Pneumothorax on Ultrasound

M-mode ultrasound images of the lungs (right and left) show a normal "lung sliding" on the right side "Right" and absence of it on the left side "Left".

Facts:

• Ultrasound can be performed to diagnose pneumothorax with high accuracy
• Normal "lung sliding" is seen when pleura moves against the chest wall during respiration. The movement is easily seen on real-time imaging and can be captured on M-mode ultrasound
• M-mode US shows normal lung sliding as a "seashore sign", in which the motion of pleura/lung produces sand-like granular appearance on the image. The non-mobile chest wall shows several uninterrupted band or "sea"
• Some diseases may produce "loss of lung sliding", most notably pneumothorax

Pneumothorax on US

• Absence of lung sliding shown on real-time imaging
• On M-mode as "barcode sign" or "stratosphere sign" (see above image labeled "left")
• More specific sign is the "lung point sign"

Our case: left pneumothorax (confirmed with radiography)

Reference:

Lichtenstein DA, Menu Y. A bedside ultrasound sign ruling out pneumothorax in the critically ill. Chest 1995; 108:1345-48.