's primary function is to serve as a reservoir for the urine so that you can accumulate the urine and then urinate at one time and then accumulate more urine.

The bladder capacity for most people, it maxes out around 400 ccs, so 400 to 500 ccs is usually the maximum bladder capacity that we'll see.

On a full bladder, you should be able to calculate that volume. On a post void, you wanna see the bladder empty completely so that there's less than about 10 ccs left in the bladder. And normal values are post void residual of less than five to 12 ccs.

When that post void residual is greater than 50 ccs, that's called remarkably abnormal.

Ultrasound Imaging and Volume Calculation

For the purposes of ultrasound, we look at the bladder in sagittal and transverse orientations, and then we use the measurements that are obtained, measurements that are transverse measurements, and then craniocaudal and anterior posterior measurements to calculate the volume of the bladder.

And you see here the formula that we tend to use, which is the pi over six times length, times width times height formula to give us a bladder volume.

And this is the full bladder, and here is the post void bladder, where after voiding, you see that the bladder volume is much smaller and the wall appears thicker.

But we use the same formula to calculate the post void residual.

So here's another patient, where we see the full bladder is the slide here on your left, and then the post void bladder is the slide on your right transverse measurement here before voiding, craniocaudal and anterior posterior measurements before voiding, and this is a relatively normal bladder volume, but post void we see that there's still quite a large residual.

And the post void residual will be calculated as this eight times, six times, seven times pi over six. And you would find that the post residual is well over 50 ccs.

So the two most common reasons for an increased post residual would either be bladder obstruction or outlet obstruction, most commonly related to an enlarged prostate or a neurogenic bladder.

Bladder Wall Evaluation

Now when we look at bladder wall, the wall of the bladder should be smooth and thin. In general, the bladder wall should be less than five millimeters in thickness.

And we like to measure that bladder wall with the urine as a nice anechoic contrast to the wall, and then with the bright fat and back of the bladder here, showing you where the other side of the wall is, the outside of the wall.

So this is bladder wall here, and this is a thick bladder wall measuring seven millimeters.

Now obviously this bladder wall is measured when the patient has a full bladder, once again a thickened wall. If it's diffuse thickening, we could be talking about outlet obstruction or a neurogenic bladder that could be diffusely thickened then often appears echogenic.

When we are talking about a neoplasm, frequently the thickening is focal, it's irregular and it's mass like.

Bladder Variations and Diverticula

We'd like to talk now about some of the variations that when seasoned bladders, bladder diverticulum is a common variation. It's not normal, but it's relatively common.

Often bladder diverticula appear right here in the posterior lateral aspect of the bladder on one side or on the other. And they appear in those areas because there's a relative weakness in the bladder wall adjacent to the ureteral insertion.

These are called hutch diverticula. And the bladder diverticulum basically is a space that holds urine and it's relatively stagnant urine, so it serves as a nidus for infection.

But in addition to that, the bladder diverticulum does not contain a full thickness of the bladder wall. So it's the mucosa, which is herniated through the muscularis because of the fact that there's no muscular lining outside here.

If there's a tumor in a bladder diverticulum, it will spread very early as opposed to we're having to first grow through the bladder wall before it spreads.

The urachal diverticulum is a congenital variation where the urachus, which is a normal embryological structure, does not involute and it persists throughout the patient's life.

And so what you see here is a persistent urachal remnant in this case, it's a diverticulum because it ends right here above the bladder.

But the urachal remnant is always at the dome of the bladder. It's always in the midline and it always points toward the umbilicus.

It may be just a rete as we see here, urachal diverticulum, or it may actually be a sinus tract where it extends all the way up to the umbilicus.

Or it may not communicate with a bladder, in which case it will be just the urachal cyst sitting out here by itself.

In this case, this is a urachal diverticulum. Once again, there'll be stasis of urine in this diverticulum, so it can serve as a nidus for infection.

But the cancers that occur in urachal diverticula are different than the cancers that occur in the bladder because the bladder is generally lined by transitional mucosa, whereas the urachus is lined by columnar mucosa.

So what you'll see here is adenocarcinoma in the urachus as opposed to a transitional carcinoma in the bladder.

Another congenital abnormality, which can interfere with bladder function is the ureterocele.

Now, as the ureter comes through the bladder wall to empty into the bladder, it comes through an area which we call the ureterovesical junction.

Sometimes there's an outpouching of the wall of the ureterovesical junction, which goes into the bladder, and that ureteral outpouching into the bladder is called the ureterocele.

You can see part of the ureterocele here. You can see the ureterocele here on this transverse image of the bladder.

These result in obstruction of ureters, they can result of stasis of urine, which results in infection.

Now, ectopic ureteroceles that is a ureter associated with the ureterocele that does not insert to the normal UVJ, but it inserts into an ectopic location that's often associated with the upper pole of a duplicated collecting system.

And in fact, what often happens is that the upper pole of that kidney is obstructed related to the ureterocele and the lower pole refluxes, because there's some abnormality of the UVJ in the lower pole.

This is another case of a ureter coming into the bladder. And you see here a small ureterocele associated with this ureter.

Other Bladder Abnormalities

Moving on to some other abnormalities of the bladder. A slide here on your left shows you bladder stones.

So here you have the bladder with two echogenic foci, each showing distal acoustical shadowing, and these are stones within the bladder.

If you ask the patient to turn or to move, you can visualize that these stones will move in the bladder.

If one turns on the color doppler, one can actually see a twinkle artifact, which is an aliasing type of artifact in the Doppler signal coming down from calcified stones.

This mass, which is protruding to the bladder here, this is simply what we call median lobe hypertrophy from an enlarged prostate bulging into the bladder.

So we were talking about stones within the bladder. Once the stones get into the bladder, usually they're not symptomatic, but on their way down to the bladder, they can be very symptomatic and usually they get stuck in the ureter and often in the distal ureter.

So here's an image of a ureter coming down to the bladder. This is a bladder, and this is a stone which is stuck in the distal ureter.

You can see the bright stone with the shadowing. They often get stuck right here at the UVJ ureterovesical junction, and this can be extremely painful until it's passed into the bladder.

But this is the gray scale image, and this is the colored Doppler image of that stone showing you that same twinkle artifact.

This is a transverse image of the bladder, showing you the gray scale of the stone right here.

When one's talking about stones, often one would like to know whether or not the bladder, the ureter is obstructed by that stone.

And so here we see a way of evaluating whether the ureter is obstructed. This is transverse images of bladder. This is the right UVJ giving you a ureteral jet, and here's the left UVJ giving you ureteral jet and visualization of these ureteral jets documents that urine is passing unobstructed through the UVJ into the bladder.

One should see a relative symmetric amount of flow, so at least two to three jets per minute from each side. Overall you should see something in the order of four to six jets per minute.

You can see slightly more if the person's over hydrated, or you can see slightly fewer if the person's dry.

But if you look at a bladder for a couple minutes and don't see any ureteral jets from one side or the other, that really suggests that that side may be obstructed.

Likewise, if you see a constant low level of dribbling as opposed to a nice jet coming out of one side, that would also suggest that that side is obstructed.

So looking into the bladder now, here's another patient. This patient actually is post prostate biopsy, and this is a transverse view and a sagittal view of the bladder.

And what we see is that there is a focal mass in the bladder, and this actually is a patient turned onto a side and that mass moves to the side.

