## Shape Features

SHAPE_Sphericity is how spherical a Volume of Interest is. Sphericity is equal to 1 for a perfect sphere.

SHAPE\_Sphericity=\frac{\pi^{1/3}\cdot(6V)^{2/3}}{A}

where $$V$$ and $$A$$ correspond to the volume and the surface of the Volume Of Interest based on the Delaunay triangulation.

SHAPE_Compacity reflects how compact the Volume of Interest is.

SHAPE\_Compacity=\frac{A^{3/2}}{V}

where $$V$$ and $$A$$ correspond to the volume and the surface of the Volume Of Interest based on the Delaunay triangulation.

SHAPE_Volume (mL and voxels) is the Volume of Interest in mL and in voxels.

SHAPE\_Volume=\sum_{i} V_i

where $$V_i$$ correspond to the volume of voxel $$i$$ of the Volume Of Interest.