Background To evaluate the utility of non-Gaussian diffusion parameters derived from the continuous-time random walk (CTRW) and fractional order calculus (FROC) models for early treatment response assessment in nasopharyngeal carcinoma (NPC) and to compare their performance with the apparent diffusion coefficient (ADC). Methods Diffusion-weighted imaging (DWI) with 13 b-values was performed before and during early treatment in 61 patients with newly diagnosed NPC. Parameters derived from the CTRW and FROC models (DCTRW, αCTRW, βCTRW, DFROC, βFROC, µFROC) and ADC, along with their percentage changes, were compared between residual and non-residual groups after concurrent chemoradiotherapy (CCRT) with (n = 56) or without (n = 5) induction chemotherapy (IC), and between partial responders and stable disease groups in the IC subgroup. Group comparisons were performed using the Mann–Whitney U test or t-test, and predictive performance was evaluated using receiver operating characteristic (ROC) and logistic regression analyses. Results For IC response, Pre-βFROC, Pre-µFROC, and Pre-βCTRW significantly differentiated partial responders from stable disease groups, with Pre-βFROC demonstrating the highest discriminatory performance (AUC = 0.798). A combined model incorporating βCTRW and µFROC further improved prediction (AUC = 0.817). For the CCRT outcome, several Pre- and Δ% parameters differed significantly between residual and non-residual groups. ΔβCTRW% achieved the highest diagnostic accuracy (AUC = 0.822), while combining ΔβCTRW% with ΔADC% yielded the best overall performance (AUC = 0.878). Conclusions Diffusion parameters derived from the CTRW and FROC models provide sensitive markers of microstructural heterogeneity in NPC and outperform conventional ADC in early treatment evaluation. Pre-βFROC, Pre-µFROC, and Pre-βCTRW are valuable for predicting IC response, whereas ΔβCTRW% shows strong potential for identifying residual tumor after CCRT. Combined predictive models further enhance diagnostic accuracy, supporting non-Gaussian diffusion imaging as a promising biomarker for early efficacy assessment and personalized management of NPC.

Non-Gaussian diffusion MRI using CTRW and FROC models for early treatment response assessment in nasopharyngeal carcinoma

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2026年1月28日

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Jun Liu,
Hengfeng Shi,
Huimin Lu,
Fei Wang,
Ming Chen,
Mengxiao Liu,
Qing Yang,
Juan Zhu,
Yinfeng Qian

摘要

Background

To evaluate the utility of non-Gaussian diffusion parameters derived from the continuous-time random walk (CTRW) and fractional order calculus (FROC) models for early treatment response assessment in nasopharyngeal carcinoma (NPC) and to compare their performance with the apparent diffusion coefficient (ADC).

Methods

Diffusion-weighted imaging (DWI) with 13 b-values was performed before and during early treatment in 61 patients with newly diagnosed NPC. Parameters derived from the CTRW and FROC models (D_CTRW, α_CTRW, β_CTRW, D_FROC, β_FROC, µ_FROC) and ADC, along with their percentage changes, were compared between residual and non-residual groups after concurrent chemoradiotherapy (CCRT) with (n = 56) or without (n = 5) induction chemotherapy (IC), and between partial responders and stable disease groups in the IC subgroup. Group comparisons were performed using the Mann–Whitney U test or t-test, and predictive performance was evaluated using receiver operating characteristic (ROC) and logistic regression analyses.

Results

For IC response, Pre-β_FROC, Pre-µ_FROC, and Pre-β_CTRW significantly differentiated partial responders from stable disease groups, with Pre-β_FROC demonstrating the highest discriminatory performance (AUC = 0.798). A combined model incorporating β_CTRW and µ_FROC further improved prediction (AUC = 0.817). For the CCRT outcome, several Pre- and Δ% parameters differed significantly between residual and non-residual groups. Δβ_CTRW% achieved the highest diagnostic accuracy (AUC = 0.822), while combining Δβ_CTRW% with ΔADC% yielded the best overall performance (AUC = 0.878).

Conclusions

Diffusion parameters derived from the CTRW and FROC models provide sensitive markers of microstructural heterogeneity in NPC and outperform conventional ADC in early treatment evaluation. Pre-β_FROC, Pre-µ_FROC, and Pre-β_CTRW are valuable for predicting IC response, whereas Δβ_CTRW% shows strong potential for identifying residual tumor after CCRT. Combined predictive models further enhance diagnostic accuracy, supporting non-Gaussian diffusion imaging as a promising biomarker for early efficacy assessment and personalized management of NPC.