Radio-Pathomic Maps of Cell Density Identify Brain Tumor Invasion beyond Traditional MRI-Defined Margins

Single-image results depicting the relationship between image intensity and cellularity for each contrast. β values for the left-handed plots indicate the change in cellularity per SD increase in image intensity and indicate positive associations for T1, T1C, and FLAIR, with the expected negative association between ADC and cellularity present. β values for the right-handed plots indicate the difference in slope among patients with GBM and NGG and Other patients, indicating that patients with GBM show less pronounced cellularity associations than patients with NGG across all image types, with the exception of T1 intensity.

A, Subject-level RMSE values for the training and test data sets. Despite some degree of overfitting, the test set RMSE indicates that the radio-pathomic model is able to accurately predict cellularity across most subjects. B, Sample predictions for test set imaging values presented in terms of their T1SUB, FLAIR, and ADC intensity values. Patterns suggest the presence of traditional imaging signatures but also indicate the lack of specificity for these signatures with regard to hypercellularity. TISUB indicates T1C–T1.

Sample predictions for 3 representative subjects, including a 43-year-old man diagnosed with a grade III anaplastic astrocytoma (A), a 48-year-old man diagnosed with a GBM (B), and a 31-year-old woman diagnosed with a grade III anaplastic astrocytoma (C). These predictions indicate that the radio-pathomic model is able to predict regions of hypercellularity beyond the contrast-enhancing region as well as in the absence of restricted diffusion on the ADC image.