title: Non-thermal ablation of rabbit liver VX2 tumor by pulsed high intensity focused ultrasound with ultrasound contrast agent: Pathological characteristics.
abstract: OBJECTIVE
  To investigate the pathological characteristics of non-thermal damage induced by pulsed high intensity focused ultrasound (PHIFU) combined with ultrasound contrast agent (UCA), SonoVue (Bracco SpA, Milan, Italy) in rabbit liver VX2 tumor.
  
  
  METHODS
  Liver VX2 tumor models were established in 20 rabbits, which were divided randomly into PHIFU combined with ultrasound contrast agent group (PHIFU + UCA group) and sham group. In the PHIFU + UCA group, 0.2 mL of SonoVue was injected intravenously into the tumor, followed by ultrasound exposure of I(SP) 5900 W/cm(2). The rabbits were sacrificed one day after ultrasound exposure. Specimens of the exposed tumor tissues were obtained and observed pathologically under light microscope and transmission electron microscope. The remaining tumor tissues were sent for 2,3,5-Triphenyltetrazolium chloride (TTC) staining.
  
  
  RESULTS
  Before TTC staining, tumor tissues in both the sham and the PHIFU + UCA groups resembled gray fish meat. After TTC staining, the tumor tissues were uniformly stained red, with a clear boundary between tumor tissue and normal tissue. Histological examination showed signs of tumor cell injury in PHIFU + UCA group, with cytoplasmic vacuoles of various sizes, chromatin margination and karyopyknosis. Electron microscopic examination revealed tumor cell volume reduction, karyopyknosis, chromatin margination, intercellular space widening, the presence of high electron-density apoptotic bodies and vacuoles in cytoplasm.
  
  
  CONCLUSIONS
  The non-thermal effects of PHIFU combined with UCA can be used to ablate rabbit liver VX2 tumors.
authors.affiliation: Bioengineering College, Chongqing University, 174 Shazhengjie St, Shapingba District, Chongqing 400044, China. lifaqi70@163.com
authors.forename: Cheng-Wen
authors.initials: CW
authors.lastname: Zhou
authors.forename: Fa-Qi
authors.initials: FQ
authors.lastname: Li
authors.forename: Yan
authors.initials: Y
authors.lastname: Qin
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Liu
authors.forename: Xiao-Lin
authors.initials: XL
authors.lastname: Zheng
authors.forename: Zhi-Biao
authors.initials: ZB
authors.lastname: Wang
mesh_terms: D055011:Ablation Techniques / Q000379:methods*; D000818:Animals; D002294:Carcinoma, Squamous Cell / Q000473:pathology* / Q000601:surgery* / Q000648:ultrastructure; D002843:Chromatin / Q000648:ultrastructure; D003287:Contrast Media; D005260:Female; D008113:Liver Neoplasms / Q000473:pathology* / Q000601:surgery* / Q000648:ultrastructure; D008297:Male; D011817:Rabbits; D014464:Ultrasonic Therapy / Q000379:methods*; D014617:Vacuoles / Q000648:ultrastructure
chemical_list: D002843:Chromatin; D003287:Contrast Media