And so what you see here, this is a big hematoma, which is present in the bladder post void.

So this is one type of bladder mass to traditional examples. This is one patient with diffuse thickening of the posterior aspect of the bladder.

And here's another patient with a very focal mass inside the bladder. And both of these are transitional cell carcinoma.

Transitional cell carcinoma generally presents as a focal mass or an irregularity.

This might be more difficult to recognize, but you should at least see that this is not diffuse thickening of the whole bladder wall, but it's just sort of this posterior and superior portion of the bladder here that appears thickened.

That's the tip off that this is a mass lesion and not just thickening associated with outlet obstruction.

Just another example, because this is such an important topic, this is a mass in the bladder. It's a focal mass here.

This mass actually happens to be centered beautifully to obstruct this left ureter. And here you see the image of the left ureter labeled to the bladder, and there's a mass here.

And so the other ureter was patent where this ureter was obstructed. And here is the mass here at the left UVJ, and here is the ureteral jet from the right UVJ.

So we can see the flow coming in on the right side, but there is no jet coming on the left side.

What you do see on the left side is there's doppler flow within the mass. So this is a hypervascular focal mass obstructing the left ureter, and that was a transitional cell carcinoma.

This is that same mass with a doppler flow in sagittal imaging.

Now, tumors of the bladder are most commonly primary tumors, but there are metastatic tumors that can come to the bladder.

Also, this is an unusual case of a patient with colon cancer where this frond like mass in the wall of the bladder is actually a metastatic disease to the bladder.

And you can see it here. Again, this is the top of the bladder here is a little bit irregular thickened, and there's a mass coming out of the bladder as well.

So this was metastatic cancer to the bladder.

Another patient with a bladder and sagittal view. You can see here a focal mass at the top of the bladder and when you turn and transverse, this is that same focal mass has a very interesting straight line going through it.

And it turns out that this is a site of a surgical suture. And so this is a focal surgical scar in the bladder, which presents now here with a mass, much less common reason for mass in the bladder.

So just to review what we've seen so far, bladder masses, we've seen stones causing mass. We've seen clots as a cause for a tumor in focal space occupying lesion in the bladder.

And then you have tumor and scar. And this is just another case here, you see the bladder, and here we see mass filling up much of the bladder.

This turns out to be advanced transitional cell carcinoma growing into the bladder.

So we're finished basically with the session that I wanted to talk to you about bladder.

Ultrasound Evaluation of the Scrotum

We're gonna move on now to discussing the scrotum and the structures within the scrotum, which is primarily discussion of the testicles.

Normal Testicular Anatomy

So the normal testicle is an ovoid shape structure. It's very well defined. It has a very smooth contour because it is surrounded by tunica.

The testicle itself has a thick tunica albuginea, and then it sits inside the tunica vaginalis, which surrounds it laterally and anteriorly.

You see the testicle and long axis is about three to five centimeters long, and this is the short axis of the testicle usually two to four centimeters.

And this line coming through here that corresponds to the mediastinum testis, which we'll talk about in just a second.

Very important, whenever you evaluate testicles, try to obtain an image where both the right and left testicle are seen at the same image, at the same depth, and you can compare the echogenicity of the two testicles.

This view goes right through the midline that separates testicles. There should be a symmetric appearance with homogeneous echogenicity.

To understand some of the ultrasonic anatomy of the testicle, it's important for us first to look at some of the anatomy that's inside that testicle.

And testicle really is an amazing structure. There are hundreds and hundreds of thousands of these seminiferous tubules that are coiled up inside a testicle.

Now they're all wrapped in this very thick tunica albuginea, and a tunica albuginea has these radiating septa, which separate the testes into somewhere between 250 and 400 separate lobules.

Each one of these lobules then contributes a duct that goes into what's we call the rete testis.

The rete testis is this network of ducts that come out of the seminiferous tubules and go through a portion of the testis, which is called the mediastinum testis.

These tubules then join to form somewhere between 10 and 15 efferent ductules, which exit the testes and join into the epididymis.

The epididymis, once again, is basically a big piece of spaghetti with multiple tubules that are coiled up and finally come through the epididymis and end at the tail of the epididymis in a single efferent duct, which becomes your ductus deferens or the vas deferens.

And so there's spermatogenesis going on in the testicle, and these spermatozoa come out through the rete testis. They go into the epididymis and finally through the epididymis into the vas deferens.

As I mentioned before, when you look at the testicle ultrasonographically, you will see that there is a straight line going through the center of the testis, and that's called the mediastinum testis.

And that linear appearance results from the convergence of these ducts into a sort of a plane in the testis.

And these efferent ductules then come out of that mediastinum testis and go in from the mediastinum testis into the epididymis.

Now, the epididymis has an anatomy which is generally described as a head, a body, and a tail.

So the head corresponds to the thickest part of the epididymis, which is usually not more than a centimeter, maximum, a centimeter and a half in diameter.

And as you go down the epididymis through the body and tail it progressively tapers.

The epididymis itself should be isoechoic to the testicle, or perhaps slightly more hypoechoic.

So here we see the head of the epididymis, the body of the epididymis and a sagittal view showing you the long axis with the tail of the epididymis down here, easily seen because there's a small amount of fluid or hydrocele within the scrotum.

Now, in addition to the epididymis sitting outside of testis, there's also two other structures. We should be aware of the appendix testis and the appendix epididymis.

These are both embryological remnants. They're found towards the upper pole of the testis, and they may look like just small little nodular excrescences coming off the testis.

These are normal. They can actually detach from the testis and may result in what we'll call later a scrotal pearl.

Benign Scrotal Findings

So a scrotal pearl is a calcification. It's seen within the layers of tunica vaginalis.

It's a little bit controversial as to whether this actually does represent a remnant of the appendix testis or the appendix epididymis that is torsed and is broken off, or whether it represents the result of an inflammatory process in the tunica.

In any event, scrotal pearls often associated with hydroceles and usually their mobile little calcified structures, the important thing to understand is that these are benign findings, and it's a leave me alone kind of finding.

So if you see a calcified mobile structure outside the testicle, that's something that's a benign structure. Don't worry about it.

We talked about in the anatomy, the testis, that the mediastinum testis contains this network of tubules. The rete testis can become dilated, and that's what you're seeing here, multiple dilated tubules.

They're parallel tubules mediastinum. It's important not to confuse these with a mass so often they're bilateral.

Here's the midline view through the left testicle, right testicle, dilated rete testis on the left, dilated rete testis on the right.

Do not mistake this for a mass. The way to tell 'em apart is the characteristic location. And if you use the proper angle, you can see these will elongate into tubules.

Here's another patient. This is the mediastinum testis, and we see the dilated rete testis here.

Dilated rete testis, by the way, are often associated with cysts within the epididymis.

Doppler Flow in the Normal Testis

Let's talk a little bit about doppler flow now with normal testis.

So the normal testis does have flow and it should be relatively symmetric flow in the two testes, and it should be a normal branching pattern within each testis where the branches run parallel to each other.

And so here you're seeing the normal branching pattern within a testis and the midline raphe view showing you relatively symmetric flow in two testes and very, very little flow is generally seen at the epididymis.

Fluid Collections in the Scrotum

Another thing that we need to consider is fluid within the scrotum. So often when there's a dilated scrotum, the question is, is there a mass there or is it fluid?

