Background and Objective: To assess the feasibility and accuracy of reconstructing time-resolved, three-dimensional, subject-specific aortic geometries from a limited number of standard cine 2D magnetic resonance imaging (MRI) acquisitions. This is achieved by coupling a statistical shape model with a differentiable volumetric mesh optimization algorithm. Methods: Cine 2D MRI slices were manually segmented and used to reconstruct subject-specific aortic geometries via a differentiable mesh optimization algorithm, constrained by a statistical shape model. Optimal slice positioning was first evaluated on synthetic data, followed by in-vivo acquisition in 30 subjects (19 volunteers and 11 aortic stenosis patients). Time-resolved aortic geometries were reconstructed, from which geometric descriptors and radial strain were derived. In a subset of 10 subjects, 4D flow MRI data was acquired to provide volumetric reference for peak-systolic shape comparison. Results: Accurate reconstruction was achieved using as few as six cine 2D MRI slices. Agreement with 4D flow MRI reference data yielded a 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. The mean absolute radius error along the aortic arch was (0.8 +/- 0.6) mm. Secondary analysis demonstrated significant differences in geometric features and radial strain across age groups, with strain decreasing progressively with age at values of (11.00 +/- 3.11) x 10-2 vs. (3.74 +/- 1.25) x 10-2 vs. (2.89 +/- 0.87) x 10-2 for the young, mid-age, and elderly groups, respectively. Conclusion: The proposed framework enables reconstruction of time-resolved, subject-specific aortic geometries from a limited number of standard cine 2D MRI acquisitions, providing a practical basis for downstream computational analysis.

翻译：背景与目的：评估利用有限数量的标准动态二维磁共振成像（MRI）采集数据重建时间分辨、个体化三维主动脉几何结构的可行性及准确性。该方法通过结合统计形状模型与可微分体网格优化算法实现。方法：对动态二维MRI切片进行人工分割，并借助可微分网格优化算法（受统计形状模型约束）重建个体化主动脉几何结构。首先基于合成数据评估最优切片定位，随后在30名受试者（19名志愿者及11名主动脉瓣狭窄患者）中开展在体采集。重建获得时间分辨主动脉几何结构，并以此导出几何描述符及径向应变。在10名受试者的子集中，采集四维血流MRI数据，为收缩峰值形态比较提供容积参考。结果：使用仅六个动态二维MRI切片即可实现精确重建。与四维血流MRI参考数据的一致性评估结果为：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。沿主动脉弓的平均绝对半径误差为（0.8±0.6）mm。次级分析显示，不同年龄组的几何特征与径向应变存在显著差异，且应变随年龄增长呈递减趋势：青年组（11.00±3.11）×10⁻²、中年组（3.74±1.25）×10⁻²、老年组（2.89±0.87）×10⁻²。结论：所提出的框架能够基于有限数量的标准动态二维MRI采集数据重建时间分辨、个体化主动脉几何结构，为后续计算分析提供了实用基础。