A comparison of the approaches to assess the abdominal aortic stiffness using M-mode ultrasonography, tissue tracking and strain rate imaging.

INTRODUCTION Which kind of ultrasound imaging technique is suitable for the assessment of the abdominal aortic stiffness are seldom reported. The purposes of this study were to explore a reliable method to evaluate the abdominal aortic stiffness in patients with hypertension among the following ultrasound imaging techniques: M-mode ultrasonography (M-mode), tissue tracking and strain rate imaging. METHODS Fifty patients with hypertension and fifty age and sex-matched healthy volunteers were involved in this study. The displacement (d), the peak strain (ε) and the peak strain rate (s) were obtained from the long-axis images of the abdominal aorta using tissue tracking and strain rate imaging, respectively. The pressure strain elastic modulus (Ep), β stiffness index and distensibility were calculated according to the conventional formulas using M-mode combined with the blood pressure. RESULTS Compared to the normal subjects, the difference between systolic diameters and diastolic diameters (∆diameter), the displacement of posterior wall (d-posterior), the difference of the displacement between anterior and posterior wall (∆ displacement), and the distensibility decreased and the Ep and β stiffness index increased in the hypertension patients There were no significant differences between the patients with hypertension and the normal subjects according to the ε, s. Among ∆diameters, d-posterior, ∆displacement, the ε and s, only ∆diameters significantly correlated with the Ep, β stiffness index and the distensibility in hypertension patients. CONCLUSIONS Strain rate imaging cannot sensitively discriminate the difference of the abdominal aortic stiffness between patients with hypertension and the normal subjects. M-mode ultrasonography is still a classical method for accessing the aortic elasticity.