A preliminary ex vivo diffusion tensor imaging study of distinct aortic morphologies.

Area of Science:

• Biomedical Imaging
• Cardiovascular Research
• Medical Physics

Background:

• Aortic pathologies like aneurysms and dissections involve microstructural changes in the aortic wall.
• Current clinical decisions rely on geometric features (e.g., aortic diameter) due to limitations in imaging microstructural information.
• Non-invasive imaging methods are needed to assess aortic tissue microstructure for better clinical insights.

Purpose of the Study:

• To investigate diffusion tensor imaging (DTI) as a non-invasive method for assessing aortic tissue microstructure.
• To explore DTI's capability in differentiating between healthy, aneurysmal, and dissected aortic tissue.
• To establish proof-of-concept for DTI's potential in clinical applications for aortic diseases.

Main Methods:

• Diffusion tensor imaging (DTI) was applied to ex vivo samples of healthy, aneurysmal, and chronic type B dissection aortae.
• Key DTI-derived metrics including fractional anisotropy, mean diffusivity, helical angle, and tractography were analyzed.
• Histological characterization was used to validate DTI findings.

Main Results:

• Distinct differences in fractional anisotropy were observed: healthy (0.24 ± 0.008), aneurysmal (0.19 ± 0.002), and dissected (0.13 ± 0.006) aortae.
• A significantly larger variation in the helical angle was found in dissected aortae (39.28 ± 11.93°) compared to healthy aortae (26.12 ± 4.60°).
• DTI metrics showed sensitivity to microstructural alterations associated with aortic pathologies.

Conclusions:

• Diffusion tensor imaging (DTI) is sensitive to pathological changes in aortic tissue microstructure.
• DTI-derived metrics can differentiate between healthy, aneurysmal, and dissected aortic tissues.
• This methodology holds promise for providing enhanced clinical insights and improving diagnostic capabilities for aortic diseases.