White matter lesions and vascular cognitive impairment: part 1: typical and unusual causes.

While the diagnosis of vascular dementia rests on established radiomorphological criteria, the term vascular cognitive impairment hitherto is less clear cut and hence the interpretation of white matter changes (WMC) widely held to be caused by vascular disease is pivotal. Part one of this review deals with the description of WMC and the underlying vascular etiologies. To some degree magnetic resonance (MR) imaging seems capable of differentiating these lesions by technical means and by depicting anatomical detail. Microangiopathy, notoriously causing white matter lesions, is focused in a broader sense, including inflammatory and hereditary causes of small vessel disease and corresponding to vascular diseases of the young. Accordingly, interpretation of a given lesion could fail if clinical aspects, such as age, guiding symptoms and acuteness are not taken into account.