Cardiac arrhythmias, arterial kinking, extensie calcification, high bifurcation, or unusual diseases (such as fibromuscular dysplasia or dissection) may make image interpretation more difficult.

• 心律失常、血管蜿蜒成结、广泛的钙化、颈内外动脉分叉部位过高、和一些罕见病（如肌纤维发育不良或动脉夹层）都可能增加分析超声成像、出具结果的难度。