COMPUTED-TOMOGRAPHY PATHOLOGICAL ASSESSMENT OF LASER-INDUCED NECROSISIN RAT-LIVER

RATIONALE AND OBJECTIVES. Interstitial laser photocoagulation (ILP) ca uses 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 marker s attached to the liver defined an imaging plane. Precontrast ''dynami c'' and delayed CT scans were performed. The size of necrosis was meas ured on CT, and macroscopically after resecting the liver. Computed to mography density numbers were measured from the necrotic area and norm al 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. CONCLUS IONS. The extent of tissue density changes on CT in rat liver after IL P match the extent of necrosis seen pathologically. The best CT techni que use assessed for evaluating laser-induced liver necrosis is dynami c contrast-enhanced scanning.