Reproducibility of ultrasonic measurement of carotid artery intima-media thickness

Objective To evaluate the reproducibility of ultrasonic measurement of carotid artery intima-media thickness(IMT)under the study condition of the project of Establishment of an Integrated System for CHD Prevention and Treatment.Methods Ten subjects were scanned twice using 2 different type ultrasound systems(used by 2 field centers separately)to evaluate the inter equipment variability.Randomly selected 2 sonographers from each center attended the reproducibility test.Fifteen subjects were scanned twice by the sonographers independently to evaluate the intra and inter operator variability.Twenty image sequences were read twice by a single reader and once by an experienced reader to evaluate the intra and inter reader variability.All images were center read.Results The mean difference of mean IMT measurements of inter equipment,average intra and inter operator,and average intra and inter reader were (0.028±0.017)mm,(0.048±0.052)mm,(0.035±0.022)mm,(0.030±0.032)mm,and(0.081±0.043)mm,respectively,while the values of max IMT were(0.047±0.029)mm,(0.090±0.09)mm,(0.055±0.044)mm,(0.062±0.053)mm,and(0.085±0.050)mm.Conclusions Mean IMT measurement is more reproducible than max IMT.The more sites measured,the better reproducibiliby can achive.Comparing with published studies,the reproducibility of IMT measurement in our study is satisfied.