Automated intima-media thickness: The Los Angeles atherosclerosis study

Common carotid artery (CCA) intima-media thickness (IMT) from B-mode ultrasound is a widely used measure of early atherosclerosis. This study evaluated within- and between-sonographer reproducibility of automated edge-tracking IMT using a low-cost mobile scanner. B-mode images of the left and right CCA were acquired on two occasions (interval of 2-14 days) by two sonographers for 38 subjects, aged 31-75 y, Reproduciblity error was measured as the mean absolute difference (MAD +/- SEM) and the standard deviation of differences (SD Delta) between repeated measurements. Within-sonographer (MAD = 0.027 +/- 0.006 mm; SD Delta = 0.044 mm) and between-sonographer errors (MAD = 0.041 +/- 0.008 mm; SD Delta = 0.064) in IMT (mean = 0.74, SD = 0.14) of a single artery were small compared to those of other protocols. Combined averaging across both body positions and arteries I educed intersonographer MAD by 47% (MAD = 0.022 +/- 0.003 mm; SD Delta = 0.029 mm), These data demonstrate that the proposed IMT protocol reduces reproducibility error by more than 50% relative to several protocols used in other major studies. (C) 1998 World Federation for Ultrasound in Medicine & Biology.