Phase‐contrast MRI‐based elastography technique detects early hypertensive changes in ex vivo porcine aortic wall

Purpose To measure the elastic properties of ex vivo porcine aortas in control and hypertensive groups using a phase contrast magnetic resonance imaging (MRI)‐based elastography technique. Materials and Methods Female domestic pigs were randomized to a normal control group (N; n = 5) or a renovascular hypertension group (HT; n = 5) for the duration of 3 months. Mean arterial pressure was significantly higher in the hypertension group than in the control group (173 ± 12 vs. 115 ± 11 mmHg, P ≤ 0.05). The animals were euthanized after 3 months of hypertension and abdominal aortas harvested. The ex vivo aortic samples were then examined using a phase‐contrast MRI‐based elastography technique. Results The Young's modulus‐wall thickness product, a reflection of vascular stiffness, was significantly higher in the hypertension group than in the control group (0.571 ± 0.080 vs. 0.419 ± 0.026, P < 0.05). Histological analysis and staining confirmed increased intima‐media thickness and collagen content in the hypertensive aorta, while elastin staining showed no difference. Conclusion The current study shows that MR elastography offers a method to study the physiologic changes in the arterial wall secondary to early hypertension. J. Magn. Reson. Imaging 2009;29:583–587. © 2009 Wiley‐Liss, Inc.