Value of contrast enhanced ultrasound in the characterization of focal fatty liver

Objectives: To evaluate the value of contrast enhanced ultrasound (CEUS) in the characterization of so called “focal fatty liver“ previously identified with conventional ultrasound (US).

Methods: From April 2005 to January 2006, 21 healthy subjects (13 males; mean age 50±12yrs) with a single hepatic nodule diagnostic for focal fatty liver at conventional US were studied. No patient had virus related hepatitis, alcoholic hepatitis, diabetes mellitus, dislipidemia or history of neoplastic disease. All patients underwent CEUS, Magnetic Resonance Imaging (MRI) and/or US-guided fine-needle biopsy with cutting-needle, when indicated.

Results: The 21 single liver nodules ranged in size from 7 to 32mm. On CEUS homogeneous parenchymal enhancement in sinusoidal phase was observed in 13 out of 21 nodules (62%) and no focal liver lesions were seen, allowing a correct diagnosis of focal fatty changes. Instead 4 nodules (19%) on CEUS showed a typical pattern of hemangioma. In 2 cases (10%) a focal nodular hyperplasia was observed on CEUS; diagnosis was confirmed at MRI in both cases. In the last two subjects (5%), CEUS showed hypovascularity in the arterial phase, and a disomogeneous enhancement in portal and sinusoidal phases. In these cases liver histology showed the presence of a cholangiocarcinoma, and a metastasis from colon cancer, respectively.

Conclusions: Our data show that CEUS are a useful tool in the characterization of liver focal fatty change seen on conventional US. CEUS seem able to differentiated between benign and malignant focal liver lesions and can be considered complementary immediate tool to conventional US.