Magnetic resonance imaging evaluation of characteristics of vascular invasion in intermediate and advanced hepatic alveolar echinococcosis.

The objective of the present study was to provide a basis for the personalized treatment of intermediate and advanced hepatic alveolar echinococcosis (HAE) by elucidating the characteristics of vascular invasion and lesion growth. A total of 160 patients with intermediate and advanced HAE who were subjected to plain as well as contrast-enhanced 3.0-T magnetic resonance imaging prior to surgery were analyzed. Pathological and intra-operative observations of the subjects were also considered. The size and location of HAE lesions, vascular invasion characteristics and growth patterns were assessed. A total of 78 patients (48.75%) had lesions involving the S5-8 segment/partial right liver lobe, 21 (13.13%) had involvement in the S2-4 segment/partial left liver lobe and 61 (38.13%) had lesions that transcended the left and right liver lobes. Pathological examination revealed that the vascular invasion rates of the hepatic portal veins, intrahepatic veins (left, central and right vein, and inferior vena cava) and hepatic arteries were 51.88, 43.28 and 26.87%, respectively. Liver hilum invasion was observed in 128 patients (80.00%), 71 of which (44.38%) presented with invasion of the primary porta hepatis, 11 (6.88%) with invasion of the secondary porta hepatis and 46 (28.75%) with invasion of the primary as well as the secondary porta hepatis. In conclusion, the growth pattern of intermediate and advanced HAE is determined by the site, blood supply and activity of the lesion. The current study demonstrated that lesions tend to invade the intrahepatic venous system and porta hepatis, and to target veins rather than arteries.