The aim of the study is to assess the value of contrast enhanced ultrasound in the evaluation of de novo focal liver lesions in clinical practice, in a prospective multi-center design.

Focal liver lesions (FLL) are quite frequently discovered in daily practice at routine ultrasound and sometimes require the use of extensive investigations for a correct diagnosis, thus increasing the costs and duration of diagnosis. On the other hand, due to screening strategies for patients with liver cirrhosis, FLL are discovered very early in these patients, and they must be evaluated in order to establish a therapeutic strategy (including transplantation, surgical resection or percutaneous echoguided procedures).

Contrast enhanced ultrasound (CEUS) using second generation contrast agents is a relatively new imaging modality that allows the characterization of FLL and allows a positive diagnosis based on the vascular pattern of the lesion. The advantages of this method are the low cost as compared with other imaging modalities and the fact that it can be performed immediately after standard abdominal ultrasound, so approximately 5 minutes after CEUS (the total duration of this investigation) a confident diagnosis can be obtained.

The place of CEUS in the diagnostic algorithm of FLL is not very well established. The European Federation of Societies for Ultrasound in Medicine and Biology (EFSUMB) issued the first Guidelines regarding the use of CEUS in 2004, revised in 2008, in which the main indications of this method are presented.

The purpose of this study is to establish the value of CEUS in the evaluation of de novo FLL in clinical practice.

The study will include patients discovered with de novo FLL at standard ultrasound in which the ultrasound study is not conclusive for the positive diagnosis (the patients with simple cysts or known FLL under CEUS follow up will be excluded form the study). The standard ultrasound will be followed by the contrast study using SonoVue® (Bracco, Italy) as contrast agent. The amount of contrast agent will be documented in every patient (it depends on the ultrasound machine used and the suspected diagnosis). The examination will be performed using the dedicated contrast software of each ultrasound machine used in the study. The investigators shall also document in every patient: the indication for CEUS study, a short history including the presence of chronic hepatopathies or malignancies, the ultrasound machine used and the operator. Each examination will last about 5 min after bolus injection and will be documented by 4 video files no longer than 30 seconds each, containing: The standard study, the arterial phase, the portal phase and the late phase. Additional loops can be stored whenever it is considered necessary.

A CEUS diagnosis will be established based on the contrast study. This will be compared with the final diagnosis which will be established based on all available imaging and clinical data: computer tomography, MRI, biopsy, follow up information. A CEUS examination will be considered conclusive if, following contrast, the FLL had a typical enhancement pattern according to the EFSUMB guidelines, and inconclusive if the enhancement pattern of the lesions was not in concordance with this guide.

The stored loops will be also revised by different operators. The study design is prospective, multi-center and will be approved by the ethical review board.

Inclusion Criteria:

• patients diagnosed with de novo FLL at standard ultrasound
• age > 18 years, male and female gender
• informed consent for the contrast enhanced study

Exclusion Criteria:

• patients with contraindication for contrast enhanced study: subjects with acute cardiac infarction, with class III/IV cardiac insufficiency, with rhythm disorders and pregnant women
• Patients diagnosed with simple cysts at standard ultrasound (biliary of hydatid)
• Patients with known FLL, for example after percutaneous treatment, in which the contrast study is used for the follow up of the patient.

The patients included in the study will be patients discovered with FLL at standard ultrasound. The focal lesions will be characterized by CEUS and the diagnosis established will be compared with the final diagnosis of the patient.

The final diagnosis will be established based on all available imaging and clinical data: computer tomography, MRI, biopsy, follow up information.