Association between the intima-media thickness of the brachiocephalic trunk and white matter hyperintensity in brain MRI

The intima-media thickness (IMT) of the brachiocephalic trunk (BCT) can be measured using duplex carotid ultrasonography, which is used for imaging the common carotid artery (CCA). However, the clinical significance of the BCT-IMT has not been studied. We reviewed 1109 stroke-free participants in the registry of the Okinawa General Health Maintenance Association. We compared the association between the BCT-IMT or the CCA-IMT with deep and subcortical white matter hyperintensity (DSWMH). The BCT-IMT was correlated with the CCA-IMT, and like CCA-IMT, it increased with advancing age. The increase in both the BCT-IMT and the CCA-IMT quartiles was correlated with the development of DSWMH. The multivariate logistic regression analysis indicated that, as observed for the CCA-IMT, the increase in the BCT-IMT was associated with a higher prevalence of significant DSWMH (Fazekas grade 2 or 3 per 0.1 mm increase in IMT; OR 1.02, 95% confidence interval 1-1.04; P=0.04). The increase in quartiles of the BCT-IMT was only associated with a higher prevalence of significant DSWMH in subjects with lower CCA-IMT (1st and 2nd quartiles, R(2)=0.18, P<0.05) but not in subjects with higher CCA-IMT (3rd and 4th quartiles). Combinations of the CCA-IMT and BCT-IMT quartiles failed to have an additive effect on the prevalence of significant DSWMH. The BCT-IMT has a similar clinical profile to the CCA-IMT in terms of its association with DSWMH. However, the CCA-IMT and the BCT-IMT did not predict DSWMH in an additive manner, and distinct mechanisms might underlie the observed thickening of the IMT in the CCA and BCT.