title: Diffusion-weighted magnetic resonance imaging to evaluate microvascular density after transarterial embolization ablation in a rabbit VX2 liver tumor model.
abstract: OBJECTIVE
  To evaluate the correlation between findings from diffusion weighted imaging (DWI) and microvascular density (MVD) measurements in VX2 liver tumors after transarterial embolization ablation (TEA).
  
  
  METHODS
  Eighteen New Zealand white rabbits were used in this study. VX2 tumor cells were implanted in livers by percutaneous puncture under computed tomography (CT) guidance. Two weeks later, all rabbits underwent conventional magnetic resonance imaging (MRI) (T1 and T2 imaging), DWI, (b=100, 600, and 1000s/mm(2)) and TEA. MRI was performed again1 week after TEA. Liver tissue was then harvested and processed for hematoxylin and eosin (H&E) staining and immunohistochemical staining for CD31to determine MVD.
  
  
  RESULTS
  VX2 liver tumors were successfully established in all 18 rabbits. Optimal contrast was achieved with a b value of 600s/mm(2).The maximum pre-operative apparent diffusion coefficient (ADC)difference value was 0.28×10(-3)±0.10×10(-3)mm(2)/s, and was significantly different (P<0.001) from the maximum postoperative ADCdifference value of 0.47×10(-3)±0.10×10(-3)mm(2)/s. However, the mean ADC value for the entire tumor was not significantly correlated with MVD (r=0.221, P=0.379), nor was the ADC value for the regions of viable tumor (r=-0.044, P=0.862). However, the maximum postoperative ADCdifference value was positively correlated with MVD(r=0.606, F=12.247, P=0.003).
  
  
  CONCLUSIONS
  DWI is effective to evaluate the therapeutic efficacy of TEA. The maximum ADCdifference offers a promising new method to noninvasively assess tumor angiogenesis.
authors: Department of Radiology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China.
authors: Ting
authors: T
authors: Qian
authors: Department of Radiology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China.
authors: Maozhen
authors: M
authors: Chen
authors: Department of Radiology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China.
authors: Feng
authors: F
authors: Gao
authors: Department of Radiology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China.
authors: Fanhua
authors: F
authors: Meng
authors: Department of Radiology, The People's Hospital of Zhangqiu, Shandong, China.
authors: Xiaohui
authors: X
authors: Gao
authors: Department of Radiology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China. Electronic address: hbyin1961@126.com.
authors: Huabin
authors: H
authors: Yin
mesh_terms: D000792:Angiography / Q000379:methods; D000818:Animals; D001158:Arteries / Q000473:pathology*; D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D003287:Contrast Media / Q000737:chemistry; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D004195:Disease Models, Animal; D004621:Embolization, Therapeutic / Q000379:methods*; D008099:Liver / Q000473:pathology*; D008113:Liver Neoplasms / Q000473:pathology*; D008833:Microcirculation; D009368:Neoplasm Transplantation; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D011817:Rabbits; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D003287:Contrast Media; D019408:Platelet Endothelial Cell Adhesion Molecule-1
keywords: Diffusion weighted imaging (DWI); Magnetic resonance imaging (MRI); Microvessel density (MVD); Rabbit VX2 liver tumor; Transarterial embolization ablation (TEA)