Age related changes of human aortic distensibility: evaluation with ECG-gated CT.

Aortic distensibility is a parameter to grade vascular diseases and age-related effects because it is related to the elastic properties of the vessel wall. In this study vascular cross-sectional area changes have been determined using ECG-gated CT to analyse the age dependency of aortic distensibility. Distensibility measurements of the aorta were performed in 31 subjects (28 to 85 years). Time-resolved images were acquired either with a 4- or 16-detector row CT system using a modified CT angiography protocol. Cross-sectional area changes of the aorta were calculated by semiautomatic segmentation, and distensibility values were obtained using additional systemic blood pressure measurements. The aorta could be segmented successfully in all subjects. A decrease of aortic distensibility with age was found (r=0.50). Below (above) the renal arteries, the annual decrease was Delta D ( infrarenal ) =(-2.1+/-0.7).10(-7 )Pa(-1)a(-1), (D ( suprarenal ) Delta=(-3.5+/-1.1).10(-7 )Pa(-1)a(-1)). Differences between the ages, the youngest third and oldest third studied, were found to be significant (P( suprarenal )=0.003; P( infrarenal )=0.025). An age-dependent decrease of aortic wall elasticity can be determined in a modified routine CT angiography study.