Interobserver variability of peak systolic velocity measurements in the common carotid artery

Abstract: Stroke is ranked as the number one cause of death in Vietnam and the second leading cause of death in the world. Stenosis in the carotid arteries is one of the major risk factors for stroke, making it extremely important to confirm the diagnosis. Duplex ultrasound including measurements of the peak systolic velocity is considered the most accurate method when it comes to screening of carotid stenosis. However, the survey method is user dependent and differences in the results related to the scanning technique of the examiner may occur. The aim of this study was to determine the diagnostic variability for measuring peak systolic velocity in the common carotid artery in order to investigate whether the obtained results differ depending on the examiner. 30 healthy volunteers underwent carotid duplex ultrasound performed by two different examiners. Peak systolic velocity was measured with pulsed waved Doppler caudally of the carotid bifurcation. A T-test and a Bland-Altman plot were later applied in order to determine interobserver variability between the examiners. Results showed no significant difference in the measurements, with a mean difference of -0.01 m/s. Despite low interobserver variability, reliable conclusions cannot be drawn from the results since both examiners lacked adequate experience.