Patent track sign

Case contributed by Matt A. Morgan
Diagnosis certain


Native kidney biopsy for unexplained proteinuria.

Patient Data

Age: 40 years
Gender: Male

Sequential images from a native kidney biopsy. The lower pole was chosen for the biopsy. After the needle was deployed and withdrawn, a "patent track" of color flow along the course of the biopsy indicates active bleeding. The patent track extends out into a small perirenal hemorrhage.

After two minutes of compression the kidney was re-imaged. The patent track was still present and the perirenal hemorrhage had increased slightly in size.

With 8 more minutes of compression, the patent track eventually closed and the size of the hematoma stabilized.

Case Discussion

This case is a good example of the patent track sign: a color Doppler signal along the course of a biopsy, indicating that the track has not collapsed/coapted and that there is still active bleeding from the procedure. The track usually extends out of the biopsied organ into a surrounding hematoma, as in this case.

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