Comparison of high-resolution diffusion-weighted imaging and diffusion kurtosis imaging for prediction of radiotherapy response in patients with nasopharyngeal carcinoma / 中华放射肿瘤学杂志

ABSTRACT

Objective In this prospective study,the performance between high-resolution diffusion-weighted imaging ( DWI) and diffusion kurtosis imaging ( DKI) for prediction of radiotherapy response in patients with nasopharyngeal carcinoma was compared. Methods Forty-one patients pathologically diagnosed with NPC received IMRT. All patients underwent conventional MRI,high-resolution DWI and DKI before and after radiotherapy (1-2 d after the plan dose was administered).All patients received conventional MRI during follow-up at 3,6,9 and 12 months after radiotherapy. According to the RECIST 1. 1( response evaluation criteria in solid tumors),all patients were divided into the response group (RG;n＝36) and non-response group (NRG;n＝5). The mean kurtosis coefficient (Kmean) and the mean diffusion coefficient (Dmean) of DKI and apparent diffusion coefficient ( ADC) of DWI were analyzed before and after radiotherapy. Results Among 41 patients,36 cases were assigned into the RG group and 5 in the NRG group. Before and after radiotherapy, all parameters significantly differed between two groups ( P＝0. 000-0. 013) except for the Dmeanand ADC prior to radiotherapy. At the end of radiotherapy,the sensitivity of Kmeanwas calculated as 87. 5% and the specificity was 91. 3% for predicting local control (optimal threshold＝0. 30, AUC 0. 924; 95%CI 0. 83-1. 00 ). Conclusion Kmeanvalue after radiotherapy is a potential biomarker for the early evaluation of clinical efficacy of radiotherapy in NPC patients.