ULTRASOUND OF THE SCROTUM - Normal

The main components when assessing the scrotum with ultrasound are the Epididymis, testis ,pampiniform plexus , spermatic cord and groin. The spermatic cord also contains the testicular, cremasteric, and deferential arteries, pampiniform plexus, nerves, and lymphatics.

Probe position longitudinal Testis.	Normal Sagittal Image Testis.
Anatomy Scrotum	Normal Sagittal image head of epididymis

PROTOCOL FOR ULTRASOUND OF THE SCROTUM

ROLE OF ULTRASOUND

Ultrasound is essentially used to investigate causes for:

• Pain
  
  • Which side?
  • Dull or sharp?
  • Constant or intermittent?
  • Acute or chronic?
  • Does it travel higher?
• Mass
• Trauma
• Infertility
• Undescended testis
• H/O Trauma ,surgery or infection?
• Reduced Sperm count
• Varicocele
• Hydrocele
• Infections (orchitis,prostatitis)
• Polycystic kidney disease
• Cryptorchidism

EQUIPMENT SELECTION AND TECHNIQUE

• Use of a high resolution probe (7-15MHZ) 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._

SCANNING TECHNIQUE

PATIENT PREPARATION

• Must make sure the patient as comfortable
• Not only is this to put the patient at ease but you will get more information out of him 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.
• Begin with a survey scan transversely down the scrotum to compare echogenicity of the testes.
• Scan each side independantly 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 visualize 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 manoeuver 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 (eg pelviclymphadenopathy)
• If a hernia is suspected, click here for hernia scanning protocol

COMMON PATHOLOGY

Extratesticular Lump or swelling

• Hydrocele
• Epididymitis, Orchitis or Epididymo-orchitis
• Epididymal Cysts
• Varicocele in the Pampiniform plexus
• Cryptorchidism or Maldescent
• Scrotal "Pearl"
• Microlithiasis (intratesticular) 

Scrotal swelling with pain - 4 main causes:

• Torsion (20%)
• Infection/inflammation (75-80%)
• Haemorrhage
• Strangulated Hernia

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. 

NOTE:

• epididymitis:torsion = 3:2 <20years
• epididymitis:torsion = 9:1 >20years

Intratesticular Lumps

• Germ Cell Tumours
• Seminoma
• Nonseminoma

For normal anatomy and scanning protocol

BASIC HARD COPY IMAGING

A scrotal series should include the following minimum images;

• Transverse image showing both testes for comparitive echogenicity
• Transverse images of each testis
• Maximum transverse measurement of each testis
• Longitudinal images of each testis
• Maximum longitudinal measurement of each testis
• Epididymis to include the head , body and tail (bilaterally)
• Vascularity of each testis with spectral trace
• Spermatic cord
• Document the normal anatomy. Any pathology found in 2 planes,
       including measurements and any vascularity
• Groin for lymphadenopathy
• Kidneys