Ensure you slide from top to bottom and examine the entire testis.
Normal testis ultrasound using a curvilinear probe for accurate measurements or to provide a more global view including surrounding anatomy and pathology.
A coronal ultrasound view using a curvilinear probe provides a good comparison and overview of both sides.
Ultrasound of normal testicular vascularity with colour doppler in a post pubescent case.
Colour Doppler should be used to assess for any injury, torsion or orchitis.
Normal Sagittal image head of epididymis
The transducer should be moved posterolaterally to view the epididymis body and tail.
The pampiniform plexus is best appreciated lateral to the testis and in the superior portion. It should be dynamically assessed with colour using a valsalva technique to appreciate reflux in the veins.
In the pre-pubescent testis, flow can be difficult to identify. Low PRF, colour gain approaching saturation, and light probe pressure are required.
Post pubescent testes should have readily identifiable venous and arterial scattered flow.
Torsion: Absent flow in one testis when flow is readily visible in the other is suggestive of torsion.
Orchitis: Diffusely increase flow in the testis. If is increased in both the testis and epididymis, it is epididymo-orchitis.
Infarct:Segmental absence of flow. Usually post trauma. There will also be segmental heterogeneity on B-mode.
Obtain a spectral doppler trace of both arterial and venous flow in the setting of suspected torsion. This may assist in the diagnosis of partial torsion, or tort/untort.
There are suggestions that resistive indices in intralobar arteries will be elevated (>.75) in the intermittent torsion group.
PITFALLS: Flow must be intratesticular. Not just capsular.
This is a common finding at rete testis.
It can extend along mediastinum testis and/or into the epididymis, particularly the epididymal head.
More common with a past history of vasectomy.
Ultrasound of ductal ectasia in a testis. Longitudinal view. The red arrows indicate the dilated (ectatic) ducts. The blue arrow indicating the ectasia extending into the epididymal head.
Ultrasound of testicular ductal ectasia in a transverse plane at rete testis. The ‘multimicro-cystic appearance is typical. Colour doppler is used to prove it is not a vascular lesion.
In transverse the vas is a hypoechoic ring with a central echogenic ‘dot’.
In longitudinal the echogenic dot will be seen as parallel echogenic lines on high frequency probes, deliniating the lumen.
Post vasectomy the vas may have a larger diameter or be slightly tortuous. It should not be mistaken for a thrombosed vein.
Common presentations and likely causes:
Acute pain – torsion/injury
Swelling – hernia/hydrocele
Absence – retractile/cryptorchid
Infection is much less common in prepubescents.
The testes should be imaged together and compared for size and echogenicity.
The normal paediatric testis volume (<8yrs) is 1-2cc.
Spectral Doppler can assist in determining if there is any torsion of the testis. This image shows normal vascularity.
When assessing for vascularity, have a low PRF (<10), turn the colour gain up to saturation then reduce until the flare resolves.
Light probe pressure.
Check for both arterial and venous flow Document with spectral doppler. Do not rely on colour alone.
Check the intratesticular arterial resistive index. If >0.75 -> ? partial or intermittent torsion.
Whirlpool sign: transverse sweep through the cord from the inguinal canal to the scrotum. With and without colour doppler. Look for the spiralling twist in the cord.
Careful search is required for the missing testis because of the small size.
A curvilinear probe may be required if the testis is not in the cord and is in the abdominal cavity.
If close to the scrotum, attempt to gently relocate the testis.
Role of Ultrasound
Ultrasound is essentially used to investigate causes for:
Dull or sharp?
Constant or intermittent?
Acute or chronic?
Does it travel higher?
H/O Trauma, surgery or infection?
Reduced sperm count
Infections (orchitis, prostatitis)
Polycystic kidney disease
Cold or patient anxiety may cause the scrotum to contract. The thickened, wrinkled scrotal skin is attenuative, reducing detail.
Whenever possible, use warm gel (and hands).
Must make sure the patient is comfortable.
Not only is this to put the patient at ease but you will get more information from the patient which will give you better clues as to what the diagnosis will be.
Using a towel or the patients gown, tuck the penis up over the symphysis to help elevate and immobilise the scrotum.
Use warm gel.
Use of a high resolution probe (7-18MHZ) is essential when assessing the internal structures of the scrotum.
Low PRF and high gain colour/power/Doppler capabilities when assessing vessels of a testis.
Be prepared to change frequency output of probe (or probes) to obtain accurate length measurements, an overview of pathology and anatomy to each other and adequately assess deeper structures in the abdomen if necessary.
Extratesticular Lump or swelling
Epididymitis, Orchitis or Epididymo-orchitis
Varicocele in the Pampiniform plexus
Cryptorchidism or Maldescent
Scrotal swelling with pain – 4 main causes:
Torsion results in acute testicular infarction and eventually an atrophic testicle and constitutes a medical emergency. Quite often these patients will bypass the imaging department and go straight to theatre.
Begin with a survey scan transversely down the scrotum to compare echogenicity of the testes.
Scan each side independently in both longitudinal and transverse planes.
You may need to apply slight pressure to immobilise the testis as you scan. However, it is important to scan with minimal pressure to visualise fluid overlying the testis.
Locate the epididymal head and follow in transverse down the body and tail.
Assess both intra and extratesticular structures with power Doppler.
The Valsalva manoeuvre or scanning in the upright position should be performed when evaluating for varicoceles or hernias.
If a varicocele is identified, the scan should be extended to assess the testicular veins for the point of origin. Such as extratesticular masses that could be compressing the vein (e.g. pelvic lymphadenopathy)