IBM SPSS version 20.0 for Windows was used for statistical analy-
sis. Chi-square tests were used to assess associations between dif-
ferent plaque morphological features, between asymptomatic and
symptomatic lesions, and between symptomatic lesions and MRA
findings. The Dice similarity coefficient and the intraclass correlation
coefficient with 95% confidence intervals were calculated to evaluate
inter-rater reproducibility.24 Statistical significance was set at P