In Vitro Validation of a Novel Image-Based Inverse Method for Mechanical Characterization of Vessels

Much interest has been generated by the prospect of analyzing atherosclerotic plaques and diseased arteries from a biomechanical perspective using computational approaches. In silico models offer quantification of biomechanical state, as well as insights that cannot be obtained by direct measurements, particularly in vivo. However, study results can be highly sensitive to model fidelity, including accuracy of patient-specific mechanical constitutive properties. Our previous work has described a novel inverse method to estimate patient-specific biomechanical tissue characteristics using intravascular imaging and demonstrated its efficacy in silico. Building upon this earlier work, we here validate the characterization approach in vitro using two different phantom models in a benchtop setting, comparing material parameters recovered by the approach in situ to those recovered through tensile testing of the phantom material. The image-based inverse method recovered the stiffness of the two phantoms with errors of 13% (3.37 ± 0.18 MPa vs. 2.98 ± 0.03 MPa) and 8.7% (788 ± 69 kPa vs. 863 ± 11 kPa). The results indicate a relatively high degree of accuracy and robustness, highlighting the potential for future in vivo application of the method.