Evaluating diffusion-weighted magnetic resonance imaging for target volume delineation in head and neck radiotherapy

Authors

Michael A. Cardoso, University of WollongongFollow
Myo Min, University of the Sunshine Coast
Michael G. Jameson, University of New South WalesFollow
Simon Tang, Liverpool Hospital
Christopher Rumley, University of New South Wales
Allan Fowler, Liverpool Hospital
Vanessa Estall, Liverpool Hospital
Elise M. Pogson, University of WollongongFollow
Lois C. Holloway, University of WollongongFollow
Dion F. Forstner, University of New South Wales

RIS ID

133855

Publication Details

Cardoso, M., Min, M., Jameson, M., Tang, S., Rumley, C., Fowler, A., Estall, V., Pogson, E., Holloway, L. & Forstner, D. (2019). Evaluating diffusion-weighted magnetic resonance imaging for target volume delineation in head and neck radiotherapy. Journal of Medical Imaging and Radiation Oncology, 63 (3), 399-407.

Abstract

Introduction

Inter‐observer variability (IOV) in target volume delineation is a source of error in head and neck radiotherapy. Diffusion‐weighted imaging (DWI) has been shown to be useful in detecting recurrent head and neck cancer. This study aims to determine whether DWI improves target volume delineation and IOV.

Methods

Four radiation oncologists delineated the gross tumour volume (GTV) for ten head and neck cancer patients. Delineation was performed on CT alone as well as fused image sets which incorporated fluorodeoxyglucose (FDG)‐positron emission tomography (PET) and magnetic resonance imaging (MRI) in the form of CT/PET, CT/PET/T2W and CT/PET/T2W/DWI image sets. Analysis of the variability of contour volumes was completed by comparison to the simultaneous truth and performance level estimation (STAPLE) volumes. The DICE Similarity Coefficient (DSC) and other IOV metrics for each observer's contour were compared to the STAPLE for each patient and image dataset. A DWI usability scoresheet for delineation was completed.

Results

The CT/PET/T2W/DWI mean GTV volume of 13.37 (10.35–16.39)cm³ was shown to be different to the mean GTV of 10.92 (8.32–13.51)cm³ when using CT alone (P < 0.001). The GTV DSC amongst observers for CT alone was 0.72 (0.65–0.79), CT/PET was 0.73 (0.67–0.80), CT/PET/T2W was 0.71 (0.64–0.77) and CT/PET/T2W/DWI was 0.69 (0.61–0.75).

Conclusion

Mean GTVs with the addition of DWI had slightly larger volumes compared to standard CT and CT/PET volumes. DWI may add supplemental visual information for GTV delineation while having a small impact on IOV, therefore potentially improving target volume delineation.