Contrast Imaging of the Scrotum - HD

Introduction

I am Professor Paul sdu, professor of Imaging Sciences at King's College Hospital, London.

I have had 15 years experience in using contrast enhanced ultrasound and I would like to present to you our experience in contrast enhanced ultrasound of the testes and the scrotal contents.

Testicular Lesions: Malignant and Benign

Testicular lesions are relatively uncommon in the adult male patient, but the intra testicular lesion always presents a problem.

Most often in the adult patient.

The intra testicular lesions are malignant up to 95% of lesions are malignant.

The rest are benign of the malignant gene lesions.

Most of these are germ cell tumors.

Germ cell tumors may be of different histological type.

They develop from either a uni potential or a toti potential cell and divide into either seminoma or non seminomas tumors.

There are a number of lesions that are benign that mimic these malignant lesions and it is very important to be able to clearly identify those lesions which are malignant from those which are benign.

A malignant lesion means the patient will lose that testicle and it clearly is of importance to the patient not to lose his testicle if that lesion is benign.

Ultrasound Appearances of Testicular Lesions

On ultrasound, these lesions may take many forms.

The classical seminoma is known to all of you as that low reflective, well circumscribed abnormality within the testes.

A teratoma which contains many different cell types will look very different with areas of calcification and mixed echogenicity.

However, these germ cells all require an orchiectomy if there is a segmental infarction or an epidermoid cyst, both of which are benign lesions and may mimic an intra testicular malignant abnormality.

Any preoperative assessment that indicates that the LE lesion is benign will take importance to allow preservation of the testes.

There are a number of lesions within the testes which cannot be characterized fully on the B mode ultrasound examination, this slide shows you a number of lesions which were not clearly identified prior to operation.

These patients had their testes taken out, but these lesions were all benign.

A recent publication out of Italy demonstrates that a large number of lesions found incidentally on the ultrasound examination and this was in patients with infertility being investigated.

For that abnormality, 80% of these incidental lesions were actually benign.

This is where adding contrast enhanced ultrasound to the examination of the testicular mass will help to determine whether or not this is a malignant or a benign abnormality.

Limitations of Color Doppler Ultrasound

Adding color doppler ultrasound to the investigation of a focal testicular abnormality may be helpful.

This landmark paper published in 1992 indicated that the use of color doppler ultrasound in a cohort of 28 patients was useful only if the tumor was greater than 1.6 centimeters in diameter.

Any increase in vascularity indicated that the abnormality was malignant.

The authors concluded that a color dopplar ultrasound was not useful for those tumors less than 1.6 centimeters, but now with the advent of better technology, we know we can ascertain color dopplar flow and the very small lesions.

An indication of malignancy is therefore the presence of hyper OT chain.

A benign lesion should demonstrate no increase in vascularity.

This is the hallmark of investigation of the focal testicular lesion with an ultrasound examination.

If we can add contrast enhanced ultrasound to this pathway, bearing in mind that contrast enhanced ultrasound exquisitely demonstrates the vascularity of the lesion, we should perhaps be able to ascertain whether or not a lesion is malignant or benign entirely based on the vascularity contrast.

Enhanced ultrasound is not the only new technique available for investigation of focal uh testicular lesions.

Elastography has also been demonstrated to be useful in ascertaining the hardness of the lesion and with the hardness of the lesion indicating the presence of malignancy.

A combination of these two techniques may in the future be much more advantageous in investigating the testicular abnormality.

Contrast Enhanced Ultrasound: Safety and Licensing

Now let's go back to contrast enhanced ultrasound.

The focus of this lecture, those of you who are not familiar with contrast enhanced ultrasound will not fully appreciate how safe this agent is.

This large study out of Italy where sono view is used, uh, predominantly to investigate liver lesions, renal lesions and lesions elsewhere in organs in Europe has demonstrated that there is very, there is, there are very, very few adverse effects.

In 0.0086% of investigations, there was mild symptoms such as itching, nausea, sense of warmth, dizziness, headache, and mild hypertension.

Very few serious adverse events occurred and these were all suitably treated.

No one died out of all these patients, so using contrast enhanced ultrasound is saved however, in Europe and in the far east, but not yet in the United States of America.

