Fig. 5.

Calibration curves of the radiomic nomogram for the disease prognosis of COVID-19 pneumonia in training set (A), internal validation set (B) and independent external validation set (C). The y-axis represents the actual probability of the COVID-19 pneumonia becoming severe, the x-axis represents the predicted risk. Dashed line was reference line where an ideal nomogram would lie. Dotted line was the performance of radiomics nomogram, while the solid line corrects for any bias in radiomics nomogram.