🤖 AI Summary
Manual landmark annotation for linear measurements of the left ventricle in B-mode parasternal long-axis (PLAX) views is time-consuming and error-prone; existing deep learning methods suffer from severe landmark misalignment.
Method: We propose a semi-automatic measurement framework integrating anatomically informed M-mode imaging and geometric constraints. First, anatomical M-mode images are synthesized from B-mode video to enhance spatiotemporal consistency of endocardial motion. Second, key anatomical landmarks are detected in the M-mode domain, and a collinearity constraint is enforced via line-based regularization to correct misalignments. Finally, optimized landmarks are projected back onto the B-mode image for quantitative measurement. The framework is architecture-agnostic and supports interactive refinement.
Results: Experiments demonstrate statistically significant reduction in measurement error versus conventional B-mode approaches (p < 0.01), with strong generalizability and clinical applicability.
📝 Abstract
Linear measurements of the left ventricle (LV) in the Parasternal Long Axis (PLAX) view using B-mode echocardiography are crucial for cardiac assessment. These involve placing 4-6 landmarks along a virtual scanline (SL) perpendicular to the LV axis near the mitral valve tips. Manual placement is time-consuming and error-prone, while existing deep learning methods often misalign landmarks, causing inaccurate measurements. We propose a novel framework that enhances LV measurement accuracy by enforcing straight-line constraints. A landmark detector is trained on Anatomical M-Mode (AMM) images, computed in real time from B-mode videos, then transformed back to B-mode space. This approach addresses misalignment and reduces measurement errors. Experiments show improved accuracy over standard B-mode methods, and the framework generalizes well across network architectures. Our semi-automatic design includes a human-in-the-loop step where the user only places the SL, simplifying interaction while preserving alignment flexibility and clinical relevance.