This contrast agent is only licensed for use in a limited number of areas.

It is licensed to be used in the liver, the heart, the breast, and for vascular areas.

Therefore, any application outside these areas are off license.

Not withstanding this, the European Federation of Societies in ultrasound and medicine and biology have issued guidelines and recommendations on non hepatic applications.

Every single one of these non hepatic applications are off license, but the accompanying editorial indicates the reasons that this is acceptable.

Advantages of Contrast Enhanced Ultrasound

First of all, contrast enhanced ultrasound has a number of distinct advantages over CT and MRI and this is particularly true in investigating lesions of the scrotal con sac.

Ultrasound remains the best modality for looking at superficial structures.

With its better resolution, you're able to actually distinguish very small abnormalities in the testes, so contrast enhanced ultrasound of the testes is very useful.

Contrast enhanced ultrasound can be performed immediately.

You don't need any preliminary laboratory testing.

You don't have to have patients who have renal problems turned away from the ex examination and you can carry it out anywhere.

You don't have to carry out the examination out within the radiology department.

You can take the machine to the patient, it operates in real time.

You can ascertain rapid changes and capture these and review these on your cine loops.

All of these off-label uses are unlikely ever to become licensed.

This is not a problem for the clinician.

This is a commercial problem,

But if you are going to use contrast outside the labeled indications, you are allowed to do it by many medical rega regulatory authorities.

And I talk now about the General Medical Council of the United Kingdom where I practice because you can use a drug off license under the following circumstances, be satisfied that it would better serve the patient's needs.

Be satisfied that there is sufficient evidence base experience of using this agent to demonstrate its safety and efficacy and you take responsibility for prescribing this medicine.

If I could in indicate to you that over 70% of drugs prescribed for children are not licensed, you will understand how many clinicians throughout the world take responsibility for a administering safe medicines to people who need them.

There should be no restriction on you using contrast enhanced ultrasound where you think it's going to be useful and beneficial to the patient.

Contrast Enhanced Ultrasound in Scrotal Diseases

Now, let's go back to look at contrast enhanced ultrasound as scrotal diseases.

I've already said that ultrasonography is the imaging modality of choice for the examination of the scrotum.

It is unrivaled in this area and most operative procedures are based entirely upon the ultrasound findings,

but occasionally these findings may be difficult to interpret and any misinterpretation has the possibility that that patient may lose the testicle.

This is a particular conundrum when there is perhaps poor differentiation between the very hypovascular and avascular lesion where if you think that there is no vascularity in that lesion that it's benign disease, it may be a poorly vascularized malignant lesion and this remains a conundrum even with the use of color Doppler ultrasound.

Adding contrast enhanced ultrasound may just tip the balance to indicate that there is vascularity.

Present color ultrasound is very observer dependent and you may not be confident of the interpretation from your examination.

Now let's look at contrast enhanced ultrasound scrotal diseases.

This is a little different from your normal contrast enhanced ultrasound examination.

For example, of the liver,

The transducers used when you're examining the liver are predominantly of the three, four or five megahertz level.

When you're examining a small part such as the testes, you're going to use higher frequency probes.

The physics of the microbubble does not allow high frequency probes to adequately vi visual.

Visualize the microbubbles, you need a higher dose than you would normally use in the liver.

Those of you who are familiar with the drug that is predominantly used in Europe so of view will know that for liver lesions you are injecting a dose of 2.4 mls, but for the testes, you would need to inject 4.8 MLS to get adequate visualization.

This is not of concern.

The initial dose finding studies indicated that the appropriate safe dose was 4.8 mls.

However, over the last 10 years, the improvement in technology has allowed you to inject smaller and smaller doses for observing lesions in the liver.

So 4.8 MLS is perfectly safe and adequate for the patient in the testes.

You're only interested in the arterial phase and the early parenchymal phase examination for about a minute to a minute and a half is all that is required.

Also, be aware that the inflamed scrotal contents are more likely to enhance to a GR to a higher degree than the non-inflamed testes, and this takes importance in the presence of epididimitis abscess formation and infarction.

The testes and the EPIs enhance rapidly, but the arrival time varies greatly between individuals.

You should take time when performing this examination.

