Low-dimensional radiomic feature patterns. The reduced radiomic feature
space, Ƒr, following the unsupervised
dimensionality reduction and feature selection operation,
Ƒ→Ƒr,
according to Equation (3). Column
vectors of Ƒr denote low-dimensional
radiomic signatures, and row vectors of
Ƒr represent a subset of radiomic
features from the complete feature space, Ƒ,
that maximize the separation of patients into clusters and minimize the
redundancy within those clusters. GLCOM = gray level co-occurrence
matrix.