X-Ray Kerley Lines Vs. Lung Ultrasound B-Lines: Clearing up Clinical Confusion
Q1: Why did sonographers name acoustic artifacts after Kerley B lines?
Early ultrasound pioneers in the late 1990s observed that diffuse vertical artifacts appeared in the exact patient populations known for Kerley B lines on X-ray: individuals experiencing pulmonary congestion. The moniker was coined as a conceptual bridge, helping conventionally trained clinicians recognize that these vertical flares corresponded to interstitial syndrome.
Q2: Can a patient have prominent ultrasound B-lines with a normal chest radiograph?
Yes. Lung ultrasound detects extravascular lung water increases as small as 10% to 15%, whereas a chest radiograph typically requires fluid expansion of 30% or more before interlobular septa become radiographically distinct. Ultrasound frequently reveals acute interstitial congestion hours before plain films show visible changes.
Q3: Which ultrasound transducer works best for identifying B-lines?
Both phased-array (cardiac) and convex (abdominal) probes excel at assessing B-lines because their low operating frequencies (2 to 5 MHz) provide the tissue penetration needed to track artifacts to the bottom of the screen. High-frequency linear probes offer superior visualization of the pleural line itself, but their shallow depth limit can prevent verification of the deep reverberation artifacts essential for a confident diagnosis.
