Table 1.
Examples of traditional radiomic features
| Feature categories | Example radiomic features |
|---|---|
| Size | Area |
| Volume | |
| Maximum 3D diameter | |
| Major axis length | |
| Minor axis length | |
| Surface area | |
|
| |
| Shape | Elongation |
| Flatness | |
| Sphericity | |
| Spherical disproportion | |
|
| |
| First-order texturea | Energy |
| Entropy | |
| 10th percentile | |
| 90th percentile | |
| Skewness | |
| Kurtosis | |
|
| |
| Second-order textureb | Gray level co-occurrence matrix |
| Gray level run length matrix | |
| Gray level size zone matrix | |
|
| |
| High-order texturec | Autoregressive model |
| Haar wavelet | |
a
First-order features describe the distribution of intensity within the segmentation.
b
Second-order features describe the statistical relationships between pixels or voxels.
c
High-order features are usually based on matrices that consider relationships between three or more pixels or voxels.