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ScrotumDemonstration data

Scrotal / Testicular Ultrasound

Scrotal ultrasound with colour Doppler is the first-line imaging test for the acute and non-acute scrotum. It reliably differentiates surgical emergencies such as testicular torsion from inflammatory conditions, characterises palpable masses as intra- or extratesticular, and evaluates varicoceles, hydroceles and trauma. Grey-scale defines anatomy and echotexture while colour and spectral Doppler assess perfusion, which is the pivotal finding in the painful scrotum.

Indications

  • Acute scrotal pain or swelling with suspected testicular torsion
  • Suspected epididymitis or epididymo-orchitis
  • Palpable scrotal or testicular mass, including staging of suspected tumour
  • Scrotal trauma with suspected rupture or haematoma
  • Varicocele assessment in infertility or scrotal ache
  • Undescended or non-palpable testis and follow-up of hydrocele or spermatocele

Contraindications & Cautions

  • No absolute contraindications; ultrasound is non-ionising and safe
  • Do not delay urological consultation for suspected torsion to obtain imaging when clinical suspicion is high
  • Severe pain may limit transducer contact; use copious warm gel and gentle technique
  • Large hydrocele or gross oedema can degrade evaluation of the underlying testis

Patient Preparation

  • No fasting or bladder preparation required
  • Warm room and warm gel to reduce cremasteric contraction and patient discomfort
  • Supine position with the penis retracted onto the lower abdomen and covered
  • Support the scrotum on a rolled towel between the thighs
  • Explain that upright positioning and Valsalva may be needed for varicocele evaluation

Technique & Parameters

  • High-frequency linear array (9-18 MHz); a lower-frequency probe for very large or oedematous scrotum
  • Systematic grey-scale survey of each testis and epididymis in longitudinal and transverse planes
  • Obligatory transverse split-screen image comparing both testes for size, echogenicity and vascularity
  • Colour Doppler optimised for slow flow: low PRF (scale), low wall filter, small colour box, high colour gain
  • Spectral Doppler to confirm intratesticular arterial and venous waveforms and document symmetric flow
  • Valsalva manoeuvre and upright imaging to demonstrate pampiniform venous reflux for varicocele

Systematic Review

  • Compare testicular size and echotexture side to side (normal homogeneous mid-level echoes)
  • Confirm symmetric intratesticular colour and spectral flow in both testes
  • Assess epididymal head, body and tail for size, echogenicity and hyperaemia
  • Evaluate the tunica vaginalis for hydrocele, pyocele or haematocele and for the tunica albuginea integrity
  • Interrogate the spermatic cord for the whirlpool sign and pampiniform plexus for varicocele/reflux
  • Characterise any focal lesion as intratesticular (malignant until proven otherwise) versus extratesticular (usually benign)

Key Findings & Significance

  • Torsion: absent or markedly reduced intratesticular colour flow, enlarged hypoechoic testis, spermatic cord whirlpool sign
  • Epididymo-orchitis: enlarged hyperaemic epididymis/testis with increased Doppler flow and reactive hydrocele
  • Intratesticular solid mass with vascularity suggests germ cell tumour; microlithiasis may coexist
  • Varicocele: serpiginous veins >2-3 mm that enlarge or reflux on Valsalva/standing
  • Rupture: disrupted tunica albuginea, heterogeneous testis with contour irregularity and haematocele
  • Extratesticular cystic lesions (spermatocele, epididymal cyst) and simple hydrocele are benign

Differential Considerations

  • Acute painful scrotum: torsion vs epididymo-orchitis vs torsion of a testicular appendage vs incarcerated hernia
  • Absent flow mimics: technical (low PRF not set) vs true torsion vs previously infarcted testis
  • Intratesticular mass: seminoma, non-seminomatous germ cell tumour, lymphoma, infarct, focal orchitis, sarcoid
  • Extratesticular mass: adenomatoid tumour, spermatocele, epididymal cyst, chronic epididymitis
  • Scrotal fluid: simple hydrocele vs pyocele vs haematocele

Pearls & Pitfalls

  • Optimise Doppler for slow flow before calling torsion; document flow in the asymptomatic side as an internal control
  • Partial or intermittent torsion may show preserved or increased flow; the whirlpool sign is more specific
  • Any solid intratesticular lesion is malignant until proven otherwise and warrants tumour markers and urology referral
  • Reactive hydrocele and skin thickening are common but non-specific in inflammation
  • Testicular microlithiasis alone does not mandate biopsy but warrants attention to associated masses and risk factors

Structured Report

  • State transducer, comparison and whether Doppler was optimised for slow flow
  • Report testicular volumes/dimensions, echotexture and symmetry of colour/spectral flow
  • Describe epididymis, tunica, hydrocele and any varicocele with vein calibre and reflux response
  • Characterise focal lesions by location, size, echotexture and vascularity
  • Give an impression addressing the clinical question (e.g. torsion vs inflammation) and recommend urgent urology referral when indicated

References

  • AIUM Practice Parameter for the Performance of Scrotal Ultrasound Examinations
  • ACR-AIUM-SPR-SRU Practice Parameter for the Performance of Scrotal Ultrasound
  • Dogra VS et al. Sonography of the Scrotum. Radiology 2003;227:18-36
  • Society of Radiologists in Ultrasound Consensus on Testicular Microlithiasis and Incidentalomas

Educational clinical decision support only. Protocols vary by institution and equipment; always confirm with a qualified radiologist and local guidelines before clinical use.