title: Mechanism and Natural Course of Tumor Involution in Hepatocellular Carcinoma Following Transarterial Ethanol Ablation.
abstract: OBJECTIVE
  To evaluate the microvascular distribution of lipiodol-ethanol, the histological change of the tumor lesion, and the status of tumor involution over time in hepatocellular carcinoma (HCC) following transarterial ethanol ablation (TEA), in lesions that showed CT evidence of complete tumor response.
  
  
  METHODS
  Patients with unresectable HCC were treated (183 patients, 242 lesions) with TEA using lipiodol-ethanol mixture (LEM) mixed in 2:1 ratio by volume and followed with CT at 3-month intervals for a median of 14.1 months. Liver tumors (n = 131) that showed CT evidence of complete tumor response, defined as the absence of any enhancing tumor throughout the follow-up period, were included. The surgical specimens of five patients who subsequently received partial hepatectomy were available for histological assessment. The microvascular distribution of LEM and the degree of tumor necrosis were analyzed. Tumor involution over time was assessed with CT in lesions that showed complete response.
  
  
  RESULTS
  Lipid stain revealed lipiodol infiltration throughout arterioles, intratumoral sinusoidal spaces, tumor capsule, and peritumoral portal venules. Complete tumor necrosis (100 %) occurred in all 5 surgical specimens. The median (IQR) percentage tumor volume compared to baseline volumes at 12, 36, and 60 months was 32 % (23.5-52.5 %), 22 % (8-31 %), and 13.5 % (6-21.5 %), respectively.
  
  
  CONCLUSIONS
  Intrahepatic HCC lesion that showed CT evidence of complete tumor response following TEA is associated with histological evidence of LEM infiltration throughout the intratumoral and peritumoral vasculature and complete tumor necrosis, as well as sustained reduction in tumor volume over time.
authors.affiliation: Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, c/o Rm 2A061, 2/F, Main Clinical Block and Trauma Centre, 30-32 Ngan Shing Street, Shatin, New Territories, Hong Kong SAR. simonyu@cuhk.edu.hk.|Vascular and Interventional Radiology Foundation Clinical Science Center, The Chinese University of Hong Kong, Shatin, Hong Kong SAR. simonyu@cuhk.edu.hk.
authors.forename: Simon Chun Ho
authors.initials: SC
authors.lastname: Yu
authors.affiliation: Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, c/o Rm 2A061, 2/F, Main Clinical Block and Trauma Centre, 30-32 Ngan Shing Street, Shatin, New Territories, Hong Kong SAR.|Vascular and Interventional Radiology Foundation Clinical Science Center, The Chinese University of Hong Kong, Shatin, Hong Kong SAR.
authors.forename: Tiffany Wing Wa
authors.initials: TW
authors.lastname: Lau
authors.affiliation: Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, c/o Rm 2A061, 2/F, Main Clinical Block and Trauma Centre, 30-32 Ngan Shing Street, Shatin, New Territories, Hong Kong SAR.
authors.forename: Peggy
authors.initials: P
authors.lastname: Tang
authors.affiliation: Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, c/o Rm 2A061, 2/F, Main Clinical Block and Trauma Centre, 30-32 Ngan Shing Street, Shatin, New Territories, Hong Kong SAR.
authors.forename: Stephen Ka Chi
authors.initials: SK
authors.lastname: Chan
authors.affiliation: Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, c/o Rm 2A061, 2/F, Main Clinical Block and Trauma Centre, 30-32 Ngan Shing Street, Shatin, New Territories, Hong Kong SAR.
authors.forename: Charmant Cheuk Man
authors.initials: CC
authors.lastname: Chu
authors.affiliation: Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, c/o Rm 2A061, 2/F, Main Clinical Block and Trauma Centre, 30-32 Ngan Shing Street, Shatin, New Territories, Hong Kong SAR.
authors.forename: Joyce Wai Yi
authors.initials: JW
authors.lastname: Hui
authors.affiliation: Department of Surgery, Prince of Wales Hospital, Shatin, Hong Kong SAR.
authors.forename: Kit Fai
authors.initials: KF
authors.lastname: Lee
authors.affiliation: Department of Anatomical and Cellular Pathology, The Chinese University of Hong Kong, Shatin, Hong Kong SAR.
authors.forename: Anthony
authors.initials: A
authors.lastname: Chan
mesh_terms: D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging / Q000628:therapy*; D016461:Chemoembolization, Therapeutic / Q000379:methods*; D000431:Ethanol / Q000008:administration & dosage; D004998:Ethiodized Oil / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D000431:Ethanol; D004998:Ethiodized Oil