The B-line is an artifact relevant in lung ultrasonography. As originally described, it has seven defining features 1:
- a hydroaeric comet-tail artifact
- arising from the pleural line
- extending indeﬁnitely
- erasing A-lines
- moving in concert with lung sliding, if lung sliding is present
B-line distribution corresponds with sub-pleural thickened interlobular septa, as demonstrated by CT, and are absent under normal conditions and present in alveolar-interstitial syndromes 2. Subpleural septal edema is postulated to provide a bubble-tetrahedron interface, generating a series of very closely spaced reverberations at a distance below the resolution of ultrasound which is interpreted as a confluent vertical echo which does not fade with increasing depth 3.
A few B-lines (less than 3/field of view) can often be found under normal circumstances, especially in the elderly, and around the base of the lungs 4.
- 1. Lung ultrasound—a primary survey of the acutely dyspneic patient. (2016) Journal of Intensive Care. 4 (1): 57. doi:10.1186/s40560-016-0180-1 - Pubmed
- 2. Volpicelli G, Mussa A, Garofalo G, Cardinale L, Casoli G, Perotto F, Fava C, Frascisco M. Bedside lung ultrasound in the assessment of alveolar-interstitial syndrome. (2006) The American journal of emergency medicine. 24 (6): 689-96. doi:10.1016/j.ajem.2006.02.013 - Pubmed
- 3. Soldati G, Demi M, Inchingolo R, Smargiassi A, Demi L. On the Physical Basis of Pulmonary Sonographic Interstitial Syndrome. (2016) Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine. 35 (10): 2075-86. doi:10.7863/ultra.15.08023 - Pubmed
- 4. Dietrich CF, Dietrich MG, Dietrich BM, Dietrich VG, Dietrich SA, Dietrich WD, Dietrich ANSS, Dietrich CXW, Dietrich FM, Dietrich YD. Lung B-line artefacts and their use. (2016) Journal of Thoracic Disease. 8 (6): 1356-1365. doi:10.21037/jtd.2016.04.55 - Pubmed