Plankton sign (ultrasound)

Last revised by Daniel J Bell on 17 Apr 2019

Citation, DOI, disclosures and article data

Citation:

Carroll D, Bell D, Plankton sign (ultrasound). Reference article, Radiopaedia.org (Accessed on 19 Apr 2024) https://doi.org/10.53347/rID-65798

DOI:

https://doi.org/10.53347/rID-65798

Permalink:

https://radiopaedia.org/articles/65798

rID:

65798

Article created:

24 Jan 2019, David Carroll ◉

Disclosures:

At the time the article was created David Carroll had no recorded disclosures.

View David Carroll's current disclosures

Last revised:

17 Apr 2019, Daniel J Bell ◉

Disclosures:

At the time the article was last revised Daniel J Bell had no recorded disclosures.

View Daniel J Bell's current disclosures

Revisions:

2 times, by 2 contributors - see full revision history and disclosures

Systems:

Chest

Sections:

Signs

Tags:

pocus, lung

The plankton sign refers to swirling, punctiform internal echoes within an otherwise anechoic pleural effusion which demonstrate slow, whirling dynamics, occasionally buffered by cardiac and respiratory impulses. When present, one may rule out a transudative effusion, and should be highly suspicious of a haemothorax as the likely aetiology. A similar sonographic appearance is present in haemoperitoneum and haemorrhagic ascites ¹.

The slow, irregular dynamics are suggestive that no direct connection with a vascular conduit is present, and the effusion would be amenable to diagnostic thoracentesis.