A 'comet tail' artefact on ultrasound of the lung is noted just below the pleural line with A-lines absent and B-lines (lung rockets) present throughout. What is the most likely diagnosis?
- A Cardiogenic pulmonary oedema (interstitial — B-line pattern) ✓
- B Normal aerated lung with reverberation artefacts
- C Pneumothorax
- D Pleural effusion
Explanation
B-lines (lung rockets, comet tail artefacts) on lung ultrasound are vertical, laser-like hyperechoic lines arising from the pleural line, reaching the bottom of the screen without fading, and moving with lung sliding. They represent thickened subpleural interlobular septa filled with fluid. Diffuse bilateral B-lines (>3 per intercostal space) indicate cardiogenic pulmonary oedema or ARDS. Pneumothorax shows absent B-lines, absent lung sliding, and a barcode sign on M-mode. A-lines (horizontal reverberation artefacts from pleural-air interface) indicate normal aerated lung. Pleural effusion appears as an echo-free space above the diaphragm.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.