Treatment response prediction of nasopharyngeal carcinoma based on histogram analysis of diffusional kurtosis imaging

Abstract

BACKGROUND AND PURPOSE: The prediction of treatment response is important in planning and modifying the chemoradiation therapy regimen. This study aimed to explore the quantitative histogram indices for treatment-response prediction of nasopharyngeal carcinoma based on diffusional kurtosis imaging compared with a standard ADC value (ADC standard ). MATERIALS AND METHODS: Thirty-six patients with an initial diagnosis of locoregionally advanced nasopharyngeal carcinoma and diffusional kurtosis imaging acquisitions before and after neoadjuvant chemotherapy were enrolled. Patients were divided into respondversus- nonrespond groups after neoadjuvant chemotherapy and residual-versus-nonresidual groups after radiation therapy. Histogram parameters of diffusional kurtosis imaging- derived parameters (ADC, ADC coefficient corrected by the non-Gaussain model [D], apparent kurtosis coefficient without a unit [K]) were calculated. The ADC standard was calculated on the basis of intravoxel incoherent movement data. The intraclass correlation coefficient, Kolmogorov-Smirnov test, Student t test or Mann-Whitney U test, and receiver operating characteristic analysis were performed. RESULTS: Most of the parameters had good-to-excellent consistency (intraclass correlation coefficient = 0.675-0.998). The pre-ADC standard , pre-ADC (10th, 25th, 50th percentiles), pre-D (10th, 25th, 50th percentiles), and pre-K50th were significantly different between the respond and nonrespond groups, while the pre-ADC 10th , pre-K 90th , post-ADC 50th , post-K 75th , post-K 90th , and the percentage change of parameters before and after neoadjuvant chemotherapy (Δ ADC 50th %) were significantly different between the residual and nonresidual groups (all P