Predicting pathological complete response to chemoradiotherapy using artificial intelligence-based magnetic resonance imaging radiomics in esophageal squamous cell carcinoma

Figure 1 Workflow of semi-automated three dimensions tumor segmentation using BD score software. A: A maximum intensity projection (MIP) image showing high-signal intensity areas automatically extracted from diffusion-weighted imaging; B: A MIP image demonstrating the manual editing process to exclude non-tumorous hyperintense structures from the initial automated segmentation; C: The final three dimensions tumor volume for radiomics analysis. The color overlay on the MIP (left) and axial (right) images corresponds to apparent diffusion coefficient values: Red (0.3-1.0 × 10^-3 mm²/second), yellow (1.0-1.5 × 10^-3 mm²/second), and green (1.5-2.0 × 10^-3 mm²/second). ADC: Apparent diffusion coefficient; MIP: Maximum intensity projection.

Figure 2 Schematic of the nested cross-validation framework for model development and evaluation. After feature selection and standardization, a nested cross-validation framework was applied. The outer loop evaluated the model’s generalization performance, while the inner loop used AutoGluon, an automated machine learning framework, for feature selection and hyperparameter tuning. CV: Cross-validation.

Figure 3 Kaplan-Meier curves for relapse-free survival. A: Comparison of relapse-free survival (RFS) based on pre-treatment gray-level co-occurrence matrix entropy (b = 1000 second/mm²). The high entropy group (n = 36) showed significantly better RFS than the low entropy group (n = 34) (5-year RFS: 72.9% vs 18.0%, P < 0.001); B: Comparison of RFS based on actual pathological complete response (pCR) status. The real pCR group (n = 15) had significantly better RFS than the real non-pCR group (n = 55) (5-year RFS: 83.9% vs 33.9%, P = 0.009); C: Comparison of RFS based on the artificial intelligence model’s prediction. The predicted pCR-positive group (n = 24) demonstrated significantly better RFS than the predicted pCR-negative group (n = 46) (5-year RFS: 73.1% vs 32.1%, P = 0.007). RFS: Relapse-free survival; pCR: Pathological complete response.