Department of Radiology and Med. Informatics, Biomedical Imaging Group Rotterdam, Erasmus MC, Rotterdam, The Netherlands.
Int J Comput Assist Radiol Surg. 2012 Mar;7(2):207-15. doi: 10.1007/s11548-011-0633-x. Epub 2011 Jun 29.
The purpose of this paper is to present a methodology to estimate the carotid artery lumen centerlines in ultrasound (US) images obtained in a free-hand examination. Challenging aspects here are speckle noise in US images, artifacts, and the lack of contrast in the direction orthogonal to the US beam direction.
An algorithm based on a rough lumen segmentation obtained by robust ellipse fitting was developed to deal with these conditions and estimate the lumen center in 2D B-mode scans. In a free-hand sweep examination, continuous image acquisitions are performed through time when the radiologist moves the probe on the patient's neck. The result is a series of images that show 2D cross-sections of the carotid's morphology. A tracking sensor (Flock of Birds) was attached to the probe and both were connected to a PC executing the Stradwin software, which relates spatial information to the acquisition data of the US probe. The spatial information was combined with the 2D lumen center estimates to provide a centerline in 3D. For validation, 19 carotid scans from 15 different patients were scanned, their centerlines calculated by the algorithm and compared with results acquired by manual annotations.
The average Euclidean distance between both among all the examinations was 0.82 mm. For each examination, the percentage of these Euclidean distances below 2 mm was calculated; the average over all examinations was 92%.
Automated 3D estimation of carotid artery lumen centerlines in free-hand real-time ultrasound is feasible and can be performed with high accuracy. The algorithm is robust enough to keep the centerlines inside the vessel, even in the absence of contrast in parts of the vessel wall.
本文旨在提出一种在自由手部检查中获取的超声（US）图像中估计颈动脉管腔中心线的方法。这里的挑战包括 US 图像中的斑点噪声、伪影以及与 US 束方向正交方向上的对比度不足。
开发了一种基于鲁棒椭圆拟合得到的粗略管腔分割的算法，以处理这些情况并估计二维 B 模式扫描中的管腔中心。在自由手部扫查中，当放射科医生在患者颈部移动探头时，通过时间连续采集图像。结果是一系列显示颈动脉形态的二维横截面的图像。将跟踪传感器（鸟群）附接到探头，两者都连接到执行 Stradwin 软件的 PC，该软件将空间信息与 US 探头的采集数据相关联。将空间信息与二维管腔中心估计值相结合，以提供三维中心线。为了验证，对 15 名不同患者的 19 个颈动脉扫描进行了扫描，通过算法计算其中心线，并与手动注释获得的结果进行比较。
所有检查中两者之间的平均欧几里得距离为 0.82 毫米。对于每个检查，计算这些欧几里得距离低于 2 毫米的百分比；所有检查的平均值为 92%。
在自由实时超声中自动估计颈动脉管腔中心线是可行的，并且可以达到很高的精度。该算法足够鲁棒，可以保持中心线在血管内，即使在血管壁的某些部分对比度不足的情况下也是如此。
