Background and Objective: We propose a shape reconstruction framework to generate time-resolved, patient-specific 3D aortic geometries from a limited number of standard cine 2D magnetic resonance imaging (MRI) acquisitions. A statistical shape model of the aorta is coupled with differentiable volumetric mesh optimization to obtain personalized aortic meshes. Methods: The statistical shape model was constructed from retrospective data and optimized 2D slice placements along the aortic arch were identified. Cine 2D MRI slices were then acquired in 30 subjects (19 volunteers, 11 aortic stenosis patients). After manual segmentation, time-resolved aortic models were generated via differentiable volumetric mesh optimization to derive vessel shape features, centerline parameters, and radial wall strain. In 10 subjects, additional 4D flow MRI was acquired to compare peak-systolic shapes. Results: Anatomically accurate aortic geometries were obtained from as few as six cine 2D MRI slices, achieving a mean +/- standard deviation Dice score of (89.9 +/- 1.6) %, Intersection over Union of (81.7 +/- 2.7) %, Hausdorff distance of (7.3 +/- 3.3) mm, and Chamfer distance of (3.7 +/- 0.6) mm relative to 4D flow MRI. The mean absolute radius error was (0.8 +/- 0.6) mm. Significant age-related differences were observed for all shape features, including radial strain, which decreased progressively ((11.00 +/- 3.11) x 10-2 vs. (3.74 +/- 1.25) x 10-2 vs. (2.89 +/- 0.87) x 10-2 for young, mid-age, and elderly groups). Conclusion: The proposed method enables efficient extraction of time-resolved 3D aortic meshes from limited sets of standard cine 2D MRI acquisitions, suitable for computational shape and strain analysis.

翻译：背景与目的：本研究提出一种形态重建框架，旨在从有限数量的标准电影式二维磁共振成像（MRI）采集中生成时间分辨、患者特异性的三维主动脉几何结构。通过将主动脉统计形态模型与可微分体网格优化方法相结合，实现个性化主动脉网格的构建。方法：基于回顾性数据构建统计形态模型，并确定沿主动脉弓的优化二维切片定位方案。随后对30名受试者（19名志愿者，11名主动脉瓣狭窄患者）进行电影式二维MRI切片采集。经人工分割后，通过可微分体网格优化生成时间分辨主动脉模型，进而提取血管形态特征、中心线参数及径向壁应变。其中10名受试者额外接受四维血流MRI检查，用于峰值收缩期形态的对比验证。结果：仅需六层电影式二维MRI切片即可获得解剖学精确的主动脉几何结构，相较于四维血流MRI的评估指标为：平均Dice系数（89.9±1.6）%，交并比（81.7±2.7）%，豪斯多夫距离（7.3±3.3）mm，倒角距离（3.7±0.6）mm。平均绝对半径误差为（0.8±0.6）mm。所有形态特征均呈现显著的年龄相关性差异，其中径向应变随年龄增长呈递进性下降（青年组、中年组、老年组分别为（11.00±3.11）×10⁻²、（3.74±1.25）×10⁻²、（2.89±0.87）×10⁻²）。结论：所提方法能够从有限的标准电影式二维MRI采集中高效提取时间分辨三维主动脉网格，适用于计算形态学与应变分析。