Distensibility can be measured non-invasively with ECG-gated CT. The reduction of distensibility within aneurysms compared to normal proximal aorta is subtle; the lack of difference between both small and large aneurysms suggests that this reduction occurs early in the aneurysm's development. Hence, reduced distensibility might be a predictive parameter in patients with high risk of aortic disease.

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.