P6.20 EFFECTS OF DIFFERENT MEASUREMENT TECHNIQUES ON CAROTID STIFFNESS EVALUATION

Abstract

In recent years, great attention has been placed on local carotid elasticity. Carotid pulse wave velocity (cPWV) can be considered a surrogate marker for carotid stiffness evaluation. Aim of this study was to compare four different techniques for carotid stiffness assessment. Ten young healthy subjects (34.7±6.9 years, 40% males, BMI 21.6±2.2 kg/m2) were enrolled. For each volunteer, four different carotid stiffness measurements were obtained: i) ultrasound carotid stiffness (CS) values were estimated from US diameter and tonometric pulse pressure measurements combined by Bramwhell-Hill equation ii) cPWVloop values were calculated from US simultaneous measurements of diameter and flow velocity using the lnD-V loop slope iii) cPWVMRI values were obtained from velocity-encoded MRI images using QA method iv) cPWVAcc values were achieved by means of a new accelerometric system which consists in two percutaneous accelerometers placed 2.4 cm apart on the subject’s neck; PWV is calculated dividing the distance between the sensors for the time delay between the signals. Table 1 shows the results of the comparisons between CS (5.39±0.76 m/s), cPWVMRI (5.81±0.77 m/s), cPWVloop (4.18±0.96 m/s) and cPWVAcc (5.12±1.25 m/s) values. All the comparisons exhibit satisfying correlations. The only non-significative bias is shown by the comparison between CS values and cPWVAcc ones while the comparison between CS measurements and cPWVloop evaluations provides the lowest standard deviation of the difference. In conclusion, this preliminary study suggests that attention should be placed when using different methods of carotid stiffness assessment, especially in case of comparison between values obtained with different methods. Mean Difference ± SD of difference (m/s) R2 CS vs cPWVloop 1.29±0.42 0.81 CS vs cPWVMRI −0.51±0.54 0.55 CS vs cPWVAcc 0.27±0.75 0.67 cPWVloop vs cPWVMRI −1.77±0.56 0.71 cPWVloop vs cPWVAcc −1.16±0.57 0.66 cPWVMRI vs cPWVAcc −0.92±0.99 0.39