Carotid IMT measurement
According to the standard protocol, the carotid IMT images were recorded by a dedicated sonographer using high-resolution carotid ultrasonography with a > 7.5-MHz liner transducer at each study site and were read by an experienced analyzer at a central core laboratory in a blinded manner. IMT measurement was performed in accordance with the Japan Society of Ultrasonics in Medicine and the Japan Academy of Neurosonology using an automated IMT measurement software program (Vascular Research Tools 5, Medical Imaging Applications LLC, Coralville, USA)