Often the reason is just a simple hydrocele, but you need to be careful because hydroceles can be associated with masses.

What is a hydrocele? Remember we talked about the fact that the testis was wrapped in the tunica vaginalis. The testis actually invaginates into the tunica, so that the tunica covers it laterally and anteriorly, but not posteriorly.

So there's tunica vaginalis coming down here, coming around the testis and coming back around the scrotum here within the layers of the tunica vaginalis where the hydrocele exists.

So there's fluid surrounding the testis on lateral aspects, superiorly inferiorly and anteriorly, but not posteriorly. The testis is attached to the scrotum posteriorly, and there should not be hydrocele there.

Congenital hydroceles may be related to incomplete closure of the processus vaginalis. So there's fluid coming down through the inguinal canal.

Usually these resolved by 18 months acquired hydroceles, and most commonly or idiopathic, but they can be associated with infections, infarctions, and trauma.

And obviously if there's a mass in testicle or mass in scrotum, you need to worry about that as a cause of hydrocele. And testicular torsion also can be associated with fluid as the hydrocele.

Evaluation of the Tender Testis: Epididymitis and Orchitis

So let's move a little bit now towards the evaluation of the tender testis. Scrotal pain is probably one of the most common complaints that people come in for where we do ultrasound of the testis, especially young men.

Epididymitis is perhaps the most common cause of acute scrotum. And here, what you use is the doppler flow to show you that this is a normal looking testis.

Here's the epididymis may be a little bit enlarged here. It may be tender when you put the ultrasound probe on the epididymis.

And when you use the Doppler evaluation, you can see that there's markedly increased doppler flow in epididymis.

So this is clearly diagnostic of epididymitis.

Remember, there should be very little to no flow normally in that epididymis orchitis is inflammation of the testis itself.

Sometimes on the gray scale you can actually see there's a heterogeneous pattern in a testicle. Testicle may be enlarged.

And once again, with doppler flow, we see markedly increased doppler flow in a testis.

If the symptoms are just on one side, if they're unilateral symptoms, you can use that median raphe view to show that there's more flow on the side of the tenderness.

Often the two come together that is epididymitis and orchitis, so we get epididymo-orchitis.

Here we have an example of a mildly heterogeneous testicle with a very heterogeneous and hypoechoic area inside this epididymis and increased doppler flow in the testis as well as in the epididymis tenderness on the side of the flow.

So this is diagnostic of epididymo-orchitis.

Another case of epididymo-orchitis. Increased flow adjacent to the testis is the epididymis here with increased flow and look at the planes of the tissue surrounding the testis.

The scrotum here is very thick walled. So we have epididymitis with inflammatory changes in the scrotum and a very small hydrocele here between the scrotal wall and the testis.

See that hydrocele is anterior to the testis, but does not appear back here behind the testis moving along.

If the epididymo-orchitis is not treated and it progresses, it could actually progress into an abscess.

Here we see scrotal abscess is low level echogenic material within the fluid here. So we have dirty fluid basically in ultrasound.

It can have septations in it that locates it off into different compartments. There can be residual material or debris sitting within these fluid collections.

This is very common for scrotal abscess. As you put the doppler on, you'll see increased flow around the periphery of the abscess because of the inflammation.

Here's a nice case of TB orchitis, short axis and long axis views of the testis. Notice the increased flow in the testis, the increased flow around the testis.

Here's increased flow again in the sagittal view. But this is really indistinguishable from any other orchitis where you happen to know this patient had TB orchitis or here's sort of the opposite situation where the scrotum actually has very thick walled, but the testis itself and the epididymis were both normal and had normal flow patterns.

But the scrotal wall was thickened, so this was fasciitis or an inflammation of the skin of the scrotum without involvement of epididymo-orchitis.

This is actually a very interesting case. This next patient was a known sarcoid patient who had scrotal involvement.

Scrotal involvement is actually relatively rare in sarcoid, but it's seen in up to 1% of patients. In general, the epididymal involvement is more common than the testicular involvement.

But whether it's in the epididymis, you're seeing hypoechoic areas or whether it's in the testicle itself, where you're seeing hypoechoic foci.

The hypoechoic foci are classic for scrotal sarcoidosis. They're not specific for it, but in the right setting you can make the diagnosis and they're these small hypo masses can calcify.

Of note. It's very difficult to distinguish them from tumors. So if you only have one of them, you may run into an issue.

But we're on the topic of testicular inflammation. We're talking about the acute testis. The acute scrotum.

Someone comes in with a painful scrotum. 80% of the time that's gonna be related to epididymitis or orchitis or epididymo-orchitis.

However, in a minority of cases, it'll be related to testicular torsion. And it's very important, it's critical to find this early in order to save a testicle.

If you can find this within 24 hours and operate on it, you have a good chance of salvaging that testicle. If you don't find it, then is a good chance a testicle will be lost to infarction.

Testicular Torsion

Why does this happen? It happens because of what's called a bell clapper deformity.

Remember we had said that the tunica vaginalis is tacked to the posterior wall of the scrotum, so it surrounds the scrotum anteriorly and laterally superiorly inferiorly, but not posteriorly.

In the bell clapper deformity, the tunica vaginalis surrounds the entire testis. And so there's nothing pinning the testis back to the scrotum.

The testis is able to move freely and it can actually twist on its stalk. And so you can end up with torsion of the testis and obstruction of the vascular flow in its spermatic cord.

There is intravascular torsion, which is the standard type proportion normally seen if it's gonna happen, it's often seen in the early teens.

And that we a common complaint for a young teenager coming in with testicular pain.

Extravaginal torsion is another type of torsion, which tends to occur in neonates.

What happens when with the torsion? Well, the problem is the testicle is twisting on the spermatic cord.

And so instead of having good flow throughout the testis here, what you're seeing is that some of the vascular supply to the testis has been obstructed.

And so you've ended up with an infarct to this portion of the testis. This portion of the testis no longer has flow. It's no longer alive.

There's a small amount of flow here in this part of the testis. And look what's happened. The infarcted portion of the testis has a very different echo texture because the testicular material here has become necrotic as compared to the normal residual testis here where there was some flow.

So ultrasound is a great way of distinguishing now between epididymo-orchitis, which we've seen in previous slides had increased flow and between torsion, which has decreased flow.

But there are multiple findings of torsion on gray scale. You can see a heterogeneous testis could be enlarged, late on, it could be atrophic.

But the early findings of a heterogeneous enlarged testis, these are overlapping now between torsion and between inflammation orchitis.

However, doppler can distinguish torsion from epididymitis because on the tender side, epididymo-orchitis will have increased flow on the side of tenderness, whereas torsion will have decreased flow on the side of tenderness.

And early on you may first obstruct the venous flow and if the torsion is twisted a little further, you may obstruct the arterial flow as well.

Post-Traumatic Testicular Findings

Moving on with the post-traumatic findings that one can see in a testicle. So long view short axis, you have a testicle post-trauma.

We see here that the surface the testicle is still smooth 'cause there's an intact tunica albuginea, but there is a unusual sort of mass occupying lesion here.

And this is a contusion of the testis in the appropriate clinical setting. Young boy just played football, got hit in the testis.

This is obviously gonna be a contusion. You can see here this is the doppler flow with color doppler with power doppler.

The normal testis has flow. The contused area does not demonstrate the presence of flow.

