MRI in the assessment of cerebral small vessel disease

Cerebral small vessel disease (cSVD) is a leading cause of vascular cognitive impairment and dementia, cerebral hemorrhages, and lacunar strokes. It is considered to be the most common clinically silent vascular brain disorder. Major forms of cSVD are age- and hypertension-associated arteriolosclerosis and cerebral amyloid angiopathy. For most types of cSVD causes and mechanisms of disease development and progression remain unknown. Detailed research of cSVD is hindered by lack of technical approaches to an in vivo assessment of microvasculature. MRI equivalents of pathological changes in cSVD might serve as surrogate markers of vascular damage and might be associated with clinical signs and symptoms. We review studies that demonstrated clinical significance of the primary MR signs of cSVD, i.e. white matter hyperintensity (formerly known as leukoareosis), lacunes, enlarged perivascular spaces and cerebral microbleeds, as well as their role in the disease progression. Recently introduced STRIVE standards established MRI changes as diagnostic criteria for cSVD. These standards may significantly improve our understanding of the role of various factors in the development of cSVD and its heterogeneity. However, individual prognostication and assessment of short-term and long-term treatment efficacy is still lacking. The use of diffusion-weighted MRI techniques for the assessment of microstructural changes of visually normal bran tissue might be helpful. Strong association between microstructural changes and clinical manifestation of cSVD supports the need for multimodal MRI studies for the assessment of pathophysiological mechanisms of the disease progression even on preclinical stages.