Figure 5

Quantitative assessment of geometric distortions in diffusion weighted imaging and quantitative assessment of distortions. An axial slice DWI of phantom (b = 0 image) is shown in (A–C). (A) Baseline image when dental braces were absent. F: frontal lobe; T: temporal lobe; BS: brainstem; C: cerebellum and O: occipital lobe. (B) Large dental braces model induced severe geometric distortions in the image and volume obliteration in frontal lobe. (C) Large dental braces model and correction device were both present. The geometric distortions were drastically decreased compared with (B) and the frontal lobe was visualized. (D) Length ratio (DWI: SE, mean (column height) + SD (error bar)) along AP direction in anterior frontal lobe, temporal lobe, fronto-parieto-occipital lobe, basal ganglia and thalami, and cerebellum are plotted for three model sizes under different conditions.