Representation in Brain Imaging Research: A Quebec Demographic Overview.

Neuroimaging research must reflect the diversity of the populations it aims to serve. This scoping review examines the demographic characteristics (age, sex, race and ethnicity, and geographic representation) of participants in brain MRI and positron-emission tomography studies conducted in Quebec, Canada, between 1992 and 2023. A total of 1,549 studies, representing 62,555 participants, were identified through searches of Medline, Embase and Google Scholar, following JBI methodology. The vast majority of studies (92.7%) were conducted in Montreal, with limited representation from other urban centers and almost none from rural areas. Reporting of demographic variables was inconsistent: 22.1% of studies failed to report participant age adequately, and 20.3% did not fully report sex. Race and ethnicity were the most poorly documented, with fewer than 4% of studies reporting this information. Among the 2,396 participants with recorded race and ethnicity, 94.2% were categorized as White, highlighting a significant mismatch with Quebec's population diversity. Healthy participant samples were largely concentrated in the 20-35 age range, while clinical populations generally aligned with the expected age of disease onset. These findings reveal major gaps in demographic representation and reporting in Quebec-based neuroimaging research. Improving diversity and transparency is essential to ensure that neuroimaging findings are generalizable, equitable and clinically meaningful. We recommend the adoption of standardized demographic reporting formats, such as the Brain Imaging Data Structure, and broader recruitment efforts to capture underrepresented groups, including rural residents and racial and ethnic minorities.