Background: Duplex Doppler ultrasonography (US) has newly suggested, being an important diagnostic technique in the non-invasive evaluation of hepatic vasculature and some hepatic parenchymal diseases. New findings suggest that diffuse fatty infiltration of liver can alter normal hepatic vein and artery doppler indices. The following study has been performed to evaluate the effect of fatty infiltration on hepatic artery resistance index and hepatic vein waveform patterns.
Methods: Sixty patients with various degrees of fatty infiltration on liver biopsy and twenty normal subjects without any sign of hepatic fat infiltration in ultrasonography examined using standard colour and spectral doppler sonography. The waveforms of Hepatic Vein were classified into three groups: regular triphasic waveform, biphasic waveform without a reverse flow, and monophasic or flat waveform. The hepatic artery resistance index was calculated as the mean of three different measurements.
Results: The mean BMI in Nonalcoholic fatty liver disease group and normal subjects was 26.9(SD=3.3) and 22.4(SD=1.7) Kg/m², respectively with a range of 22 up to 44 Kg/m². Abnormal Hepatic Vein waveforms (biphasic and monophasic) were found more frequently in doppler sonography (p<0.001) in patients with Nonalcoholic fatty liver disease (12 biphasic and 17 monophasic) compared to normal subjects. Hepatic artery resistance index was significantly lower in Nonalcoholic fatty liver disease patients [0.7(SD=0.1)] compared to normal ones [0.8(SD=0.0)] (p<0.001).
Conclusions: The incidence of abnormal hepatic vein waveforms is significantly higher in patients with fatty infiltration compared to those who had no abnormality in liver ultrasonography and these patients had a significant lower hepatic artery resistance index.