The arteries enhance first followed within seconds by complete parenchymal enhancement, the scrotal wall tends to enhance to a lesser degree than the contents.

There is no accumulation of microbubbles in the paradigm of the testes and enhancement declines over a very per variable period of time such there is min such that there is min minimal residual enhancement at three minutes.

Again, this is ver very variable in the inflamed testes experiences needed when examining the scrotal contents and the advice would be that you learn to do contrast enhanced ultrasound at the level of the liver or the kidneys before you attempt to do scrotal contrast enhanced examinations.

Recommendations for Use in Scrotal Diseases

Now, there are certain recommendations for the use of contrast enhanced ultrasound and scrotal diseases and I am going to demonstrate to you in the next few slides the data that is available and published in the European Federation's guidelines, the use of contrast in scrotal diseases.

Torsion of the Spermatic Cord

First of all, let's look at the to at torsion of the spermatic cord contrast.

Enhanced ultrasound may be used as a problem solving technique in children with small testes where conventional doppler imaging methods provide suboptimal assessment of flow.

Sensitivity of color doppler flow diminishes with the size of the testes.

The truly intravascular contrast agent, however, will demonstrate vascularity and this can be used when there is a suspicion of torsion.

There is, however, a whole body of thought which suggests that if there is a submission of torsion, no imaging is necessary, an operation should be performed.

There is actually at the moment no data available to tell you how to use contrast enhanced ultrasound in spermatic cord torsion.

A small series of patients with torsion were examined and contrast enhanced ultrasound confirmed the complete absence of vascularization, but this didn't add any clinical information to the the Unenhanced color Doppler ultrasound examination, so at the moment there is no clear role for the use of contrast enhanced ultrasound in testicular torsion.

However, if you have a problem such as this demonstrated here where you have very severe epidermal which results in global infarction of the testes, you can use your contrast enhanced ultrasound to demonstrate the complete absence of vascularity in that testes and this will influence the operative management.

These patients have complete infarction of the testes.

The surgeons will remove this testes to alleviate pain and you are able to give this information to the surgeons that there is absence of vascularity to allow this procedure to be performed with confidence.

Increased enhancement in the EPIs is clearly demonstrated and on this view you can see two small abscesses forming in the epididymus.

There is absolutely no vascularization of the testes.

There is no blood supply to that testes, that testes will not survive.

Orchidectomy is the correct management.

Segmental Infarction

Let's look at another problem with the testes segmental infarction.

This has a very variable appearance on conventional B mode and color Doppler ultrasound.

The benign nature of the lesion is established by its shape with markedly diminished or absent color doppler flow.

Traditionally, these segments of infarction have been been described as wed shaped.

However, not all segmental infarctions are wed shaped.

Some may be round and may appear exactly like a poorly vascularized rounded tumor.

With contrast enhanced ultrasound, the subacute segmental infarction characteristically exhibits a per lesional rim of enhancement which diminishes over time and is eventually lost with changes in the lesion shape and shrinkage.

Following these lesions up with contrast, enhanced S ultrasound will allow the physician to document this change and be confident that the lesion is benign.

This is, this is an example of a segmental testicular infarct, which looks very much like a tumor.

However, there is no color doppler flow to that area and there is confidence that this is unlikely to be a tumor.

Adding contrast at this stage allows the physician to clearly identify an area of infarction and to manage this patient conservatively.

This is an example on the B mode ultrasound of a very abnormal looking rounded area in the mid aspect of the testes, which following contrast, enhanced ultrasound demonstrates no enhancement at all.

There is no vascularity in this region.

It is very likely to be areas of infarction and not tumor and close follow up will allow this diagnosis to be confirmed.

The absence of vascularity following the administration of contrast is very striking.

You should be able to see a single bubble traversing a blood vessel in the testes, not because that bubble is so big, but the reflection of ultrasound allows that bubble to be tracked.

If the bubble moves across the field of view, that area is vascularized.

The microbus are truly intravascular and do not leak.

This is a very important point to understand.

This is not like contrast enhanced contrast enhanced ct.

It clearly shows an area of vascularity.

This is an important paper published by our group to demonstrate that these appearances are seen in many patients with segmental infarction and you can follow this pattern over a period of time.

