Internal carotid artery stenosis (ICAS) is a well-known risk factor for stroke. However, treatment efficacy evaluations are currently limited by widely unknown ICAS-effects on brain microstructure. Two promising parameters to study pathophysiological changes in white matter (WM) are fractional anisotropy (FA) and mean diffusivity (MD), derived from established diffusion-tensor imaging. We evaluated FA- and MD-maps in 15 ICAS-patients before and after revascularization. Our results demonstrated globally unimpaired FA and MD before treatment, even in watershed areas, which are especially vulnerable to hemodynamic impairments. Postinterventional structural results were stable. Thus, absence of ischemic events and successful treatment are indicated.