Patent track sign (ultrasound)

Last revised by Assoc Prof Frank Gaillard on 25 Apr 2019

Patent track sign is a finding on color Doppler ultrasound, representing blood traveling along the course a biopsy needle track. It can occur after a biopsy of any organ, but is more often seen after liver or kidney biopsies.

Radiographic findings

  • linear color Doppler flow along the course of a biopsy needle track
    • the color Doppler flow is often disorganized
  • the track often extends out of the organ into an adjacent hematoma
  • spectral Doppler tracings of the track have not been found to be predictive of the severity of the hemorrhage

Treatment and prognosis

Visualization of the sign is associated with risk factors for post biopsy bleeding. According to one source, the patent track sign can be seen in 12% of liver biopsies 1, but the significance of seeing a patent track sign has unclear prognostic implications. 

The patent track often resolves after five minutes of post biopsy compression. If it continues after 5 minutes, this is associated with subsequent post biopsy bleeding.

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Case 1: native renal biopsy
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.