Scrotum and Testes Ultrasound Tutorial Notes

Ultrasound Appearance – Spermatic Cord

Common Indications for Scrotal/Testes Ultrasound

• Pain (acute/chronic)

  • Associated with redness/swelling

  • Accompanied by fever

  • Associated with abnormal lie of testes

• Trauma

• Lump/mass

• Swelling

• Looking for undescended testes

• Evaluate for infertility

Testes/Scrotal Ultrasound Procedure

• Maintain professionalism and patient privacy.

• Explain procedure and gain consent.

• Allow patient to change and position supine on the bed.

• Obtain full clinical history.

• Use warm gel (to avoid cremasteric reflex, which can cause contraction, wrinkles, thickness and poor attenuation).

• Elevate the scrotum with a towel underneath or resting on closed thighs.

• Place penis on patient’s abdomen, held by gown or patient, and keep still.

• Disinfect transducer post-procedure.

• Leave patient to change in privacy with towels to clean off gel.

Ultrasound Images Required

• High-frequency linear probe (be prepared to change frequency or to curved probe to obtain accurate length or demonstrate relationship of pathology to anatomy).

• Image in transverse of both testes to document lie.

• Image both testes in two planes:

  • Transverse (upper/mid/lower)

  • Longitudinal (med/mid/lat)

• Measurements taken in long and trans, generate volume (LxHxW).

• Assess epididymis in entirety with images of head/body/tail.

• Evaluate and image spermatic cord

• Assess testes and epididymis with color Doppler and PW Doppler trace to assess blood flow.

• Take a color image in trans of both testes at once for any flow discrepancy/torsion.

• Take comparison view of right and left testes as beneficial.

• Palpate, localize, and image any particular lump the patient can feel.

• Document any pathology found in two planes including measurements and vascularity.

• Perform the Valsalva manoeuvre when evaluating for varicoceles or hernias

• Assess groin if necessary for lymphadenopathy.

• Kidneys may be required in some workplaces, especially looking for a renal tumour causing compression of the renal vein if a varicocele is found.

Normal Testes Ultrasound Images

• Testes oval, smooth, homogenous.

• Usually vertical lie unless bell clapper deformity.

• Surrounded by thin echogenic fibrous band representing visceral component of tunica vaginalis.

• Normal volume between 12-19cc post-puberty, then decreases with age $(N volume between 12-19cc)$

• Normal size approximately 3-5cm length, 2-3cm width and AP measurement $(N size approx. 3-5cm length, 2-3cm width)$

Normal Color Doppler Image

• Assess for torsion.

• Make sure low PRF and high color gain set first on asymptomatic side.

• Also need a spectral Doppler trace of arterial and venous flow.

• Flow must be intratesticular to rule out torsion.

Normal Epididymis

• Moving transducer posterior and lateral allows assessment of body and tail of epididymis.

Ultrasound Normal Anatomy

• Epididymal head

• Epididymal body

• Scrotal wall

• Testicle

• Mediastinum testis

• Tunica albuginea

• Vas deferens

• Epididymis

• Appendix epididymis

• Appendix testis

• Tunica albuginea

• Skin

• Parietal layer tunica vaginalis

• Visceral layer of tunica vaginalis

• Cremaster muscle

Normal Variant - Rete Testis

• Tubular ectasia - dilated testicular mediastinal bubbles.

• Multiple small cystic or tubular anechoic structures that replace and enlarge the testicular mediastinum.

• No specific shape.

• No mass effect.

• No internal vascularity

Normal Variant - Mediastinum Testis

• Supports the rete testis and testicular vessels as they enter and exit the testis.

• Appears as a linear echogenic band at posterior part of testis on ultrasound

Normal Appendix Epididymis or Appendix Testis

• A developmental remnant of the Mullerian duct on the upper pole of testis inside a groove between testis and epididymal head.

• Best seen when there is a hydrocele.

• Usually oval, isoechoic with testis and can have blood flow within.

