Comparison of high-resolution diffusion-weighted imaging and diffusion kurtosis imaging for prediction of radiotherapy response in patients with nasopharyngeal carcinoma

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 Dmean and ADC prior to radiotherapy. At the end of radiotherapy, the sensitivity of Kmean was 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 Kmean value after radiotherapy is a potential biomarker for the early evaluation of clinical efficacy of radiotherapy in NPC patients. Key words: Nasopharyngeal neoplasm/radiotherapy; Diffusion-weighted imaging; Diffusion kurtosis imaging