Abdominal aortic aneurysm (AAA) rupture causes death in 90% of AAA patients. Clinically, the rupture potential is evaluated using AAA diameter. Aortic stiffness can potentially provide more accurate rupture risk assessment. Therefore, the aim of this study is to use non-invasive MR elastography (MRE) to estimate aortic stiffness in AAA patients, and study the relationship between stiffness and AAA diameter. Results showed that aortic stiffness varied during the serial follow-up, demonstrating (1) no correlation between AAA stiffness and diameter, and (2) AAA diameter may not be an accurate indicator for rupture potential.