Abdom Radiol (NY). 2026 Jul 13.
Chong Wang,
Zhen Wang,
Xiaohan Liu,
Chen Wu,
Xiaolong Wang,
Shang Jin,
He Zhang,
Yixin Xu,
Aiyun Sun,
Tao Ding,
Kai Xu,
Yankai Meng.
BACKGROUND: Perineural invasion (PNI) is a key prognostic determinant in gastric adenocarcinoma but remains radiologically occult on conventional CT.
PURPOSE: To develop and validate an integrated model combining dual-energy CT (DECT)-derived functional spectral slopes and subregional habitat signatures for the preoperative prediction of PNI.
MATERIALS AND METHODS: In this retrospective study, 175 patients (median age, 66 years; interquartile range, 58-73 years; 131 men) with gastric adenocarcinoma who underwent preoperative DECT between 2023 and 2025 were evaluated. Patients were randomized into a training cohort (n = 122) and an internal test cohort (n = 53). Tumor subregions were parcellated into three biologically distinct habitats using voxel-wise clustering. Stable habitat features (ICC ≥ 0.75), three-phase spectral slopes, and a Habitat-Graph Neural Network (H-GNN)-derived Topological Interaction Score (TIS)-capturing spatial adjacency relationships between habitat subregions-were collectively submitted as candidate predictors to LASSO regression for construction of the final Spectral-Habitat Signature. Diagnostic performance was evaluated using the area under the receiver operating characteristic curve (AUC). Clinical utility was assessed via decision curve analysis.
RESULTS: PNI was pathologically confirmed in 46.9% (82 of 175) of patients. The integrated Spectral-Habitat model achieved an AUC of 0.832 (95% CI: 0.760, 0.898) in the training cohort and 0.758 (95% CI: 0.666, 0.845) in the internal test cohort. A stratified 5-fold cross-validation demonstrated the stability of the framework, yielding a mean AUC of 0.765 (SD, 0.084). The combined model significantly outperformed the extracellular volume (ECV) model (AUC, 0.758 vs. 0.544; P < .001). Equilibrium-phase spectral slope emerged as a decisive functional biomarker. Model calibration was excellent in the test cohort (P = .560, Hosmer-Lemeshow test). Decision curve analysis demonstrated a substantial net clinical benefit across threshold probabilities of 10%-80%.
CONCLUSION: In this retrospective single-center study, an integrated model leveraging functional spectral kinetics and subregional spatial heterogeneity showed potential for the preoperative stratification of occult perineural invasion. However, these preliminary findings derived from a limited sample size require further validation in larger, multi-institutional prospective cohorts before clinical implementation in surgical planning.
Keywords: Stomach Neoplasms, Dual-energy CT, Perineural Invasion, Spectral Slope, Tumor Habitat