Role of fusion imaging technique by a combined CT/MRI ultrasound navigation system in the diagnosis of small HCC (<20 mm) on cirrhosis

Purpose: Aim of the present study was to test the potential of the ultrasound (US)-based Virtual Navigator® (VN) system (Esaote, Genova, Italy) in the identification and characterization of small (<2cm) lesions in cirrhosis detected by ce (contrast-enhanced)-CT and ce-MR imaging and suspected to be hepatocellular carcinoma (HCC), but not visualized by a previous standard US scan. Methods and Materials: Fourteen cirrhotic patients (9M; 5F), mean age 69.6±6.2 (SD) years, in whom ce-CT or ce-MR detected 17 new lesions (13.6±3.8 mm) suspected to be HCC, but not identified by US (performed blindly to CT/MR) were submitted to ce-US (CEUS) focused to the target zone identified by the navigation system, which displays simultaneously the CT/MR images reconstructed in 3D and realtime ultrasonography. A final diagnosis was established with coincidental findings according to the international guidelines or by follow-up in discordant cases. Results: A final diagnosis of HCC was reached in 15/17 cases. VN identified and showed typical CEUS pattern in 12/15 HCC (80%) (four identified at conventional US with VN and eight only after CEUS); 3/12 lesions (20%) could not be identified with VN. The 2/17 remaining lesions were not visualized by VN and finally judged as CT/MR false positives, as they disappeared also at CT/MR during a 12-month follow up. Conclusion: Our preliminary results show that VN improves the potential of US in identifying and characterizing HCC in cirrhosis, permitting achievement of diagnosis according to non invasive criteria and opening the way for potential percutaneous ablation strategies.