testicular torsion U.S

Radiographic features

Ultrasound

Ultrasound is the modality of choice for evaluating the potentially torted testis. It is simultaneously able to assess the structure of the testis as well as the vascularity, all without subjecting the gametes to ionising radiation. The examination also allows the radiologist to clinically assess the patient and extract any pertinent history.

The most important part of the examination is comparison to the normal side

The key findings of a torted testis include :

altered blood flow
- in incomplete torsion
  - elevated resistive index (RI > 0.75) ³
  - to and fro flow
- in complete torsion
  - absence of blood flow in both the testis and epididymis
increase in size of the testis and epididymis
homogenous echotexture
- early finding, prior to necrosis
heterogenous echotexture
- a late finding (after 24 hours), implies necrosis
- hypoechoic regions represent necrosis
- hyperechoic regions represent haemorrhage (if testis is reperfused)
twisted spermatic cord may be visible
reactive hydrocoele
reactive thickening of the scrotal skin with hyperaemia and increased flow on colour
doppler examination
peripheral testicular neovascularisation
- only seen after a number of days and represent recruiting and enlargement of small peripheral collaterals
- only peripheral and patchy portions of the testis are perfused

It is important to realise that epididymo-orchitis can closely mimic the appearances of a both torsion and spontaneously de-torted testis . The only way to exclude torsion from the differential
is if changes are entirely confined to the epididymis with a completely normal testis

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