Imagine you’re at a dance party, and everyone is moving and grooving on the dance floor. But in the shadows, there is a group of dancers who move uniquely, adding complexity to the overall dance. These dancers represent white matter hyperintensities (WMHs) in the brain—a marker of cerebral small vessel disease. WMHs appear as hyperintense areas in the cerebral white matter, seen on MRI scans. While previous research has focused on the overall volume of WMHs, recent studies have explored their spatial patterns and distributions. This systematic review examines 41 studies that investigate the association between WMH spatial patterns and risk factors/clinical diagnoses. The findings reveal that WMHs exhibit spatial heterogeneity across impairments, diseases, and pathologies, as well as sex and vascular risk factors. This granular analysis provides a deeper understanding of the underlying neuropathology and effects of WMHs. It’s like shining a spotlight on those hidden dancers at the party! To learn more about this fascinating research, check out the full article.

BackgroundWhite matter hyperintensities are an important marker of cerebral small vessel disease. This disease burden is commonly described as hyperintense areas in the cerebral white matter, as seen on T2-weighted fluid attenuated inversion recovery magnetic resonance imaging data. Studies have demonstrated associations with various cognitive impairments, neurological diseases, and neuropathologies, as well as clinical and risk factors, such as age, sex, and hypertension. Due to their heterogeneous appearance in location and size, studies have started to investigate spatial distributions and patterns, beyond summarizing this cerebrovascular disease burden in a single metric–its volume. Here, we review the evidence of association of white matter hyperintensity spatial patterns with its risk factors and clinical diagnoses.Design/methodsWe performed a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) Statement. We used the standards for reporting vascular changes on neuroimaging criteria to construct a search string for literature search on PubMed. Studies written in English from the earliest records available until January 31st, 2023, were eligible for inclusion if they reported on spatial patterns of white matter hyperintensities of presumed vascular origin.ResultsA total of 380 studies were identified by the initial literature search, of which 41 studies satisfied the inclusion criteria. These studies included cohorts based on mild cognitive impairment (15/41), Alzheimer’s disease (14/41), Dementia (5/41), Parkinson’s disease (3/41), and subjective cognitive decline (2/41). Additionally, 6 of 41 studies investigated cognitively normal, older cohorts, two of which were population-based, or other clinical findings such as acute ischemic stroke or reduced cardiac output. Cohorts ranged from 32 to 882 patients/participants [median cohort size 191.5 and 51.6% female (range: 17.9–81.3%)]. The studies included in this review have identified spatial heterogeneity of WMHs with various impairments, diseases, and pathologies as well as with sex and (cerebro)vascular risk factors.ConclusionThe results show that studying white matter hyperintensities on a more granular level might give a deeper understanding of the underlying neuropathology and their effects. This motivates further studies examining the spatial patterns of white matter hyperintensities.

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