Now, the previous example, the testicle itself was intact and you saw the smooth border. This is another post-traumatic example, but here we see that instead of a smooth testicular margin, there is a lumpy, bumpy kind of margin of stuff.

Looks like spaghetti coming out of the testicle. And this is testicular rupture.

So here the tunica albuginea is no longer intact. There's a heterogeneous testicle. The testicular contents are protruding into a hydrocele, which is now surrounding testicle.

It can be difficult to distinguish these contents from hemorrhage in the scrotum.

Doppler identifies normal testicular tissue. So we use a doppler here just to show that there is flow in a testicular tissue.

If you do surgery immediately, the salvage rate can still be relatively high.

Benign Testicular Lesions

Next, we're just gonna move on to some benign findings in the testicle, which are important to recognize because they are leave me alone findings.

This is a transverse image of a testicle. On a margin of the testicle we see a small cyst. It's anechoic, it has posterior acoustic transmission.

This is a tunica albuginea cyst. Often they are multiple, usually they're small and they can be seen around the periphery the testicle, they have absolutely no significance.

Peritubular cysts are also possible within the testis, they can be near the mediastinum testis, they're often associated with epididymal cysts and they can be up to two centimeters in size.

In addition to cysts. One can see calcifications along tunica. If it moves around, you would call it a scrotal pearl.

If it doesn't, it may just be a calcification of the tunica related to previous inflammation. In any event, the patient's not symptomatic. It's a leave me alone lesion.

Important to see it and recognize it as a benign post-inflammatory process.

Now, when we talked before about dilatation of the rete testis, I mentioned that that could be associated with epididymal cysts or spermatocele.

And here we see some examples. This is the testis here and this is the epididymis. And in the epididymis there is a cyst.

And here's another example, a cyst in the epididymis. And yet another cyst in the epididymis.

Two types of cysts, epididymal cyst versus spermatocele. Both may be related to prior trauma or epididymitis.

However, the cyst is gonna have just clear fluid in it. Whereas the spermatocele has spermatozoa in it and may have thick milky fluid.

Usually we don't know the difference because we don't really care. They're both benign findings, and no one's gonna aspirate it.

But if you were to aspirate, you'd be able to easily tell a epididymal cyst from a spermatocele.

Spermatoceles are often seen incidentally in older men, and often they are multiple.

Here's an example of what I was talking about. Here is a large cyst associated with the epididymis, and here is a dilated rete testis, dilated rete testis cysts associated with the epididymis, and perhaps some cysts actually intratesticular as well.

So these are all sort of associated with each other and common to find them together again.

Here is your spermatocele spermatocele, another view. And this is the same patient here as the mediastinum testis and is a slightly dilated rete testis, which is sort of makes the mediastinum thicker and more obvious.

Varicocele

Now the dilated rete testis and the spermatoceles need to be distinguished from the other dilated structure, which is commonly seen around the testicle. And that is varicocele.

Varicoceles basically are dilated veins. There's a pampiniform plexus of veins around a spermatic cord and surrounding the epididymis.

They generally should be veins that are less than two millimeters in size. When they dilate up to be greater than two or three millimeters, they're called varicoceles.

They may be associated with incompetent valves, which allow the blood to come back down. They're more common on the left side than the right side.

This may be because of the nutcracker effect of the SMA and the left renal vein, and the fact that the left gonadal vein empties into the left renal vein.

But in any event, the major significance of these is that they're thought to be associated with male infertility.

And the reasoning is because the presence of a varicocele heats up the scrotum, there's more blood flow in the scrotum. There's more body heat in the scrotum, and spermatogenesis requires a lower temperature to be successful.

And so with the higher temperature associated with varicoceles, you may have a problem with spermatogenesis.

Another issue is that varicoceles, when they become engorged, can actually become tender.

And so a patient may present where there's pain and standing up, which is relieved by laying back down. And the pain gets worse with standing and is clearly associated with some dilatation of some venous structures in the scrotum.

So varicoceles may be treated for either of those two reasons.

Example of varicocele. Here's dilated tubular structure in the scrotum, and this is the doppler flow with Valsalva.

Show you that you can fill it with color flow.

Now, varicoceles in general are outside the testicle. They're in the pampiniform plexus, which is spermatic cord.

However, there also are intratesticular varicoceles. And here we see an example. This is a testis.

And the Doppler shows you there's a dilated tubular structure within the testis. And that tubular structure is a varicocele.

And you know it's a varicocele because of the flow, but it's also often associated with extratesticular varicoceles.

And when you see the tubular structures inside and outside, they're gonna be varicoceles inside and outside.

As opposed to if you didn't see the varicocele outside, you might have thought that was gonna be dilated rete testis.

If you did not have the doppler flow moving along to some other congenital issues that can happen with the testis.

Congenital Testicular Abnormalities

Testes are supposed to be in the scrotum. Most babies are born with the testis in the scrotum, but about three and a half percent of newborns have an undescended testicle at birth.

So that is to say that when they're born, the testicle is somewhere up in the inguinal canal and it's not present with scrotum.

Most of these will descend on their own so that only about 1% persist at a year. But the ones that persist need to be treated, they need to bring that testicle down to the inguinal canal because if we leave the testicle up high, it's gonna be associated with infertility and more.

Importantly there is an increased risk of testicular cancer with long-term non-descended testicle. Often that's a seminoma is the type of cancer you might find.

Another topic talking about painful groin. Sometimes the doctor has trouble making the diagnosis on clinical exam.

I feel a mass there. I'm not sure if it's a hernia or not. I'm not sure if I really feel something coming down.

Well, ultrasound is a great extension of the physical examination with ultrasound. You can look at the groin in real time.

You can ask the patient to Valsalva or cough watch for herniation of a structure down into the into the groin and through the inguinal ligaments, you can actually characterize the hernia tissue to see if it's fat or see if it's a liver bowel.

You always do this examination with the patient standing up 'cause that's the orientation. We're too much more likely to see a hernia.

So here we see a small amount of fluid and we see this is mesenteric fat herniating down. Once again, this is the piece of omentum herniating down into the inguinal ligaments.

Microlithiasis

Microlithiasis is a very interesting topic. It's something that's relatively common, and it's also relatively controversial.

So here we see an ultrasound evaluation of a testis. This testicle has one little bright spot in it, but here's another testis.

And this testis has multiple, multiple bright spots throughout this testis. These tiny little echogenic areas are called microliths or small stones.

There may be an association of testicular cancer, specifically seminoma with microlithiasis. It's a rather controversial topic.

The risk may increase with a larger number of calcifications. In general, when there's more than five of these little calcifications, we call that microlithiasis, classical microlithiasis, and we usually tend to ask for a follow-up ultrasound.

Although the literature does remain controversial on this, it is unclear if these people really have a increased risk of testicular cancer.

If they don't, then the reason that we find all the cancers in these studies that report them is probably 'cause of a population bias in the people who are evaluated with ultrasound, who tend to have both masses in the testicle.

And we find the incidental microlithiasis.

Doppler Flow in Testicular Masses

Doppler flow. The question now is, does doppler flow help you in diagnosing a testicular mass?

Well, any mass that's over one and a half centimeters in size tends to have flow. So the doppler, the flow may actually help you see the borders of the mass where the normal vessels are sort of splayed around the mass.

But the presence or absence of flow within a tumor in the testis does not help you distinguish what type of tumor that is.

