Variational Mode Decomposition for B-Lines Segmentation in Lung Ultrasound Images: An Improved Approach

Accurate and rapid detection of B-lines— vertical hyperechoic artifacts in lung ultrasound (LUS) images—is essential for diagnosing and monitoring pulmonary diseases. We propose a novel algorithm based on Variational Mode Decomposition (VMD) for automatic segmentation and quantification of B-lines in LUS frames, marking the first application of VMD in this context. Each frame is treated as a two-dimensional signal and decomposed into intrinsic frequency modes, isolating characteristic vertical structures while suppressing noise and irrelevant anatomy. A block- wise projection strategy enhances structural consistency and robustness under low-contrast conditions. Evaluated on 116 annotated images from 42 patients using a portable convex probe, the method achieved a precision of 0.87, recall of 0.79, F1-score of 0.83, and Dice coefficient of 0.79. Although slightly below top deep learning models, its low computational complexity makes it suitable for real-time, point-of-care ultrasound systems. Future work may combine VMD with neural networks or beamforming to further improve performance.