OBJECTIVES To develop and evaluate a fully automatic method to measure diameters of the ascending and descending aorta on non-ECG-gated, non-contrast computed tomography (CT) scans. MATERIAL AND METHODS The method combines multi-atlas registration to obtain seed points, aorta centerline extraction, and an optimal surface segmentation approach to extract the aorta surface around the centerline. From the extracted 3D aorta segmentation, the diameter of the ascending and descending aorta was calculated at cross-sectional slices perpendicular to the extracted centerline, at the level of the pulmonary artery bifurcation, and at 1-cm intervals up to 3 cm above and below this level. Agreement with manual annotations was evaluated by dice similarity coefficient (DSC) for segmentation overlap, mean surface distance (MSD), and intra-class correlation (ICC) of diameters on 100 CT scans from a lung cancer screening trial. Repeatability of the diameter measurements was evaluated on 617 baseline-one year follow-up CT scan pairs. RESULTS The agreement between manual and automatic segmentations was good with 0.95 ± 0.01 DSC and 0.56 ± 0.08 mm MSD. ICC between the diameters derived from manual and from automatic segmentations was 0.97, with the per-level ICC ranging from 0.87 to 0.94. An ICC of 0.98 for all measurements and per-level ICC ranging from 0.91 to 0.96 were obtained for repeatability. CONCLUSION This fully automatic method can assess diameters in the thoracic aorta reliably even in non-ECG-gated, non-contrast CT scans. This could be a promising tool to assess aorta dilatation in screening and in clinical practice. KEY POINTS • Fully automatic method to assess thoracic aorta diameters. • High agreement between fully automatic method and manual segmentations. • Method is suitable for non-ECG-gated CT and can therefore be used in screening.

中文翻译：

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在非对比增强CT上自动进行胸主动脉的3D分割和直径测量。

目的开发和评估一种在非ECG门控，非对比计算机断层扫描（CT）扫描中测量升主动脉和降主动脉直径的全自动方法。材料与方法该方法结合了多图集配准以获得种子点，主动脉中心线提取以及最佳表面分割方法以提取中心线周围的主动脉表面。从提取的3D主动脉分割中，在垂直于提取的中心线的横截面切片上，在肺动脉分叉处以及在上下3厘米处以1-cm的间隔计算升主动脉和降主动脉的直径这个水平。通过骰子相似性系数（DSC）评估了细分重叠，平均表面距离（MSD），肺癌筛查试验的100次CT扫描的直径和类内相关性（ICC）。直径测量的可重复性在617个基线-一年的随访CT扫描对上进行了评估。结果手动和自动分割之间的一致性很好，DSC为0.95±0.01，MSD为0.56±0.08 mm。手动分割和自动分割得到的直径之间的ICC为0.97，每级ICC的范围为0.87至0.94。对于所有测量，ICC为0.98，每级ICC的可重复性在0.91至0.96之间。结论即使在非ECG门控，非对比CT扫描中，这种全自动方法也可以可靠地评估胸主动脉的直径。这可能是评估筛查和临床实践中主动脉扩张的有前途的工具。要点•评估胸主动脉直径的全自动方法。•全自动方法和手动分割之间的高度一致性。•该方法适用于非ECG门控CT，因此可用于筛查。