The average of integrated backscatter (AII) was measured and corrected as follows: IBS%= AII of plaque/ AII of adventitia of the same site.

• 脱机后分析，感兴趣区（ROI）分别置于同一斑块内3个不同位置，记录每个采样的IBS均值（AII），并采取如下方法校正，用斑块同侧的颈动脉外膜的IBS值校正斑块AII值，即AII校正值（IBS%25）= 斑块AII值/同侧外膜AII值×100%25 。