Liver hemodynamic patterns in nonalcoholic steatosis: Doppler ultrasonography and histological evaluation.

BACKGROUND

The aim of this study was to evaluate hepatic Doppler ultrasound (US) indices for steatosis diagnosis and grading, having biopsy as reference.

METHODS

Doppler and conventional US were performed in 49 healthy volunteers, without risk factors for nonalcoholic fatty liver disease (NAFLD), and in 49 patients with NAFLD and at least one risk factor: obesity, dyslipidemia and/or diabetes mellitus. Significant alcohol intake and hepatitis B or C were exclusion criteria. NAFLD patients were biopsied, and steatosis severity graded histologically. Portal Venous Pulsatility Index (PVI), Hepatic Artery Resistance Index (HARI) and Pulsatility Index (HAPI) were analyzed in hilum. Hepatic vein waveform pattern (HVWP) was classified as triphasic, biphasic or monophasic. Two pathologists analyzed histological samples. ROC curve defined sensitivity and specificity and multivariate analysis defined an equation for classifying patients.

RESULTS

In NAFLD group, 89.79% had histologic criteria for non-alcoholic steatohepatitis (NASH). Mild steatosis was present in 44.89%, moderate steatosis in 38.77% and severe steatosis in 16.32%. In NAFLD group, 65.29% were obese and body mass index (BMI) had significant correlation with steatosis grading (r=0.77; P<0.0001). PVI correlated with presence of steatosis (r=-0.69, P<0.0001) as HVWP (r=-0.61, P< 0.0001). PVI ideal cutoff for predicting steatosis was 0.26 (sensitivity, 91%; specificity, 79.6%). The equation 16.15PVI+1.96HVWP enables to differentiate the healthy and the steatosis patients. HARI and HAPI could not differentiate the healthy from the steatosis group. None of the indices correlated with steatosis grading.

CONCLUSIONS

Portal and hepatic vein indices allow non-invasive steatosis diagnosis but are limited to quantify it. Histology remains important for steatohepatitis diagnosis and for steatosis grading.