Hepatic alveolar echinococcosis: MRI findings

The purpose of this study was to describe the magnetic resonance imaging (M RI) appearance of hepatic alveolar echinococcosis (HAE) on T-1-weighted, T- 2-weighted and postgadolinium images. A total of 13 lesions were demonstrat ed in 13 patients. All patients underwent MR examination at 1 T imager. MR examinations included precontrast T-1-weighted breathing averaged spin echo (SE), breath-hold spoiled gradient echo, T-2-weighted TSE sequences with a nd without fat suppression, and T-1-weighted breath-hold spoiled gradient e cho (SGE) sequence following i.v. after gadolinium administration. All lesi ons were confirmed with histopathology. HAE hepatic lesions revealed geogra phic patterns of variable signal intensities on noncontrast T-1- and T-2-we ighted images. Slightly hyperintense, iso- and hypointense signal on T-1-we ighted images corresponded to calcified regions, which appeared hypo-isoint ense signal on T-2-weighted images. Necrotic areas were hypointense signal on T-1-weighted and hyperintense signal on T-2-weighted images. On postgado linium images, lesions did not reveal enhancement. Dilatation of intrahepat ic bile ducts distal to HAE abscesses were observed in five patients and po rtal vein invasion or compression was observed in four patients, lobar atro phy of the liver was coexistent finding in cases with portal vein compressi on. The MRI appearance of HAE abscesses included large irregularly marginat ed masses with heterogenous signal on T-1- and T-2-weighted images and lack of enhancement with gadolinium. (C) 2000 Elsevier Science Inc. All rights reserved.