Reducing Registration Error in Cross-beam Vector Doppler Imaging with Position Sensor

Various vector Doppler methods have been proposed in the last several decades to overcome the Doppler angle dependency in both conventional spectral Doppler and color Doppler by measuring both the speed and direction of blood flow. However, they have not been adopted for routine use because most of them require specialized hardware, which is not available in commercial ultrasound systems. An alternative approach (cross-beam method) that uses color Doppler images obtained from different steered beam angles is more feasible, but there is error in registering multiple color Doppler images because they are not acquired simultaneously. To alleviate this problem, we have evaluated a cross-beam vector Doppler system that registers spatially with a position sensor two color Doppler images from two different angles and temporally with ECG synchronization. The registration error was reduced to an average of 0.92 mm from 2.49 mm in 9 human subjects. Vector Doppler carotid artery images of a healthy subject and a patient with atherosclerotic plaques are also presented.