MR elastography of the human abdominal aorta: A preliminary study

Purpose: To investigate the feasibility of using MR elastography (MRE) for the evaluation of the stiffness of in vivo aortic wall. Materials and Methods: To validate the experimental approach for imaging the aorta in vivo, a gel phantom with an embedded porcine aorta was imaged in the presence of fluid flow within the aorta. The potential changes in the elasticity of the vessel wall with changes in pressure were investigated. The feasibility of performing MRE of abdominal aorta was assessed in five volunteers (age, 22-40 years; body mass index, 21.5-25.2 kg/m²). The pulse-gated cine MRE technique was used to study the wave propagation along the aorta throughout the cardiac cycle and provide estimates of aortic stiffness in diastole. Results: In the phantom study, the wave propagation was well visualized within the porcine aorta embedded in the gel phantom. An increase of the Young's modulus-wall thickness (E*t) product with the increase in static pressure was observed. In the in vivo study, the waves were well visualized within the lumen of abdominal aorta in the five volunteers in diastolic phase, but they were not well visualized during systole. Conclusion: MRE is feasible for noninvasively assessing the stiffness of the abdominal aorta and merits further investigation.