title: Assessment of glioma response to radiotherapy using 3D pulsed-continuous arterial spin labeling and 3D segmented volume.
abstract: BACKGROUND
  Gliomas are the most common primary brain tumors in adults, in some cases, radiotherapy may be the preferred treatment option especially for elderly people who cannot endure surgery. Therefore, it is necessary to evaluate the effects of radiotherapy on glioma. Arterial spin labeling (ASL) is an MR imaging technique that allows for a quantitative determination of cerebral blood flow (CBF) noninvasively. Tumor volume is still an important determinant for evaluating treatment response. The purpose of this study was to investigate the relationship between the tumor perfusion parameters and tumor volume and assess the effects of radiotherapy on glioma using pulsed-continuous arterial spin labeling (pcASL) technique.
  
  
  METHODS
  35 patients with gliomas, histologically classified as low-grade group (n=16) and high-grade group (n=19), treated with radiotherapy only or before using other therapies were included in this study. MR examinations, including T1 weighted image and pcASL, were performed before and 4, 8, 12, 16 weeks after radiotherapy. Regional CBF of normal tissue, mean tumor blood flow (TBFmean), maximum tumor blood flow (TBFmax), and tumor volume were evaluated at each time point. Both the percentage change in CBF (CBF ratio), TBFmean(TBFmeanratio), TBFmax(TBFmaxratio) and the percentage change in tumor volume (volume ratio) were calculated using values obtained before and after radiotherapy. The correlation between the volume ratio and CBF ratio, TBFmeanratio, TBFmaxratio was assessed using linear regression analysis and Pearson's correlation.
  
  
  RESULTS
  The TBFmeanand TBFmaxof high-grade gliomas were significantly higher than that of low-grade group. In high-grade group, a strong correlation was demonstrated between the tumor volume and the TBFmaxbefore radiotherapy (R2=0.35, rs=0.59, p<0.05). There was also a significant correlation between the TBFmaxbefore radiotherapy and the tumor volume ratio before and 8 weeks after radiotherapy (R2=0.56, rs=-0.74, p<0.05).
  
  
  CONCLUSIONS
  The TBFmaxmeasured using pcASL could assess tumoral grade and also could become a potential tool for evaluating the therapeutic effects of radiation.
authors: Department of Radiology, Nanjing General Hospital of Nanjing Military Command, PLA, No.305, East Zhongshan Road, Nanjing 210002, Jiangsu, China.
authors: Peng
authors: P
authors: Wang
authors: Department of Radiology, Nanjing General Hospital of Nanjing Military Command, PLA, No.305, East Zhongshan Road, Nanjing 210002, Jiangsu, China.
authors: Jianrui
authors: J
authors: Li
authors: Department of Radiology, Nanjing General Hospital of Nanjing Military Command, PLA, No.305, East Zhongshan Road, Nanjing 210002, Jiangsu, China.
authors: Qiang
authors: Q
authors: Diao
authors: Department of Radiology, Nanjing General Hospital of Nanjing Military Command, PLA, No.305, East Zhongshan Road, Nanjing 210002, Jiangsu, China.
authors: YuanKai
authors: Y
authors: Lin
authors: Department of Radiology, Nanjing General Hospital of Nanjing Military Command, PLA, No.305, East Zhongshan Road, Nanjing 210002, Jiangsu, China.
authors: Jun
authors: J
authors: Zhang
authors: Department of Radiology, Nanjing General Hospital of Nanjing Military Command, PLA, No.305, East Zhongshan Road, Nanjing 210002, Jiangsu, China.
authors: Lin
authors: L
authors: Li
authors: Department of Radiology, Nanjing General Hospital of Nanjing Military Command, PLA, No.305, East Zhongshan Road, Nanjing 210002, Jiangsu, China.
authors: Gang
authors: G
authors: Yang
authors: Department of Radiology, Nanjing General Hospital of Nanjing Military Command, PLA, No.305, East Zhongshan Road, Nanjing 210002, Jiangsu, China.
authors: Xiaokun
authors: X
authors: Fang
authors: Department of Radiology, Nanjing General Hospital of Nanjing Military Command, PLA, No.305, East Zhongshan Road, Nanjing 210002, Jiangsu, China.
authors: Xie
authors: X
authors: Li
authors: Department of Radiology, Nanjing General Hospital of Nanjing Military Command, PLA, No.305, East Zhongshan Road, Nanjing 210002, Jiangsu, China.
authors: YingQi
authors: Y
authors: Chen
authors: Department of Radiology, Nanjing General Hospital of Nanjing Military Command, PLA, No.305, East Zhongshan Road, Nanjing 210002, Jiangsu, China. Electronic address: lingzheng1989@yeah.net.
authors: Ling
authors: L
authors: Zheng
authors: Department of Radiology, Nanjing General Hospital of Nanjing Military Command, PLA, No.305, East Zhongshan Road, Nanjing 210002, Jiangsu, China. Electronic address: guangminglu1905@163.com.
authors: Guangming
authors: G
authors: Lu
mesh_terms: D000368:Aged; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging / Q000473:pathology; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology* / Q000532:radiotherapy*; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging / Q000473:pathology* / Q000532:radiotherapy*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D013113:Spin Labels; D016896:Treatment Outcome; D047368:Tumor Burden
chemical_list: D013113:Spin Labels
keywords: Cerebral blood flow (CBF); Gliomas; Pulsed-continuous arterial spin labeling (pcASL); Radiotherapy; Tumor blood flow (TBF)