To investigate the value of intravoxel incoherent motion (IVIM) diffusion-weighted magnetic resonance imaging (DW-MRI) in predicting the early response to induction chemotherapy (IC) and chemoradiotherapy (CRT) in nasopharyngeal carcinoma (NPC).Methods:
Fifty NPC patients who received IC and CRT underwent an IVIM DW-MRI on a 1.5-Tesla MRI scanner. The pretreatment and posttreatment (20 days after IC initiation) IVIM-based parameters (ADC, D, D*, and f), and their percentage changes (▵%), were compared between the effective (complete response or partial response) and ineffective (stable disease) groups based on RECIST 1.1, and between the residual and nonresidual groups.Results:
None of the perfusion-related parameter' values showed significant differences between the effective and ineffective groups (p values for pref, postf, ▵%f, preD*, postD*, and ▵%D* were 0.364, 0.129, 0.792, 0.804, 0.167, and 0.428, respectively), or between the residual and nonresidual groups (P values for pref, postf, ▵%f, preD*, postD*, and ▵%D* were 0.328, 0.776, 0.546, 0.558, 0.214, and 0.414, respectively). The ineffective group exhibited higher preADC, higher preD and lower ▵%D values than the effective group (all P < 0.001). The nonresidual group had lower preD, lower preADC and higher ▵%D values (all P < 0.05) than the residual group. ▵%D had the highest area under curve (0.859) in predicting the response to IC, whereas preD had the highest area under curve (0.841) in predicting tumor residue after CRT.Conclusion:
Diffusion-related IVIM-based parameters might be more helpful than perfusion-related parameters in predicting the early effects of IC and CRT for NPC. J. Magn. Reson. Imaging 2016;43:1179–1190.