[Pathological observation after MRI guided high intensity focused ultrasound therapy for ablating the liver tissues adjacent to goat portal vein].

The present study was aimed to investigate the pathological changes after magnetic resonance imaging (MRI) guided high intensity focused ultrasound (MRgHIFU) therapy for ablating the liver tissue adjacent to goat portal vein. Fifty goats were involved in this study. Normal liver tissues at 0, 5, and 10 mm distance from portal vein, respectively, were ablated with MRgHIFU. Among the 50 tested subjects, 40 goats were sacrificed immediately after the operations, and the other 10 were sacrificed 7 days after the procedure for pathological examination of the targeted areas and the contiguous portal veins. Coagulation necrosis was observed in all the treated liver tissues. Collagen swelling (CS) and vessel wall fracture (VWF) emerged more frequently in the 0 mm group than that in the 5mm group: CS [0 mm group VS 5mm group = 27/40 (67.5%) VS 7/40 (17.5%), P < 0.05], VWF [0 mm group VS 5mm group = 8/40 (20%) VS 0/40 (0%), P < 0.05]. Seven days after ablation, no portal vein damages (CS and VWF) were observed under light microscope. The results indicated that MRgHIFU could be used to ablate the liver tissue adjacent to goat portal vein effectively, which may cause blood vessel damage when the focus is on the wall of blood vessels (0 mm). However, the pathological results indicated that these damages are reversible.