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Small DWI lesions after intracerebral hemorrhage

The MRI era has provided vascular neurologists with a number of novel imaging markers that associate with clinical outcomes in stroke and cerebrovascular disease. Examples include periventricular white mater hyperintensities, lobar and deep cerebral microbleeds, cortical superficial siderosis, and cerebral microinfarcts.1,2 Recently, MRI-visible perivascular spaces (or Virchow-Robin spaces) have been associated with both deep and lobar intracerebral hemorrhage (ICH),3 and have therefore garnered increasing attention. Although classically thought of as extensions of the subarachnoid space coursing with penetrating cerebral vessels, evolving data suggest that Virchow-Robin spaces may actually be interstitial fluid-filled cavities and not contiguous with the subarachnoid space.4 While it is not yet clear whether all MRI-visible perivascular spaces carry the same risk implications across patient populations, their frequent coexistence on MRI and spatial association with incident ICH raise the hypothesis that they represent another imaging marker of cerebral small vessel disease and may therefore provide clues regarding the initiation and progression of related clinical and imaging phenotypes.