Fig. 3: CSF-to-blood clearance.

Inter-individual variability in CSF-to-blood clearance for the diagnosis categories shown for the A reference (REF), B idiopathic normal pressure hydrocephalus (iNPH), C communicating hydrocephalus (cHC), D arachnoid cyst (AC), E idiopathic intracranial hypertension (IIH), and F spontaneous intracranial hypotension group. The curves show individual posterior dose-normalized predicted concentrations of gadobutrol over time, and the black lines signify the mean concentration for each group, averaged at each time point. G The individual posterior predicted dose-normalized blood concentrations of intrathecal gadobutrol from the population pharmacokinetic model, averaged at each time point by group, illustrates differences between groups. The distribution of individual pharmacokinetic parameters for the entire cohort is shown as a histogram of parameter distribution for the H absorption half-life (T_{1/2, abs}), I time to maximum concentration (T_max), J lag-time (T_lag), K maximum concentration (C_max), and L area under the curve (AUC) from zero to infinity for the entire cohort of patients (n = 106). The association between pharmacokinetic parameters and plasma biomarker concentrations is here illustrated by a significant negative correlation between average plasma concentrations of Aβ42 and lag-time (T_lag) in M, the iNPH cohort, and N, the entire patient cohort. Scatter plots are shown with fit lines, Pearson correlation coefficients, and significance levels. Source data are provided as Source Data file.