Figure 2.

For PTCs with heterogeneous echogenicity (A), regions of interest (ROIs) are drawn to include the nodule (1) and the surrounding normal thyroid tissue (2). The mean gray scale values for the PTCs and the surrounding normal thyroid tissue were 31.9 and 83.8, respectively, and the UGSR was 0.381 (31.9/83.8). For NGs with heterogeneous echogenicity (B), regions of interest (ROIs) are drawn to include the nodule (1) and the surrounding normal thyroid tissue (2). The mean gray scale values for the NGs and the surrounding normal thyroid tissue were 74.7 and 84.9, respectively, and the UGSR was 0.879 (74.7/84.9). Note that the ROI (red cycle) should be drawn around the largest area of the echo‐dominated region of heterogeneous echogenicity nodules. PTCs, papillary thyroid carcinomas; NGs, nodular goiters; UGSR, ultrasound gray scale ratio