Association between diffusion tensor imaging findings and domain-specific cognitive impairment in cerebral small vessel disease: a protocol for systematic review and meta-analysis

INTRODUCTION: Cognitive impairment is the main clinical manifestation of cerebral small vessel disease (CSVD). However, the mechanism and structural damage in different domains of cognitive disorders are poorly understood. There is an urgent need to quantify the relation between diffusion tensor imaging (DTI) data and impaired cognitive testing in CSVD, which may help to find biomarkers for early diagnosis or treatment evaluation. We aim to summarise the understanding of association between DTI findings and domain-specific cognitive impairment. METHODS AND ANALYSIS: PubMed, EMBASE, Web of science, Cochrane library, Chinese National Knowledge Infrastructure Databases, Wanfang, SinoMed and VIP will be searched, from 1 January 1994 to 1 August 2021. The ClinicalTrials.gov and Chictr.org.cn records will also be searched to identify further potential studies. The included studies should report fractional anisotropy and/or and mean diffusivity/apparent diffusion coefficient data for one or more individual regions of interest in DTI analysis. Meanwhile, cognitive testing scores are also needed. This systematic review will be reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The quality of cohort or case–control studies will be evaluated by the Newcastle-Ottawa Scale, and the cross-section studies will be evaluated by Agency for Healthcare Research and Quality scale. Meta-analysis, subgroup and sensitivity analyses, and publication bias will be all performed with Stata. ETHICS AND DISSEMINATION: Patients and the public will not be involved in this study. The existing data from published studies will be used. The findings from this research will be relevant information regarding the association of DTI metrics with cognitive disorder, which will be published in a peer-reviewed journal. If we need to amend this protocol, we will give the date of each amendment, describe the change and give the rationale. Changes will not be incorporated into the protocol. PROSPERO REGISTRATION NUMBER: CRD42021226133.