title: Automated intima-media thickness: the Los Angeles Atherosclerosis Study.
abstract: 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 (SDdelta) between repeated measurements. Within-sonographer (MAD=0.027+/-0.006 mm; SDdelta=0.044 mm) and between-sonographer errors (MAD=0.041+/-0.008 mm; SDdelta=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 reduced intersonographer MAD by 47% (MAD=0.022+/-0.003 mm; SDdelta=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.
authors.affiliation: Department of Preventive Medicine, Institute for Health Promotion and Disease Prevention Research, University of Southern California School of Medicine, Los Angeles 90033-4500, USA. jimdwye@hsc.usc.edu
authors.forename: J H
authors.initials: JH
authors.lastname: Dwyer
authors.forename: P
authors.initials: P
authors.lastname: Sun
authors.forename: H
authors.initials: H
authors.lastname: Kwong-Fu
authors.forename: K M
authors.initials: KM
authors.lastname: Dwyer
authors.forename: R H
authors.initials: RH
authors.lastname: Selzer
mesh_terms: D000328:Adult; D000368:Aged; D001161:Arteriosclerosis / Q000150:complications / Q000000981:diagnostic imaging* / Q000503:physiopathology; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging*; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000503:physiopathology; D003362:Cost-Benefit Analysis; D005500:Follow-Up Studies; D006801:Humans; D015141:Los Angeles; D008875:Middle Aged; D015588:Observer Variation; D010865:Pilot Projects; D015203:Reproducibility of Results; D017539:Tunica Intima / Q000000981:diagnostic imaging*; D014463:Ultrasonography; D014741:Video Recording