More important than doppler flow is the distinction of whether the mass you're seeing is intratesticular or extratesticular.

Most intratesticular lesions are malignant. Only a minority of extratesticular lesions are malignant.

Most lesions are extratesticular come from the spermatic cord. We're looking at lipomas, and lipomas the spermatic cord are often also associated with hernias.

Other types of mesodermal tumors or fibromas. And the most common malignancy extratesticular is the sarcoma.

This obviously is an intratesticular lesion, and this is a heavily calcified lesion. We'll talk about the characterization of intratesticular masses in just a moment.

Intratesticular Masses

So the intratesticular masses are broken up into different types of masses. The most common is the germ cell tumor line.

And here we see a testicle where there is a relatively well-defined hypoechoic lesion. The doppler shows you this well-defined rounded mass, which is vascular hypervascular.

This turns out to be a seminoma. 40% of germ cell tumors are seminoma.

So it's the most common germ cell tumor. Usually well marginated in hypoechoic is usually not cystic and not calcified.

As opposed to the embryonal cell lesions, which are slightly less common, there are more aggressive tumor and therefore they're not so well defined.

They're very inhomogeneous and they often invade out of the testicle. They will also often have cystic areas and calcifications, which would not be classical for seminomas, that teratomas often have a mixed echo texture.

They're often inhomogeneous. They may have cysts and they're often calcified.

The image that I showed you in the previous slide of the calcified lesion in the testicle, that was a teratoma.

Problem is you can also have teratocarcinomas where the teratoma is associated with a malignancy as well.

And finally, a much less common tumor of the germ cell line is the choriocarcinoma, which is a hypoechoic can aggressive tumor

As opposed to germ cell tumors, which were far and away the most common tumors in the testicle. Stromal tumors are much less common.

They count for only 5% of all testicular tumors. This happens to be a stromal tumor, but there's no way you could distinguish this from a seminoma.

There are multiple cell types of stromal tumors there. Leydig cell, the most common of the Leydig cell, 15% of them are symptomatic because of estrogen production.

The other stromal tumors include a theca cell, the granulosa cell, the lute cell. They sit totally on the fibroblasts, so usually they're hypoechoic when they're small.

Just as seen here. The large tumors can be more complex in appearance, but it's in your differential diagnosis.

You're not gonna be able in general to distinguish these from seminoma.

Extratesticular Masses

Now, we said that most of the extratesticular tumors are benign. Epididymal tumors are 10 times less frequent than testicular tumors.

The most common epididymal tumor is the benign adenomatoid tumor. And it is actually counts for 30% of all extratesticular masses, most commonly seen at the tail of the epididymis.

You treat it with local excision because it is possible there could be malignancy there. But they tend, they are benign so and so once you treat it, that's the complete treatment for the patient.

Other epi tumors include the leiomyoma, which is a benign tumor of smooth muscle and a papillary cystadenoma.

Now an interesting tumor that should be mentioned when we discuss the testicle is lymphoma.

And the reason is because the testicle tends to be a sanctuary for lymphoma after chemotherapy. Chemotherapy often does not penetrate into the testis as well as it does to other areas.

So you may treat lymphoma in the rest of the body, but still have a small hypoechoic area at the bottom of its testis.

Looking at it in transverse, this is a hypoechoic lesion. It turns out to be recurrent lymphoma status post chemotherapy.

And finally, I told you that the intratesticular stuff tends to be malignant. The extratesticular stuff tends to be benign, but not all of it.

Here is a scrotal mesothelioma. And so remember there's a lining here. There's a mesothelial lining, the tunica vaginalis, and so tumors of that lining can mesotheliomas.

And here we see focal mass in the scrotum with a hydrocele and with flow in that mass. And this was mesothelioma.

Okay, so we finished sort of our rapid discussion through the scrotum. Now we've discussed testicular masses and extratesticular masses.

We've discussed the acute scrotum. We've talked about the distinction between epididymitis and epididymo-orchitis on the one hand, and between testicular torsion on the other hand.

These are very important topics. And these are the two most important reasons. You'll be asked to look at the scrotum evaluation of tumor and evaluation of the acute scrotum.

Ultrasound Evaluation of the Prostate

The last part of our lecture, we'll move on to the prostate And we'll start with some gross anatomy of the prostate and then we'll look more in more detail.

Gross Anatomy of the Prostate

So this is a prostatectomy specimen and what you're seeing here is this is the base of the prostate at the base of the prostate.

The seminal vesicles come in and the vasa deferentia come in, and then the prostate tapers towards this apex and urethra comes through the prostate.

It enters at the base when the bladder sits here at the base enters here and it comes out the apex of the prostate.

So the prostate is under the urinary bladder. The seminal vesicles project posteriorly and superiorly from the base of the prostate.

And the prostate apex is just behind the symphysis pubis and the urethra comes through.

Ultrasound Approach to the Prostate

That ultrasound of the prostate is preferentially done with a trans rectal approach. That's the way of getting closest to the prostate.

It gives you the best images of the prostate. The probe uses anywhere from six to 10 megahertz.

This is a trans rectal image. The probe is in the rectum. This is the rectal wall here and the perirectal fat here.

And here we see the prostate sitting in front of the rectum. The probe is placed directly on the peripheral zone of the prostate.

The apex of the prostate often is not as well visualized. And the central zone here, fibromuscular stroma, which is up here, is often obscured by a process called benign prostatic hypertrophy or BPH, which tends to be in the middle of the prostate.

Objectives of Prostate Ultrasound

So what are the objectives of doing prostate ultrasound? Well, there really are two situations where you would do prostate ultrasound.

One is for benign disease, the other is for malignancy. Benign disease means you're gonna looking for inflammatory processes in the prostate or evaluating infertility.

And malignancy is usually being done because someone felt the mass or there's an elevated PSA. And so you're looking at the prostate to see where is the malignancy.

Can I direct a biopsy into the prostate?

When We do ultrasound of the prostate, we have several objectives. First off, we're gonna document the size of the gland and I'll show you how to measure the prostate and how to calculate its volume.

We're going to look at the overall echo texture. We're gonna look for hypoechoic areas, which can be signs either of inflammatory processes or of cancer.

We're gonna look for focal lesions as opposed to diffuse architecture abnormalities.

We're gonna look for the seminal vesicles to make sure they're both present, that they're symmetric, that they're not obstructed.

We're gonna look at the vasa deferentia to make sure they're present. And the evaluation of the seminal vesicles and vasa deferentia and the ejaculatory ducts is particularly important when we're dealing with infertility workup.

And finally, we're gonna look at the periprostatic fat down here because that fat plane is often invaded when there's a prostate cancer that's aggressive and come outside the prostate.

Now in this patient we actually see two very nice little echogenic foci here on either side of midline. This is some secretions inside the ejaculatory ducts of a patient who's being evaluated for infertility and has his ejaculatory ducts plugged up with these concretions.

Prostate Volume Calculation

Okay, so prostate volume. So you're gonna get two images. The prostate, this is the sagittal image on the transrectal view bladders up here, apex of the prostate down here we see the urethra coming through the prostate.

That's what the arrows show you. You're gonna measure a craniocaudal dimension. You're gonna measure an anterior to posterior dimension.

Those are two dimensions of the prostate. Then you're gonna do the transverse image of the prostate, get the maximum transverse dimension.

