FIG. 4.

Images from a representative PTC patient with ETE (female, 47 years old). (a) T1-weighted MR image. (b) T2-weighted MR image. (c) DW-MR image (b=500 s/mm²). The area outlined in red is the region of PTC, and the area outlined in green is the region with normal thyroid tissue. (d) ADC map overlaid on DW-MR image (b=0 s/mm²). (e) Histopathological hematoxylin and eosin (H&E) image of a PTC with features of a tall cell variant (total magnification, 10×). (f) Histopathological H&E image of a PTC showing ETE (total magnification, 4×). The ADC value for the PTC (tumor size on pathology was 25 mm) was lower than that for normal thyroid tissue (1.65±0.18×10⁻³ mm²/s vs. 2.45±0.22×10⁻³ mm²/s).