Fig. 3: Accuracy of brain volumes varies as a function of the initial image acquisition resolution at LF.

a The Dice similarity coefficient of the hippocampus derived from LF T1w images of anisotropic (T1 AXI) or varying isotropic resolutions was compared to 1 mm MP-RAGE images acquired at 3 T. Dice scores were higher when isotropic voxels ≤ 3 mm were used (p < 0.001) and (b) similar accuracy was obtained from T2w images (p < 0.001 for voxels ≤ 3 mm). c Re-scanning demonstrates higher test-retest agreement in 3.0 mm isotropic relative to anisotropic counterparts (T1w, p = 0.0059; T2w, p = 0.014). Similar improvements in the Dice coefficient were observed for voxel sizes ≤ 3.0 mm for the lateral ventricle volume and whole brain using (d) and (g) T1w images, e and h T2w images and (f) and (i) test-retest analysis, respectively. For each subpanel, the box plots show the median, the interquartile range, and the Tukey whiskers and the individual data points are shown adjacent to the box plots. The Wilcoxon signed rank test was used for analysis for n = 20 biological replicates, except for the test-retest analysis where n = 10. Source data is available via the following link: https://doi.org/10.7910/DVN/9PANMC. T1w, T1 weighted; T2w, T2 weighted; AXI, axial. * p < 0.05, ** p < 0.01 for all panels.