Background: The purpose of the study was to assess the quality of performance of wide-band, phase inversion harmonic power Doppler sonography in the diagnosis of focal nodular.
Material and Methods: During a period of one year, thirty-one patients with FNH previously confirmed by ultrasound-guided biopsy, surgical resection, dynamic helical computed tomography or magnetic resonance imaging were examined. The study protocol consisted of B-mode gray scale sonography, color Doppler, power Doppler examinations, and helical CT scans. Then, PI scans were performed
after the intravenous injection of 2.5 g of Levovist.
Results: The images obtained by the B-mode gray scale were typical for focal nodular hyperplasia in 13 lesions only (32.5%), and obtained by color, power Doppler sonography in 25 lesions (62%). On the contrary, all patients with focal nodular hyperplasia were diagnosed based on the wide-band, phase inversion power Doppler sonography findings. The common enhancement pattern at pulseinversion
harmonic US was filling in a central tumor artery with further centrifugal development of contrast. Then during early arterial phase, all typical anatomical features of FNH as ‘star sign’ or ‘spoke-wheel’ pattern were clearly visible. In 3 cases, computed
tomography and magnetic resonance imaging have failed to disclose pathology while phase inversion sonographic images were completely suggestive which was later confirmed by histologic examination.
Conclusions: Our data demonstrates the usefulness of wide-band, phase inversion harmonic power Doppler sonography in the differential diagnosis of hepatic focal nodular hyperplasia by visualizing all characteristic anatomical details.

Keywords: Liver, FNH, Contrast Media, Contrast Media - diagnostic use, Focal Nodular Hyperplasia - ultrasonography, Image Enhancement - methods, Imaging, Three-Dimensional, Liver - ultrasonography, Polysaccharides - diagnostic use, Tomography, Spiral Computed, Ultrasonography, Doppler, Color, Ultrasonography, Doppler, Pulsed - methods, young adult