ESAOTE Europe BV, Maastricht, The Netherlands.
Ultrasound Med Biol. 2010 Mar;36(3):467-79. doi: 10.1016/j.ultrasmedbio.2009.12.007.
Transcutaneous ultrasound measurements of common carotid artery (CCA) diameter and intima-media thickness (IMT) give insight on arterial dynamics and anatomy, both correlating well with atherosclerosis and risk of cardiovascular disease. We propose a novel automatic algorithm to estimate CCA diameter and IMT in ultrasound (US) images, based on separate analysis of anterior and posterior CCA walls and able to distinguish internal (intima-intima) and external (adventitia-adventitia) diameter. The method combines off-line signal- and image-processing techniques to accommodate echo images acquired at a frame rate of 30 Hz and composed directly from RF data, circumventing digital video-grabbing. Segmentation consists of automatic CCA recognition, followed by adventitial delineation performed with a sustain-attack filter with exponentially decaying reference functions. Intimal delineation is then based on the multiscale anisotropic barycenter (MAB), which is an extension of a known delineation method involving the "first order absolute central moment" of the echo amplitude. An automatic measure of the quality of the US beam incidence for each wall is superimosed on the CCA contour overlays for visual feedback. Validation is carried out on 36 US CCA acquisitions from 12 healthy volunteers, as well as on synthetic US images. Results indicate good accuracy on synthetic US images (within 1.3% for diameter and 3% for IMT). The in vivo intra-recording beat-to-beat variations are on average lower than 50 microm for external diameter and IMT, and lower than 100 microm for internal diameter. A comparison with a commercial device (ART.LAB system) shows that the proposed algorithm performs better in terms of inter-recording precision. The beam incidence control significantly improves the repeatability of IMT estimates, and motivates sonographers actively to maintain a proper scan plane throughout the acquisition to minimize the incidence of confounding factors. The method is clinically viable, providing robust estimates of CCA internal and external diameter and IMT waveforms for both CCA walls, even at a low B-mode update rate of 30 Hz.
经皮超声测量颈总动脉（CCA）直径和内膜中层厚度（IMT）可深入了解动脉动力学和解剖结构，这两者均与动脉粥样硬化和心血管疾病风险密切相关。我们提出了一种新的自动算法，用于在超声（US）图像中估计 CCA 直径和 IMT，该算法基于对前壁和后壁 CCA 进行单独分析，并能够区分内部（内膜-内膜）和外部（外膜-外膜）直径。该方法结合了离线信号和图像处理技术，可适应 30Hz 帧率采集的回波图像，并直接由 RF 数据构成，从而避免了数字视频抓取。分割包括自动 CCA 识别，然后使用具有指数衰减参考函数的持续攻击滤波器进行外膜描绘。然后，基于多尺度各向异性质心（MAB）进行内膜描绘，MAB 是一种已知的基于回波幅度“一阶绝对中心矩”的描绘方法的扩展。为每个壁自动测量 US 波束入射的质量，并叠加在 CCA 轮廓覆盖层上以提供视觉反馈。该方法在 12 名健康志愿者的 36 次 US CCA 采集以及合成 US 图像上进行了验证。结果表明，在合成 US 图像上具有良好的准确性（直径的误差在 1.3%以内，IMT 的误差在 3%以内）。体内逐次心跳的变化，对于外部直径和 IMT 平均值小于 50 微米，对于内部直径平均值小于 100 微米。与商业设备（ART.LAB 系统）的比较表明，该算法在记录间精度方面表现更好。波束入射控制显著提高了 IMT 估计的可重复性，并促使超声医师在整个采集过程中积极保持适当的扫描平面，以最大程度地减少混杂因素的影响。该方法具有临床可行性，即使在 30Hz 的低 B 模式更新率下，也能为两个 CCA 壁提供 CCA 内部和外部直径以及 IMT 波形的稳健估计。
