Comparison between automated and manual measurements of carotid intima-media thickness in clinical practice

Abstract

Cláudia Maria Vilas Freire1,2, Antonio Luiz Pinho Ribeiro1, Felipe Batista Lima Barbosa1, Anelise Impelisiere Nogueira1, Maria Cristina Costa de Almeida1,2, Márcia Melo Barbosa2, Ângela Maria Quintão Lana3, Ana Cristina Simões e Silva4, Antônio Ribeiro-Oliveira Jr11Department of Internal Medicine, School of Medicine, 3Statistics Laboratory, Veterinary Department, 4Department of Pediatrics, School of Medicine, Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, Brazil; 2Ecocenter, Hospital Socor, Belo Horizonte, MG, BrazilBackground and aim: The measurement of carotid intima-media thickness (cIMT) has been used as a marker of arterial wall disease. Manual measurements have been performed in most epidemiological studies, but, due to the introduction of new technologies, automated software has been increasingly used. This study aimed to compare manual versus automated cIMT measurements in common carotid (CC), bifurcation (BIF), and internal carotid (IC).Methods: Automated and manual cIMT measurements were performed online in 43 middle-aged females. Carotid segment measurements were compared by Bland–Altman plot and the variation and repeatability coefficients between observers were also determined for comparison.Results: The average timespan for manual measurements (57.30 s) were significantly higher than for automated measurements (2.52 s). There were no systematic errors between methods in any carotid segments. The variation coefficient was 5.54% to 6.34% for CC and BIF, 9.76% for IC, and absolute differences were 85% below 0.1 mm and 70% below 0.05 mm. Interobserver agreement showed no systematic error. The variation and the repeatability coefficients were better for the automated than manual measures.Conclusion: Although both methods are reliable for cIMT measurements, the automated technique allows faster evaluation with lesser variability for all carotid segments currently used in atherosclerosis research.Keywords: intima-media thickness, atherosclerosis, carotid segments, automated method, manual measurement, bland–altman plot