In Vivo Strain Analysis of Dilated Ascending Thoracic Aorta by ECG-Gated CT Angiographic Imaging
- 325 Downloads
Accurate assessment of aortic extensibility is a requisite first step for elucidating the pathophysiology of an ascending thoracic aortic aneurysm (ATAA). This study aimed to develop a framework for the in vivo evaluation of the full-field distribution of the aortic wall strain by imaging analysis of electrocardiographic- (ECG) gated thoracic data of 34 patients with ATAA. Seven healthy controls (i.e., non-aneurysmal aorta) from patients who underwent ECG-gated CT angiography for coronary artery diseases were included for comparison. To evaluate the systolic function, ECG-gated computed tomography (CT) angiography was used to generate patient-specific geometric meshes of the ascending aorta, and then to estimate both the displacement and strain fields using a mathematical algorithm. Results evidenced stiff behavior for the aneurysmal aorta compared with that of the healthy ascending aorta of the controls, with patients over 55 years of age displaying significantly lower extensibility. Moreover, the patient risk as quantified by the ratio of in vivo strain to the ruptured one increased significantly with increased systolic blood pressure, older age, and higher pressure-strain modulus. Statistical analysis also indicated that an increased pressure-strain modulus is a risk factor for ATAAs with bicuspid aortic valve, suggesting a different mechanism of failure in these patients. The approach here proposed for the in vivo evaluation of the aortic wall strain is simple and fast, with promising applicability in routine clinical imaging, and could be used to develop a rupture potential criterion on the basis of the aortic aneurysm extensibility.
KeywordsAscending thoracic aortic aneurysm strain ECG-gated CT angiography Rupture risk Bicuspid aortic valve
This work was supported by a “Ricerca Finalizzata” grant from the Italian Ministry of Health (GR-2011-02348129) to Salvatore Pasta, and by the Fondazione Ri.MED for research on aneurysm biomechanics.
- 2.de Beaufort, H. W., F. J. Nauta, M. Conti, E. Cellitti, C. Trentin, E. Faggiano, G. H. van Bogerijen, C. A. Figueroa, F. L. Moll, J. A. van Herwaarden, F. Auricchio, and S. Trimarchi. Extensibility and distensibility of the thoracic aorta in patients with aneurysm. Eur J Vasc Endovasc Surg 53:199–205, 2017.CrossRefPubMedGoogle Scholar
- 5.Girdauskas, E., M. Rouman, K. Disha, B. Fey, G. Dubslaff, B. Theis, I. Petersen, M. Gutberlet, M. A. Borger, and T. Kuntze. Functional aortic root parameters and expression of aortopathy in bicuspid versus tricuspid aortic valve stenosis. J Am Coll Cardiol 67:1786–1796, 2016.CrossRefPubMedGoogle Scholar
- 9.Kim, K. H., J. C. Park, H. J. Yoon, N. S. Yoon, Y. J. Hong, H. W. Park, J. H. Kim, Y. Ahn, M. H. Jeong, J. G. Cho, and J. C. Kang. Usefulness of aortic strain analysis by velocity vector imaging as a new echocardiographic measure of arterial stiffness. J Am Soc Echocardiogr 22:1382–1388, 2009.CrossRefPubMedGoogle Scholar
- 11.Krishnan, K., L. Ge, H. Haraldsson, M. D. Hope, D. A. Saloner, J. M. Guccione, and E. E. Tseng. Ascending thoracic aortic aneurysm wall stress analysis using patient-specific finite element modeling of in vivo magnetic resonance imaging. Interact Cardiovasc Thorac Surg 21:471–480, 2015.CrossRefPubMedPubMedCentralGoogle Scholar
- 19.Pape, L. A., T. T. Tsai, E. M. Isselbacher, J. K. Oh, P. T. O’Gara, A. Evangelista, R. Fattori, G. Meinhardt, S. Trimarchi, E. Bossone, T. Suzuki, J. V. Cooper, J. B. Froehlich, C. A. Nienaber, and K. A. Eagle. Aortic diameter ≥5.5 cm is not a good predictor of type A aortic dissection—observations from the international registry of acute aortic dissection (IRAD). Circulation 116:1120–1127, 2007.CrossRefPubMedGoogle Scholar
- 25.Wittek, A., K. Karatolios, C. P. Fritzen, J. Bereiter-Hahn, B. Schieffer, R. Moosdorf, S. Vogt, and C. Blase. Cyclic three-dimensional wall motion of the human ascending and abdominal aorta characterized by time-resolved three-dimensional ultrasound speckle tracking. Biomech Model Mechanobiol 15:1375–1388, 2016.CrossRefPubMedGoogle Scholar
- 27.Yuda, S., R. Kaneko, A. Muranaka, A. Hashimoto, K. Tsuchihashi, T. Miura, N. Watanabe, and K. Shimamoto. Quantitative measurement of circumferential carotid arterial strain by two-dimensional speckle tracking imaging in healthy subjects. Echocardiography 28:899–906, 2011.CrossRefPubMedGoogle Scholar