Most Common Pathology

Extratesticular lump or swelling

• Hydrocele (pyocele or haematocele)

• Epididymitis/orchitis/epididymo-orchitis

• Epididymal cysts

• Varicocele in pampiniform plexus

• Cryptorchidism (undescended testes)

• Scrotal pearl (free floating calculus within tunica vaginalis)

Scrotal swelling with pain

• Torsion

• Infection/inflammation

• Haemorrhage

• Strangulated hernia

Intratesticular lumps

• Germ cell tumor (most common)

• Seminoma

• Non-seminoma

Hydrocele

Two main types

• Communicating: fluid collects around the patent processus vaginalis which communicates with the peritoneum

• Spermatic cord hydrocele: can be encysted (no communication with peritoneum – spermatic cord cyst), or funicular (communicates with peritoneum at internal ring but doesn’t surround the testes)

Clinical Presentation

• Painless scrotal swelling/mass or enlargement

• Can become painful if infected (pyocele - complication of epididymo-orchitis, testicular abscess, trauma, or surgery)

• Haematocele - usually from trauma to scrotum or surgery

Epididymal Cyst

Epididymitis and/or Epididymo-Orchitis

Clinical Presentation

• Gradual onset swelling and pain

• Very tender to touch

• Can be caused by STD or UTI

• Infection begins in bladder or prostate, spreads through ductus deferens and lymphatics of spermatic cord to epididymis

• Infection begins at the tail then progresses to body/head/testis

• Epididymo-orchitis less common initially

Ultrasound Appearance

• Epididymis is increased in size

• Epididymal tail most affected

• Can get reactive hydrocele and scrotal wall thickening

• Can have hypo/hyper or heterogeneous appearance depending on the time of the scan

• Increased vascularity in epididymis or both testis and epididymis

Varicocele

• Abnormal dilatation of the pampiniform plexus (>3mm)

• Primary (majority) are from incompetent or absent valves in testicular vein

• Left affected > Right.

  • Can be due to the left testicular vein being longer and inserting into the left renal vein at a right angle.

  • Right testicular vein is short and inserts into IVC, therefore less backpressure.

• Secondary - from increased pressure in testicular vein from compression (lymphadenopathy, renal mass, renal vein compression in nutcracker syndrome)

Clinical Presentation

• Can be asymptomatic

• If symptomatic

  • Scrotal mass/swelling

  • Scrotal pain

  • Infertility

Ultrasound Appearance

• Dilated veins >3mm with Valsalva within pampiniform plexus

• Can also have dilated veins at epididymal head, laterally and inferiorly to testis

Treatment

• Often no treatment or surgery to seal off the affected vein

• If chronic pain can’t be managed

Testicular Trauma

• Rupture

• Fracture

• Torsion

• Intratesticular haematoma

Clinical Presentation

• Can be from a blunt or penetrating injury or surgery

• Pain/swelling

Ultrasound Appearance - Rupture

• Can have haematocele

• Disruption of tunica albuginea (echogenic line covering testes is irregular, not continuous or retracted

Ultrasound appearance infarct/ischemia

• Heterogenous patchy testis

• Can present similar to torsion, however, infarct is due to increase intra-testicular pressure, causing venous obstruction and infarction

Testicular Rupture

• Disruption of tunica albuginea

• Hypoechoic avascular area

Testicular Torsion

Three types

• Intravaginal (most common) due to bell clapper deformity

• Extravaginal – torsion at the level of the external ring

• Long mesorchium – twist in the tissue overlying the vasculature anteriorly between the epididymis and tunica vaginalis

• Torsion occurs when the testis torts on the spermatic cord cutting off the blood supply

• Bell clapper Deformity

  • tunica vaginalis has abnormally high attachment to the spermatic cord, leaving the testis free to rotate.

  • Gives predisposition to intravaginal torsion

Clinical Presentation

• Testicular torsion is usually spontaneous or in the setting of minor/incidental trauma.

• The onset of severe testicular pain is sudden and is not relieved by the elevation of the scrotum.

• There should be no fever or urethral discharge.

• Sometimes may be intermittent symptoms due to spontaneous detorsion, so-called “intermittent testicular torsion”.

  • Often results in short periods of acute groin pain accompanied by vomiting and subsequent spontaneous relief may be a typical patient history in these cases.

