Volonghi Paola, Tresoldi Daniele, Cadioli Marcello, Usuelli Antonio M, Ponzini Raffaele, Morbiducci Umberto, Esposito Antonio, Rizzo Giovanna
Institute of Molecular Bioimaging and Physiology, CNR, Segrate (MI), Italy.
Philips Healthcare, Monza, Italy.
Magn Reson Med. 2016 Feb;75(2):873-82. doi: 10.1002/mrm.25630. Epub 2015 Mar 10.
To propose and assess a new method that automatically extracts a three-dimensional (3D) geometric model of the thoracic aorta (TA) from 3D cine phase contrast MRI (PCMRI) acquisitions.
The proposed method is composed of two steps: segmentation of the TA and creation of the 3D geometric model. The segmentation algorithm, based on Level Set, was set and applied to healthy subjects acquired in three different modalities (with and without SENSE reduction factors). Accuracy was evaluated using standard quality indices. The 3D model is characterized by the vessel surface mesh and its centerline; the comparison of models obtained from the three different datasets was also carried out in terms of radius of curvature (RC) and average tortuosity (AT).
In all datasets, the segmentation quality indices confirmed very good agreement between manual and automatic contours (average symmetric distance < 1.44 mm, DICE Similarity Coefficient > 0.88). The 3D models extracted from the three datasets were found to be comparable, with differences of less than 10% for RC and 11% for AT.
Our method was found effective on PCMRI data to provide a 3D geometric model of the TA, to support morphometric and hemodynamic characterization of the aorta.
提出并评估一种从三维电影相位对比磁共振成像（PCMRI）采集中自动提取胸主动脉（TA）三维几何模型的新方法。
所提出的方法由两个步骤组成：TA的分割和三维几何模型的创建。基于水平集的分割算法被设定并应用于以三种不同模式采集的健康受试者（有和没有敏感度编码[SENSE]缩减因子）。使用标准质量指标评估准确性。三维模型以血管表面网格及其中心线为特征；还从曲率半径（RC）和平均扭曲度（AT）方面对从三个不同数据集获得的模型进行了比较。
在所有数据集中，分割质量指标证实手动轮廓和自动轮廓之间具有非常好的一致性（平均对称距离<1.44毫米，骰子相似系数>0.88）。从三个数据集提取的三维模型具有可比性，RC的差异小于10%，AT的差异小于11%。
我们的方法被发现在PCMRI数据上有效，可提供TA的三维几何模型，以支持主动脉的形态测量和血流动力学特征分析。
