Ex Vivo Micro-Computed Tomography-based Three-Dimensional Modeling and Biomechanical Assessment of the Human Aortic Root.

INTRODUCTION: Understanding the biomechanical behavior of the aortic root is essential for improving surgical planning and patient-specific simulations. Traditional tests such as planar biaxial testing are limited by small sample size and loss of three-dimensional (3D) structure. We propose a novel method combining static pressurization and micro-computed tomography (CT) imaging of intact human aortic roots to simultaneously obtain accurate 3D geometry and biomechanical data. OBJECTIVE: To evaluate the mechanical properties of healthy human aortic roots under physiological pressure conditions. METHODS: Ten aortic roots were collected from unused human donor hearts (non-cardiac death) with family consent. The roots were gradually pressurized from 20 to 120 mmHg in 20 mmHg increments and scanned at each step using high-resolution micro-CT. Measurements included diameter, stress-strain curves, and Young's modulus. RESULTS: 3D reconstructions of all ten aortic roots were successfully performed. The mean donor age was 61.2 years (49.5 - 65.6). At 80 mmHg, the median diameter of the sinotubular junction was 32.2 mm (29 - 36). Stress-strain analysis revealed non-linear behavior, with significantly lower stiffness at low pressure (20 - 80 mmHg, median Young's modulus 0.6 [0.5 - 0.8] MPa) compared to high pressure (80 - 120 mmHg, 3.2 [2.5 - 5.6] MPa, P = 0.001). CONCLUSION: This study demonstrated that ex vivo micro-CT combined with static pressurization can reliably evaluate the mechanical properties of healthy human aortic roots under physiological pressure ranges. The method provided high-fidelity 3D reconstructions and reproducible biomechanical metrics, consistent with existing literature. These results supply robust input for computational modeling and may help optimize rootsurgical procedure.