Liver Electrical Impedance Tomography for Early Identification of Fatty Infiltrate in Obesity

Abstract

Non-alcoholic fatty liver disease (NAFLD) is endemic in developed countries and is one of the most common causes of cardiometabolic diseases in overweight/obese individuals. While liver biopsy or magnetic resonance imaging (MRI) is the current gold standard to diagnose NAFLD, the former is prone to bleeding and the latter is costly. We hereby demonstrated liver electrical impedance tomography (EIT) as a non-invasive and portable detection method for fatty infiltrate. We enrolled 19 subjects (15 females and 4 males; 27 to 74 years old) to undergo liver MRI scans, followed by EIT measurements via a multi-electrode array. The liver MRI scans provided subject-specific a priori knowledge of the liver boundary conditions for segmentation and EIT reconstruction, and the 3-D multi-echo MRI data quantified liver proton-density fat fraction (PDFF%) as a recognized reference standard for validating liver fat infiltrate. Using acquired voltage data and the reconstruction algorithm for the EIT imaging, we computed the absolute conductivity distribution of abdomen in 2-D. Correlation analyses were performed to compare the individual EIT conductivity vs. MRI PDFF with their demographics in terms of gender, BMI (kg{middle dot}m-2), age (years), waist circumference (cm), height (cm), and weight (kg). Our results indicate that EIT conductivity (S{middle dot}m-1) and liver MRI for PDFF were not correlated with the demographics, whereas the decrease in EIT conductivity was correlated with the increase in MRI PDFF (R = - 0.69, p= 0.003). Thus, EIT conductivity holds promise for developing a non-invasive, portable, and quantitative method to detect fatty liver disease.