Proof of principle: Estimation of liver function using color coded Doppler sonography of the portal vein.

BACKGROUND:The diagnostic value of Doppler ultrasonography of the portal vein for the evaluation of liver function is still contradictory. OBJECTIVE:Aim of this study was to test the relationship between clinical liver function tests based on MRI and breath testing and blood flow in the portal vein. METHODS:The portal vein velocity was measured by color coded Doppler ultrasonography (CCDS) and tested against the relative enhancement (RE), a MRI-based index of liver function. The signal intensity in the liver parenchyma was assessed before (pre) and after (post) administration of contrast agent, the RE was calculated afterwards. Further, the liver function was also assessed using a 13C-Methacetin-based breath test. The blood flow in the portal vein was tested for possible correlation applying Pearson's correlation coefficient. RESULTS:Using CCDS, all patients show a hepatopetal portal blood flow. The portal vein velocity is decreasing with progression of liver damage and there was a significant correlation of portal velocity with SI post (r = 0.411, p = 0.024). However, the portal velocity did not correlate significantly with the 13C-MBT readout (r = 0.233; p = 0.216), SI pre (r = 0.271, p = 0.147) or the relative enhancement (r = 0.303; p = 0.103). CONCLUSIONS:The results of this proof-of-principle study indicate that CCDS-based assessment of portal velocity is of only limited value for the evaluation of liver function.