COMPUTED-TOMOGRAPHY PATHOLOGICAL ASSESSMENT OF LASER-INDUCED NECROSIS IN RAT-LIVER

RATIONALE AND OBJECTIVES. Interstitial laser photocoagulation (ILP) causes localized tissue necrosis. This study was performed to determine 1) whether the changes seen on computed tomography (CT) correspond to the necrosis pathologically, and 2) which CT technique best shows the necrosis. METHODS. Eighteen Wistar rats had ILP to their liver using a neodymium yttrium aluminum garnet [Nd:YAG] laser. Radio-opaque markers attached to the liver defined an imaging plane. Precontrast ''dynamic'' and delayed CT scans were performed. The size of necrosis was measured on CT, and macroscopically after resecting the liver. Computed tomography density numbers were measured from the necrotic area and normal liver for each CT technique. RESULTS. There was a good correlation between the necrosis size on CT and pathologically (P <.001), Maximum lesion-to-liver contrast was obtained on ''dynamic'' CT scans. CONCLUSIONS. The extent of tissue density changes on CT in rat liver after ILP match the extent of necrosis seen pathologically. The best CT technique use assessed for evaluating laser-induced liver necrosis is dynamic contrast-enhanced scanning.