Intravoxel incoherent motion MR imaging in nasopharyngeal carcinoma: comparison and correlation with dynamic contrast enhanced MR imaging

Objectives: To compare accuracy and assess agreement between intravoxel incoherent motion (IVIM) magnetic resonance (MR) perfusion-related parameters and quantitative dynamic contrast-enhanced (DCE) MR parameters in nasopharyngeal carcinoma (NPC).

Results: D, f, D*, K^trans , K_ep and V_p were significantly lower in the high stage group while V_e was significantly higher in the high stage group. Optimal cut-off values were: D=0.749 × 10^-3 mm²/s; f=0.145; D*=100.401 × 10^-3 mm²/s; K^trans =0.571/min; K_ep =0.8196/min; V_e =0.6556 %; V_p =0.0757 %. D* (p=0.001), K^trans (p<0.001), V_e (p=0.014) were all reliable independent predictors for AJCC staging. IVIM-MR perfusion-related (f, D*) and DCE-MR (K^trans , K_ep , V_e , V_p ) parameters were significantly correlated (p<0.001).

Materials and methods: 75 patients with newly diagnosed NPC were prospectively recruited. Diffusion-weighted MR and DCE-MR imaging were performed with respective IVIM (D, f, D*) and DCE (K^trans , K_ep , V_e , V_p ) MR parameters calculated. Patients were stratified into low and high tumor stage groups according to American Joint Committee on Cancer (AJCC) staging for determination of the predictive powers of IVIM-MR and DCE-MR parameters using t-test, ROC curve analyses and multiple logistic regression analysis. Correlation between IVIM-MR perfusion-related and DCE-MR parameters was assessed using Spearman's rank correlation.

Conclusion: IVIM-MR perfusion-related and quantitative DCE-MR parameters were significantly correlated in the assessment of NPC and were both reliable independent predictors in the prediction of AJCC staging. IVIM-MR perfusion imaging can be a potential useful non-invasive perfusion imaging tool for clinical use in the assessment of NPC.