Quantitative evaluation of real-time maximum liver capacity (LiMAx) and time intensity curve (TIC) analysis in...

To compare the diagnostic performance of real-time maximum liver capacity (LiMAx) with dynamic contrast-enhanced ultrasound (CEUS)-based liver microcirculation.

23 patients underwent liver function capacity (LiMAx) test and consecutive or previous CEUS examinations. A bolus injection of 1.4 ml sulfur hexafluoride microbubbles was administered for CEUS measurements (1-6 MHz) and quantitative perfusion analysis (TIC) was performed with an integrated perfusion software using stored cine-loops. Two perfusion-parameters, time to peak (TtoP) and area under the curve (Area), were evaluated in liver parenchyma and portal vein using TIC analysis.To compare quantification parameters, patients were classified in patients representing a healthy population (LiMAx value >315 μg/kg/h) and those representing patients with liver disease (LiMAx value <315 μg/kg/h).

Comparing perfusion parameters derived from portal vein measurements, TtoP and Area were higher in patients with normal liver function TtoP: 25.0±8.4 s, Area: 1483±920 a.u. compared to patients with impaired liver function TtoP: 22.4±14.0 s; Area 1351±1212 a.u. This difference however was not statistically significant (p = 0.52, p = 0.48).In parameters derived from measurements in liver parenchyma TtoP was higher (38.5±11.3 s) and Area was lower (999±632 a.u.) in patients with normal liver function compared to patients with impaired liver function (TtoP; 30.6±11.0 s, p = 0.156; Area: 1202±719 a.u.) (p = 0.16, p = 0.56).In a simple linear regression model, none of the perfusion parameters measured in portal vein (TtoP portal, Area portal) and liver parenchyma (TtoP liver, Area liver) correlated significantly with respective LiMAx values (p = 0.194-0.950).

Within the framework of this study, CEUS-based perfusion parameters were not able to assess severity of liver disease, assessed with LiMAx- test.