Aim: To compare gross tumor volume (GTV) definition in locally advanced head and neck squamous cell carcinoma (LAHNSCC) using diffusion-weighted magnetic resonance imaging (DW-MRI) and computed tomography (CT) with intravenous contrast.
Patients and methods: Patients with LAHNSCC were imaged with CT and DW-MRI before treatment. GTV was delineated in both CT and DW-MRI images by two investigators. CT and MRI images were co-registered and volume data were extracted for statistical analysis.
Results: In general, DW-MRI volumes [based on the apparent diffusion coefficient (ADC)] were smaller than CT-based volumes. For all patients, GTV delineation based on pre-treatment DW-MRI was significantly smaller than that based on CT scan (CT-GTV) (p=0.0078). The mean difference (95% limits of agreement) between the two investigators was -0.37 cm(3) for CT-GTV and 0.17 cm(3) for ADC-GTV measurements, respectively.
Conclusion: DW-MRI radiotherapy GTVs are smaller than CT-based targets with less interobserver variability. Further validation of these preliminary results is necessary in a much larger patient group.
Keywords: ADC; DW-MRI; Target volume; head and neck cancer; radiotherapy.
Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.