Lung Ultrasound: Breaking Free from Artifact Labels and Misnomers

Background Lung ultrasound (LU) has now become an indispensable diagnostic tool, fulfilling his prediction. However, outdated concepts and terminologies in LU interpretation require reevaluation to align with current clinical knowledge. Aim of Study The study aims to modernize lung ultrasound (LU) interpretation by transitioning from artifact-based terminologies, such as A-lines and B-lines, to nomenclature that emphasizes anatomical and clinical significance. This approach seeks to enhance diagnostic precision and utility in critical care and respiratory medicine. Method After CT examination a review and reinterpretation of LU findings were performed, integrating insights from over 600 patient ultrasound examinations. The study redefined common terminologies like A-lines, B-lines, and C-lines based on their anatomical origins and clinical relevance. A novel diagnostic framework—Merlin’s space, including the Healthy and Sick Bat Signs—was introduced to differentiate normal from pathological lung conditions. Results A-lines were redefined as horizontal hyperechoic lines representing air-tissue interfaces, observed in both healthy lungs and pathological states (e.g., abscesses, COPD, asthma, pulmonary embolism, bronchiectasis hydropneumothorax). B-lines were interpreted as vertical streaks indicating interstitial fluid, with the number reflecting the severity of conditions like pulmonary edema and inflammation. Advanced cases exhibited a "waterfall sign." C-lines were clarified as pleural irregularities rather than artifacts, indicative of structural changes such as fibrosis or chronic inflammation. Merlin’s space was systematically evaluated through its components: the twinkling white area, grey-in-black zone, and rib shadows, enabling rapid differentiation between healthy (Healthy Bat Sign) and diseased states (Sick Bat Sign). Conclusions This study advocates for a paradigm shift in LU interpretation, focusing on anatomical and clinical findings rather than artifact-based descriptions. By adopting descriptive and pathology-oriented nomenclature, clinicians can improve diagnostic accuracy and make timely, informed decisions. The proposed framework—incorporating the Healthy and Sick Bat Signs—offers a practical, radiation-sparing alternative to traditional imaging methods, aligning LU practice with modern medical standards. This distinct approach to pulmonary ultrasound interpretation draws upon the groundbreaking work of Prof. Daniel Lichtenstein and the efforts of all who have championed the value of this examination. While this paradigm shift may not be immediately embraced, the article trusts in the ethical understanding of its audience and draws inspiration from the wisdom of Charles Sidney Burwell: “Half of what we are going to teach you is wrong, and half of it is right. Our problem is that we don't know which half is which.”