Ultrasonographic diagnosis of hepatic fungal infection.

Background: Hepatic fungal infection is difficult to diagnose early because of the lack of related clinical knowledge. In this study, we analyzed the ultrasonic manifestations of hepatic fungal infection, in order to determine the diagnostic value of ultrasonography.

Methods: In 8 patients with hepatic fungal infection, the results of color Doppler flow images (CDFI) and contrast-enhanced ultrasonography (CEUS) were compared with those of ultrasound-guided biopsy.

Results: In the 8 patients with pathologically proven hepatic fungal infection, 5 showed multiple hypoechoic lesions with unequal sizes in the liver, commonly less than 2 cm in diameter. Some of the hypoechoic lesions showed a hyperechoic strip in the periphery, while a minority showed a "bull's eye" pattern, which is considered a typical manifestation of metastatic hepatic carcinoma. Solitary lesions in the right lobe of the liver were found in the other 3 patients. No blood flow signals were found in any lesions with CDFI. In the lesions a "filling defect" pattern was shown by CEUS, indicating no enhancement in the arterial phase, the portal vein phase and the delayed phase, except for 3 patients, in whom the lesions were slightly enhanced in the periphery during the early arterial phase.

Conclusions: Hepatic fungal infection is characterized by an ultrasonic manifestation of multiple hypoechoic lesions with inequal size. A small number of lesions may show a characteristic "bull's eye" appearance. Moreover, a "filling defect" pattern on CEUS is helpful to make a correct diagnosis. In addition, ultrasound-guided biopsy is an important method for accurate diagnosis of hepatic fungal infection.