MRI and Fazekas Scale

Each participant completed the structural MRI scan consisting of T1, T2, and FLAIR sequences using a 1.5-Tesla MR scanner. The specific parameters for the MRI scan were: 3D-FLAIR: repetition time (TR)/echo time (TE)/inversion time (TI) = 9,000/2,500/85 ms, slice thickness = 5 mm, echo train length (ETL) = 16, matrix size = 512 × 512 mm; T1: TR/TE = 250/2.48 ms, slice thickness = 5 mm, ETL = 1, matrix size = 320 × 320 mm; and T2: TR/TE = 6,000/99 ms, slice thickness = 5 mm, ETL = 18, matrix size = 640 mm × 640 mm.

The grade of WMLs was then assessed separately by two neurologists using the Fazekas scale based upon the brain structural MRI of each participant (14). Both neurologists were blinded to the hypertensive status and other demographic and clinical information of each participant. The Fazekas scale divided the white matter into periventricular and deep white matter, and each region was scaled at a grade ranging from 0 to 3 (i.e., four grades) depending on the size and confluence of lesions. The grade of WMLs was scored primarily on the FLAIR images, and the T2 and T1 images were also used when necessary. If there was a difference between the scales given by the two neurologists, the scale was determined and approved after a careful discussion between them (only five cases were assessed differently). The scale of the whole white matter (i.e., the sum of WML grades in periventricular and deep white matter) ranged from 0 to 6 and was used in the following analysis. Greater Fazekas scale reflected higher grade of WMLs.