• Physical examination may reveal elevation of the affected testis, an absence of the cremasteric reflex, transverse lie of the testis, anterior rotation of epididymis, and pain relief with successful manual detorsion.

Cremasteric reflex

• When the inner thigh is stroked, the cremaster muscle contracts and pulls up the ipsilateral testicle toward the inguinal canal

Ultrasound Appearance:

• Compare symptomatic side to the normal side.

• No blood flow or altered blood flow to testis - first to disappear is venous flow.

  • In complete torsion – there is no blood flow to testis or epididymis

• ‘Whirlpool Sign’ - twisting of the spermatic cord - refers to the mass with concentric layering just superior to the testis representing the “coiled spermatic cord components”.

  • This is typically visualized using a longitudinal and/or oblique transducer orientation to visualize the course of the spermatic cord

Acute Stages (<6-12 hours)

• Increase in the size of the testis and epididymis (especially in acute stages)

• Homogeneous echotexture (early finding, before necrosis)

• Reactive thickening of the scrotal skin with hyperemia

Later stages (>24 hours)

• Heterogeneous echotexture / hypoechoic regions represent necrosis / hyperechoic regions represent heamorrhage

• Reactive hydrocele

DDX

• It is important to realize that epididymo-orchitis can closely mimic the appearances of torsion as well as spontaneously detorted testis. Correlate clinically.

Treatment

• Surgical exploration to assess the ‘twisting’ of the spermatic cord and to untwist it (de-torsion) to restore blood supply.

• Time critical as >6 hrs – there will be permanent damage to the testicle.

  • Nearly most patients require testicle removed (orchidectomy) if surgery is delayed >12 hours.

• Torsion treatment within 6 hours – high chance of salvaging testicle.

• If the testicle has already infarct – then it needs to be removed because it increases the risk of infection and abscess formation if it is kept.

• Surgeons often perform an ‘orchidopexy’ which is fixing the testicle by sutures, so it doesn’t twist in the future (in an attempt to minimize risk due to the bell-clapper deformity).

  • They often fix the other testis also so it doesn’t run into the same issue in the future.

Case Studies

Case 1

History

• Enlarging left testis for 2 ½ months

• 70 y/o male

Description

• Solid

• Lobulated/irregular

• Hypoechoic

• Heterogenous with multiple echogenic foci

• Increase in vascularity

Radiologist report

• The left testis is almost completely occupied by a lobulated solid mass with some increased vascularity present.

  • Measures at least 3.4 x 2cm in diameter and appears suspicious for neoplasia.

• The epididymis appeared normal.

• The right testis, although having even echotexture without mass infiltration, shows a small peripheral calcific density of 1mm diameter. No further microcalcification seen.

• Cursory examination of the inguinal regions and pre-aortic regions showed no evidence of lymphadenopathy.

• As discussed a urological assessment and CT scan of the chest, abdomen, and pelvis should follow given this suspicious, probably primary germ cell tumour of the left testis.

Case 2

Pathology

• Anechoic tubular structures located in the pampiniform plexus

• Increase in vascularity and diameter with Valsalva

Radiologist Report

• The testes are symmetric and normal in size

• Homogenous echotexture and normal vascularity

• No testicular mass

• No hydrocele seen

• There is a small left varicocele 3.2mm

• There is no other scrotal pathology

Case 3

History

• History of right testicular Ca with surgery.

• For surveillance

Description

• Anechoic fluid-filled structure

• Well circumscribed

• Round/oval

• Posterior enhancement

• Reverberation artefact

Diagnosis

• Testis prosthesis

Case 4

History

• Rt testicular pain and swelling 5 days

• 70 y/o male

Epididymis

• Heterogenous tubular structure

• Mix of hypoechoic and hyperechoic areas

• Appears bulky

• Increase in vascularity

• Abnormal in appearance: epididymitis

Area Around the Epididymis and Testis

• Predominantly Anechoic area surrounding epididymis and testis

• Contains multiple echogenic septations

• No flow

Diagnosis

• Possible pyocele as a result of epididymo-orchitis