Take those three numbers, multiply them by pi over six. As we saw before for doing bladder volume. We use the same formula for the prostate ellipsoid to get the prostate volume.

The weight of the prostate and grams is very similar to the volume of the prostate and ml because the specific gravity of the prostate is basically one gram per cc.

The normal prostate should be less than 25 ccs or 25 grams in size.

Normal Prostatic Echo Texture

The normal prostatic echo texture shows you an echogenic outer gland. So the outer part of the gland, which is against your probe here posteriorly and comes around the prostate laterally, tends to be more echogenic, whereas the inner part of the prostate tends to be more hypoechoic.

And frequently we're examining patients who have benign prostatic hyperplasia or BPH and the inner part of their gland is often very heterogeneous.

So here we have some examples of some abnormal outer glands. So here is a very hypoechoic appearance to the outer gland.

A very irregular margin to the prostate. In general, if I were to teach you how to look at a prostate ultrasound, I would tell you this is almost diagnostic of prostate cancer.

Of course, this happens to be prostatitis in this case, but just to show you how these things can mimic each other.

The hypoechoic appearance with the irregular contour is almost always associated with prostate cancer.

This is a hypoechoic appearance throughout the entire posterior aspect of prostate. And this turns out to be an infiltrating prostate cancer.

Notice that in this case, the peripheral zone tends to less echogenic or darker as compared to the inner gland, which is more echogenic.

And that's because of the abnormal echo texture in the outer gland.

When we image the prostate, we use the image in transverse and sagittal planes. The transverse plane is very nice for comparing one side to the other.

So here this is a normal echo texture on the right side, this is an abnormal hypoechoic echo texture on the left side, the difference in echo texture is your tip off here, that this is a cancer and this is a cancer.

And if you look carefully, there's a slight irregularity of the contour here as well. Invasion through the perirectal fat from the prostate into the rectum.

But the transverse image allows you to make that comparison of side to side. It allows you to look at the neurovascular bundle here and here to check them for symmetry.

You can see the seminal vesicles and check those for symmetry. And we often use the transverse imaging plane as the plane preferred for biopsy because you can actually tell how far out you are laterally.

And it turns out that prostate biopsy should probably be done in a very lateral orientation.

Here's the sagittal image. We always use both a transverse and a sagittal image. We see hypoechoic mass in transverse image.

We'll go to the sagittal image to confirm that it's really present. The sagittal image is also better for evaluating the base and the apex of the prostate.

'cause you can see when you're at the base and where the apex ends, the ejaculatory ducts come from the SV into the urethra and they can be imaged in a sagittal view.

Seminal vesicles are often seen more throughout their length on a sagittal image. And sagittal views are very commonly, especially out in the community.

Sagittal images are probably the most common method used to guide prostate biopsy.

So here's back a transverse image again. Here we see the neurovascular bundles. Two, the big venous structures and the neurovascular bundle.

The structures are not so well seen on this side because they're shadowed out. But there's nice normal echogenic peripheral zone, slightly heterogeneous inner gland related to BPH and neurovascular bundle.

Prostatic Urethra and Related Structures

Now the prostatic urethra can sometimes be very difficult to image in our patients because they often have BPH and obscures the urethra.

The example I'm showing you here is a patient who has a Foley catheter. The Foley makes the urethra extremely obvious.

It also tends to straighten out the urethra a little bit. Urethra tends to come down to the level of the verumontanum.

The verumontanum is where the ejaculatory ducts insert into the prostatic urethra. And there's what we call a pre prostatic urethra, which runs from the bladder neck down to the verumontanum.

And then the post prostatic urethra comes down to the apex of the prostate. And there's usually a 35 degree turn between those two portions of the urethra.

In this case, you can actually see the urethra very well 'cause it's distended by the Foley catheter.

This patient does not have a Foley catheter, but you can still see the urethra. It's marked by some corpora amylacea or some bright echogenic markers here, which are probably within periurethral glands.

This urethra is surrounded by a hypoechoic structure here at the top of the prostate.

So remember, the urethra comes down from the neck of the bladder here. That's the base of the prostate toward the verumontanum, and then from the veru toward the apex.

Now that part of the urethra here, the pre prostatic urethra from the neck of the bladder down to the veru, is surrounded by muscle. That's the internal sphincter.

And sometimes that muscle can look hypoechoic. It's very important to know that anatomy, because you do not wanna mistake this for a mass around the urethra.

If you were to mistake this for mass around urethra, you would probably end up biopsying this area and perhaps end up biopsying the urethra, which is in general not a recommended procedure, because it results in a lot of hematuria.

Remember, the internal sphincter comes off the bladder. It's continuous with the bladder and it ends at the level of the veru.

Seminal Vesicles and Vasa Deferentia

When we look at the prostate, we always look at the seminal vesicles. Seminal vesicles are just above the prostate.

They angle posteriorly from the prostate and they have to be symmetric. I mean, here's the size, the average size for seminal vesicle, but we don't look that much at the average size.

But we look at the symmetry. This here is the vas deferens coming in medially here and here. And this part here is SVN.

Each side, the seminal vesicles themselves taper as you get towards the apex of the prostate. So here we see vesicle tapering here.

This is the arrow pointing to the vasa deferentia arrow pointing to the this is the ampullary portion of the vasa deferentia and a seminal vesicle coming here.

Now the vasa deferentia is most clearly seen here 'cause this is the most distended part of the vas, it's called the ampullary portion.

But if you turn on this, you can actually follow this vas deferens out and sometimes you can follow it out laterally to where the ureter crosses under the vas deferens.

Ductal ectasia is a process where there is dilatation of the ducts within the seminal vesicle.

Here's a patient with bilateral ductal ectasia. Ductal ectasia is often associated with BPH.

So the benign prostatic hyperplasia results in enlargement to the prostate and a relative blockage to the egress of the seminal fluid from the seminal vesicle and therefore duct ectasia bilaterally.

If ductal ectasia is unilateral. One should be looking for a reason to see if there's a mass or some kind of calculus obstructing the seminal vesicle on that side.

Duct ectasia is probably the most common abnormality that one we'll see the seminal vesicle.

This is probably the least common abnormality one we'll see, which is seminal vesicle cyst. An isolated cyst is seminal vesicle, extremely rare.

Most of the time when you think of a seminal vesicle cyst, if you look harder, you'll probably see that it's hooks up with the ductal structures and it's really ductal ectasia.

But isolated seminal vesicle cysts are associated with congenital anomalies of the seminal vesicle and of the kidney.

The seminal vesicle happens to be a mullerian structure. And so this will be associated with other types of mullerian abnormalities.

Talking about mullerian structures, the mullerian duct comes down into the middle of the prostate at the base of the prostate, and cysts.

There are midline cysts that are actually in the prostate or exophytic above the prostate. May be remnants of this embryologic mullerian duct.

And they're called mullerian duct cysts. The significance really is to recognize this is a benign process.

And unless the mullerian duct is causing symptoms, if it's infected or if it's obstructing the ejaculatory ducts, there's no reason to treat it, just let it be.

The other cyst that can be seen in the prostate is the ejaculatory duct cyst. And in general, the ejaculatory duct cyst.

Here is the just off midline. You can see the dilated seminal vesicle. There's actually ductal ectasia, the seminal vesicle.

There's a little calculus here in ejaculatory duct, and there's a cyst in ejaculatory duct here.

