CALGARY NORMATIVE STUDY: STUDY DESIGN OF A PROSPECTIVE LONGITUDINAL STUDY TO CHARACTERIZE POTENTIAL QUANTITATIVE MR BIOMARKERS OVER THE ADULT LIFESPAN

ABSTRACTIntroductionA number of magnetic resonance (MR) imaging methods have been proposed to be useful, quantitative biomarkers of neurodegeneration in aging. The Calgary Normative Study (CNS) is an ongoing single-centre, prospective, longitudinal study that seeks to develop, test and assess quantitative MR methods as potential biomarkers. The CNS has three objectives: first and foremost, to evaluate and characterize the dependence of the selected quantitative neuroimaging biomarkers on age over the adult lifespan; secondly, to evaluate the precision, variability and repeatability of quantitative neuroimaging biomarkers as part of biomarker validation providing proof of-concept and proof-of-principle; and thirdly, provide a shared repository of normative data for comparison to various disease cohorts.Methods and AnalysisQuantitative MR mapping of the brain including longitudinal relaxation time (T1), transverse relaxation time (T2), T2*, magnetic susceptibility (QSM), diffusion and perfusion measurements, as well as morphological assessments are performed. The Montreal Cognitive Assessment (MoCA) and a brief, self-report medical history will be collected. Mixed regression models will be used to characterize changes in quantitative MR biomarker measures over the adult lifespan. In this report on study design, we report interim prevalence and demographic information of recruitment from 28 May 2013 to 31 December 2018.Ethics and DisseminationParticipants provide signed informed consent. Changes in quantitative MR biomarkers measured over the adult lifespan as well as estimates of measurement variance and repeatability will be disseminated through peer-reviewed scientific publication.STRENGTHS AND LIMITATIONSBoth cross-sectional and longitudinal quantitative MR data is being acquired in a large sample normal aging population to characterize changes in these potential neuroimaging biomarkers over the adult lifespan.Clinical and multiple quantitative imaging data are being collected and shared with the research community.Measures of repeatability and a process to update the imaging protocol are included in the study design.Associated self-reported medical history and cognitive assessments are limited