Gao Xinpei, Boccalini Sara, Kitslaar Pieter H, Budde Ricardo P J, Attrach Mohamed, Tu Shengxian, de Graaf Michiel A, Ondrus Tomas, Penicka Martin, Scholte Arthur J H A, Lelieveldt Boudewijn P F, Dijkstra Jouke, Reiber Johan H C
Division of Image Processing, Dept. of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
Dept. of Radiology, University Medical Center Rotterdam, Rotterdam, The Netherlands.
Eur J Radiol. 2017 Aug;93:1-8. doi: 10.1016/j.ejrad.2017.04.020. Epub 2017 Apr 26.
Automatic accurate measuring of the aortic annulus and determination of the optimal angulation of X-ray projection are important for the trans-catheter aortic valve replacement (TAVR) procedure. The objective of this study was to present a novel fully automatic methodology for the quantification of the aortic annulus in computed tomography angiography (CTA) images.
CTA datasets of 26 patients were analyzed retrospectively with the proposed methodology, which consists of a knowledge-based segmentation of the aortic root and detection of the orientation and size of the aortic annulus. The accuracy of the methodology was determined by comparing the automatically derived results with the reference standard obtained by semi-automatic delineation of the aortic root and manual definition of the annulus plane.
The difference between the automatic annulus diameter and the reference standard by observer 1 was 0.2±1.0mm, with an inter-observer variability of 1.2±0.6mm. The Pearson correlation coefficient for the diameter was good (0.92 for observer 1). For the first time, a fully automatic tool to assess the optimal projection curves was presented and validated. The mean difference between the optimal projection curves calculated based on the automatically defined annulus plane and the reference standard was 6.4° in the cranial/caudal (CRA/CAU) direction. The mean computation time was short with around 60s per dataset.
The new fully automatic and fast methodology described in this manuscript not only provided precise measurements about the aortic annulus size with results comparable to experienced observers, but also predicted optimal X-ray projection curves from CTA images.
自动准确测量主动脉瓣环以及确定X射线投影的最佳角度对于经导管主动脉瓣置换术（TAVR）至关重要。本研究的目的是提出一种用于在计算机断层扫描血管造影（CTA）图像中量化主动脉瓣环的全新全自动方法。
采用所提出的方法对26例患者的CTA数据集进行回顾性分析，该方法包括基于知识的主动脉根部分割以及主动脉瓣环方向和大小的检测。通过将自动得出的结果与通过半自动描绘主动脉根部和手动定义瓣环平面获得的参考标准进行比较，来确定该方法的准确性。
观察者1得出的自动测量瓣环直径与参考标准之间的差异为0.2±1.0mm，观察者间差异为1.2±0.6mm。直径的Pearson相关系数良好（观察者1为0.92）。首次提出并验证了一种评估最佳投影曲线的全自动工具。基于自动定义的瓣环平面计算出的最佳投影曲线与参考标准在头/尾（CRA/CAU）方向上的平均差异为6.4°。平均计算时间较短，每个数据集约60秒。
本文描述的全新全自动快速方法不仅提供了与经验丰富的观察者相当的关于主动脉瓣环大小的精确测量结果，还能从CTA图像预测最佳X射线投影曲线。
