Figure 1
Post-SRS changes in tumour total sodium concentration (TSC) and diffusion metrics (MD, FA). (A) Line-graphs demonstrating temporal trend in mean tumour TSC (mM), MD (mm2 s−1 × 10−6) and FA (no units) for five VS. Average trend (red line) across all tumours also shown. (B) Representative TSC and diffusion metric maps from the right-sided growing VS shown in Panel A (patient 4, P4). From left to right: co-registered voxelwise maps of TSC, MD, and FA. Note the observable increase in TSC at 2 weeks, 8 weeks and 6 months post-SRS compared to pre-treatment values within the tumour (arrow) and the comparatively later visible increase in MD and reduction in tumoural FA observable at 6 months post-SRS. (C) Histogram of voxelwise TSC values within the tumour shown in panel B (patient 4, P4). From left to right: Pre-treatment, 2 weeks post-treatment, 8 weeks post-treatment, and 6 months post-treatment. Note the rightward shift in voxelwise TSC values at 2 weeks, 8 weeks, and 6 months post-treatment compared to pre-treatment values. ***p < 0.001 for comparison with pre-treatment TSC value, repeated-measures ANOVA with post hoc (Bonferroni) analysis of pairwise comparisons. Arrows show movement in histogram relative to preceding imaging timepoint. FA Fractional anisotropy (no units); MD Mean diffusivity (mm2 s−1 × 10−6); TSC Total sodium concentration (mM).
