Fig. 5
a Coronal T2-weighted (echo time 50 ms) magnetic resonance images of pure gelatin (left) and agar (right), trays 1 and 2, showing that gelatin qualitatively returns high signal at all concentrations, whereas agar returns lower signal as concentration increases (the bottom two wells were filled with doped water). Attenuation values (HU) (b) T1 (c), and T2 (d) at different gelatin/agar concentrations. These graphs confirm relatively small differences in HU as the concentration of both substances increases and show that the T2 relaxation time is long in all gelatin samples and short in agar samples. Bland–Altman plots comparing differences between the two test–retest measurements for HU (e) T1 (f), and T2 (g). Solid lines represent the mean difference, and dashed lines the 95% limits of agreement