Comparing the measurement of deformations of phantoms of the aorta from image obtained by MRI and stereovision

The study of the wall strain distribution could be helpful to improve the decision criterion for surgery of aortic aneurysm. Recently, numerical simulations can complete the data obtained from imaging measurement in order to develop reliable models. However, the used medical imaging tools are not experimentally validated, in metrological point of view. The aim of this study focused on accuracy and reliability of measurement obtained from kinetic MR sequences. The measures of deformations from MRI were compare to those obtained from stereovision system. Cylindrical phantom of silicone material similar to arterial behavior simulated a symmetric aneurysm was designed. A MRI compatible experimental system reproducing a cardiovascular system with phantom was developed. The acquisition of 40 images per cardiac cycle is triggered with a simulated ECG signal with the same frequency as the pump. In parallel, in-vitro measurement by stereovision system were acquired to obtain local strain by 3D reconstruction with digital image correlation (DIC). The maximum strain calculated with MRI and stereovision at the level of the maximum strain, as the evolution of the strain field along the aneurysm with a pressure of 136 mmHg, are close.