UPDATE Characterization of benign hepatic tumors arising in fatty liver with SonoVue and pulse inversion US T. V. Bartolotta, 1 M. Midiri, 1 M. Galia, 1 G. A. Rollandi, 2 F. Cademartiri, 3 R. Lagalla, 1 A. E. Cardinale 1 1 Department of Radiology, University of Palermo Via Del Vespro 127, 90127 Palermo, Italy 2 Emergency Department, Second Service of Radiology, S. Martino Hospital, Largo Benzi 10, Genova 16132, Italy 3 Department of Radiology, Erasmus Medical Center, Dr. Molenwaterplein, 40, 3015GD, Rotterdam, The Netherlands Abstract Background: We describe the spectrum of contrast- enhancement patterns of benign hepatic tumors arising in fatty liver on contrast-enhanced ultrasound (US). Methods: Sixteen patients (12 women and four men) with 27 benign hepatic tumors (17 hemangiomas, eight focal nodular hyperplasias, and two hepatocellular adenomas) arising in fatty liver underwent baseline and pulse inversion US after administration of SonoVue. Two experienced radiologists evaluated baseline echogenicity and dynamic enhancement pattern of each lesion in comparison with adjacent liver parenchyma. Results: After administration of SonoVue, in the arterial phase 13 of 17 hemangiomas showed peripheral globular enhancement and one showed a rim of peripheral enhancement, followed by progressive centripetal fill-in, which was complete in 10 of 14 cases and incomplete in four. Three of 18 hemangiomas showed rapid and com- plete fill-in in the arterial phase. Eight of eight focal nodular hyperplasias became hyperechoic in comparison with adjacent liver parenchyma in the arterial phase and slightly hyperechoic or isoechoic in the portal venous and delayed phases. Both adenomas showed strong arterial contrast enhancement that became less intense in the portal venous and delayed phases. Conclusion: Contrast-enhanced US after administration of SonoVue enables depiction of typical contrast- enhancement patterns in most benign hepatic tumors arising in fatty liver, thus providing useful clues for characterization. Key words: Liver neoplasms, ultrasound—Ultrasound —Contrast media—Pulse inversion imaging—Fatty liver In Italy ultrasound (US) usually is the first-line imaging technique in the diagnostic workup of patients with liver disease. The high prevalence of benign hepatic lesions in the general population (up to 52% in autopsy studies) and in patients with known malignancies explains the need for accurate characterization [1, 2]. Unfortunately, gray-scale US is commonly reported as a nonspecific technique in the diagnosis of hepatic liver tumors due to lack of a characteristic echo pattern [3, 4]. Further, in clinical practice the presence of a diffuse liver disease such as steatosis may largely alter the gray-scale US appearance of hepatic tumors [5]. Newer US techniques recently have been introduced, such as pulse inversion (PI), which works by transmitting through medium two identical pulses with reverse polarity and adding the two resultant returned signals [6]. The fundamental linear components, mainly arising from tissues, are cancelled, whereas nonlinear harmonic com- ponents, which originate from the interaction of the US beam with the microbubbles of contrast agent, are pre- served, thus making this technique extremely sensitive to microbubble-based US contrast agents [7]. Some studies have demonstrated that PI with a first-generation, air- based contrast agent (SHU-508A) is helpful in diagnos- ing hepatic tumors [8–10]. However, a study has high- lighted the likelihood that diffuse liver steatosis may mask contrast enhancement of focal nodular hyperplasia (FNH) of the liver, thus hampering reliable character- ization [11]. Correspondence to: T. V. Bartolotta; email: tv_bartolotta@yahoo.com ª Springer Science+Business Media, LLC 2006 Published online: 30 March 2006 Abdominal Imaging Abdom Imaging (2007) 32:84–91 DOI: 10.1007/s00261-005-0074-5