Role of parametric imaging in contrast-enhanced sonography of hepatic focal nodular hyperplasia

Purpose. To assess the value of parametric imaging during contrast-enhanced sonographic examination in the diagnosis of focal nodular hyperplasia (FNH) of the liver. Materials and Methods. Thirty-one patients with solitary FNH underwent contrast-enhanced sonographic examination between January 2003 and June 2004 using SonoVue and a Sequoia scanner equipped with Cadence Contrast Pulse Sequencing software. Contrast enhancement from a time sequence of perfusion frames was estimated using QontraXt software, which provides quantification of perfusion parameters. From the time-intensity curves, we obtained the following parameters: peak enhancement value, Tr (time recovery corresponding to time needed to reach 63% of the peak value), beta parameter corresponding to the exponential factor, and slope corresponding to the slope of the tangent to the arterial phase of enhancement. Results. Among the 4 parameters studied, the slope of the arterial phase of enhancement was the most sensitive to image the centrifugal arterial flow originating from the central portion of the lesion, whereas peak enhancement value and Tr were the most sensitive to image full enhancement of the lesion. A blinded review revealed equivalent sensitivity in the diagnosis of FNH between the interpretation of the original videoclips and that of the parametric images. Conclusions. The results of this study show that parametric imaging can be used in place of original videoclips for clinical reporting of FNH; furthermore, it could help less-experienced sonologists diagnose FNH. (C) 2006 Wiley Periodicals, Inc.