title: Early detection of Lewis lung carcinoma tumor control by irradiation using diffusion-weighted and dynamic contrast-enhanced MRI.
abstract: OBJECTIVE
  To investigate the correlation between diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) derived parameters and radioresponsiveness of Lewis lung carcinoma (LLC) tumor.
  
  
  METHODS
  LLC tumor growth in C57BL/6 mouse limb was used for the experiment. The tumors were irradiated with 10 Gy×5, or 30 Gy×2 vs. sham irradiation. Fourteen tumors were subjected to DW-MRI and DCE-MRI pre-radiotherapy and weekly imaging after radiotherapy. The temporal changes in apparent diffusion coefficient (ADC) and DCE-MRI derived parameters (K(trans), k(ep), v(e), and v(p)) were correlated with tumor size, and were histologically compared with CD31 staining of resected tumors.
  
  
  RESULTS
  The 10 Gy×5 dose inhibited tumor growth for a week, while 30 Gy×2 controlled tumor growth for a 3-week observation period. One week after radiotherapy (week 2), irradiated tumors showed significantly higher values of ADC than untreated ones (10 Gy×5, p = 0.004; 30 Gy×2, p = 0.01). Significantly higher values of v(e) were shown earlier by 30 Gy×2 vs. sham (p = 0.01) and 10 Gy×5 vs. sham irradiation (p = 0.05). Sustained higher v(e) from 10 Gy×5 compared to sham irradiated tumors was evident at week 3 (p = 0.016) and week 4 (p = 0.046). A 13.8% early increase in ADC for 30 Gy×2 tumor group (p = 0.002) and a 16.5% increase for 10 Gy×5 group were noted (p = 0.01) vs. sham irradiation (which showed a 2.2% decrease). No differences were found for K(trans), k(ep), or v(p). Both radiotherapy groups demonstrated significant reduction in microvessel counts.
  
  
  CONCLUSIONS
  Early increase in ADC and v(e) correlated with tumor control by irradiation.
authors: Graduate Institute of Oncology, National Taiwan University College of Medicine, Taipei, Taiwan.
authors: Jason Chia-Hsien
authors: JC
authors: Cheng
authors: Ang
authors: A
authors: Yuan
authors: Jyh-Horng
authors: JH
authors: Chen
authors: Yi-Chien
authors: YC
authors: Lu
authors: Kuan-Hung
authors: KH
authors: Cho
authors: Jian-Kuen
authors: JK
authors: Wu
authors: Chien-Jang
authors: CJ
authors: Wu
authors: Yeun-Chung
authors: YC
authors: Chang
authors: Pan-Chyr
authors: PC
authors: Yang
mesh_terms: D000818:Animals; D018827:Carcinoma, Lewis Lung / Q000175:diagnosis* / Q000473:pathology / Q000532:radiotherapy*; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging; D055088:Early Detection of Cancer / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D047368:Tumor Burden / Q000528:radiation effects
chemical_list: D003287:Contrast Media
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