Diffusion kurtosis imaging predicts neoadjuvant chemotherapy responses within 4 days in advanced nasopharyngeal carcinoma patients.

PURPOSE: To explore the clinical value of diffusion kurtosis imaging (DKI) and monoexponential diffusion-weighted imaging (DWI) for predicting early response to neoadjuvant chemotherapy (NAC) in patients with nasopharyngeal carcinoma (NPC). MATERIALS AND METHODS: Fifty-nine patients with stage III-IVb NPC underwent four 3.0T MR scans: prior to, and on the 4th, 21st, 42nd days after NAC initiation. The parameters of DKI (corrected diffusion coefficient, D; excess diffusion kurtosis coefficient, K) and monoexponential DWI (apparent diffusion coefficient, ADC) were obtained at the first three scans. Statistical methods included Student's t-test or Mann-Whitney U-test, receiver operating characteristic (ROC) curve analyses and paired X(2) test. RESULTS: D(pre) in responders group (RG) was significantly lower than nonresponders group (NRG) (1.029 +/- 0.033 vs. 1.184 +/- 0.055, x10(-3) mm(2) /s, P = 0.020). ADC(day4) and DeltaD(day4) were the most useful parameters of the two diffusional models to distinguish RG from NRG, respectively (area under the curve, 0.761 vs. 0.895). DeltaD(day4) was more sensitive than ADC(day4) to predict treatment response to NAC (P = 0.006). CONCLUSION: Both DKI and monoexponential DWI showed potential to predict treatment response to NAC prior to morphological change. DKI may be superior to monoexponential DWI for predicting early response to NAC in patients with locally advanced NPC.