Estimation of velocity vectors and evaluation of accuracy using two types of multi-angle Doppler methods on improved stenotic vessel models

Carotid artery stenosis is a major risk factor for cerebrovascular disease, requiring accurate and early diagnosis. In this study, we propose an improved stenotic blood vessel model that accounts for in vivo vascular geometry. Using two transmit center frequencies, we evaluated accuracy in estimation of blood flow velocity vectors with a multi-angle Doppler method implemented via plane wave imaging (PWI) and multi-line transmission imaging (MLTI). Among the tested conditions, MLTI at 6.94 MHz achieved the lowest root mean square error excluding bias error (RMSEexBE). However, it exhibited the highest bias error (BE), and its lower aliasing limit led to velocity folding under severe stenosis. In contrast, while the RMSEexBE in PWI was slightly higher than that in MLTI, the BE was significantly lower.