This study investigated for the first time brain ischemic involvement in 19 consecutive neurologically asymptomatic PNH patients by non-enhanced cerebral MRI, and by intracranial arterial and venous angio-MRI. Eleven cases (58%, 7 aged <65) showed pathological findings: 9 white matter (WM) abnormalities related to chronic ischemic small vessel disease, 2 a focal abnormality >5 mm, and 5 cases a score >4 by the age-related white matter changes (ARWMC) scale. Compared with age and sex-matched controls (1:2 ratio), patients showed an increased frequency of periventricular WM vascular degeneration (32% versus 5.2%, p = 0.04) and of severe lesions (ARWMC scale score >4) (26% versus 2.6%, p = 0.05), and a higher overall ARWMC scale score (3.5 ± 1.07 versus 2.0 ± 0.8, mean ± SD, p < 0.0001). Notably, vascular abnormalities suspected for prior partial venous thrombosis, were observed in PNH cases only. MRI lesions were not related to blood counts, hemolytic markers, clone size, disease duration, and therapy with eculizumab. Neurological examination was unremarkable in all patients but one (Parkinson disease). Psychiatric assessment revealed a case of generalized anxiety disorder, 1 bipolar disorder type 2, and 1 adjustment disorder. In conclusion, brain MRI may be useful at diagnosis and during the course of the disease to explore subclinical neurological involvement.