Reproducibility of Carotid Intima-Media Thickness Measurements in Young Adults

Abstract

To prospectively compare the reproducibility of carotid intima-media thickness (CIMT) measurements obtained from the right and left carotid arteries in young adults by using ultrasonographic (US) images acquired at the maximum dimension, minimum dimension, and electrocardiographically (ECG)-triggered cardiac end diastole. This study was HIPAA compliant and approved by the institutional review board; all participants provided informed consent. Medical history, anthropometric measurements, and blood pressure (BP) values were obtained from 50 men and 50 women aged 18-25 years. Images of the common carotid arteries were acquired from three independent complete cardiac cycles by using a 15L8-MHz US transducer. CIMT was measured on the images of each cycle that depicted the narrowest and widest vessel diameters, and at the R wave of the ECG. Measurements from the right and left carotid arteries were analyzed by using paired t tests; possible sex differences, by using unpaired t tests. Reproducibility was determined by using coefficients of variation and intraclass correlations (ICCs). Pearson correlations and multiple regression analyses were used to compare CIMT, body mass index (BMI), and BP. CIMT values were 7.2% and 7% greater in frames showing the narrowest lumen diameter and in R-wave ECG-triggered frames, respectively, than in those with the widest diameter. CIMT measurements were 2.2%-3.1% greater in the right carotid artery than in the left (P < .001) and were significantly related to BMI (r = 0.40, P < .001) and systolic BP (r = 0.34, P < .001). ICCs were stronger when assessments were obtained in three different cardiac cycles (0.92-0.98), rather than in one (0.79-0.91). In healthy young adults, reproducibility of CIMT measurements is greatest when combining values from both carotid arteries and/or from the maximal and minimal arterial diameters.