Enlarged Perivascular Spaces and Age-Related Clinical Diseases.

Perivascular spaces are the fluid-filled areas surrounding small blood vessels in the brain, and they may play a role similar to lymphatic vessels in clearing metabolic waste. When their diameters exceed 1 mm, as measured by structural magnetic resonance imaging, they are classified as enlarged perivascular spaces (EPVS). Previously, EPVS were considered to be benign, but increasing evidence suggests that their existence may be associated with various clinical diseases. Here, we review recent clinical studies to understand the potential clinical implications of EPVS. We also review the anatomy and imaging characteristics of EPVS and discuss four causal hypotheses for their formation and associated risk factors. Due to differences in research methods and concerns across studies, unified conclusions are difficult to achieve. Overall, more basic high-quality research is needed to clarify the subject and provide more concrete theoretical support.