Model-free parameters of IVIM combined with tumor aggressiveness indicators in predicting 5-year treatment outcome in NPC

Motivation: The postprocessing of IVIM is relatively laborious within multiple b-value settings. Streamlining the b-value configuration and postprocessing may promote its widespread use while ensuring the clinical efficacy. Goal(s): To assess the value of model-free parameters (virtual magnetic resonance elastography [vMRE] and signature-index [S-index]) of IVIM and tumor aggressiveness indicators (tumor growth type [TGT] and contralateral pharyngeal recess invasion [CPRI]) in predicting 5-year treatment outcome. Approach: Prospective inclusion of 106 patients with regular follow-up. Selection of appropriate statistical methods to construct models. Results: vMRE and S-index were the independent predictors of long-term survival. Combined with TGT and CPRI can further improved the predictive performance. Impact: Two model-free parameters simplified the clinical process without compromising the efficacy. vMRE/S-index and TGT/CPRI shown for the first time to predict long-term survival in NPC, helping with clinical treatment decisions.