Key imaging characteristics of features of SVD. A) diffusion-weighted image of an acute small deep (‘lacunar’) infarct (arrow): <2cm diameter, hyperintense on diffusion imaging, FLAIR and T2-weighted imaging, hypointense on T1-weighted imaging. B) Lacune on FLAIR imaging: a CSF-containing cavity, >3mm and <1.5cm diameter, in white or deep grey matter or brainstem, signal characteristics of CSF on other sequences. C) WMH on FLAIR imaging: hyperintense areas on FLAIR and T2 in white and deep grey matter and brainstem, occasionally hypointense on T1 but often not visible, may coalesce when numerous. D) Perivascular spaces on T2-weighted imaging, hyperintense due to containing CSF-like fluid, <3mm diameter, round or linear in white or deep grey matter, visible on T1-weighted imaging when prominent.