Multi-atlas-based Segmentation of the Parotid Glands of MR Images in Patients Following Head-and-neck Cancer Radiotherapy.
Xerostomia (dry mouth), resulting from radiation damage to the parotid glands, is one of the most common and distressing side effects of head-and-neck cancer radiotherapy. Recent MRI studies have demonstrated that the volume reduction of parotid glands is an important indicator for radiation damage and xerostomia. In the clinic, parotid-volume evaluation is exclusively based on physicians' manual contours. However, manual contouring is time-consuming and prone to inter-observer and intra-observer variability. Here, we report a fully automated multi-atlas-based registration method for parotid-gland delineation in 3D head-and-neck MR images. The multi-atlas segmentation utilizes a hybrid deformable image registration to map the target subject to multiple patients' images, applies the transformation to the corresponding segmented parotid glands, and subsequently uses the multiple patient-specific pairs (head-and-neck MR image and transformed parotid-gland mask) to train support vector machine (SVM) to reach consensus to segment the parotid gland of the target subject. This segmentation algorithm was tested with head-and-neck MRIs of 5 patients following radiotherapy for the nasopharyngeal cancer. The average parotid-gland volume overlapped 85% between the automatic segmentations and the physicians' manual contours. In conclusion, we have demonstrated the feasibility of an automatic multi-atlas based segmentation algorithm to segment parotid glands in head-and-neck MR images.
Radiation Oncology, China-Japan Union Hospital of Jilin University, Changchun, China.
Guanghui
G
Cheng
Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA.
Xiaofeng
X
Yang
Radiation Oncology, China-Japan Union Hospital of Jilin University, Changchun, China.
Ning
N
Wu
Radiation Oncology, China-Japan Union Hospital of Jilin University, Changchun, China.
Zhijian
Z
Xu
Radiation Oncology, China-Japan Union Hospital of Jilin University, Changchun, China.
Hongfu
H
Zhao
Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA.
Yuefeng
Y
Wang
Radiation Oncology and Winship Cancer Institute, Emory University, Atlanta, GA, USA.
Tian
T
Liu
Image registration; MRI; head-and-neck cancer; parotid gland; radiation toxicity; segmentation; support vector machine; xerostomia