Non-invasive ultrasonic measurement of the elastic properties of the human abdominal aorta

Abstract

A new echo tracking device linked to real time ultrasonic B mode equipment was developed to measure non-invasively the elastic properties of the human abdominal aorta. Pulsatile diameter change and mean diameter of the abdominal aorta were measured in 61 subjects with this ultrasonic device. Strain and pressure-strain elastic modulus E_p were calculated from pulsatile diameter change, diameter, and pulse pressure obtained by the auscultatory method. Strain significantly decreased with age; 0.076(0.024) (mean(SD)) in group 1 (20 young adults below the age of 35 years); 0.048(0.024) in group 2 (21 middle aged subjects between the ages of 35 and 60 years); and 0.030(0.010) in group 3 (20 elderly subjects over the age of 60 years). E_p values were 0.99(0.34)× 10⁵, 1.55(0.68)× 10⁵, and 3.80(2.05)× 10⁵ N·m⁻² in groups 1, 2, and 3 respectively. E_p in group 3 was significantly higher than in groups 1 and 2. The regression equation relating Ep to age was E_p = (−0.72 + 0.058×age)×l0⁵ N·m⁻² (r=0.73). The E_p value and its age related increase agreed with the findings in postmortem arteries. The elastic properties of the abdominal aorta could, therefore, be determined non-invasively by this ultrasonic method.