Ejaculatory duct cysts are often associated with dilatation of the ejaculatory ducts, and they may be associated with infertility.

So it's a chicken and egg question here is as to whether the ejaculatory duct cyst is the cause of the obstruction or the obstruction somehow results in an ejaculatory duct cyst.

Zone Anatomy of the Prostate

Before we go any further talking about the ejaculatory ducts and the relationships of the different parts of the prostate, it's important to understand the zone anatomy.

And the zone anatomy here is basically a way of breaking up the prostate into four different zones, and categorizing where the lesions are.

So the inner gland, which we talked about before when we talked about benign prostatic hyperplasia, consists of the tissue, which is right around the urethra, which is the periurethral tissue, and a very small amount of tissue, which is present only above the level of the veru, which is the transition zone.

So in a normal teenager, probably no more than 5% of the volume of the prostate consists of this periurethral tissue and its transition zone material.

The outer gland is a much, much more significant part, more substantial part of the prostatic volume. And that consists of the central zone, which is present from the base of the prostate up to the veru and the peripheral zone.

Each one of these zones has glands that open into the urethra. So there are prostatic secretions that end up in the urethra from each one of these zones.

So the four glandular zones are the periurethral zone, the transition zone, the central zone and the peripheral zone.

These two, the periurethral transition zones are part of the inner gland. The central peripheral zones are part of the outer gland.

On ultrasound, we cannot distinguish central zones from peripheral zone. They are both in the outer gland.

It's very important to understand that nomenclature. So if someone says to you central zone, that does not mean that they're talking about the inner part of the prostate.

That may very well be at the base of the prostate in the outer part of the prostate. Okay, but pathologically, that's defined as central zone tissue.

And it all empties through ducts just above the level of veru.

Finally, there's fibromuscular stroma, which is present anteriorly in the prostate. That is not glandular tissue.

On ultrasound, we can differentiate the inner gland from the outer gland. The distinction usually is that of a different echogenicity.

The inner gland being more hypoechoic, the outer gland being more echogenic.

Here again, inner gland being more hypoechoic, outer gland being more echogenic.

The process of benign prostatic hyperplasia is almost exclusively in the inner gland, usually involves mostly transition zone.

There's, remember the inner gland was supposed to be 5% of the prostate volume, but look at this, this is much more than 5%.

In fact, this is more than 50% of the prostate volume. And this is the prostate of benign prostatic hyperplasia, enlargement of the inner gland, which is associated with aging in the normal adult in our country.

So this is outer gland here, which could be central zone and peripheral zone. And this is inner gland, which is mostly transition zone hyperplasia.

So if there's any one thing I need you to take home from this lecture is that there's glandular anatomy of the prostate dividing it into the inside periurethral tissue and transition zone.

The outer gland central zone, a peripheral zone. This is commonly affected by BPH.

A small minority of cancers are seen in the inner gland. Our diagnosis of cancer predominantly involves the outer gland, central zone, and peripheral zone.

And prostatitis also predominantly involves the outer gland of the prostate.

Benign Prostatic Hyperplasia (BPH)

So let's talk about some of these entities. Now, clinical BPH is a clinical entity. You see poor bladder emptying urinary retention, so increased post void residual.

You can see detrusor instability. So the person is not able to hold and release urine properly.

It can lead to urinary tract infections because their stasis of urine never empties out of the bladder.

BPH can be responsible for hematuria and can also be responsible ultimately for obstruction leading to renal insufficiency.

The diagnosis is made by the digital rectal exam and ultrasound, and by the clinical symptoms.

Now, we can often find enlargement of the prostate by ultrasound, which will give us the ultrasonic diagnosis of BPH, but that may or may not be associated with clinical symptoms.

So here is an example of ultrasonic BPH. Here's the prostate, here's the inner gland, which is so large.

It's extending all the way up into the bladder. And this is a type of BPH, which is commonly called median lobe hypertrophy.

The older anatomic descriptions of the prostate had a lobar anatomy. The median lobe was that part that was in the middle that bulged up into the bladder neck.

We still retain that nomenclature for this type of BPH, but we do not believe that there really is a true median lobe as opposed to a lateral lobe.

That's an old nomenclature, which is no longer used in the prostate literature.

Prostatitis

Now, prostatitis can be acute or chronic. Only about 5% of prostatitis is bacterial.

Most of prostatitis is either non bacterial, which means you can isolate something like chlamydia from it or prostatic pain, which is prostatic pain or symptoms not related to any identifiable source of infection.

So here's a patient with prostatitis. You can see a heterogeneous outer gland. You can see increased flow in some areas, which may be markers of prostatitis prostatitis progresses.

One can actually have abscesses form within the prostate. And here we see multiple anechoic areas in this prostate.

Some of them are surrounded by markedly increased blood flow as seen in the Doppler. And so that's classic for prostatitis.

Okay, so we talked just for a couple minutes on prostatitis. Perhaps the more important or more common reason for doing prostate ultrasound is prostate cancer.

And here it's usually being done because there was an abnormal rectal examination or because there was some type of abnormality on a PSA blood test.

Prostate Cancer Imaging

What does prostate cancer look like? Well, classically prostate cancer and gray scale is hypoechoic.

There you see the hypoechogenicity, it bulges the contour of the prostate. So there's a contour abnormality and echo texture abnormality.

I'll tell you that less than 50% of prostate cancers are obvious like this. But this is the classic description.

And often the color doppler will show increased flow within the prostate cancer, which is what you're seeing here.

The normal peripheral zone has very little doppler flow, but with cancer as greater the cancer goes up, especially we see more and more doppler flow.

So great on gray scale prostate cancer is usually isoechoic to hypoechoic. This is an infiltrating prostate cancer in the outer gland.

Rarely is it echogenic. Often you can see a contour bulge, especially more advanced prostate cancer.

But how the cancer looks depends on the size of the lesion, depends on the degree of cellular differentiation And on the fibrotic reaction that you might see within the prostate to the cancer.

Now this cancer here happens to be very apparent. It's hypoechoic. It's a high grade tumor Gleason nine and 10, and that's why it's so obvious there's a slight irregularity of the prostate contour.

There's a narrowing of the periprostatic fat planes. These are all signs of an echo texture abnormality and a abnormality, which is bulging into the periprostatic fat.

Now, in addition to the gray scale abnormalities, people have done a lot of work using doppler of the prostate to try to identify prostate cancer.

Doppler tends to show increased flow to the areas of prostate cancer. These have been classified either as focal increased flow or increased flow surrounding the cancer or diffusely increased flow.

The bottom line is any kind of increased flow is a marker for possible prostate cancer. And looking for increased periprostatic flow will increase your sensitivity for detection of prostate cancer.

However, as I will show you later, it's not a very specific marker.

Prognostically, if you have a cancer and it has doppler flow, the presence of increased doppler flow within a cancer is a poor prognostic sign for that cancer.

Here is a patient who actually was a friend of mine who had been biopsied several times previously. They could not find his cancer.

There was no gray scale abnormality here, but there was increased doppler flow in the midline here, posteriorly in the peripheral.

So now urethra sits right up here. Increased flow is right over here. So what we did was, and this is power doppler showing the increased flow in the midline.

This is color doppler showing increased flow in the midline. What we did was we came from the side and biopsied through this area of increased flow, we're able to show Gleason seven cancer.

