1H-MR spectroscopy and diffusion tensor imaging of normal-appearing temporal white matter in patients with nasopharyngeal carcinoma after irradiation: Initial experience

Authors

  • Wei Feng Xiong MD,

    1. Department of Medical Imaging Center, Nanfang Hospital, Southern Medical University, Guangzhou, China
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  • Shi Jun Qiu PhD,

    Corresponding author
    1. Department of Medical Imaging Center, Nanfang Hospital, Southern Medical University, Guangzhou, China
    • Department of Medical Imaging Center, Nanfang Hospital, Southern Medical University, Guangzhou, China; No.1838 Guangzhou Avenue North, Guangzhou, Guangdong 510515, China
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  • Hong Zhuo Wang MD,

    1. Department of Radiology, Yuebei People's Hospital of Shantou University Medical college, Shaoguan, China
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  • Xiao Fei Lv MD

    1. State Key Laboratory of Oncology in South China and Department of Medical Imaging and Interventional Radiology, Sun Yat-Sen University Cancer Center, Guangzhou, China
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Abstract

Purpose:

To detect radiation-induced changes of temporal lobe normal-appearing white mater (NAWM) following radiation therapy (RT) for nasopharyngeal carcinoma (NPC).

Materials and Methods:

Seventy-five H1-MR spectroscopy and diffusion-tensor imaging (DTI) examinations were performed in 55 patients before and after receiving fractionated radiation therapy (total dose; 66–75GY). We divided the dataset into six groups, a pre-RT control group and five other groups based on time after completion of RT. N-acetylaspartic acid (NAA)/choline (Cho), NAA/creatine (Cr), Cho/Cr, mean diffusibility (MD), functional anisotropy (FA), radial diffusibility (λ), and axial diffusibility (λ||) were calculated.

Results:

NAA/Cho and NAA/Cr decreased and λ increased significantly within 1 year after RT compared with pre-RT. After 1 year, NAA/Cho, NAA/Cr, and λ were not significantly different from pre-RT. In all post-RT groups, FA decreased significantly. λ|| decreased within 9 months after RT compared with pre-RT, but was not significantly different from pre-RT more than 9 months after RT.

Conclusion:

DTI and H1-MR spectroscopy can be used to detect early radiation-induced changes of temporal lobe NAWM following radiation therapy for NPC. Metabolic alterations and water diffusion characteristics of temporal lobe NAWM in patients with NPC after RT were dynamic and transient. J. Magn. Reson. Imaging 2013;37:101–108. © 2012 Wiley Periodicals, Inc.

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