Application of machine learning based on radiomics in the discrimination of intracranial germ cell tumours

Among germ cell tumours, germinomas are extremely sensitive to radiotherapy and chemotherapy. Histological diagnosis is important for clinical treatment decisions. This study aimed to identify germinomas and non-germinomatous germ cell tumours (NGGCTs) using radiomics-based machine learning (ML).

The present retrospective study comprised 141 patients diagnosed with intracranial germ cell tumours (ICGCTs), 71 germinomas, and 70 NGGCTs. Radiomics features were quantitatively extracted from magnetic resonance imaging (MRI) sequences, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), T2 Fluid-Attenuated Inversion Recovery (T2-FLAIR), diffusion weighted imaging (DWI) (b=1,000), apparent diffusion coefficient (ADC) images, and contrast-enhanced T1WI. Based on the combination of three feature selection methods and three classification methods, the optimal model was screened out from the internal test set. A combined model of clinical-multi-sequence radiomics was ultimately created by combining with statistically significant clinical features. The performance of the models was evaluated using the area under the curve (AUC), accuracy, sensitivity, specificity, and F1-score.

The combination of the least absolute shrinkage and selection operator (LASSO) and logistic regression (LR) yielded the optimal diagnostic performance in the multi-sequence radiomics model, as evidenced by an AUC value of 0.823 in the internal and 0.804 in the external test set. In the combined model, the AUC values of the internal and external tests were 0.838 and 0.809, respectively. The DeLong test revealed no significant difference between multi-sequence radiomics and the combined model, indicating that the inclusion of clinical characteristics did not significantly improve diagnostic accuracy.

ML based on radiomics may provide a non-invasive approach for the clinical differentiation of intracranial germinomas and NGGCTs.