Spontaneous or traumatic twisting of testis & spermatic cord within scrotum, resulting in vascular occlusion/infarction

Absent or decreased abnormal testicular blood flow on color Doppler US

Findings vary with duration and degree of rotation of cord

Unilateral in 95% of patients

Role of spectral Doppler is limited; may be helpful to detect partial torsion; in partial torsion of 360° or less, spectral Doppler may show diminished diastolic arterial flow

Spiral twist of spermatic cord cranial to testis and epididymis causing torsion knot or whirlpool pattern of concentric layers

Varying degrees of ischemic necrosis & fibrosis depending on duration of symptoms

Undescended testes have increased risk of torsion

Intravaginal torsion: Common type, most frequently occurs at puberty

Acute scrotal/inguinal pain; swollen, erythematous hemiscrotum without recognized trauma

Reducing time lag between onset of symptoms and time of surgical or manual detorsion is of utmost importance in preserving viable testis

Nonviable testicle usually removed; higher risk of subsequent torsion on contralateral side

Venous obstruction occurs 1st, followed by obstruction of arterial flow, which leads to testicular ischemia

Scan testes side-by-side in single image

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  Side-by-side color and power Doppler to demonstrate asymmetry in blood flow to affected side

  
  
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  Side-by-side grayscale to demonstrate asymmetry in orientation of testicle

Must document which side is symptomatic