With regression, there is enhancement in the periphery of the lesion.

There's sometimes enhancement of remaining areas of vascularity within the lesion, but follow up will always show regression.

Trauma

Let's move on to another not uncommon problem in the young fit athletic male patient trauma,

conventional B mode and color doppler assessment of the testes and trauma is well established, but this often underestimates the extent of injury.

If the injury is large and there is no chance of saving the testes, it is far better to remove the testes early on.

The ultrasound examination.

Besides looking for the integrity or interruption of the surrounding tunica of the testes also demonstrates for the surgeon the extent of viable testicular tissue.

If this is large, testicular sparing surgery may be performed.

A color doppler ultrasound assessment does not always clearly demonstrate the fracture lines, the intra testicular hematoma and the amount of viable test testes.

This is where contrast enhanced, enhanced ultrasound will add a great deal to your examination.

In this example of a patient with a fracture across the testes with a surrounding hemato seal with color dopplar ultrasound not completely demonstrating the vascularity of the testes, the addition of contrast enhanced ultrasound will demonstrate that there is no viability present in that testes except for a very small area at the upper pole.

This testes will not survive an operation early on in the period of management of this patient will benefit the patient.

Look at this patient.

This patient sustained an injury when hit by a very hard ball On the B mode ultrasound.

There are areas of hematoma present within the upper aspect of the testes, but the color doppler ultrasound does not clearly show where the area of demarcation of viable and unviable testicular tissue is the addition of contrast.

Enhanced ultrasound shows the fracture line shows the upper pole avascular testes and this is the non-viable testes.

There was sufficient testes still being vascularized to allow the surgeon to remove the upper aspect of the testes and preserve the rest of the testes following operation on the images on the right of this slide, contrast enhanced ultrasound showed that there was viability in the entire remaining testes.

This is a very useful application of contrast enhanced ultrasound in the testes and should help surgeons delineate the surgical plane.

Inflammation

Let's move on now to inflammation.

Epididimitis is usually a clinical DI diagnosis and is usually easily confirmed and collared up ultrasound.

The addition of contrast enhanced ultrasound will allow you to determine whether or not an abscess is appearing.

This is a non vascularized area and will not enhance if you can detect an abscess at an early stage or delineate the extent of a large abscess.

This will allow prompt treatment if an abscess is developing oral antibiotics need to be changed to intravenous antibiotics and surgical management with drainage may be required.

The addition of contrast enhanced ultrasound may also show you whether or not there's thrombosis in the spermatic cord vessels, especially in very severe inflammation.

These are two patients with entirely different abnormalities in the testes as a result of very severe inflammatory change in the first patient.

There is thrombosis in the vein in the spermatic cord and there is venous infarction.

In the testes contrast.

Enhanced ultrasound shows that the border is well delineated.

There is peripheral enhancement and no internal vascularization.

This is a venous infarction.

The second patient has very severe epididymitis, but he has also developed an abscess within the testes.

The abscess is very different from the venous infarction.

The walls of the abscess are irregular and septations are forming across the abscess.

This is again very clearly demonstrated with contrast enhanced ultrasound.

The management of these two patients may be identical.

This patient may require an orchiectomy, but the etiology is clearly demonstrated.

Conservative measurement may be undertaken in the case of the venous infarction with time allowing the regression of the area of infarction and the extent of viable tissue becoming obvious.

The abscess, however, is unlikely to rapidly resolve patient's symptoms will remain.

An orchiectomy is almost invariably required

Tumors and Complex Cysts

tumors and complex cyst.

Again, the guidelines have a section which looks at tumors and complex cysts.

We've seen seen earlier that color Doppler ultrasound is thought not to be sensitive when the tumor is less than 1.5 centimeters.

This however, with the advent of the very high technical components of new machines, this may no longer be true.

However, the differentiation of tumors from simple cysts with the addition of contrast enhanced ultrasound and demonstrating echogenic debris without vascularization is a straightforward examination.

With contrast enhanced ultrasound, nearly all testicular tumors will demonstrate vascular vascularization on contrast enhanced ultrasound.

Therefore, contrast enhanced ultrasound is useful to confirm the presence or absence of vascularity.

