Charting the velocity of brain growth and development

Brisbane Convention & Exhibition Centre 

Normative modelling (NM) is an emerging method for parsing heterogeneity of brain imaging phenotypes[1–4]. Until now, however, NM has focused on the estimation centiles derived from cross-sectional data ('distance centiles'). While distance centiles quantify individual's deviation from the median, they cannot quantify longitudinal change, and of movements across centiles across time. To estimate the significance of such centile crossings, velocity centiles are needed. These map the rate of change and require a fundamentally different approach. They can also only be estimated from longitudinal data.
Further, 'thrive lines'[5] can be derived from estimates of the correlation between two successive measurements.[6] These are defined as a +/- 1.96 SD rate of change. Translated to neuroimaging, a change outside of a projected thrive line ('failure to thrive') would signify a change more extreme than 97.5% of the population between those two measurements.
Here, we present three fundamental novelties: we update our large scale pre-trained normative models[7] using an advanced non-Gaussian model[8], we augment our previous cross sectional data set[7] with 23264 longitudinally processed scans from 10812 subjects and we estimate velocity centiles and thrive lines for 148 cortical[9] and 37 subcortical[10] regions of interest (ROIs). To our knowledge, this provides the first method that enables statistical quantification of change in brain imaging derived features at the level of the individual.