Semi-automated tracking and continuous diameter monitoring of inferior vena cava in simulated and experimental ultrasound imaging

Assessment of respirophasic diameter fluctuations of the inferior vena cava (IVC) is detrimentally affected by its concomitant displacements. This study aims at presenting and validating a method to compensate for IVC movement artifacts while continuously measuring its diameter in an automated fashion (with minimal interaction with the user) from a longitudinal B-mode ultrasound (US) clip. Performance was tested on both experimental US clips collected from 4 healthy subjects and simulations, implementing rigid IVC displacements and pulsation. Compared to the traditional M-mode measurements, the new approach systematically reduced errors in caval index (CI) assessment (range over maximum diameter value) by an extent depending on individual vessel geometry, IVC movement and choice of the M-line (the line along which the diameter is computed). In experimental recordings, it identified both the cardiac and respiratory components of IVC movement and pulsatility and evidenced the spatial dependence of IVC pulsatility. IVC tracking appears a promising approach to reduce movement artifacts and to improve reliability of IVC diameter monitoring.