BIOIMPEDANCE: NEW APPROACH TO NON-INVASIVE DETECTION OF LIVER FIBROSIS - A PILOT STUDY.

BACKGROUND: Fibrosis are common structural hepatic change in patients with chronic hepatitis. Liver biopsy is the gold standard for determining the extent of liver fibrosis. Considering the technical difficulties and cost, improvements in non-invasive screening tools are greatly needed. Bioimpedance have been shown to be safe to evaluate tissue fibrosis.

OBJECTIVE: To assess the utility of using monofrequential bipolar bioimpedance for the detection of severity of liver fibrosis consistent with chronic viral hepatitis C infections.

METHODS: One hundred and ten patients were studied prospectively and formed two groups according to the lab tests results for the detection of HCV, ALT and AST: Group 1 Control (n=50 healthy patients with HCV negative and with ALT and AST values within the normal clinical range) and Group 2 Positive (n=60 patients positive for anti-HCV positive) which were biopsied. All patients underwent an examination with an Electro Sensor Complex, bioimpedance technology. To compare the groups 1 and 2, the ROC curves was used to determine the specificity and sensitivity of the bioimpedance to detect liver fibrosis. To identify liver fibrosis severity the Group 2 Positive was subdivided according to the liver biopsy results (Metavir fibrosis score) into: Sub Group 2A (F0-F1 n=25) - patients without or with minimal portal fibrosis and Sub Group 2B (F3-F4 n=20) patients with numerous septa/cirrhosis. A statistical analysis was conducted to analyze the bioimpedance data differences in delta of the conductance.

RESULTS: From the comparison between Groups 1 and 2: 1) The delta value for conductance in the pathway representing the right foot-left hand minus left hand-right foot demonstrated a sensitivity of 85% and a specificity of 78% with a cutoff value ≤5 and P=0.0001. 2) For the comparison between Sub Group 2A (Metavir F0+F1) and Sub Group 2B (Metavir F3+F4), the neural network for the Electro Sensor Complex data demonstrated a sensitivity of 85% and a specificity of 72% with a cutoff probability >50% and P=0.001. AUCROC=0.81.

CONCLUSION: Bioimpedance technology had good level sensitivity and acceptable specificity for detecting liver fibrosis using delta of the conductance. There is a potential for the use of bioimpedance technology as non-invasive approaches for screening of liver fibrosis.