MRI-based radiomics reveals disc-level radiomic heterogeneity and is associated with symptom severity in single-level...

To characterize adjacent-level disc radiomic differences and symptom associations in single-level lumbar disc herniation (LDH) on sagittal T2-weighted MRI.

This retrospective single-center study included 100 patients with MRI-confirmed single-level LDH. The index herniated disc (Label 1) and cranial adjacent disc (Label 2) were segmented in all patients; the caudal adjacent disc (Label 3) was analyzed when anatomically present and a complete radiomics record was available (n = 68). A total of 107 original PyRadiomics features were extracted per ROI. Paired Wilcoxon signed-rank tests with Benjamini-Hochberg false discovery rate correction were used for Label 1 vs. Label 2, Label 1 vs. Label 3, and Label 2 vs. Label 3. Sensitivity analyses excluded shape features, repeated Label 1 vs. Label 2 in complete three-level cases, stratified by index level, and compared index with non-index discs at the same anatomical level. Symptom associations were assessed using Spearman and partial Spearman analyses.

Pfirrmann grades differed across available levels in complete three-level cases (median [IQR]: 3 [2-3], 2 [2-2], and 2 [2-3] for Labels 1-3; Friedman p < 0.0001). Radiomics identified 71, 86, and 47 significant features for the three paired comparisons, respectively. Substantial non-shape differences remained after excluding shape features (59/93, 75/93, and 34/93 significant features). A non-shape summary score (PC1) at the index level was associated with VAS (rho = 0.49) and ODI (rho = 0.41), with similar adjusted results.

MRI-based radiomics provides complementary quantitative disc phenotyping in single-level LDH, revealing robust adjacent-level differences and moderate cross-sectional symptom associations. Longitudinal evaluation and external validation are required before prognostic use.