Introduction: Pneumothorax is a life-threatening condition resulting from the entry of air into the pleural cavity. The most popular imaging test used in its diagnosis is classical X-ray, and in doubtful cases, also computed tomography (CT). However, ultrasound (US) is becoming increasingly popular. Thanks to the development of diagnostic criteria, it is possible to quickly, safely, and extremely effectively detect pneumothorax using lung ultrasound. Despite its many advantages, this method has certain limitations, including conditions and diseases whose images may falsely suggest pneumothorax. Methods: The following paper is based on a compilation of our own experiences from approximately 350 lung ultrasound examinations and a literature review to identify as many clinical conditions as possible that may falsely suggest an ultrasound image of pneumothorax, along with potential causes of error, taking into account the sonomorphology and pathophysiology of the lesions. Additionally, criteria have been developed to differentiate specific conditions from pneumothorax, and a classification has been prepared based on the difficulty of differentiation, with particular emphasis on situations requiring conclusive additional testing. Conclusions: Ultrasound diagnosis of pneumothorax must be closely correlated with the clinical presentation to avoid errors. Adherence to diagnostic criteria will prevent errors in most cases. Less experienced examiners should pay particular attention to subtle differences in pleural sliding.
Jarosławski et al. (Wed,) studied this question.