So let's just look at some more examples of prostate cancer. Here we have transverse images through the prostate going from the base down to the apex.

This actually is a sagittal image of the prostate, but this is base mid gland to apex and there's a hypoechoic area with a big bulge of the prostate gland and with increased doppler flow all along the left side of this gland.

And this is a blow up of it. Massive amount of hypoechoic material along the whole left side of this prostate.

Increased periprostatic flow. So this is a diffuse cancer, which is spread along left side of the prostate.

This is the sagittal image. This is the seminal vesicle at the base of the prostate. There's the apex large hypoechoic lesion extending from base to apex.

We said there were different Doppler patterns one could see in prostate cancer. Here is a prostate cancer.

There is surrounding flow around this cancer. It's a hypoechoic lesion. It's associated with a slight bulge of the contour and it's associated with doppler flow around the cancer.

Now interestingly, here's another hypoechoic lesion and has increased flow around this lesion, but this is prostatitis.

So notice how these findings are not specific.

Advanced Techniques: Elastography

We talk about evaluation of the prostate. It wouldn't be fair to go through this without also talking about some of the more advanced techniques that are being used to evaluate the prostate.

One of these techniques is elastography. Another one of them is contrast imaging. And we'll talk about both of these.

Now, elastography is basically a map of tissue stiffness. And basically the changes in the ultrasound RF speckle pattern with external pressure can be used to map out the elasticity of different parts of the prostate.

And that's called creates a picture, which are called the elastogram.

Most of the elastography systems that are out there right now use that RF speckle pattern and the change that speckle pattern with external pressure to make the elastogram.

There are some newer systems out there now, which we'll use what we call an ultrasound shear wave to create the elastography picture.

We're not gonna go into the difference between those now, only to say that the newer systems with the shear wave may actually provide a better way of getting a uniform elastography picture throughout the prostate.

Here's an example. This is the gray scale image showing you a hypoechoic nodule in the right apex of the prostate.

This turns out to be a Gleason seven tumor, and this is the elastogram in that area. And you can see the dark blue here corresponds to the hard nodule.

And the darker color here corresponds to something that is less elasticity on your elastogram.

Yet another example here is a focal hypoechoic nodule. This is the Gleason nine and 10, very high grade prostate cancer.

This is the color Doppler showing you markedly increased flow, not only in the lesion but adjacent to the lesion, probably related to spread of prostate cancer up into prostate here.

But here's the elastogram, and you can see that this lesion is harder than the adjacent normal prostate.

Okay? So elastography is one method that has been used, has been described for looking for prostate cancer.

That's still under investigation and we're still waiting the final analysis as to whether we can improve our distinction between cancers and normal tissue with elastography.

Advanced Techniques: Contrast-Enhanced Ultrasound

Another technique, which is perhaps further down the road is the use of ultrasound contrast agents.

Now, ultrasound contrast agents are a way of looking at the vascularity, and basically what they do is they enhance the acoustic reflectivity of whatever tissue they're in.

And in the prostate, they're in the blood vessels. So they're gonna enhance the reflectivity on the visibility of the small vessels.

There's a non-linear frequency response, so that even though you are transmitting at a certain fundamental frequency F zero and you're receiving that same frequency F zero,

when the transmitted ultrasound hits the contrast agent, it also comes back in harmonics of that original frequency.

So the fundamental frequency is F zero, the harmonics are two times three times four times F zero, and you can receive those in distinguish that those have come from contrast material.

So there are multiple different ways of visualizing ultrasound contrast agents. I'll show you a little bit some of the color and power doppler methods, but we actually prefer to use some of the gray scale methods and the gray scale methods.

Provide use harmonic imaging as we just talked about before. So you can distinguish what's coming from the contrast by the frequency of the sound that's returning.

And there are different ways of doing that harmonic imaging. But basically, once we have the gray scale image, we actually see the areas of increased vascularity as brighter because the contrast agent tends to cause increased reflectivity.

This image was created with something called intermittent imaging with a very low mechanical index.

So we image the prostate only perhaps once every two, three, or even five seconds. So we allow the contrast agent to get well into the vascular bed before we image it.

And the reason we do that is because the imaging itself tends to destroy some of the contrast agent as you're doing the imaging.

So in order to maximize your ability to see the agent distally within the capillary bed, we turn the ultrasound off for a couple seconds and then we turn it on intermittently and we also lower the mechanical index as much as possible so that we can still get a good image, but we try to destroy as few bubbles as possible.

Turns out that as you do intermittent imaging, the longer you delay between the scans, the more you allow in contrast to get into smaller vessels.

So you somewhat of a size selective type of vascular imaging of the distal circulation.

But here is an example of the distinction that one might see between continuous imaging of contrast, where you're only seeing it in large vessels and you're actually seeing nothing in the prostate

to intermittent imaging of the same patient, where with a three or four second interscan delay, you're now seeing an area which is very brightly enhancing.

And this turns out to be a Gleason nine lesion in the left base of the prostate.

Another example, continuous imaging with contrast agent shows you very little in real time. You could actually see the agent going through larger vessels, but the intermittent imaging shows you a clear area of enhancement associated with a Gleason six lesion in the left base of the prostate.

So if you wanna see the neovascularity, we actually have to use a shorter interscan delay to actually see the vessels themselves.

We use a longer interscan delay if we wanna actually see the enhancement pattern in the vascular volume. And we try to use a relatively low MI to reduce the contrast destruction.

And here's a nice example. This is the prostate. Here's your area of echogenicity.

This is enhancement of a Gleason seven tumor.

Now remember we said you could have enhancement on gray scale and here you see it. This is the baseline image where the cancer is not apparent.

Here's the bright contrast enhancement on harmonic gray scale imaging.

But if you look at the color and power images, baseline color and power didn't show too much, but post contrast, there's increased color flow in the prostate and increased power doppler flow in the prostate.

And that's very clearly seen after contrast administration.

So color and power are other ways of looking at contrast enhancement. The issue with color and power is there's blooming artifact, so it's very difficult to localize things as well with color as it is with gray scale At the present.

Summary of Prostate Imaging

To summarize, imaging of prostate cancer, half of prostate cancers are invisible with conventional gray scale imaging with conventional color and power doppler.

And in fact, if you look at a conventional ultrasound detection of prostate cancer is probably minimally better than chance.

And so that's why most people do prostate biopsies now do systematic biopsies where they spatially distribute the biopsy cores all around the prostate to try not to miss something.

The future, however, we hope, holds better doppler techniques for cancer detection, identification of cancer tissue with elastography and perhaps selective enhancement of the neovessels with contrast enhanced intermittent imaging.

And then improve biopsy techniques based upon these improved imaging techniques, which will limit the number of biopsy sites and find more of the clinically significant high volume, high grade tumors.

So I'm trying to give you a very rapid fly through of prostate imaging here with some of the newer techniques that are used for prostate imaging.

In summary, prostate imaging is done for a couple benign reasons, infertility, inflammatory processes.

When you're looking at infertility, you're trying to see is there an obstruction of the ejaculatory ducts, is there an absent vas deferens or seminal vesicle.

When you're looking for inflammatory lesions, you wanna make sure there's no abscess sitting in the prostate.

And then when you're looking for tumor, you're trying to basically direct your biopsies into the area that's gonna maximize the positive biopsy yield.

Thank you very much for your attention.