title: Comparison of semi-automated and manual measurements of carotid intima-media thickening.
abstract: Carotid intima-media thickening (CIMT) is a marker of both arteriosclerotic and atherosclerotic risks. Technological advances have semiautomated CIMT image acquisition and quantification. Studies comparing manual and automated methods have yielded conflicting results possibly due to plaque inclusion in measurements. Low atherosclerotic risk subjects (n = 126) were recruited to minimise the effect of focal atherosclerotic lesions on CIMT variability. CIMT was assessed by high-resolution B-mode ultrasound (Philips HDX7E, Phillips, UK) images of the common carotid artery using both manual and semiautomated methods (QLAB, Phillips, UK). Intraclass correlation coefficient (ICC) and the mean differences of paired measurements (Bland-Altman method) were used to compare both methodologies. The ICC of manual (0.547 ± 0.095 mm) and automated (0.524 ± 0.068 mm) methods was R = 0.74 and an absolute mean bias ± SD of 0.023 ± 0.052 mm was observed. Interobserver and intraobserver ICC were greater for automated (R = 0.94 and 0.99) compared to manual (R = 0.72 and 0.88) methods. Although not considered to be clinically significant, manual measurements yielded higher values compared to automated measurements. Automated measurements were more reproducible and showed lower interobserver variation compared to manual measurements. These results offer important considerations for large epidemiological studies.
authors.affiliation: Department of Cardiology, Tallaght Hospital, Dublin 24, Ireland.
authors.forename: Oscar
authors.initials: O
authors.lastname: Mac Ananey
authors.affiliation: Department of Cardiology, Tallaght Hospital, Dublin 24, Ireland.
authors.forename: Greg
authors.initials: G
authors.lastname: Mellotte
authors.affiliation: Department of Cardiology, Tallaght Hospital, Dublin 24, Ireland.
authors.forename: Vincent
authors.initials: V
authors.lastname: Maher
mesh_terms: D000328:Adult; D059168:Carotid Intima-Media Thickness; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000453:epidemiology / Q000473:pathology; D004730:Endothelium, Vascular / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged