Carotid Artery Motion Estimation from Sequences of B-mode Ultrasound Images: Effect of Dynamic Range and Persistence

Abstract

Motion of the carotid artery wall can be quantitatively estimated from sequences of B-mode ultrasound images. Ultrasound scanner settings, including dynamic range and persistence, can affect the appearance of anatomical structures, and consequently, the results of motion analysis. In this paper, the effects of dynamic range and persistence were studied, in an attempt to suggest optimal values for reliable motion analysis. Image sequences were recorded using four different values for dynamic range, namely 0, 48, 66 and 90 dB, and three different values for persistence, namely 0, 5.6 and 50. Radial and axial displacements as well as the correlation coefficients were estimated using block-matching from recordings of about 3 sec duration. The variances of radial and axial displacements were not significantly affected by changes in dynamic range and persistence. The mean value of the correlation coefficient, which is an index of the reliability of motion analysis, was also not significantly affected by these settings. However, an increase in persistence increased the delays between peak radial displacements and cardiac systole. It is suggested that high values of dynamic range (66 or 90 dB) and low values of persistence (0 or 5.6) are used for motion analysis based on block-matching.