Predicting rupture locations of ascending aortic aneurysms using CT-based finite element models

Area of Science:

• Biomedical Engineering
• Computational Mechanics
• Cardiovascular Imaging

Background:

• Ascending aortic aneurysms pose a significant mortality risk, necessitating accurate rupture prediction.
• Computational models, specifically finite element (FE) models, show promise in improving rupture risk assessment over traditional diameter-based methods.
• The reliability and predictive timeframe of FE models for determining ascending aortic rupture location remain largely uninvestigated.

Purpose of the Study:

• To evaluate the capability of FE models, derived from computed tomography (CT) scans, in predicting the rupture location of ascending aortic aneurysms.
• To determine the temporal reliability of FE model predictions for ascending aortic rupture location.

Main Methods:

• Acquired pre- and post-rupture CT scans from 12 patients undergoing emergency surgical repair for ascending aorta rupture.
• Utilized rigid iterative closest point (ICP) registration to align post-rupture geometries with pre-rupture FE models.
• Compared predicted high equivalent strain regions from FE models with actual rupture sites.

Main Results:

• FE models successfully predicted rupture location in 5 patients with scan intervals of 20 days to 2 years and 3 months.
• Rupture location prediction failed in 4 out of 5 patients when the interval between scans exceeded 3 years.
• Accurate strain distribution in FE models depended on pre-rupture scan resolution and contrast agent presence.

Conclusions:

• FE models show potential for predicting ascending aortic aneurysm rupture location, particularly for shorter time intervals between scans.
• A time interval likely exists beyond which FE model predictions of rupture location may become unreliable.
• Findings may inform the clinical validation of FE models for ascending aortic aneurysm rupture risk assessment.