Automated Detection of Intima-Media Complex Boundaries in Longitudinal Section of Carotid Artery by Fitting Echo Model Composed of Multiple Ultrasonic Pulses to Measured Signal

摘要

The measurement of the intima-media thickness (IMT) of the carotid arterial wall, i.e., the distance from the lumen-intima boundary (LIB) to media-adventitia boundary (MAB), is important to diagnose the early-stage atherosclerosis since the IMT correlates very well with pathohistologic measurements for assessing cardiovascular risk. In the present study, an echo model was generated based on a transmitted ultrasonic pulses measured with a hydrophone. Since the redundant echo is present in the actually measured echo from the arterial wall, multiple ultrasonic pulses are employed to compose the echo model. The echo model is fitted to the RF signal measured in vivo using the normalized mean squared error (MSE) method where the positions of the models, which give the minimum error of the measured from the model signals, are determined as the boundaries of LIB and MAB. The position of the MAB is determined as the position of the fitted model signal with maximum amplitude.