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.
- 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.
- 1. Kim KW, Kim MJ, Kim HC, Park SH, Kim SY, Park MS, Kim TK. Value of "patent track" sign on Doppler sonography after percutaneous liver biopsy in detection of postbiopsy bleeding: a prospective study in 352 patients. AJR. American journal of roentgenology. 189 (1): 109-16. doi:10.2214/AJR.07.2071 - Pubmed
- 2. Longo JM, Bilbao JI, Barettino MD, Larrea JA, Pueyo J, Idoate F, deVilla VH. Percutaneous vascular and nonvascular puncture under US guidance: role of color Doppler imaging. Radiographics : a review publication of the Radiological Society of North America, Inc. 14 (5): 959-72. doi:10.1148/radiographics.14.5.7991826 - Pubmed
- 3. Rubens DJ, Gottlieb RH, Fultz PL. Role of color Doppler imaging in interventional sonography. Journal of clinical ultrasound : JCU. 27 (5): 259-71. Pubmed