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.

OBJECTIVES

To assess disease-free survival (DFS) in head and neck squamous cell carcinoma (HNSCC) treated with (chemo)radiotherapy ([C]RT).

METHODS

Pretreatment MR-images of 78 patients were retrospectively studied. Apparent diffusion coefficients (ADC) were calculated with two sets of two b-values: 0-750s/mm(2) (ADC750) and 0-1000s/mm(2) (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.

RESULTS

Median 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<0.001). Tumor volume (sensitivity: 73%; specificity: 57%) and lymph node ADC1000 (sensitivity: 71-79%; specificity: 77-79%) were independent significant predictors of DFS without and with including CE-T1WI (P<0.05).

CONCLUSIONS

Pretreatment primary tumor volume and lymph node ADC1000 were significant independent predictors of DFS in HNSCC treated with (C)RT. DFS could be predicted from ADC-values acquired without and with including CE-T1WI in image analysis. The inclusion of CE-T1WI did not result in significant improvements in the predictive value of DWI. DWI without including CE-T1WI was highly reproducible.