Lung point sign of pneumothorax on ultrasound

Case contributed by Dr Andrew Dixon

This case featured in our 2016 Trauma Radiology Course which is now available to view online.

In the absence of pneumothorax, the two pleural layers slide along each other creating a series of comet tail artefacts on ultrasound referred to as the sliding sign. However when air sits in the pleural space and separates the two pleural layers no sliding is seen, referred to as absent sliding sign.

The junction between sliding lung and absent sliding is known as the lung point and identification of this is near 100% specific for pneumothorax and also gives an indication of pneumothorax size by its location. It is not able to be found in all pneumothorax cases (sensitivity is around 65%) especially large pneumothoraces where the lung is collapsed and there is globally absent sliding. 

This case was confirmed on subsequent CT scan. 

Case Discussion

Example of the lung point sign which is a highly specific sign of pneumothorax on ultrasound

Case courtesy of Dr Kylie Baker. 

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Case information

rID: 45149
Published: 16th May 2016
Last edited: 28th Jul 2016
System: Chest
Inclusion in quiz mode: Included

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