Predictive value of diffusion-weighted imaging without and with including contrast-enhanced magnetic resonance imaging in image analysis of head and neck squamous cell carcinoma

ObjectivesTo assess disease-free survival (DFS) in head and neck squamous cell carcinoma (HNSCC) treated with (chemo)radiotherapy ([C]RT).MethodsPretreatment MR-images of 78 patients were retrospectively studied. Apparent diffusion coefficients (ADC) were calculated with two sets of two b-values: 0–750s/mm2 (ADC750) and 0–1000s/mm2 (ADC1000). One observer assessed tumor volume on T1-WI. Two independent observers assessed ADC-values of primary tumor and largest lymph node in two sessions (i.e. without and with including CE-T1WI in image analysis). Interobserver and intersession agreement were assessed with intraclass correlation coefficients (ICC) separately for ADC750 and ADC1000. Lesion volumes and ADC-values were related to DFS using Cox regression analysis.ResultsMedian follow-up was 18 months. Interobserver ICC was better without than with CE-T1WI (primary tumor: 0.92 and 0.75–0.83, respectively; lymph node: 0.81–0.83 and 0.61–0.64, respectively). Intersession ICC ranged from 0.84 to 0.89. With CE-T1WI, mean ADC-values of primary tumor and lymph node were higher at both b-values than without CE-T1WI (P