In situ visualization of aortic dissection propagation in notched rabbit aorta using synchrotron X-ray tomography

Aortic dissection is a complex, intramural, and dynamic condition involving multiple mechanisms, hence, difficult to observe. In the present study, a controlled in vitro aortic dissection was performed using tension-inflation tests on notched rabbit aortic segments. The mechanical test was combined with con-ventional (cCT) and synchrotron (sCT) computed tomography for in situ imaging of the macro-and micro-structural morphological changes of the aortic wall during dissection. We demonstrate that the morphol-ogy of the notch and the aorta can be quantified in situ at different steps of the aortic dissection, and that the notch geometry correlates with the critical pressure. The phenomena prior to propagation of the notch are also described, for instance the presence of a bulge at the tip of the notch is identified, de-forming the remaining wall. Finally, our method allows us to visualize for the first time the propagation of an aortic dissection in real-time with a resolution that has never previously been reached.Statement of significance With the present study, we investigated the factors leading to the propagation of aortic dissection by reproducing this mechanical process in notched rabbit aortas. Synchrotron CT provided the first visuali-sation in real-time of an aortic dissection propagation with a resolution that has never previously been reached. The morphology of the intimal tear and aorta was quantified at different steps of the aortic dissection, demonstrating that the early notch geometry correlates with the critical pressure. This quan-tification is crucial for the development of better criteria identifying patients at risk. Phenomena prior to tear propagation were also described, such as the presence of a bulge at the tip of the notch, deforming the remaining wall.(c) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this study, a controlled in vitro aortic dissection was performed on notched rabbit aortic segments using tension-inflation tests. Conventional and synchrotron computed tomography were used to observe the macro- and micro-structural morphological changes of the aortic wall during dissection. The study demonstrated that the morphology of the notch and the aorta can be quantified at different steps of the aortic dissection, and the notch geometry correlates with the critical pressure. The method allowed for the real-time visualization of aortic dissection propagation with unprecedented resolution.