There is however very little evidence in the literature with regards to these findings and a lot of this is based on personal experience.

This is a large seminoma in the testes measuring over 1.5 centimeters.

There is clear demonstration of vascularity in the 1.5 centimeter tumor following the administration of contrast.

The parenchyma is less enhanced experience shows that this vascularity is very transient, lasting anything between 20 and 30 seconds before that tumor washes out.

This is an example of a lymphoma.

This tumor behaves very differently with con.

The addition of contrast lymphoma tends to grow along the lines of the anatomical structures without distorting vessels and vessels can be seen very clearly through the tumor.

In contrast to that of a primary germ cell tumor where is disorder of the vessels.

It is however important to note that contrast enhanced ultrasound at the moment cannot tell the difference between the different histological types.

For example, this is a late cell tumor.

Late cell tumors tend to be more vascular than primary germ cell tumors and the vascularity tends to last longer.

However, this should not be used to differentiate this tumor from a primary germ cell tumor.

In this case, it's important to ascertain that this incidentally discovered low reflective abnormality in the testes is vascularized.

This will allow the appropriate management either to watch and see what happens to this lesion over a period of several months or to allow surgical resection under ultrasound guidance.

Here is another not very common intra testicular lesion, but importantly benign.

This is an epidermoid cyst.

Only one to 2% of testicular tumors are epidermoid cyst.

There are characteristic features on the B motor ultrasound examination.

The classical onion ring appearance as demonstrated in this example allows the confident diagnosis of the benign epidermoid cyst.

However, there are other types, densely calcified, calcified cyst or just a mixed heterogeneous, poorly defined abnormality.

The key to the diagnosis is the complete absence of vascularity.

An epidermoid cyst is a true cyst containing ca cating material.

The color dopplar ultrasound is usually very good at showing that there is no vascularity, but the addition of contrast to the examination allows greater confidence in interpretation.

In this case, there is increased enhancement around the periphery of the lesion, not because of inflammatory change but of compression of the surrounding testicular parenchyma.

Compare the example I've just shown you to the example of an atypical um, epidermoid cyst where is calcification of the rim and no vascularity within the central aspect.

This too is an epidermoid.

The complete absence of vascularity within this lesion allowed for a targeted excision biopsy of the lesion rather than subjecting the patient to a total orchiectomy.

So in summary, in the group of patients with an incidental lesion discovered in the testes with no clear demonstration of what this abnormality is on the baseline examinations, contrast can add to your diagnosis.

In the first patient with increased vascularity, this is likely to be a tumor and the second paper patient with no increase in vascularity.

This is likely to be a benign abnormality, which in this case was a focal area of scarring following a testicular biopsy.

Let me illustrate this with a a single case.

This is a young man who presented with acute scrotal pain.

There were three lesions seen in the testes.

One was an area of mixed reflectivity larger than the other two with no colored doppler flow.

The other two lesions were of lower uniform reflectivity with some colored doppler flow.

The addition of contrast at this stage demonstrates increased vascularity in the two lesions, which showed some increased calo dola flow, but the larger lesion was completely avascular on histology.

Two seminomas were demonstrated corresponding to the vascularized lesion and the larger mixed reflective avascular lesion was in fact a testicular infarction.

But this diagnosis was confidently made prior to the operation.

Summary

Let me summarize the, the recommendations for the use of contrast enhanced ultrasound in the testes.

This can be used to discriminate focal testicular lesions into those that are vascular and those that show no enhancement, potentially identifying lesions without malignant potential.

Secondly, it can discriminate areas of non-viable tissue and testicular trauma contrast and detect and characterize areas of segmental infarction.

And finally, it can discriminate areas of abscess formation in severe epidermal.

It's important to know and to realize that these are findings based on very little literature at present.

This will change in the future, but the main use of contrast enhanced ultrasound is to demonstrate those areas of vascularized tissue from non vascularized tissue.

This in the future will be the most important use of contrast enhanced ultrasound in the testes.

Finally, there are publications out there combining the use of contrast in enhanced ultrasound with B mode and color Doppler ultrasound and also adding tissue elastography to aid in the diagnosis.

This again may become more important in the future.