Table 5. Occurrences of the top ten features used in the surveyed papers.
| Feature | Occurrences |
|---|---|
| TSH (thyroid-stimulating hormone) | 39 |
| T3 (triiodothyronine) | 28 |
| Age | 28 |
| Gender | 27 |
| Pixel value | 19 |
| TT4 (total thyroxine) | 19 |
| FTI (Free T4 Index) | 18 |
| T4U (T4 Uptake) | 18 |
| Pregnancy | 14 |
| T4 (thyroxine) | 14 |