title: Light and electron microscopic analyses of immediate and late tissue damage caused by radiofrequency ablation in porcine liver.
abstract: Radiofrequency ablation (RFA) is an effective procedure for localized hepatocellular carcinoma. Contrast-enhanced CT depicts the ablated area as a hypoattenuated area without hepatic blood flow; however, light microscopy does not show obvious necrosis in the ablated area. We evaluated liver tissue changes after RFA by light microscopy and electron microscopy. The normal livers of three anesthetized pigs were coagulated using RFA after laparotomy. The liver was examined immediately, and 1 week after operation by light and electron microscopy. After RFA, the liver parenchyma surrounding the needle electrode was brown in color and surrounded by a red marginal zone separate from the normal liver parenchyma. Hematoxylin-eosin staining of the central area did not show cell necrosis, and the structures of liver sinusoids, liver cell cord and the nuclei of hepatocytes were preserved. However, electron microscopic examination of tissue immediately after RFA showed destruction of mitochondria of hepatocytes and fixation of sinusoidal cells. One week later, there was a large quantity of debris in the enlarged sinusoids, in addition to irreversible destruction of hepatocyte organelles. RFA of the porcine liver causes hepatocyte damage. This damage was not evident by light microscopy but clearly identified by electron microscopy.
authors.affiliation: Second Department of Medicine, Kurume University School of Medicine, Kurume 830-0011, Japan. ryoko-kuro@k6.dion.ne.jp
authors.forename: Ryoko
authors.initials: R
authors.lastname: Kuromatsu
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Tanaka
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Shimauchi
authors.forename: Riko
authors.initials: R
authors.lastname: Harada
authors.forename: Eiji
authors.initials: E
authors.lastname: Ando
authors.forename: Satoshi
authors.initials: S
authors.lastname: Itano
authors.forename: Ryukichi
authors.initials: R
authors.lastname: Kumashiro
authors.forename: Shuichi
authors.initials: S
authors.lastname: Fukuda
authors.forename: Koji
authors.initials: K
authors.lastname: Okuda
authors.forename: Michio
authors.initials: M
authors.lastname: Sata
mesh_terms: D000818:Animals; D017115:Catheter Ablation; D008099:Liver / Q000473:pathology / Q000528:radiation effects* / Q000648:ultrastructure; D008854:Microscopy, Electron; D013552:Swine / Q000378:metabolism*