Vet Detective · Ultrasound physics teaching guide
Reverberation, A-lines and Vertical Lung Artefacts
A simplified comparison of horizontal A-line reverberation and vertical artefacts arising from the pleural line. This is an artefact-recognition aid, not a lung-ultrasound scoring or diagnostic tool.
A-lines-only example selected. Illustration paused.
EXAMPLES:
Outgoing packet
Reflected echo (each round trip)
Pleural line / stylised vertical artefact
A-lines are displayed at repeated intervals because delayed echoes are assigned greater depth
Conceptual sound-path view
Simple A-line model; vertical-artefact mechanism deliberately simplified
Simplified lung-ultrasound display
Illustrated examples, not patient images or protocol scores
A-line reference: In this simplified model, repeated reflections between the transducer and a strong pleural–lung interface return progressively later. The system assigns those delayed echoes to greater depths, creating horizontal A-lines at approximately regular intervals. An A-line pattern is common in aerated lung but is not, by itself, a diagnosis or proof of normal lung.
Interpretation boundary: Absence of visible pleural sliding at one site is not specific for pneumothorax. It can occur with other pulmonary, pleural, ventilatory or technical conditions. Conversely, convincing lung sliding or a vertical artefact arising from the pleural line argues against pleural air at that specific point. Pneumothorax assessment requires a validated scanning protocol, multiple sonographic signs and the clinical context; this toggle is not a diagnostic test.
Vertical artefacts are also non-specific. Their number, distribution, pleural-line appearance and associated direct findings must be interpreted with the examination protocol, patient history and other imaging. This guide does not label a lung field “wet”, grade disease severity or distinguish cardiogenic from non-cardiogenic disease.
Vertical artefacts are also non-specific. Their number, distribution, pleural-line appearance and associated direct findings must be interpreted with the examination protocol, patient history and other imaging. This guide does not label a lung field “wet”, grade disease severity or distinguish cardiogenic from non-cardiogenic disease.
Recognition checklist: A conventionally defined B-line is a discrete, hyperechoic vertical artefact that arises from the pleural line, extends to the far field without fading and moves synchronously with pleural motion. Short vertical artefacts or lines that do not arise from the pleural line should not automatically be counted as B-lines.
Protocol boundary: B-line thresholds and regional scoring differ by veterinary protocol, transducer, patient population and study purpose. Apply the definitions and site map of one validated protocol consistently. This conceptual slider intentionally has no numerical B-line score or diagnostic threshold.
Protocol boundary: B-line thresholds and regional scoring differ by veterinary protocol, transducer, patient population and study purpose. Apply the definitions and site map of one validated protocol consistently. This conceptual slider intentionally has no numerical B-line score or diagnostic threshold.