Prevalence and clinical relevance of diffusion-weighted imaging lesions

Objective To examine the association of diffusion-weighted image (DWI) lesions with markers of cerebrovascular disease, neurodegeneration, and cognitive functioning and to further explore the evolution of these DWI lesions and their link to risk of dementia, stroke, or TIA in the Rotterdam Study.

Methods Two thousand one hundred seventy-six participants with baseline MRI scans (assessed between January 2009 and December 2013) and data on incident clinical outcomes (until January 2016) were included. DWIs were inspected for presence of acute or subacute lesions. Markers of cerebrovascular disease, brain tissue segmentation, and microstructural integrity were collected. Cognition was assessed with a detailed neuropsychological test. Evolution of DWI lesions was evaluated on follow-up scans.

Results Thirty-three individuals (1.5%) had ≥1 DWI lesions. Persons with lacunes, white matter hyperintensities (WMHs), and reduced white matter microstructural integrity were more likely to have DWI lesions. Persons with DWI lesions performed worse on Stroop test 1. For 17 of 33 persons, follow-up scans were available to determine lesion evolution. During a mean follow-up of 4.7 years, 58.8% of DWI lesions appeared as WMHs, 17.6% developed cavitation, 5.9% changed into cortical cerebral microinfarcts, and 17.6% disappeared. People with DWI lesions at baseline were at increased risk of strokes (hazard ratio 3.72, 95% confidence interval 1.35–10.27).

Conclusion Asymptomatic DWI lesions in community-dwelling persons are associated with markers of cerebral small vessel disease, reduced microstructural integrity, and worse cognition. Presence of DWI lesions increases the risk of further strokes. Future investigations will have to show whether screening and treating persons with DWI lesions can effectively reduce the burden of stroke.